Over size piston

[joe_indi]

I tried  rejuvenating some old Stihl 046 cylinders by  installing cast iron sleeve inserts in them.
They worked fine except for a slight drop in power, which, I suspect is due to the increased friction from a non-chromed cylinder surface.
To compensate for this power loss I am planning to try over sized pistons.
I dont want to make BB type of modifications, they would decrease the life of the crankshaft drastically.
Just an increase in piston diameter by 0.5 - 1.0mm.
So what would be a safer or better  option  52.5mm or 53mm instead of the standard 52mm.
Getting it made is no problem as an Indian piston manufacturer will do it for me, provided I give him an order for a minimum 100 pieces.
I am running his 52mm pistons currently without any disastrous results.Cost? 25% of the original.
BTW the sleeves are being made for me by a local shop.They charge me the equivalent of $20 US for each sleeve installed and polished in the cylinder , after porting.
Is this cost okay?

Joe   

[Al_Smith]

 Well Joe either people work extremely cheaply in India or you tell a good story .

However with a cast iron cylinder one must remember you have to have some run time on them before they get seated in .Don't expect them to come up to power after running  2 tanks of fuel .

I've only ever done one engine with an iron sleeve and that was a 125 McCulloch .On that engine I fitted the sleeve  to piston clearence at .0045".

It does just fine but I don't have enough run time on it ,even after 4 years to have the thing "broken in "yet but it still has plenty of power .

The best thing to do is set that thing a tad bit rich and run it like you stole it .After about 10-15 tanks of fuel lean it out to normal and run it hard .It will either blow apart like a dollar watch or get with the program like it should . That iron will wear in and the thing should be all right in time .

[joe_indi]

Well Joe either people work extremely cheaply in India or you tell a good story

Though 0ne USD is approximately 42 to 45 Indian Rupees, I made it 50 rupees to a dollar for easier calculation.
I will tell you the 'story' in rupees.
The cast iron sleeve job cost 1000 rupees
An Indian piston for a 046 costs 250 to 1500 rupees depending on the quality of build
Re-working the bearing seats on the crankcase of a saw costs 800 to 900 rupees
Riveting a new bar nose to a  guide bar costs  35 rupees
Buffing a scoured cylinder costs 25 rupees.
Re-conditioning a worn inner of a clutch drum using the inner sleeve of a ball bearing costs 250 rupees.(BTW a local 6202 bearing costs 55 rupees and a 6201 45 rupees)
Installing a gunmetal thread insert  to replace worn out threads including the gunmetal costs 50rupees  that is for sizes 4mm to 6mm. Add 10 to 15 rupees for 8 or 10mm.
Re-doing the threads for the guide bar threads with cast iron sleeves costs 100 rupees each.
Re-doing the worn out threads on the cylinder for the spark plug including filling up with aluminum using TIG welding 650 rupees.
Re-conditioning the big end of a 066 crankshaft with needle cage from, God knows where : 350 rupees.
All that is what I pay the neighborhood  tooling shop for these jobs.
Here is what I charge for some of the work I do (materials excluded):
1500 rupees for a full engine job.
600 rupees for piston replacement including cylinder polishing.
250 rupees for a complete carb re-building.
25 rupees for grinding an out of shape chain
10 rupees for changing stuff like a starter rope , clutch or muffler.
Engine tune-up is done free of cost.

A good cup of coffee costs 10 rupees  a liter of mineral water 25 and a 2 liter bottle of Coke 45.

Al, now you decide for yourself whether I tell good stories or we work cheap out here.

Joe

[wannabeonetoo]

 WOW !! and we wonder why we are losing our manufacturing jobs 
  Steve

[Al_Smith]

   

Al, now you decide for yourself whether I tell good stories or we work cheap out here.

Joe

Well ,far be it for me to cast stones .I mean everything on the internet I take as Gospel truth but It's your story ,tell it as you wish .

Now as far as cheap parts that get shipped over the Pacific,I'm on the opposite end of that stuff .

In the interest of peace and harmony I won't really opine on that subject but only to say my thoughts are not favorable to the wholesale exporting of US jobs . Therefore no rant and rave will be forth coming on that subject from my keyboard .

[beenthere]

Joe
Good information, and I think you do enjoy cheaper labor and you do tell us good information. No doubt in my mind. Hope you continue to do so.

Harder for us to understand that in countries such as yours, there are people who are working for less, but I believe they need to work to eat. I suspect India doesn't have the welfare system our country has to support. And that is going to quickly get much more expensive for us. 

I recall being in Turkey, where getting an automobile repaired after a fender-bender was extremely cheap. Reason being that nearly everyone could hammer out the bent parts, mud in the wrinkles, and do the labor to sand and paint. Do the work right on the streets. So it was cheaper relative to how we get it done. There was no welfare system in Turkey, I was told. For kids out on the street, they were taken to State operated carpet mills and put to work weaving carpets. That was somewhat sad to see, but relative to being out homeless or running the streets, probably better for them to work for the State for very little money.

[mrcaptainbob]

Interesting info, Joe_Indi. How does the income compare to the general cost of living there?

[joe_indi]

..How does the income compare to the general cost of living there?

We have both extremes here, the very rich and the really poor who starve without the luxury of a single square meal a day.
And there is the middle class which fills up the gap between the extremes.
Cost of living here depends on your choice of life style.
You could have a simple but decent meal where you can eat till you bust for a sum as low as 15 rupees .This is the same meal a tourist would shell out $100   when he tries out the ethnic food here!
You could also pay  1500 to 2000 rupees for a meal, just to prove how much you have come up in life.
Some things you might consider luxuries are simple things for us.
Tailor stitched clothes are cheaper than store stuff.
Its still cheap to have somebody else iron your clothes at $1 for about 25 pieces of clothing.
A part time help comes for a  $1.50 a day.
A full time driver for your car would cost you $100 a month.
My son's college education costs $ 1000 a year.
My daughter's school education costs 400.
I was staying in a 2000sq. feet house with 3 bedrooms for a rent of $80.

