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Safe Running Exhaust Temperature in F. or C. Degree's.. Anyone Know the Ans. ?

Started by H60 Hawk Pilot, December 27, 2010, 09:04:51 PM

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H60 Hawk Pilot


I'd like to know the Safe but Highess Allowable Temperature for a Saw Engine under load.

This would be the Temp No#   _ _ _   F.  for a Saw in a Cut and Cutting a Log at WOT.  I'd like to have this High Temp/ Figure (Exhaust Gas Temp.)  for Saw Tuning and make sure I'm on the safe side (temp. range wise).  I have a Fuel Air Mixture Meter and IR Heat Gun and would like to get a temp. number to tie (all values) everything together.

My Guess is  875  F.  but it's just a guess.


Avery
Case 1150B & IHC TD-340 Dozer's, IHC 4WD 3800 & CAT 436B Hoe's, Franklin 170, Semi's: (1) Freightliner, (2) KW's, Marmon, Mack w/ Prentice Ldr., F-700 Crane Trk., (6) Mid Size Trk's. - Dumps, Flats, 1 Ton w/ 40 ft. 5th Whl. & (4) Semi Tlr's., LM 2000 Mill, (2) XL 12's., Solo 681, EFCO 152, Old Iron.

Tom

 smiley_whacko smiley_tom_dizzy02

Sheez, Avery.  That's a tall order.   Are you really going to stay on top of this, even if you find out what it is?   :D :P

H60 Hawk Pilot

I sure will, it's how I do business, I just need a good number.

I have my Heavy Truck Tractor set up with it's EGT Gage and it's calibrated...  the max. temp on a long pull is 975 F. for best engine life. This is a CAT diesel that's modified engine from stock fuel settings for use as -- HD Low Boy Truck Tractor.

The chainsaw ain't No Diesel but it's a high performance eng. and made out of good stuff.  If I had a good number (EGT XXX) I'd plug it in... that simple. This Ques. may Not be tall order for Chainsaw Geek's.... I'm asking & taking a shot that someone may know.   

Avery
Case 1150B & IHC TD-340 Dozer's, IHC 4WD 3800 & CAT 436B Hoe's, Franklin 170, Semi's: (1) Freightliner, (2) KW's, Marmon, Mack w/ Prentice Ldr., F-700 Crane Trk., (6) Mid Size Trk's. - Dumps, Flats, 1 Ton w/ 40 ft. 5th Whl. & (4) Semi Tlr's., LM 2000 Mill, (2) XL 12's., Solo 681, EFCO 152, Old Iron.

Jeff

Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

Reddog

So what variables are going to put in this equation? Because it is not one simple number.
I can think of two easy variables that would change that number.

So  smiley_whacko

H60 Hawk Pilot

Operating Variables will be  Temp. and Humdity to start with, then the saw construction materials (internal guts) and maintaining a long (time) cut and establish good recordable data, about 30/ 45 sec's. should do it per one test cycle.

Gas will (for me) be 92+ Octane (high test).

The Saw will be Operated in a Large Sized Log  at WOT, Sharpen Chain with two people, one operating the saw and the other collecting the data.

I'd like to know what the max. cyl. temp. allowed ... as it exit's the exh. .  This is the highest temp. (allowed) for best power and No Damage to Eng. on a day to day operating basis.

When the magic (EGT X) number did not come up here ____ . ; I thought of this ....  check the two new saws I have and record the EGT, RPM, Fuel/ Air Ratio under load & record these value's as a base line.  One saw is high perfomance and the other has a polution type muffler system. I'm thinking the polution type saw runs hotter than the non restrictive  (hot rod saw) muffler saw.  I'd like to set both saws up... to run at the very top of their performance envelope. Just looking to tweek the saws with small (eng.) change's to get them there.

I have the time (retired) available and eng. test equipment and looking for a EGT Number _ _ _ ?    

I thought about contacting the Saw Company's but they'd never transfer me to the engineering dept. with my question. The folks that build hot saw professionally would know what is too hot (cyl. temp).  Do you know of a web site where they deal with chainsaws and mod's. and such ?

Closing Note:  Not Looking to make a big deal out this question, my little Winter project with my Son in our shop.

