MS 880 Given to Me

[PP4218]

Bob H,

Also, I'm not saying I disagree with you on the failure. I want to make this saw better so the failure mode is different. This saw is only as strong as it's weakest link. In this case, the OEM piston was the weak link and failed due to overheating (regardless of cause). Retained heat due to overheating can be worked around with piston coatings, cylinder design and materials used (as I posted above) and exhaust/muffler design.

For example, my saw has the aluminum muffler with clip-on retention. Later MS 880 models went to bolt on. Is one design better for heat emissivity? I do think so. I think the aluminum model gets rid of heat better and faster than the later steel mufflers. Is one more expensive to produce than the other? Of course. The steel model had to be cheaper so cost was taken out of the muffler while still meeting noise requirements.

Can a saw be ported for more power? Of course, people here do it all the time. OEM isn't good enough, it's designed for the masses and profitability. Saws get tuned for more power. Why not better longevity? That's what I want.

 

[Bob Hedgecutter]

Bob H,

This saw is only as strong as it's weakest link. In this case, the OEM piston was the weak link and failed due to overheating (regardless of cause). Retained heat due to overheating can be worked around with piston coatings, cylinder design and materials used (as I posted above) and exhaust/muffler design.

OEM piston was not the weak link- had the saw been running and run to spec, the piston would still be fine and the original owner still be running it.
Cure the "overheating" problem and OEM pistons survive- throw coated this or slicker that at it without fixing the "overheating" and you are throwing bad money after good.
You might have pinched pennies on old Fords- but you were not part of the Stihl R&D team for the 880.
The very fact there is room for "improvement" in any saw via the porting route, shows you they were designed to meet a criteria of power and longevity, not cost cutting- cost cut on a saw or send a new design out with known faults and sales will drop like a monkey holding a hot rock- most major saw manufacturers have made that mistake at least once- the 880 was not one of them.

 

[PP4218]

You and I are in agreement on the fact I was not on the Stihl R&D Team. I guess this means that you were?

 

[Bob Hedgecutter]

No, I certainly was not, closest I have ever been is Frankfurt airport!
But then I never claimed the piston they designed was any kind of weak link either.

 

[PP4218]

Ok, no worries. You and I are in the same boat then. Neither one of us knows what the design specification is for the MS 880 Piston.

Therefore, I'm going to use an existing design I've reviewed and move forward with improvements to this known design.

 

[av8or3]

I’m out. Good luck.

 

[Maintenance supervisor]

A lean condition can create heat, which can include but not limited to, pin hole in the impulse line, fuel line, intake,crankshaft seals,loose spark plug, and decomp leaking.
Diagnosis of the original problem is the only mitigating factor for fixing this saw.

 

[BrettS]

I’m out. Good luck.

Don't let the door hit ya where the good Lord split ya....

 

[Vintage Engine Repairs]

I’m out. Good luck.

Sadly, he doesn’t realise the opportunity he’s just lost with your offer.

 

[rogue60]

He has to be trolling taking the piss there is no way anyone could be this clueless LOL

 

[trains]

Seems odd to blame a piston for burning up on the piston not being good enough, when, they fail due to other contributing factors, like poor fuel/ straight fuel, with no oil, or an air leak, tuned incorrectly running lean, over heated, over sped etc.

When tuned correctly, and not run lean, abused, or straight fueled, the original piston/ cyld will give a very good service life.

His saw, his choice, sad if he dosent take good advice when its given.

 

[Vintage Engine Repairs]

He has to be trolling taking the piss there is no way anyone could be this clueless LOL

I get that feeling too..

 

[Bob Hedgecutter]

He has to be trolling taking the piss there is no way anyone could be this clueless LOL

Allen Kerr's little brother- Wayne.