A MS460 costs about $1100, an 18" RSC chain $24, a Husky 372 about $1000.
A chainsaw with the operator works 8 hours for $70 , inclusive of fuel, oil and meals and lodging for the operator.
A chainsaw operator will work for $10 a day plus expenses.
Cutting cost of a  metric ton of timber is $2 .

A worker on a farm is paid $5  to 8 a day and is happy with that if his wife too earns nearly as much since he could put three square meals on the table and still afford a school education for his 2 or 3 kids .
Probably he would also pickup a motor cycle on a bank loan.
Even the grass root level workers here seem to have cell phones these days.
TVs are there with cable or satellite connections in most houses.
The same goes for PCs.


Joe

[stonebroke]

So are things getting better over there?

Stonebroke

[joe_indi]

So are things getting better over there?

Stonebroke

If better means progress towards wrong values, the answer is no.
People are leaving villages to seek jobs in urban areas, not just cities, but also in factories.
This leaves less people to work the land.
Once the present generation of farm hands are no more, there are very few left to take up their jobs.
The next generation has eyes only on a job connected with Information Technology. I cannot blame them. When their parents earn a monthly income of about $250 the children, if they land the right job, take home about $ 500.
With this kind of windfall, people can afford consumer goods, cars and motorcycles.They can also afford new clothes at shorter intervals, improved homes, more shopping , eating out......all the things that 'progress' brings.
This in turn has caused towns to grow, more industries to feed the growing demand and, unwanted things like conversion of farm land into residential or commercial areas.
The urbanization has put pressure on basic requirements like water, and waste management.The former is in short supply and the latter keeps building up.
But this is not happening uniformly all over the country. In various parts of the country the ones who used to starve still starve, the ones who used to walk a couple of miles to get a bucket of water continue to do it, kids who use candles to study, keep buying candles. And worst of all you see people sit and weep over, even they don't know why.

Joe

With this kind of progress, Heaven alone knows what is going to happen in the future.

Joe

[VT]

Good reading Joe.
What is your trade / business ? Mechanic , 100 pistons is needing 100 saws , so that is not a good investment in my eyes. Also what is the fuel type your using on the saws, When i worked in China , finding good quality fuel was the problem for  some of the imported fancy cars they had there.
I was sent to repair there imported cars. Leaded fuel and poor quality was the problem. This was in 1995-8.

VT

[joe_indi]

What is your trade / business ? Mechanic
VT

Though I trained in the hotel trade, and ran my own restaurant years ago, I turned to retailing  micro irrigation , chainsaws and brush cutters.Though I had no formal training in the business, I taught myself to repair the ones that I sold.They do say a year of real experience is worth more than a college degree.
14 years into this business, I am still my own mechanic, because that way I never stop learning.The present post on over size pistons is an example.

100 pistons is needing 100 saws , so that is not a good investment in my eyes.
VT

Not out here where they ruin their saws cutting rubber trees.Each machine averages at least a piston a month.Some of my best customers walk in twice a week for a piston change!!
That's no story Al. honest.
So, 100 pistons would not last me more than a couple of months.
My customers have started to ruin their cylinders too, that's why I need to make it cheaper for them with a sleeve job for their cylinders.

Joe

[VT]

Well Joe if you see the 100 Saw's , then Pistons would be in order.
I'm glad i don't see rubber trees , I have had most of my saws since new and still the same piston's.
Softwood here, Fir, Hem,pine ,cedar .

Joe i think the economy / World / is going to have a bump larger than rising metals $$ and fuel prices, That is also another thing to keep in mind. Always a gamble , but thats what keeps the smart mind experience , more than a college degree.

Let Me and others here know whats happening in India always , I always find reading about other country's great.

VT

[Jim Spencer]

Joe;
The last time I was in India was in 1968.  I was Installing an engine machining line at Hindustan Motors in Utapara just near Calcutta.
I can believe every word you wrote.  At that time I could hire a servant for a approx. 1-2 rupees a day.   I hope and pray that India continues to make progress in their standard of living.  The life of an indian child is just as precious as that of an American child.
The Indian engineers were better educated than I was as an American engineer but corruption was so prevalent that business was almost impossible.  To buy anything required a bribe under the table.  The problem with India was not lack of knowledge but corruption even though it is the largest democracy on earth.  Too many blood sucking corrupt politicians.  The U.S. has been heading in the same direction the last 8 years.  We lucked out the last election and hopefully we have a leader who will have a transparent Administration.

[joe_indi]

The problem with India was not lack of knowledge but corruption

Jim,

In a land where many people have no idea when they would have their next meal or where so many starve to death what else could one expect?
Since you have been here, you might also know that at times people even sold their children so that the rest of the family could have a square meal.
But that is not unique just to India, I think this has been a practice all over Asia.
But this practice is not a product of the 19th or 20th centuries.
I think we had people starving since ancient times.
Corruption too has been passed down through the centuries.Bribes can be classified int two categories in my opinion.
Money paid for getting something do that  is completely  against the law and..
money paid to speed up things, which can also be classified as 'Speed Money'.

Corruption among politicians, irrespective of the country is a different cup of tea.
My personal opinion is that   politics was one's life's mission in the good old days,  but nowadays it is just a source of easy income, but unlike  other jobs, the earning is done in the most dishonorable way.

Joe

[Al_Smith]

  [
Not out here where they ruin their saws cutting rubber trees.Each machine averages at least a piston a month.Some of my best customers walk in twice a week for a piston change!!
That's no story Al. honest.
So, 100 pistons would not last me more than a couple of months.
My customers have started to ruin their cylinders too, that's why I need to make it cheaper for them with a sleeve job for their cylinders.


 Joe

Well Joe ,of course this is the internet and I like a good story as well as the next guy ,but a saw eating up two pistons a month is stretching it just a tad bit . Are they running sand mixed in the fuel or something ? What about the cylinders and the rest of the workings of these abused saws ,it takes more than a piston to make a saw go putt putt putt ya know .

Go get em ,I won't say a thing you already have an enraptured audience .