Avery    

Case 1150B & IHC TD-340 Dozer's, IHC 4WD 3800 & CAT 436B Hoe's, Franklin 170, Semi's: (1) Freightliner, (2) KW's, Marmon, Mack w/ Prentice Ldr., F-700 Crane Trk., (6) Mid Size Trk's. - Dumps, Flats, 1 Ton w/ 40 ft. 5th Whl. & (4) Semi Tlr's., LM 2000 Mill, (2) XL 12's., Solo 681, EFCO 152, Old Iron.

weimedog

Actually an interesting question....but I think your thinking in Diesel logic. (My old Big Cam Cummins wanted to see 1100 degrees max before the turbo and 800 max after on the pyrometer driven thermostats...)(food for thought to figure how much energy was captured by that turbo and jammed back in the form of intake pressure....) part of that diesel logic was the turbo's ability to handle heat as well as on a specific series of diesels there had been bundles of test data relative to a given setup's (CPL for Cummins) power & reliability. Even with knowing parameters of exhaust temps, you had to know your setup up to know what changed so you could see the effects on power & exhaust temps, for example when I buillt an old BCII to a different CPL where cam timing was advanced & a different turbo and manifold were used vs. original CPL...exhaust temp was one of the first things I looked at as a gauge to see if it was going to handle the mountain work I did...before heading to Estes park with a load! But as you obviously know, all kinds of thing effected those temps. Simple things like exhaust back pressure, more complex things like  injector timing (with either the cam or those rocker boxes on those old Cummiins) , injector adjustment (3in lbs vs. 5in lbs) the "buttons" in the pump (pressure)..on and on!

I'm not certain the same logic applies here. Partly because of the fact that these are two strokes (vs. more linear 4 strokes that simply as a byproduct of their fundamental design, have much more control, therefor consistent & more predictable conditions; of the flow of gasses thru a given motor)  and partly the differences in exhaust ports & mufflers and where its even possible to take a measurement. More variations from saw to saw exhaust designs, Those open modded mufflers will allow the exhaust temps to drop faster than those choked up eco mufflers. Also the standard array of things, compression, mixture, ignition timing, like diesels. SO many variables. I think what is more relevant on two strokes is combustion chamber & cylinder wall temperatures. I think the logic would be relative to the temperature two stroke lubrication begins to fail...that's too hot! Also I'm not even certain "generic" exhaust temps numbers are a way to ascertain efficiency of combustion because of those design differences from saw to saw is going to allow different temperature drops from the time of combustion to point of exhaust...and that is before you consider the effects of the new fuel air mix driving out the exhaust..and now also the effects of the "strato" charged "wall" of air also driving out exhaust....maybe if on a particular saw empirical data can be gathered along with those temps either with a dynamometer of some other device to measure power as a function of exhaust temps...would be time consuming, but interesting just the same.
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

H60 Hawk Pilot

I Copy All That  and  Read your Reply Twice.

My Target EGT ____ is aimed at High Temp. Damage to the Piston and Cyl. Assy. .   I have torn all types of (aicraft, diesels, gas (2 & 4 Cyc.)  and turbines) engines down. When I worked for Cummin's was assigned to the the Warranty Dept. .  I really learned about Internal Eng. Failure (the cause).  Cummins Engineering was always testing different designs and some worked and some did not. I'm starting to get off the (exact) chainsaw engine question, so back to it (below).

Note to Weimedog -- You will recall the Question regarding the Efco and the CA Smog Muffler on it.  I'm about to start on this saw and want to get my 15 YO involved.  In that muffler post... the details and result we were looking for was covered.  We wanted to improve the Performance of the saw eng. by making small changes to the exhaust and retuning carb. . Folks sent me picture's of saw engines that were mod'd and what works.

My Son is just starting to have a real interest in go fast cars and want's my Camaro (I don't think so) for his 1st car & has his learner's permit now. I have discussed this little saw mod. with him from A to Z.  He has been at my shop when it was open but was too young to get involved in things at that time and was the No# 1 cleaner upper. I have done a lot of eng. test and really like Engine's and getting the most from them.  I use a (Clayton) 800 HP wheel dyno for big trucks and 400 HP (Go Power) dyno for Engines out of chassis. All my shop equipment is back in PA. I'm in FL until June & none of this equip. would be of use anyway for the saw mod. project.