 

[PP4218]

Nope, no trolling - just don't like to use unsupported anecdotal "because I said so" advice. Just hoping to get advice from persons that actually have built an MS 880 before. Was on the phone with Stihl tech support. The person I spoke with recommended that I buy 1124 141 2202 manifold as a replacement for my existing manifold (I am taking cookies advice and replacing seals/gaskets/hoses/carb kit/filters).

So, I took the advice of Sthil TS and ordered the part - the part came in yesterday and it was the wrong part. Seems even Stihl can give faulty advice - huh, the OEM was wrong?!?

As DND 9000 said, they are not interchangeable. Here are the pictures of the original:



And here is the replacement part I received using the advice I got from Stihl:




So maybe the OEM isn't infalliable after all?

 

[PP4218]

"He has to be trolling taking the piss there is no way anyone could be this clueless LOL"

"I won't post in your thread again with good advice the hurt feelings are already off the chart lol"

You know, you said you wouldn't be back commenting in this thread. It's clear to me that you can't do that, but that's okay.

I appreciate the humor! LOL

 

[PP4218]

I’m out. Good luck.

PM sent

 

[PP4218]

Seems odd to blame a piston for burning up on the piston not being good enough, when, they fail due to other contributing factors, like poor fuel/ straight fuel, with no oil, or an air leak, tuned incorrectly running lean, over heated, over sped etc.

When tuned correctly, and not run lean, abused, or straight fueled, the original piston/ cyld will give a very good service life....

I'm not blaming the piston. The piston failed due to overheating. I absolutely get that. I want to move past that point of failure and move the failure to a different point.

For example, your car overheats and you replace the radiator. Your car overheats again and you replace the radiator.

You didn't fix the problem, you fixed the symptom.

The piston overheating is a symptom, not a problem. The problem was caused by an external factor (dull chain, operator error, bad gas, etc.). Replacing the OEM piston with another exact same piston will lead to the same exact failure mode in the same condition.

Doing the same thing over and over and expecting different results is a waste of time and money.

I am hoping with the change in piston to make the system more robust and ameliorate a potential problem with the piston. Hopefully the change will move the failure to the muffler by moving the heat to the aluminum body for more effective dissipation/emission.

 

[PP4218]

That is why I posted the info earlier about emissive rates, but I'm thinking no one got that. The heat in the combustion chamber produces work. Once that work is complete, it is waste product. The newer cylinders with nikasil reject heat better than chrome lined and lead to higher exhaust temperatures as less heat is absorbed by the cylinder. If the piston can not reject that heat, but instead adsorbs it, it will approach it's physical property limits sooner, hence the scoring.

A piston coating is a short term answer. There is also a change in the metallurgy of the piston answer. A change in cylinder lining will help as well. Chrome absorbs heat better that nikasil. So a chrome lined bore will result in lower exhaust temperature gases as the heat will be moved to the cylinder cooling fins more quickly.

There are a lot of different answers to helping the piston cope.

I will be using the OEM cylinder as it cleaned up okay (thanks to singinwoodwackr, BrettS, and Maintenance supervisor for their helpful advice on that) and the AM piston with a specialized coating.

I believe it will last just fine, but if it fails, then I'll just redo it. And I'll post the results so those who choose to can say "I told you so".

 

[Vintage Engine Repairs]

Op, it’s quite clear many members (myself included) don’t see eye to eye with you here, but best of luck with your saw repair none the less.

You have certainly managed to have gotten under the skin of many members and if you weren’t intentionally trolling, you were doing a good job of it unintentionally lol.

 

[PP4218]

Op, it’s quite clear many members (myself included) don’t see eye to eye with you here, but best of luck with your saw repair none the less.

You have certainly managed to have gotten under the skin of many members and if you weren’t intentionally trolling, you were doing a good job of it unintentionally lol.

Definitely not my intention. If I have upset some members here, please accept my apology. I am used to spirited conversations regarding problem solving.

I hope no one is offended by my comments, but again, if I have hurt some feelings here I do humbly apologize for doing so.