[beenthere]

I'm more than willing to listen to what joe_indi has to say, without ridin him about it.
Seems we have learned several things from joe.

Believe the parts you want Al. To me, everyone has something to contribute.

[Tom]

Me too.

[VT]

Me three , plus i HAVE been outside !!



Mr Joe , just tell us more , And if your going with 100 pistons , etc, why not buy a cyl boring machine.

VT

[joe_indi]

Well Joe ,of course this is the internet and I like a good story as well as the next guy ,but a saw eating up two pistons a month is stretching it just a tad bit . Are they running sand mixed in the fuel or something ? What about the cylinders and the rest of the workings of these abused saws ,it takes more than a piston to make a saw go putt putt putt ya know .

Go get em ,I won't say a thing you already have an enraptured audience

Waal Al,
If the internet is only for fairy tales, why dont you take a trip down here and see for yourself what they do to chainsaws in my country.
If the Indian (read cutting in rubber) saw owner's  primary concern  is getting the maximum  output out of the, so that he can recover his capital investment in the shortest period along with a handsome profit, a couple of pistons lost in between is nothing for him.
Yes we loose quite a lot of crankshafts, crankcases and cylinders too.Also a lot of tank housings get crushed by trees falling the wrong way in cross winds.

Jim Spencer has been to India and he worked in one of the few automobile plants here in those days.
So, he knows that in India, unlike in the West, we retain our automobiles for 10, 20 or even 30 years.We dont have junkyards for cars in India like you might have. You will see all them on the roads, till they die.
But, here we dont hold onto the pro chainsaws for very long like you might want to do.They get used to the maximum in a year's time, 8 to 12 hours a day, every day.Maybe a couple of days off for holidays.Now, 12 hours might set your head shaking in disbelief.If possible  they cut trees with the help of the headlights of the trucks, at times, till midnight.
The main reason being that the market value for rubber wood fluctuates more or less like the  Dow Jones Index. So time is a very important factor.You can loose your earnings if you are late by a couple of hours in delivering.

Okay, that briefly explains the circumstances under which the saws are used.
There are a couple of other factors too.
When you work a saw in your country, you are comfortable in  protective clothing.Here such clothing would cause us to sweat.The Indian operator sweats even  in his cotton tee shirt, cotton shorts and beach sandals.This comparison is just to give you an idea of the increased ambient temperature here.
The MS460 we get here is the same model that goes to USA/ Canada.Nothing is different.So just think for a moment of the difference in temperature. Right now the day temperature here  in the shade is a 'comfortable' 29 deg Centigrade, with a humidity level of 54%.

Until 2001 -2002 the MS460 had the same jets in the carbs as the older 046, that is 0.70. Nowadays it is a leaner 0.68.
The present day crankshafts carry the flywheel for a little bit of advanced ignition timing compared to the older ones.
(You will not find that one in any books or on the net.I compared a 90's crank with a new crank.You will just have to take my word on that one.)

Though our gasoline is officially rated at RON86, the actual value varies to the extremes due to adulteration.So, an average RON of 82  is more true.
Quality of two stroke oil varies from fully synthetic to 100% spurious, usually composed of used gear oil thinned down with diesel!

Though I can tell you more, I think I will stop here.

If you still want to think all this is part of my fairy tale, that is fine with me. Enjoy it as just that, like you said, at least I tell a good story.

Al_Smith lives inside a bubble.

VT,
Look at it from Al's side of things. A guy half way round the globe writes these wild stories on the internet.

Mr Joe , just tell us more , And if your going with 100 pistons , etc, why not buy a cyl boring machine.

Now, we are back where I started this thread.cylinder boring and installing sleeves is what I am trying to do.
Since I cannot afford a sleeve making machine the making of the ports are done by hand, not very precise in shape or in position.So there is too much of variation in air flow velocity and engine performance(power).
So, I had the bright idea of getting slightly oversize pistons made, to compensate for the loss.What I needed  was an opinion on which would be a better over size,  1mm or .5mm.
Since this thread was getting me no answer I went ahead and decided on .5mm.
I should be getting the first few 52.5mm pistons any day now.

Joe

[james]

joe  starting at .5 mm is a good idea , it gives you the ability to re-bore out to 1 mm later if needed to extend the life of the jugs before you need to replace them start with .5 mm oversize then go up to 1 mm oversize if the sidewalls are thick enough 
james

[Tom]

I'm really curious about how the effort will be accepted by the cutomers.  Tell us more when you get into the nitty gritty of the sale.

[isawlogs]

Joe , I like reading your post on here . Thanks for putting them up .
 That being said , is it an availability issue with the mixing oil or cost that makes for the guys to use used oil cut with deisel as mix . Or is it all that is made available ...

   

[VT]

Im thinking cost isawlogs.

I have used a line-bore tool to over size barrels . Ill post a pix of it..

VT

LISLE 15000 CYLINDER HONE

[Al_Smith]

Me too.

Oh ,you guys' take this stuff too seriously .I have no idea if Joe alias India is actually being serious about this or rather being entertaining .No matter ,weather I or anybody else believe it or not ,it's entertaining .

However on the true meaning of rebuilding saws and having done 3 or 4  myself of course I would question poor old Joe on this stuff having traveled that road a time or two . I can't help myself .However Joe can tell his story as he wishes .

[logwalker]

Joe, is your question about oversize pertaining to the bore or a tighter fit on the piston? I didn't understand it.

It seems to me that if there was some way to improve the fuel and oil mix the original nikasil cylinders would last much longer. Why do you think the saws go bad so quickly?

Joe from the U.S.A.

[joe_indi]

Joe, is your question about oversize pertaining to the bore or a tighter fit on the piston? I didn't understand it.

It seems to me that if there was some way to improve the fuel and oil mix the original nikasil cylinders would last much longer. Why do you think the saws go bad so quickly?

Joe from the U.S.A.

