Stihl 029 super rings didnt seat???

[smallengineredemption]

Hey guys I just rebuilt an 029 super for a neighbor. It was rough, I had to remove lots of transfer. Put meteor piston caber rings. Saw runs cuts and idles, all be it roughly idle. The problem is blowback. I am going to change the intake boot as this is basically all I didn't replace for rubbers. But I do not think it's the issue. The plating had a questionable spot, not a score but appeared it had like a narrow divot.... Anyway before I give up on it wanted some other opinions what I might be missing just incase.

Other 029/290 question, I have a cpl that don't like to settle back down after being wide open. You have to blip the Throttle as they seem to idle at like 3300 instead of 2600 I like to keep em arnd

Now I did put duck bill aftermarket tank vents but I wouldn't think this would cause that but it's possible I suppose..thoughts??

 

[a. palmer jr.]

I have a saw here that someone put the duckbill vent in upside down and it didn't work so well..

 

[smallengineredemption]

I have a saw here that someone put the duckbill vent in upside down and it didn't work so well..

This one only goes one way it's a duck bill on a hose... but ya it's deff not backwards

 

[stihltech]

Scuffed up the whole bore?

 

[smallengineredemption]

Scuffed up the whole bore?

Ya it was bad, I took it back apart, should have measured bore before hand, no good lesson learned pay more attention don't cut corners bc it is difficult to dig out tools in the tiny shed shop. But he has his saw back with an 029 top end and I ported the muffler seems happy. Which is all that matters

 

[Vintage Engine Repairs]

Spit back is either from a worn skirt, cylinder or clearance issue between the two.

 

[smallengineredemption]

Carb issues, air leaks also cause blow back this saw was a worn cylinder however, ring gap prior to break in was .025" after it was dern near 1mil

Spit back is either from a worn skirt, cylinder or clearance issue between the two.

 

[Vintage Engine Repairs]

Carb issues, air leaks also cause blow back this saw was a worn cylinder however, ring gap prior to break in was .025" after it was dern near 1mil

Can you explain how an air leak or carb issue causes spitback?

 

[smallengineredemption]

Yes absolutely, I actually have a video on it. I had an air leak where the carb seats against the rear handle gromet and intake boot on an 028 recently AND and ms290. Now the cause, I will say is just a theory based on my logical conclusions of what I think I know. But, air is pulled in from the very rear (furthest point from your intake port) and this allows the full to be pulled into your cylinder. If air is being pulled in BEFORE this point, we'll you end up unable to pull all of that fuel in, thus causing it to "blow back". All I can say is I'm speaking from literal personal recent experience. Plus if you fuel inlet jets are too rich, too much fuel is being forced into the venture thus causing some of it to blow back since not enough air us being pulled into the intake. Your thoughts??

 

[cookies]

low compression causes spitback due to low vacuum not atomizing the fuel, it needs a new cylinder. Fix it right the first time...vac/pressure test the other saws case and fuel tank, carb could be out of adjustment or bad diaphragms.

 

[Vintage Engine Repairs]

Yes absolutely, I actually have a video on it. I had an air leak where the carb seats against the rear handle gromet and intake boot on an 028 recently AND and ms290. Now the cause, I will say is just a theory based on my logical conclusions of what I think I know. But, air is pulled in from the very rear (furthest point from your intake port) and this allows the full to be pulled into your cylinder. If air is being pulled in BEFORE this point, we'll you end up unable to pull all of that fuel in, thus causing it to "blow back". All I can say is I'm speaking from literal personal recent experience. Plus if you fuel inlet jets are too rich, too much fuel is being forced into the venture thus causing some of it to blow back since not enough air us being pulled into the intake. Your thoughts??

If the skirt and cylinder is within clearance, it essentially shuts the intake port closed. Doesn’t matter what is happening between the air filter and the intake port, if the port is closed, nothing will go back.

Now, it’s not a sealed valve, there has to be some
clearance and thus very small amounts of charge can be spat back, but it’s negligible and on an engine within spec you won’t get any noticeable amount of 2t charge on the air filter

Working off the assumption that a p&c in clearance closes that port, any wear will allow an increasingly proportional amount of fuel back through the intake.

The only times I have ever had spitback is through worn skirts. Not to say other causes don’t create the symptom. Just never had it happen.

 

[smallengineredemption]

If the skirt and cylinder is within clearance, it essentially shuts the intake port closed. Doesn’t matter what is happening between the air filter and the intake port, if the port is closed, nothing will go back.

Now, it’s not a sealed valve, there has to be some
clearance and thus very small amounts of charge can be spat back, but it’s negligible and on an engine within spec you won’t get any noticeable amount of 2t charge on the air filter

Working off the assumption that a p&c in clearance closes that port, any wear will allow an increasingly proportional amount of fuel back through the intake.

