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big bore 028?

Started by Pounce2181, September 23, 2009, 11:49:16 PM

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Pounce2181

Someone told me they modified their 028 by using a 038 jug and piston. Is this possible? He said he used it in a stock saw comp and got disqualified after they found out at the local festival. I would have figured the crankcase would be diff. But I am new to tinkering with chainsaws so I am still a little confused with what stihl used with what models.

joe_indi

Though not one of the experts here, going by the parts list and their description, this is what I think:
Gaskets are not interchangeable, the same is the case of the piston pins, the piston and needle bearings.
The base of the jug probably differs, in relation to the 4 fastening screws, easily solved by some careful filing with a saw file.
But, what about the needle bearings?
The 028 has a needle bearing having 10x14x13mm (id x od x length)
The dimensions of the 038  needle bearing is 12x16x13mm.
So a major mod like changing the con rod or altering its dimensions would be required.

Joe

Al_Smith

You can get carried away trying to make Frankenstein saws  when a stock saw configuration might serve better .

There are a few worth pursuing such as the 034/036 top end or a few using Husqvarna saws but most are just chasing the rainbow .

I've investigated a few but just found them to be an exercise in futility  unless a person just wanted to exercise their skills at maching and I personally don't need the practice . ;)

Pounce2181

sounds like a lot of work for nothing to me

Pounce2181

Does any one know the max rpm for a 028 wood boss? Just curious. Never used a 028 before or seen one run, so just trying a little comparo. Thanks for all the info. Maybe we can return the favor someday.

Al_Smith

028---12,500 .   028 super---13,000

Pounce2181

Thanks. I was gonna see how it related to how i have normaly tuned my saw. Usually I turn the screws until its at its highest rpm then back off a tad. I haven't never thought about over speeding. I have a echo 602 that I has been run like that for years and never had tach on it.

Al_Smith

Far be it for me to tell anyone how to tune their saws .However most tune them for that "4 cycle" cackle or running just a tad rich in air .Once you hit the cut all that richness smooths out and turns into power . Whatever it runs,it runs .Could be 12 thou or 14  depending on elevation ,temperature or several other things .

I know a lot of pro racers that don't ever rely on  tachometers to set their saws but do it all my ear . They might use a tach just for reference  though .

I also know a few rather less experianced so called builders that nearly wear out their tachometers of which is rather amusing if you ever see it in person . :D

Al_Smith

An after thought on this tuning business .A couple of old adages have been around for years and years and still apply .

First ,there is not substitute for displacement .Secondly it takes fuel to make power .

If you've ever experianced operating modified saws that last statement will hit home because they do go through fuel .

The last saw engine I tweeked was a Stihl MS 200T and it goes through fuel like nearly twice the amount of a stock version . I didn't think it was possible to suck down that much fuel on such a small  engine  :D. It's still a neat little saw no matter how much fuel it uses .

Pounce2181

Sounds like a pretty neat project. I am not looking to create monters or anything of the sort. Just some tinkering to improve a little bit.

Pounce2181

okay while I have it down a friend of mine said he has a piston and jug for a 028 super, he said I could have it for 20.00. Is there a site where I can find part numbers to match up to make sure this is what I am getting? I figure its relatively inexpensive so why not. From what I have compiled up its 2 mm bigger.

Al_Smith

 There are 3 sizes of pistons listed for that model .42 mm .1118-030-2000 .

44 mm  1118-030-2001 and 46 mm 1118-030-2003 .

I don't have the cylinder numbers because the parts numbers I have indicate they were sold as sets with the piston included .

Fact is evidently at the date of publication of my parts lists the 42 mm was only available with a piston for repairs and most likely was an older version of this engine .

Pounce2181

how many cubic inches is an 028av woodboss? The new ones are 3.33.

Al_Smith

I don't know neccessarily about the "wood boss " but the 028 is 47 cc,the 028 super is 51.5 and the MS 280 is 54.2 .

I also have no idea if the 280 cylinder would work on an 028 .

One of the tree trimmers whos' saw I tinker with recently came accross an 028 WB .

Without castings espersions I was less than impressed with that saw  but I suppose for 50 bucks it would serve for a crew of groundies that likely could destroy an anvil with a feather given enough time .

Jim Spencer

I never have been able to understand why a Farmer Mechanic would think they could improve on an automobile, tractor or chainsaw when the manufacturer has been spending millions and a whole group of engineers working to make a product perform the best of their ability.¢

Al_Smith

Oh most likely you don't understand it  because you never did it .

I'll agree some of it is a waste of time but some is not .An example of tractors which you mentioned is two Fergeson TO 20's  from the early 50's I own with more power than a standard bore TO 30 . The rebuild kits for the big bore were cheaper than standard bore in that case .

With saws for the most part it's nothing but a hobby but it's not for everybody of course . In my case I get a lot of enjoyment of the abilty to get a saw to cut at about the same preformance level of one in the next size class .

Most of them were derilects before I rebuilt and reworked them so there isn't a ton of money involved .The end results are a lighter weight saw that goes like the wind . 8)

olyman

Quote from: Jim Spencer on October 09, 2009, 04:43:24 PM
I never have been able to understand why a Farmer Mechanic would think they could improve on an automobile, tractor or chainsaw when the manufacturer has been spending millions and a whole group of engineers working to make a product perform the best of their ability.¢
tractor pullers come to mind. they really alter the character of the engine!!!

Pounce2181

Alot of people do stuff for the fun of it. If I am going repair something and I am going to find away to make it better if possible to make it a little more worth while. I just like to tinker with stuff and a repair gives me an excuse lol.

I race cars and for the most part its just fun, no big dividends. I have a job to make me my money lol.

Al_Smith

Oh it's neat to tinker and make frankenstien saws ,a part here ,a part there .

Now it's one thing to mix and match and remachine parts to fit providing you have a pile of parts and the where will all to do the machining .If you had to buy the parts plus pay for the machine work you're just as well off to buy a larger saw .

This is in no way talking about most  of the race saws which are redesigned works of art but intended to run for only small periods of time . These things have so many custom made parts from a variety of sources and a small fortune in both time and money invested in them they are out of the reach of most saw owners .

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