Joe (from U.S.A.),my question was about the bore, not the clearance.
Whether the bore of the cylinder is nikasil, hard chrome or plain cast iron, the guys here are wrecking them.I  manage to run 3 - 4 pistons on the original cylinders with a lot of buffing and polishing ( by the way the cordless electric chain grinder  with an emery stone is great for this job).
But at some point of time the bore becomes too wide or too scoured to be serviceable.
Bad fuel and oil is the main cause. But old containers being used to carry fuel is also a reason.

........................However on the true meaning of rebuilding saws and having done 3 or 4  myself of course I would question poor old Joe on this stuff having traveled that road a time or two . I can't help myself .

So ask me Al.

VT, this tool is fine for polishing cylinders.But will it useful for increasing the bore by removing metal of, say 0.25mm thickness?

..is it an availability issue with the mixing oil or cost that makes for the guys to use used oil cut with deisel as mix . Or is it all that is made available ...
  

Two stroke oil cost $ 3 to $ 4 a liter.And it is available everywhere.But you need to be careful to make sure that you get the genuine stuff.
Used oil is free. A liter of diesel costs less than a dollar .
The owners are being gypped by unscrupulous shops with the oil:diesel mix.They pay for the real stuff but get the bad one.
The real bad oil comes from another racket prevalent here.
Agents go around to automobile service stations collecting the oil that is drained out of engines after the first 1000 or so kilometers (first free service)
This oil still looks new except for the fine cloud of ground metal content.
Sulfuric acid is mixed into the oil. The acid dissolves all the metal content.The mixture, when allowed to stand for a while, separates, with the oil now free of the metal.
It now looks like brand new unused oil.
But the emulsifiers in the oil hold back some of the acid.
This oil is sold as cheap chain oil.After a week, the oil pump and oil tank start corroding.
The oil feed stops.
In the worst cases, the crankshaft starts corroding near the clutch side oil seal.The oil seeps into the crankcase.
What this oil does to the bearings and needles of the crankshaft I leave to your imagination.

Joe

 

[Al_Smith]

Im thinking cost isawlogs.

I have used a line-bore tool to over size barrels . Ill post a pix of it..

VT

LISLE 15000 CYLINDER HONE
(Image hidden from quote, click to view.)

I've got one that is nearly identical to that ,with the diamond stones for doing hard nickle .

However bear in mind the plated lining in a saw cylinder is very thin .For all intents they cannot be resized in the true sense of the word .

A cast iron cylinder can be resized but a plated one cannot unless it was replated .

That in itself costs several hundred dollars usually .I imagine though that good old Joe could get it done for a dollar -2.98 if the work falls in line with other prices in that land so far away .

[VT]

Joe ,, AL
this resizing is for a steel / cast iron sleeve with ports and piston rings that key and that are Chrome M or S~~~ to any other type of alloy for rings. This type or hone is what i picked because a true "rod resizer " or line hone (sunnen) is huge coin . I have one PLUS ..

If the Cylinder  is polished Alum/silcone-abbr then that hone or any type of machining is NOT GOING TO WORK.
I have done steel sleeved alum barrel fins many time and then just picked my rings to the steel and lubes to use , better to replace rings over barrels..
All real Euro cars run hard holes and soft rings , piston ring-land machining is only for  the failing 3.
cylinder ridge reamer is a very rude tool..

VT

[Al_Smith]

VT ,I have worked in or around automotive engine plants for the best part of 35 years .Fact is I've worked on more Sunnen line hones than I care to mention .Oil sodden rascals with honing oil dripping down the back of your neck,yuck .

Expensive ,only a large scale operation can afford .Just the price of the diamond hone stones cost a kings ransom .

That said ,those little Lisle hones can do a good enough job on an iron cylinder for a chainsaw,motorcycle whatever .

Now where or why people ever get the idea you can resize a plated cylinder is beyond my comprehension . Further more even if you could replate a cylinder and replace a piston with some off the wall size it would cost more than the saw is worth .

Chainsaws are not like Chevy 350's that every after market supplier makes over sized pistons for .

Sure ,maybe Joe can get pistons made for next to nothing .You can even make rings if you have the where with all .The bottom line is that other than for reasons of experimentation it's not economically feasible .

[VT]

That said ,those little Lisle hones can do a good enough job on an iron cylinder for a chainsaw,motorcycle whatever .

Now where or why people ever get the idea you can resize a plated cylinder is beyond my comprehension . Further more even if you could replate a cylinder and replace a piston with some off the wall size it would cost more than the saw is worth .

Chainsaws are not like Chevy 350's that every after market supplier makes over sized pistons for .

Sure ,maybe Joe can get pistons made for next to nothing .You can even make rings if you have the where with all .The bottom line is that other than for reasons of experimentation it's not economically feasible .

I haven't pulled a chainsaw apart for sometime now, I was a$$uming that saws had a iron liner (iron cylinder ) but if your saying that it's a (polished Alum/silcone-abbr plated cylinder) Im with you Also Al..

It won't work.
As for what we call ""economically feasible"" it sometimes is in other places...

[Al_Smith]

 I imagine without researching that most likely McCulloch was about the last to use reboreable iron cylinders . I'm guessing late 70's to early 80's the practice was discontinued in favor of plated cylinders .

The 10 series Macs for example are one of the longest production run of any saw ever built with few exceptions .I have several from the early days with iron liners and 3 or 4 later ones ,in fact one of the last which uses  a plated cylinder .

Regarding plated cylinders they seldom will actually show much taper and ovality .Much more than a couple of thou would be through the plating and most likely hang the engine once that happens .

On a rebuild some people hone them ,some do not .I've done both but only very very lightly  with the hone .Many people would be surprised how many saws run pretty good with a few scratches ,longer and better than most would ever think possible .

Fact is I've rebuilt several Stihl where the piston had literally grenaded and they ran fine ,still do as a matter of fact . If a saw can give good service while being used by a tree service you know it has to be pretty tough .

[joe_indi]

I imagine without researching that most likely McCulloch was about the last to use replaceable iron cylinders . I'm guessing late 70's to early 80's the practice was discontinued in favor of plated cylinders .

Al,
I am no engineer.But since you have worked in automotive plants, tell me this, was the iron cylinders discontinued due to poor performance or was the plated cylinder introduced more for reducing production costs.