The only times I have ever had spitback is through worn skirts. Not to say other causes don’t create the symptom. Just never had it happen.

Same, however these two saws, one is a BRAND NEW top end, the other, I measured bore 43.97mm on the dot, ring gap was 17thou so was not any kind of top end issue, I replaced grommets on one and BOOM no more blowback, other is still waiting for me to have time to change intake boot

 

[smallengineredemption]

low compression causes spitback due to low vacuum not atomizing the fuel, it needs a new cylinder. Fix it right the first time...vac/pressure test the other saws case and fuel tank, carb could be out of adjustment or bad diaphragms.

Again respectfully keep up dernit, the saw is done and HAS BEEN DONE I vac pressure test EVERY SAW I WORK ON I measure bore and ring gap if it is a rebuild, I just didn't measure bore on this one only ring gap but it was low enough. When you are trying to save a neighbor money, not all of us can afford a new top end ok neighbor, the other saw, it's already been thru the ENTIRE RIGA MAROR which is why it boiled down to brake fluid to find an undetected air leak, again it is between the carb and intake boot, they have NOTHING to do with this 029 which had blowback bc the break in after transfer removal proved the cylinder was too far gone to save. There's a difference between doing it right the first time and some of us ain't got $249.99 plus tax and freight for an oem top end. Or even the $165 for meteor. Chineese I will not even install.

 

[cookies]

Again respectfully keep up dernit, the saw is done and HAS BEEN DONE I vac pressure test EVERY SAW I WORK ON I measure bore and ring gap if it is a rebuild, I just didn't measure bore on this one only ring gap but it was low enough. When you are trying to save a neighbor money, not all of us can afford a new top end ok neighbor, the other saw, it's already been thru the ENTIRE RIGA MAROR which is why it boiled down to brake fluid to find an undetected air leak, again it is between the carb and intake boot, they have NOTHING to do with this 029 which had blowback bc the break in after transfer removal proved the cylinder was too far gone to save. There's a difference between doing it right the first time and some of us ain't got $249.99 plus tax and freight for an oem top end. Or even the $165 for meteor. Chineese I will not even install.

I separated the two different diagnostic necessities for the two different saws, Keep up. You knew the high probability that saw #1 would need a cylinder kit before it was torn down yet you continued to do it knowing they never intended to fund the rebuild and after all that you failed to perform your extensive check list of measurements no oem repair manuals list after finding plating damage and just went ahead and bought the odd ball 029 super piston and stuffed into it anyways instead of stepping back and looking for a used oem 029/ms290 (yes it will fit and work) cylinder that costs 45 bucks on fleabay and a meteor piston for a total under 100 bucks.
Then you come here and say you have carb spit back and a 1mm ring gap and I explain you have low compression then tell me you refuse to use cheap parts and explain they have no money. They have no money, you did this to yourself so either give it back like it is or put a pos 35 dollar 039 cylinder kit on it and cry a little inside because you did the work twice and wasted a new piston and had to use crap parts.

Tear the other saw all the way apart and look at the lip seals on the crank seals, put a new boot and carb on it to be done toying around and call it a day.

 

[smallengineredemption]

I separated the two different diagnostic necessities for the two different saws, Keep up. You knew the high probability that saw #1 would need a cylinder kit before it was torn down yet you continued to do it knowing they never intended to fund the rebuild and after all that you failed to perform your extensive check list of measurements no oem repair manuals list after finding plating damage and just went ahead and bought the odd ball 029 super piston and stuffed into it anyways instead of stepping back and looking for a used oem 029/ms290 (yes it will fit and work) cylinder that costs 45 bucks on fleabay and a meteor piston for a total under 100 bucks.
Then you come here and say you have carb spit back and a 1mm ring gap and I explain you have low compression then tell me you refuse to use cheap parts and explain they have no money. They have no money, you did this to yourself so either give it back like it is or put a pos 35 dollar 039 cylinder kit on it and cry a little inside because you did the work twice and wasted a new piston and had to use crap parts.

Tear the other saw all the way apart and look at the lip seals on the crank seals, put a new boot and carb on it to be done toying around and call it a day.