This little chainsaw muffler mod. .. should be a No Brainer.  So.. I was laying the ground work for him to set up a spread sheet and plug in values.  We'd run the Efco 151 saw before any mod. and record all the data. Then, we'd mod. the muffler, little by little and run the saw under load.  Also, We'd run the saw without any test equipment and eval. the saw by how it perform's... it's cutting speed.. just like anyone that's been working on saws and tune's by ear; looking for straight out performance.  My Son need's to learn to work without the test gear and that's how I learned years ago. However, I want him to learn both ways (low & high tech.) for general knowledge.

Back to the Wanted Value for Max Temp. (continous)  _ _ _ ?  Every engine has a design (range) cyl. temp. that should be maintained to provide internal part (piston, cyl., rings) reliability through out the design life (hours) by the manuf. .  Bad things happen with over heat, heat stress cracks, swelled piston and scored cyl. walls and on & on.  Lot's more to the story but these are the 1st ones I can think of with an overheated cyl. .  I will have a temp. value from the 1st data sheets. Just estimating before hand on the smog saw.. It should be lower after the muffler modification.  I'd estimate that 25 degrees over the stock setting temp. would be a Yellow Temp. Reading and something is wrong and stop and correct X ?

I have the time and this little saw mod. is not a big deal and should be fun and benefit him and the saw performance and add to (aquired) mech. knowledge. I'm estimating about 5 or 6  hours in the entire project.  

So, if the question is too far over the Top... I'm not trying to ask a question to labor the FF board with a unrealistic type question.  I was looking for a value (max. continous  EGT Temp.) and lot's of folk's here have lot's of savy and come from all walks of life.

Avery
 
Case 1150B & IHC TD-340 Dozer's, IHC 4WD 3800 & CAT 436B Hoe's, Franklin 170, Semi's: (1) Freightliner, (2) KW's, Marmon, Mack w/ Prentice Ldr., F-700 Crane Trk., (6) Mid Size Trk's. - Dumps, Flats, 1 Ton w/ 40 ft. 5th Whl. & (4) Semi Tlr's., LM 2000 Mill, (2) XL 12's., Solo 681, EFCO 152, Old Iron.

ladylake

In snowmobiles it's around 1100 with a probe inside the pipe about 6" from the exhaust port.    Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Al_Smith

I can't add anything to this discussion other than relating dyno tests for auto engines .

On the extended wear tests on 460 Fords which was 30 days straight at 80 percent throttle simulating the load of a 30 percent grade ,the manifolds would turn orange .That is around 1400 degrees on cast iron .

Surprisingly after such punishment ,a tear down usually would not show any appriciable wear .Meaning the cooling and oil were doing their job . An old navy chief engineman once told me you wear the engine out more on start up than you do running it .

Jeff

Ya know what, I think if you figure all this stuff out ahead of time, there is a real chance the saw life could be extended right up until the point where you back over it with your pickup.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

H60 Hawk Pilot

Never backed over one yet, was taught to keep them safe between two trees (on the ground) or reloaded back in the truck or tractor. If I didn't... got a knot in the head, seemed to be an effective learning tool (used by my Father).

Was looking to teach my Son something and should work for us.
Case 1150B & IHC TD-340 Dozer's, IHC 4WD 3800 & CAT 436B Hoe's, Franklin 170, Semi's: (1) Freightliner, (2) KW's, Marmon, Mack w/ Prentice Ldr., F-700 Crane Trk., (6) Mid Size Trk's. - Dumps, Flats, 1 Ton w/ 40 ft. 5th Whl. & (4) Semi Tlr's., LM 2000 Mill, (2) XL 12's., Solo 681, EFCO 152, Old Iron.

weimedog

All good stuff.....the two things I have found that work for setting up the saws for reliability are spark plug checks, which are a poor mans way of getting both a sense of fuel mixture and combustion temps...(Remember color will change from other things like timing as well as carb adjustments) and an inductance tachometer to get a real time rpm data and define a baseline. I do have temp probes and a lazer surface temp device but I haven't used them much....only have two hands and the plug check has been my approach since the 1970's. (Yea...an old fart)
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

H60 Hawk Pilot

Rodger that !