Joe

[Al_Smith]

 As far as I know the only US produced auto engine ever to use a plated cylinder was the Chevy Vega and it was a piece of junk . 30 miles per gallon of gas ,100 miles per quart of oil .

Modern engine have cast in place cast iron cylinders  ,actually nodular iron  which is a tad bit harder than standard gray cast iron . It also has slightly different characteristics than gray cast also .

For what it's worth about the only reason they ever went to an aluminum engine was for weight reduction .

As far as what type cast for a cylinder liner ,probabley grade 50 fine grain would be best .It has good machining properties and good heat transfer .


I imagine though that for a price ,L A sleeve compnay would make a zillion of them but of course for a price . Wiseco would make pistons also but again with a price tag .

For that matter a gent on another site makes custom pistons also .

Again I add that some thing of the nature of iron sleeving a saw engine is out of the ordinary .In my case had that SP 125 Mac not have been a rare saw I wouldn't have fiddled with it .

If I knew how to post pictures I would show the operation .I've had the set up on 4 or 5 sites so far  of how I did it .It wasn't that hard to do just real time consuming .

[joe_indi]

While 96 pistons were dispatched by road, the 4 that I asked to be sent through air arrived yesterday.
I has one cylinder that already had a CI sleeve installed for a 52mm piston.The shop honed it to take the new 52.5mm piston.
I got the re-honed cylinder an hour ago.
I just finished installing it on the saw and started it for the first time.
It is really great!
What I noticed different from the 52mm sleeve was that the wee bit of extra piston dia. gives that needed power to rotate the engine without any hassle in idle.

What I mean is, that with the 52mm sleeve, the LA screw had to be turned in fully along with some 'fancy' setting  of the H and L screws just to give it an uneven idle which kept the engine from dying.But things used to improve within a few days of use and within a week a normal carb setting was possible.

But with the new 52.5mm piston, the carb setting was not too different from the regular setting.
L was set 1/2 turn out, H   one full turn out and the LA about one extra turn in.
The idle is smooth.
The engine note is much deeper at idle and the growl during acceleration is more pronounced.
Though I did not want to risk the new piston and sleeve at full rpm, I blipped the throttle a few times.The acceleration is much better and though the muffler is stock, it sounds like a 'semi'- Magnum.
(I do 'semi' - Magnum conversions by replacing the stock exhaust cover with a Magnum cover. Jet is changed from 0.68 to 0.70.)

Could 0.5mm make that much of a difference?

I would like to post some pictures and maybe some videos (you tube??).I have to get a new camera since my son has gone and lost my camera recently.

I was also thinking if some of you are keen, I could sent a couple of these pistons to one of you who could pass them along to the others.
There are no strings attached to this offer.I don't want any payment for them.But since I will have to pay for the post, I cannot afford to send more than 5.
So if anybody is interested, arrange it between yourselves and give me an address to which I can send them.
I also have a few oil seals made locally suitable for 029 and 039.
I could send them also if anybody wants them.

I will post again on the progress of the 52.5 piston/sleeve combo once the saw has run in.

Joe
 

[Rockfarmer]

This has been a very entertaining read 

I belive Joe India,.. i think

As far as the Chevy Vega, I had one of those sackless wonders,.. my first car,.. going up hills was torture!!

I think they switched to chrome bore for weight, cost and heat transfer. But I dont think they are as durable, rebuildable or salvagable as cast iron sleeves or bores. My friend had a sled with nikasil liners and he ran it out of oil and it seized. We waited for it to cool down, mixed up some 2 stroke gas, put in some oil, rocked the clutch back and forth to free it up, got it running, by the end of the day it had 125 psi comp, we were like WOW 

Joe India,.. a pic is worth a thousand words. I'd love to see some pics of the trashed saws, boxes of blown up pistons, piles of saws awaiting repairs and any other neat stuff you got laying around. And tell your kid not to play with your camera anymore or your going to make him work in the carpet factory!!  jk of course  ,..    Cool thread!!   B

[Al_Smith]

I doubt there is any more drag with an iron cylinder as there is with a plated one .

Good old Joe has to bear in mind that a newly  assembled engine has to seat in the rings before it runs correctly .

They've tried about everything known for cylinders .Some aircraft engines use 4140 steel sleeves . I suppose for strength because I can't think of any other reason .

If iron were not a good cylinder material then 95 percent of the auto type engines made would use something else . For some reason a plated cylinder just hasn't been real successfull in any thing but a two cycle .

The Vega was a lemon as was some of the lawn mower engines that tried plating .

I've heard some yuppy type high dollar sports car is trying it now .I'll bet dollars  to donuts it's hard nickle though and not chrome .

[VT]

Porch is and there pushing a new one from Chev this year.
Not forgiving in the least are those type of engines.



VT.

[Jim Spencer]

My computer has been out of commision for a few weeks but I am the Jim Spencer who spent some time in India way back in 1968 installing an engine machining line at Hindustan Motors in Utaparra just outside of Calcutta.
If any of you get a chance you should go see the movie Slumdog Millionaire.  Then you will understand what happens in India to the working class people.
There are the workers and then there are the Non-working elite who cheat the workers out of everything they can.   India is the largest Democracy on the planet with over 1 Billion people but the politicians are very corrupt.  India has been going thru the same thing for the last 50 years that the U.S. has been going thru for the last 8 years.  The difference is that India because of their superstitions and uneducated class, has not been able to purge their crooks as easily as we have.  India only recently has been making tremendous progress because of Hi-Tech companies utilizing their cheaper labor pool.
Back in the 60's, 70's, 80's cylinder bores were the same material as the engine block and I don't know anyone who used sleeves unless they had Aluminum blocks.
Jim

[joe_indi]

Back in the 60's, 70's, 80's cylinder bores were the same material as the engine block and I don't know anyone who used sleeves unless they had Aluminum blocks.
Jim

Jim, my Dad had a '61 Hindustan Ambassador.He used it till he passed away in '98.
It had 'Morris' on the block instead of the subsequent 'Hindustan'.
The cast iron engine block had to be sleeved twice.This was to start all over again with standard pistons when the over sizes ran out.