How about you go find Jesus you filthy vile person. You clearly missed EVERYTHING I said and missed the point I don't PAY 40 for meteor I supply it. I AM CALLED TO LOVE MY NEIGHBOR I DON'T GIVE A **** IF I HAVE TO WORK 40 HOURS SANDING TRANSFER. MY RING GAP AT INSTALL WAS WELLLLLLLL WITHIN THE OEM STIHL GOLD LEVEL MECHANIX GUIDE OF 2021 AND I DON'T DO SORRY ASS 40 BUCK CHINESE TOP ENDS BECAUSE 1 OUT OF EVERY 2 HAS BAD TIMING. Sorry neighbor but I'm so ****ing tired of ass holes like you ******** in the **** soup of life just because you don't love yourself. Keep up ass hole both these saws are cutting wood to keep those families warm. It's not always about making a buck or not spending my time cold hearted selfish dirty vile hateful human being. Lemme guess you probably say you know Jesus being that ****** when you come in on a thread WEEKS later and don't even understand what's going on. It's ok neighbor I still love you ass hole even though you're not being a good neighbor. Let me know if I can do anything to make your life better.

 

[smallengineredemption]

Oh and hey

Again respectfully keep up dernit, the saw is done and HAS BEEN DONE I vac pressure test EVERY SAW I WORK ON I measure bore and ring gap if it is a rebuild, I just didn't measure bore on this one only ring gap but it was low enough. When you are trying to save a neighbor money, not all of us can afford a new top end ok neighbor, the other saw, it's already been thru the ENTIRE RIGA MAROR which is why it boiled down to brake fluid to find an undetected air leak, again it is between the carb and intake boot, they have NOTHING to do with this 029 which had blowback bc the break in after transfer removal proved the cylinder was too far gone to save. There's a difference between doing it right the first time and some of us ain't got $249.99 plus tax and freight for an oem top end. Or even the $165 for meteor. Chineese I will not even inst

Oh

I separated the two different diagnostic necessities for the two different saws, Keep up. You knew the high probability that saw #1 would need a cylinder kit before it was torn down yet you continued to do it knowing they never intended to fund the rebuild and after all that you failed to perform your extensive check list of measurements no oem repair manuals list after finding plating damage and just went ahead and bought the odd ball 029 super piston and stuffed into it anyways instead of stepping back and looking for a used oem 029/ms290 (yes it will fit and work) cylinder that costs 45 bucks on fleabay and a meteor piston for a total under 100 bucks.
Then you come here and say you have carb spit back and a 1mm ring gap and I explain you have low compression then tell me you refuse to use cheap parts and explain they have no money. They have no money, you did this to yourself so either give it back like it is or put a pos 35 dollar 039 cylinder kit on it and cry a little inside because you did the work twice and wasted a new piston and had to use crap parts.

Tear the other saw all the way apart and look at the lip seals on the crank seals, put a new boot and carb on it to be done toying around and call it a day.

And hey neighbor this saw the 029 super had 144lbs the other had 165 if i remember correctly

 

[Maintenance supervisor]

I've rebuilt a few of these, I like the cheap 039 conversion kits.
One thing I noticed is that the flywheel key likes to shear on these. A timing issue can cause spitback also.
If you ever need a decent used cylinder post it in the wanted ads here , guys probably have some sitting around for free ! Hell I probably have one you could have.

 

[Vintage Engine Repairs]

How about you go find Jesus you filthy vile person. You clearly missed EVERYTHING I said and missed the point I don't PAY 40 for meteor I supply it. I AM CALLED TO LOVE MY NEIGHBOR I DON'T GIVE A **** IF I HAVE TO WORK 40 HOURS SANDING TRANSFER. MY RING GAP AT INSTALL WAS WELLLLLLLL WITHIN THE OEM STIHL GOLD LEVEL MECHANIX GUIDE OF 2021 AND I DON'T DO SORRY ASS 40 BUCK CHINESE TOP ENDS BECAUSE 1 OUT OF EVERY 2 HAS BAD TIMING. Sorry neighbor but I'm so ****ing tired of ass holes like you ******** in the **** soup of life just because you don't love yourself. Keep up ass hole both these saws are cutting wood to keep those families warm. It's not always about making a buck or not spending my time cold hearted selfish dirty vile hateful human being. Lemme guess you probably say you know Jesus being that ****** when you come in on a thread WEEKS later and don't even understand what's going on. It's ok neighbor I still love you ass hole even though you're not being a good neighbor. Let me know if I can do anything to make your life better.

Stihl don’t offer ring end gap clearance specs

 

[smallengineredemption]

I've rebuilt a few of these, I like the cheap 039 conversion kits.
One thing I noticed is that the flywheel key likes to shear on these. A timing issue can cause spitback also.
If you ever need a decent used cylinder post it in the wanted ads here , guys probably have some sitting around for free ! Hell I probably have one you could have.

I always need good cylinders lol

 

[smallengineredemption]

Stihl don’t offer ring end gap clearance specs

Read back neighbor. Yes I gave ring gap. Too busy to argue with you neighbor