I was thinking about the Spark Plug Reading and how they shows sign's of overheat on the insullator (color).  Also, little Alu. specks on the insullator is very bad... piston top cook.

Good point's for anyone regarding spark pugs...  light tan or brown  indicates the right running color (heat range, fuel mixture and/or oil burning in cyl.) to look for on the insullator nose.  I still have my Champion Spark Reader Tool and Chart Examples somewhere, bought it about 35 years ago... simple and works 100%. 

Avery   
Case 1150B & IHC TD-340 Dozer's, IHC 4WD 3800 & CAT 436B Hoe's, Franklin 170, Semi's: (1) Freightliner, (2) KW's, Marmon, Mack w/ Prentice Ldr., F-700 Crane Trk., (6) Mid Size Trk's. - Dumps, Flats, 1 Ton w/ 40 ft. 5th Whl. & (4) Semi Tlr's., LM 2000 Mill, (2) XL 12's., Solo 681, EFCO 152, Old Iron.

lumberjack48

Hawk, the company didn't transfer you because they don't know the temp number, their waiting for you to find the right stable non scoring number.

Happy New Year
Third generation logger, owner operator, 30 yrs felling experience with pole skidder. I got my neck broke back in 89, left me a quad. The wife kept the job going up to 96.

kenskip1

This has to be one of the best posts of the year! I would send a message to The chainsaw Guy.He has answered several of my queries, Ken


Stihl The One
Stihl Going Strong
Stihl Looking For The Fountain of Middle Age

ScottWojo

The real question is where you are going to measure the temp.  Are you going to measure the Gas temp out of the saw?  Or just measure surface temp on the cylinder  or Muffler?  And is the person who gives you the correct thermodynamics calculation is right or wrong,  or talking out his own exhaust port.

Too many variables.  How long do you run the test?  In the wood?  Ambient temp?  type of Fuel?  Type of oil? Air Filter?  No Air Filter?  Phase of the Moon?  Is the operator wearing boxers or briefs?

Even better Idea,  what differences will you get with a Piston with a white top?  Ceramic coated combustion area?   What happens when you coat the interior of the muffler and exhaust port with White ceramic?

What temperature differences do you get with higher priced racing Oils?

All these questions can be done one at a time by visiting Walmart and buying a poulan.  Something goes wrong (make sure it does) take it back and tell em its a POS and blew up the first time you used it.  (just kidding here guys.)

Gary_C

Quote from: kenskip1 on January 01, 2011, 10:45:00 PM
This has to be one of the best posts of the year!


The whole year?     :)

Is that most interesting, most informative, or funniest?     ::)
Never take life seriously. Nobody gets out alive anyway.

jteneyck

The temps. are likely higher than you are guessing.  I worked on catalytic converters for cars, trucks, and buses mostly, but some on 2 stroke devices as well.  In nearly all cases, exhaust temp. increases as displacement goes down.  Small 2 strokes had higher average exhaust temps. than most 4 strokes.  What were the temps.  Cars typically run in the 600 C range, but can spike over 900C occassionally.  Small 2 strokes typically ran much hotter, around 800C engine out temp., and could easily spike much higher.  Measuring these temps. is pretty difficult, and it's hard to get the same results as someone else unless you use exactly the same equipment and protocol.  You could measure 700 C and someone else 400 C on the same saw by using slightly different equipment and sensor location.  Here's a link to an SAE article (note that Stihl was a co-author) which shows some temps. they measured on a catalytic muffler.  You can see that the temperature outside of the catalyst was running around 800C during their testing.  Inside the catalyst it was screaming hot.  Automotive people use temp. data for material design purposes, but rely on other measurements (rpm and O2 sensors, for example) for engine control.  I think chainsaw control should be similar.  Keep the rpm below the recommended limit, and listen for that 4-cycle burble. 
http://www.emitec.com/download/vortraege/en/2004_01_0149.pdf

H60 Hawk Pilot

Mr. Jteneyck

The Stihl Article, page 3 was really informative. The saw I'm work with is thw Efco 151 ahnd the CAT muffler is just lie the CAT Stihl per the picture.