Update on the oversize pistons:
I have hit a small stumbling block.The saw was running fine initially but withing a day or so the rings wear out with a resulting ring gap of 1 to 2 mm!!
It took me and the tooling shop quite some time to figure out that the reason was limitations of machining.
Since the cylinder is closed at one end a honing tool like the one suggested by VT cannot be used.So machining is limited to a lathe.The fine grooves created wear out the piston in no time.
We have finally tried 2000g silicon carbide paper which gives a better finish to the cylinder. 3000g paper would have been better, but is not available now.
So we are stuck with using 2000g.
But rings still wear out, though they last longer now.
But once the cylinder has got polished by usage, the next set of rings do not wear out.
So, this is what I intend to do.Get 2 sets of rings with each piston, one set chromed.The chromed one will be used once the cylinder has seated.Maybe $2/- extra and the cylinder has to be lifted once more.But the end results should pay for that, hopefully.
BTW.Sleeves that are now being used are those made for 100cc 2 stroke motorcycles.They have a cylinder bore of 52mm(Yamaha)
Joe

[Al_Smith]

Since the cylinder is closed at one end a honing tool like the one suggested by VT cannot be used.So machining is limited to a lathe.The fine grooves created wear out the piston in no time.
 

The Lisle precision hone will get nearly to the end of a blind end cylinder.I've done it many a time .The portion it won't reach is above the piston ring travel .

[joe_indi]

Al,
Thanks for the very valuable suggestion.
Unfortunately the honing tool here sticks out an inch at the end, it is not flat like the Lisle.
But you have got some old gears in my gray matter going, so let me see if I can pick up something from the local shops.

Right now we were in the process of constructing a honing tool(more of a polishing tool) using two brushcutter pistons welded together, with two vertical slits which can hold emery paper.A piston pin with an old con rod welded to a crude U-J cross is to serve as the bit to go onto the drill.
May not be as fast as the Lisle but hope to get the job done eventually.

Joe

[Rockfarmer]

HI JOE !!!   

[logwalker]

How about using a flexhone?

http://www.brushresearch.com/flex-hone.php?gclid=CNOF9PHC4pgCFRxNagoddTNZdA

[Al_Smith]

The problem with a flex hone or shoe hone for that matter is the fact they will not hone true regarding taper and ovality .What you might end up with is an egg shaped funnel .

The only commercially made precision hone is the Lisle type . This type will hone true which is what you need to resize a cylinder .

A cylinder with slots in it for holding abrasive paper is nothing but a lap .They work but won't really hold size like a true hone . I've got a couple of them for doing small holes like  3/4" to 1 1/4" . They are made with segments like the Lisle using tapered cones on the ends
The problem is that you cannot adjust them without removing them from the hole .

[Dave Hanny]

Very interesting reading about the state of affairs in India.

[VT]

Al Smith ,

I agree.

Joe more power to ya. wear in is good oil , and cooler loads, you need to keep it well lubed and cool loads till it's set in.
VT

[Al_Smith]

 This conversation of over sized pistons comes up on other forums .It's the general consensus that to do so at least in North America is a costly endeavor .

What goes on in India is anybodies guess but on this side of the pond because of environmental problems plating companies any more are few and far between . The cost is almost prohibitive in most cases . It would cost about as much to get a cylinder re plated as to purchase a new one .

Strictly my opinion but other than experimental or restoration type stuff it would seem to me re plating is an exercise in futility .

[joe_indi]

I have purchased a new camera, so I was able to snap some pictures of the process involved in installing a CI sleeve on a chainsaw (MS460) cylinder.
I have uploaded the first lot of ten pics into my gallery.

http://www.forestryforum.com/gallery/index.php?cat=15459

I shall upload more in installments so as not to sacrifice the quality of the pics.
Could somebody suggest how I should upload a video.
Joe

[Rocky_J]

The video should be uploaded to Youtube. This forum isn't set up to host video.

And I agree with Al, resleeving or plating a small cylinder is not practical or even possible here in the USA. I just rebuilt a 460 using an aftermarket piston and cylinder from Bailey's, $115 for the kit.

[Rockfarmer]

I have purchased a new camera, so I was able to snap some pictures of the process involved in installing a CI sleeve on a chainsaw (MS460) cylinder.
I have uploaded the first lot of ten pics into my gallery.

http://www.forestryforum.com/gallery/index.php?cat=15459

I shall upload more in installments so as not to sacrifice the quality of the pics.
Could somebody suggest how I should upload a video.
Joe

Nice work Joe! Great pics 

[VT]

Nice Pix Joe ,

Good work !!

VT

[joe_indi]

Rockfarmer, VT,
Thanks.
I have not been too communicative lately on the oversize piston because, for some time it seemed that I had run into a brickwall.
Under under load the engines were overheating, pistons were seizing slightly and the were rings wearing out too quickly.
I solved the wearing out of the rings by using chromed rings.
It took me some serious experiments with some pistons, an oven and a vernier caliper to arrive at the conclusion that the material of the pistons that I got made here differ quite a lot from that of the original.
The local piston has a higher expansion rate when hot.So usual allowance for piston clearance is not adequate.
The only way round this problem it seemed was to increase the diameter of the cylinder sleeve a wee bit more.
It tried this on two saws.When cold, the piston clearance is quite a lot, and the engine runs rough at idle.But, in less than a minute, once the engine heats up things are a whole lot different.
Once the piston expands, the engine is much smoother.And the extra cylinder diameter ensures that the pistons don't seize now.
These two saws are under going some trials, which have been positive for the week before Easter.
We are having elections here right now and nobody works for the next couple of days.
Once the saws run for another week I will check the pistons any rings for wear.
I shall post the results then.
Joe

[baronthered]

Hello new here. Joe this is a very interesting thread and I enjoy hearing about the way you can accomplish things the way you do. You are proving that ingenuity and curiosity can solve big problems.

[Beweller]

The thermal expansion coefficient for aluminum is about 3 times larger than for cast iron.  If cold clearance is correct for an Al sleeve, it will be very tight with a cast iron sleeve at operating temperature..

Increasing the bore from 52 to 52.5 mm will increase the displacement by about 2 percent, and if nothing else is changed, the power should also increase by 2 percent.  Goining to a 53 mm bore will give a 4 percent increase in displacement.

[joe_indi]

The thermal expansion coefficient for aluminum is about 3 times larger than for cast iron.  If cold clearance is correct for an Al sleeve, it will be very tight with a cast iron sleeve at operating temperature..

Increasing the bore from 52 to 52.5 mm will increase the displacement by about 2 percent, and if nothing else is changed, the power should also increase by 2 percent.  Goining to a 53 mm bore will give a 4 percent increase in displacement.

The CI sleeve that I had initially used had a bore with 0.1mm clearance at the rings for the 52.5mm piston.
But due to the problem of expansion the bore size has been increased to give 0.5mm rings clearance.
In a regular cylinder such a clearance would be considered time for a change of piston or cylinder.But in the case of this piston, once the engine runs for 30 seconds  the piston expands and the engine runs much more smoothly.

Even if  the increase in power is only 2%, wouldn't the increase in torque be more substantial?

For example, the Stihl FS200  and the FS250 brushcutters are identical in  all aspects even in the 2.2hp power output, except in their engine displacements.
The 250 has more torque because the engine displacement is 40.2cc compared to the 200's 36.3cc.
I was using this as a sort of 'thumb rule' in my experiments with a slightly bigger piston.

[Beweller]

First, my old eyes deceived me.  When I looked up the cast iron expansion, I managed to read its density.  In fact, the Al expansion is twice that of cast iron.  How significant this is depends on how hot the piston gets, and I don't know the answer to that question.

Here we go again.  Power is torque times speed.  For the same power, if you get more torque you get less speed.  A saw should be designed so that it operates at maximum power.  That is the condition that cuts wood the fastest.  Achieving that condition involves both the sprocket and the chain pitch to match the engine to the load.

Increasing the bore PROBABLY increases the torque, but displacement is dependent on both bore and stroke.  I do not see any firm connection between displacement and torque.

[joe_indi]

Increasing the bore PROBABLY increases the torque, but displacement is dependent on both bore and stroke.  I do not see any firm connection between displacement and torque.

What if the stroke is unchanged but the bore increases?
Doesn't that increase the displacement.
As you mentioned, there is a drop in the maximum speed of the engine, but in this case that is not a big issue, considering that maximum usable power is at 9000 to 9500 rpm
I have noticed that a saw that had a maximum rpm of 13700 has only  12500 with the over size piston.However the  saw has more power at lower rpms now so under load I don't think the engine speed drops as much as before.I think that the bigger bore has also been the cause for the usable power to be available at a lower rpm.What I mean is that when smaller branches are to be cut, just short blips on the throttle are sufficient.
In auto techie lingo, would I be correct in stating that the engine develops a broader power band with the maximum rpm trimmed off a bit?
 

 

[Rockfarmer]

I think that the bigger bore has also been the cause for the usable power to be available at a lower rpm.
In auto techie lingo, would I be correct in stating that the engine develops a broader power band with the maximum rpm trimmed off a bit?
 

 

Yes Joe!!  They call them "Supers" !!

[Ianab]

Totally off topic...but

Reminds me of my friends old Lotus Ford Escort (Late 6Os vintage). He rebuilt it with with hi-tech (1980s) forged pistons. Exactly the same situation. When it was cold it rattled and smoked a bit, but after a few minutes it ran smooth.

110mph in a 1600cc 1969 Ford Escort is one of those things you dont forget 

Traumatised for life....   Ian

http://www.motorbase.com/vehicle/by-id/1305/

[joe_indi]

Yes Joe!!  They call them "Supers" !!

Rockfarmer
If those are called  Supers, what are Magnums?

[Rockfarmer]

Yes Joe!!  They call them "Supers" !!

Rockfarmer
If those are called  Supers, what are Magnums?

I wish I knew Joe!  I have a couple 045 Supers and the only difference between them and the 045 is 2mm on the pis/cyl. The 045's were 49,50 + 52mm, the supers were 54mm and the mag was 56mm. They all use the same case, crank and rod. I think there were some small differences on the intakes as well with the mag but I really dont know.

Funny story Ian 

[Al_Smith]

   .
In auto techie lingo, would I be correct in stating that the engine develops a broader power band with the maximum rpm trimmed off a bit?
 

 

In a manner of speaking . Depends on a lot factors not just bore size .

For example a Ford 300 cubic inch I6 develops max power at most likely 2800-3400 rpm . An old John Deere 70 gaser only runs at around 1100 rpm max but puts out max power at around 800 .

In my opinion it's rather pointless dealing with saw engines to worry weather it cranks out another 600 rpm's or so because they are going to run wherever they run at with regards to speed .

[Dave Hanny]

   .
In auto techie lingo, would I be correct in stating that the engine develops a broader power band with the maximum rpm trimmed off a bit?
 

 

In a manner of speaking . Depends on a lot factors not just bore size .

For example a Ford 300 cubic inch I6 develops max power at most likely 2800-3400 rpm . An old John Deere 70 gaser only runs at around 1100 rpm max but puts out max power at around 800 .

In my opinion it's rather pointless dealing with saw engines to worry weather it cranks out another 600 rpm's or so because they are going to run wherever they run at with regards to speed .

They may run whatever they're gonna run, but the RPM or it simply running doesn't seem to be the question here - is it running 'better' at whatever RPM it is now running (i.e. is it developing an appreciable increase in either the amount, or the usable range, of torque to make the saw more useful when in whatever range it likes to run).

The I-6 was an great motor the way it came from Ford (the power range was already 'broad' due to them choosing the right cam).  But I've seen the same 300 I-6's made for specific applications that are cammed to run at one RPM, period, to develop its power.  The latter motor would be frustrating and nearly useless in an automobile or truck. 