I had a (sort of) lunch bet with one of the FF Members that someone would come up with the information I was looking for and your (nearly) spot on.

Thanks'

Avery   
Case 1150B & IHC TD-340 Dozer's, IHC 4WD 3800 & CAT 436B Hoe's, Franklin 170, Semi's: (1) Freightliner, (2) KW's, Marmon, Mack w/ Prentice Ldr., F-700 Crane Trk., (6) Mid Size Trk's. - Dumps, Flats, 1 Ton w/ 40 ft. 5th Whl. & (4) Semi Tlr's., LM 2000 Mill, (2) XL 12's., Solo 681, EFCO 152, Old Iron.

AlanPage007

I have seized three saws doing large log ripping.  Am about to set up a test standard for monitoring such saws in the range of conditions they encounter.  My goal is to develop a temperature monitor to shut down the saw if the safe zone is breached.  I propose to do this with a limit switch that becomes part of the muffler.  Our experience is that the damage occurs from excessive heat buildup on the starter side of the piston and exhaust side of the cylinder.  This could be a very inexpensive component to add to any saw and would be easy to change, immobilize or remove if it became problematic.

Has anyone seen such a device employed?

Ianab

Never seen one, but the idea has merit. What possibly happens is that a bit of crud in the carb, or a slight air leak leans out the saw. Not enough for the operator to notice, but enough to overheat the saw under heavy load.

I would think that a thermocouple in the exhaust would let you monitor the temp, with a digital thermometer at first. Then a little electronic circuit, maybe a couple of warning LEDs, and a relay to activate the ignition kill switch as a last resort.

Exact cut out temp would be adjustable, you would calibrate it so it was in the "green" in normal use. If the temp went up, you would investigate, if it went up too much, the saw stops.  Because the kill switch works by shorting out the spark, unplugging the whole unit from the saw would disable the cut out, and allow the saw to run normally.

I know aircraft engines are often fitted with exhaust temp monitors, as varying altitude and mixture settings can cause the same issues there.  You just want mini version of that. Electronics could fit in a cig packet size and be powered by a 9v battery?

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

CTYank

Quote from: H60 Hawk Pilot on December 28, 2010, 10:38:22 AM
Rodger that !

I was thinking about the Spark Plug Reading and how they shows sign's of overheat on the insullator (color).  Also, little Alu. specks on the insullator is very bad... piston top cook.

Good point's for anyone regarding spark pugs...  light tan or brown  indicates the right running color (heat range, fuel mixture and/or oil burning in cyl.) to look for on the insullator nose.  I still have my Champion Spark Reader Tool and Chart Examples somewhere, bought it about 35 years ago... simple and works 100%. 

Avery

Not so IME working on racing 4-strokes years back. The spark plug area of interest is the BOTTOM 1/8" or so of the insulator, where it meets the plug metal body. If that's tan, you're "golden." Presuming everything else is "in the park."

Some of the discussion here seems to be leading to "over-thinking" and over-complicating. Meaning- if the engine 4-strokes when you lift in the cut @WOT, combustion conditions are fine. Assuming good quality & ratio of oil, and adequate air-cooling, longevity will be fine.

Some people are engine-killers; they'll pay.
'72 blue Homelite 150
Echo 315, SRM-200DA
Poulan 2400, PP5020, PP4218
RedMax GZ4000, "Mac" 35 cc, Dolmar PS-6100
Husqy 576XP-AT
Tanaka 260 PF Polesaw, TBC-270PFD, ECS-3351B
Mix of mauls
Morso 7110

John Mc

Some of the things you might check before going to an automatic cut-out:

1) are you trying to rip too much tree for your saw?

2) For extended ripping, you probably want to be set up on the rich side (more so than for regular felling and bucking)

3) Make sure you are using fresh, premium octane fuel - this is especially important when running hard and hot, which ripping generally is (the heat has not time to dissipate as it does when making the shorter-duration felling or bucking cuts).  The hotter it's running, the less margin you have for other problems - higher octane can help avoid at least one of the problems (fuel tends to lose octane as it is stored, as some components evaporate off)
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

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