What joe is wondering is if he was able to take the saw and make the usable range broader, which does seem to mean it will be easier to work with when felling all day long.

I, personally, don't know how to figure it beyond just using a saw pre and post-joe.  Usually increasing the overall weight of the rotating parts (simply put: increasing the weight of the flywheel - but any weight that needs rotated by a motor will have the same effect) creates the effect that joe_indi is suggesting he got (a more usable range, and the ability to stay in that range when working).  But joe went the opposite direction in weight... he's using a lighter piston.  If he went for a ligher piston than stock, alone - without increasing bore, the saw should feel as if it revs up (and down) faster, but it would lose some usability in its range of power.  But he did two things: lightened the overall 'flywheel-effect' AND increased the bore size a bit.  The two could cancel each other out in as far as the effect to the usuable power range for all I know.

[isawlogs]

  I dont know how to mesure any of the modes you made and tranfer that to energy, but I sure do like reading this thread.      I am also glad you posted pics on how things got done    Thanks .

[Dave Hanny]

I take back what I said about the piston's weight being the same as a flywheel - the piston stops and changes direction a lot, so a lighter piston can (in my mind) only help improve the saw's performance.

Still don't have a clue as to what the effect would be on usable torque range - but since the lower weight is one less thing the saw has to overcome when actually sawing a log... it would seem that it would help it to stay at its peak torque a little longer.

[Cut4fun]

If you have a piston that is 1mm to 2mm bigger and it works in the saw you want to use it in.
You can take and send the piston with the cylinder to a shop up north and they will bore and fit the piston and then re-plate the cylinder for a fee $$$.  Dont see any reason to do that in a work saw.

If this has already been answered I am sorry, I ain't going back to read 4 pages.

[joe_indi]

I've added some images of the oversize piston, the new chrome rings and the sleeved cylinder.

http://www.forestryforum.com/gallery/thumbnails.php?album=2273

I've also uploaded pictures of an air filter that came on a 046 in 1999 (??).
Does anybody know whether they are still available?

joe

[Cut4fun]

If you are talking about the 1605 air filter in the pic Stihl HD type, 1605 was replaced with alot better HD 1654 flocked and 1653 wire mesh. Now my numbers could be off, so hopefully someone in the know will chime in.

[Rocky_J]

I don't have the part number either, but the current MS460 air filter will fit that saw. There is the main air filter element as well as a prefilter wrap that fits over the filter. The prefilter keeps the vast majority of dirt from ever reaching the main filter, so it doesn't need cleaning as often and will last almost forever.

[Al_Smith]

I've added some images of the oversize piston, the new chrome rings and the sleeved cylinder.
 ?

joe

The work looks good Joe . As I said before though that type of rework is cost prohibitive in this country .

About the only resleeving or re-plating that is done is for restoration or racing which really could be classified as experimental .

That stuff,restoration ,racing falls under a different catagory than rebuilding a working saw . For the later the price of a new cylinder and piston may equal about half the price of a new saw .Often the saws may only get one top end rebuild then they are just parts saws or scrapped out .

After that guys like me end up with them and nurse them back to health .However guys like me do not depend on a saw to make a living with either .I can afford for one to take a fit on me now and again .Pro loggers and tree service workers cannot .

[Rocky_J]

What Al was trying to say (before he got sidetracked talking about his old saw collection  ) is that we have environmental laws here which make it prohibitively expensive for anybody to set up a shop doing that type of work. That, and we can buy aftermarket pistons and cylinders so cheaply that there just isn't any market for it. For the cost of doing all that custom work, you can buy factory replacement parts and have money left over.

[Al_Smith]

Well now all are  not really moldy oldies .Most of them are though ,I'll grant you that .

That aside a pro saw user can't be fiddley ---around trying to get somebody to make an oddball 1/2 mm sized piston to keep his or hers saws operational for them to make a living with .

Not saying in any way it's not a worthy cause just not expediant in the broad scope of things .

Now granted some missfit gearhead like myself might endeaver to do that stuff but good heavens if I charged my shop rates for that stiuff you could get a thousand bucks in reworking a 300 dollar saw .That would fly about as far as a lead balloon .

[joe_indi]

Okay Folks,
Here is the latest on my endeavor.
I finally got the diameter corrected for the sleeve.
This put an end to hours of buffing down pistons.The solution was so simple, and it was right there from the beginning.
My first mistake was in thinking that the 046/MS460 piston had a diameter of 52mm.
It does not! It is the cylinder bore that is 52mm!!
Here is what I for when I measured an original piston:
 Diameter at the top of the piston was  51.75mm and at the skirt was 51.95mm.
This goes into a cylinder with a 52mm bore.
I measured the oversize piston.
Diameter at the top was 52.25mm and at the skirt 52.45mm.
An overall increase of .5mm.
All I had to do was to machine the bore to 52.5mm.
This worked wonders. But then the honing marks were not considered.
Within a week, when the bore was polished during the run in, the bore diameter had increased to nearly52.65mm.
So to compensate, the machining was limited to 52.48mm.
During the machining, the tool kept impacting on the cylinder top.These marks were smoothed off, but at the cost of reduced compression.
A kindly soul from this forum advice me on how to measure the squish and take necessary corrective action.
The same kindly soul also recommended a slight port advance at the exhaust.
The correct squish and the port advance have worked wonders.
Saws with the latest sleeves have completed more than a month without any problems.
I have no idea how, but fuel consumption has decreased by a good 15%.
Output from the saws have increased.
Outside the cut the rpm does not climb to 13500 or 14000.It stays at a respectable 13000.
But in the cut, the rpm does not drop as much as a regular saw.

I am thinking of trying out a 53mm piston soon, that is if my friendly neighborhood piston manufacturer agrees to make me some.

Al,
I do understand that doing all this might not be possible in your part of the woods.But then you have many other thing going f.
Like a leg of ham, good bacon, a juicy hamburger,.......
Joe

 

[rebocardo]

On  a V-8, 4 stroke, running 1 hp per1ci, torque and HP equalize/cross about 5200 rpm, at what RPM does that happen on a 2 stroke engine?