crank to rod bearing - play?

[echobite]

Hello, this is my first post here. I have a stihl 036 pro that has quite a bit of play at the crank to rod bearing. I was wondering if there is supposed to be a little bit of play or not. I don't think there should be any play just snug and smooth. I can move the rod back and fourth maybe .050 or .070 thousandths or so on each movement back and fourth. The piston - rod is quite wobbly too. Interestingly the head is is in pretty dang condition. Piston has moderate scuffing. Saw had 145psi when I got it. I used it hard for 3-hrs of owning it. Starts up great, Idles good, high rpm pretty good. It does feel like it's down on power and once its gets warm to hot it leans out and then hard to keep the tune. I never noticed the crank or rod knock when running the saw, I only heard it after I took the clutch and flywheel off and spun the crank. The head was still attached. The knock was very clear.

I bought this saw not knowing that it had less life than I originally thought. Still runs.

Also, I was wondering if these pictures can identify any crank damage. I only see casting imperfections?

 

[EFSM]

Don't be concerned about side-to-side play. The piston centers the connecting rod, preventing it from contacting the crank lobes. Usually the only play to be concerned about is up-and-down; make sure that there is no slop when turning the flywheel back and forth. The piston should immediately start moving up and down. However, having wobble might indicate that the rollers are worn towards the outside somehow, maybe due to an improperly turned cylinder base?
Welcome to the forum!

 

[cus_deluxe]

side to side is normal, up and down is no good. aside from the debris that fell into crankcase, it looks to me like that bottom end is super dry and your piston is apparently scored a bit on ex side. just out of curiosity what mix oil/ratio do you use?

 

[Duce]

What does intake side of piston look like?

 

[Mad Professor]

Saw need a bath before pulling the jug.

Might be time new piston/seals and cleaning up the cyl plating.How do they look?

 

[echobite]

Thanks for the replies. I have more information and pictures on following up. I have found that there is slight up - down movement on the piston. I can hear it too. The exhaust side of the piston and cylinder have the most wear. I got bored one night and took a dremel and removed some carbon deposits on the exhaust port. I accidently hit the piston with my dremel. I knew better and cursed mysef but knew that I was going to take the saw apart and rebuild it anyways. The picture with my fingernail points to my mishap. I ran the saw like that for a few cuts and never ran it again.

I bought this saw from someone that tuned it for 40:1 so I kept using that ratio. Also, I had a really tough time trying to clean this saw. I don't have an air compressor or parts washer. I can take it to a local repair shop and have them clean up the saw before I put it back together.

Can I get away with buying a new meteor cylinder and piston kit and just slap it back together? I just bought a pressure and vac tester as well. Also, the cylinder seems to be in a decent shape. I don't feel anything catching on my finger nail while running my finger along the cylinder walls.

 

[echobite]

cylinder

 

[echobite]

2 more of the cylinder

 

[echobite]

I took the piston off and the needle bearing pins started falling out of the cage. I believe this is the main culprit of the saw failing. The crank bearings seem fine. No play. I tried pressure testing the saw through the impulse line and with the head on but couldn't get any pressure. I think it's because I tried using a bicycle rubber tube to block the intake and exhaust but I think I had a leak. I guess I need thicker rubber. I got impatient and decided I'll redo the pressure/vac test after I put a new cyl and piston on.

 

[Mad Professor]

I'd try to clean that cylinder and see if the plating is OK under the transfer. OEM cylinders are better quality than AM.

For cleaning up saws remove the clutch and flywheel and scrape as much of the thick crud off. Then I use diesel fuel, several parts brushes and toothbrush. I finish up with some detergent to get the diesel off.

This is an 026 that was absolutely caked in filth.

 

[echobite]

^

I'll work on cleaning the saw. I think that oem cylinder is in good shape after cleaning it with some scotchbrite
and possibly running a ball hone if it's not too expensive to purchase.. I'll just take my time with it. I have to be careful on how much I want to spend since Its an old saw.

When you say detergent, do you mean like dawn soap and water or something else?

 

[hacskaroly]

I don't have an air compressor or parts washer

Same here, I just use de-greaser with rags and brushes. At this point, it might be best to take as much of it apart and give it a good clean with what you have.

Its an old saw.

It's not that old and they are good saws, so they ware well worth putting money into them to keep them going. I have an 046 and an 066, though I don't spend the money to get NOS parts, I do use used or aftermarket parts where I can too. I just found a Husky 55 at the dump a few weeks ago and it was a dirty mess. I have taken it all the way down to splitting the case to clean it, put new bearings in and getting it back together. It was missing parts when I found it so I have gotten an aftermarket recoil. I think it will be a good 50cc addition to what I have! Now if you want to talk about an old saw, I have a 1947 Prentice-Reed 1200 Craftsman 1200...that one is old!

 

[Junk Meister]

I would put the cyl back on leave the piston out/off and do a vacuum/pressure test . Warm and not keeping a tune could be a bad crank seal. (flywheel side usually fails first but replace both of them) The 026/260 saws had a habit of failing seals as they aged. Lean mix might have helped the wrist pin brg fail from lack of lube. Some one will hopefully chime in.

 

[Mad Professor]

^

I'll work on cleaning the saw. I think that oem cylinder is in good shape after cleaning it with some scotchbrite
and possibly running a ball hone if it's not too expensive to purchase.. I'll just take my time with it. I have to be careful on how much I want to spend since Its an old saw.

When you say detergent, do you mean like dawn soap and water or something else?

Yes dish detergent in warm water, gets the diesel/smell off. Diesel get the oily crud off first, both are cheaper than degreaser.

No need for ball hone, you can damage port edges if not careful. Some wet/dry paper and/or scotchbrite and your fingers will work. Start out coarse depending on amount of transfer then go to finer paper (100-320), I use soapy water here too.

You want ALL the transfer off. Like this

 

[echobite]

I'll continue to work on this saw. I bought it knowing that it's a well built saw and a hot-rodding saw and wanted to learn about saws. I'm pressured to get the leftover trees cut up in my yard. I live in a neighborhood where it's acceptable to do this type of work but I can't let it sit in the yard for too long. I have certification training all this week at work so I won't be able to work more on the saw until next week.

Yesterday, I put the head back on and used the bicycle tire tube again. I had to double up the tube on the exhaust side. 3mm thick. It's still too thin but was able to get it to not leak. I need 5-6mm thick rubber to do this correctly. I found a leak on the clutch side crank seal and a massive leak at the decompression valve so much that I had to take it out and use my finger to seal the hole while pumping. Interestingly, I found that there wasn't a rubber grommet present. Part number 1122 084 1405 Besides the old decomp valve and washer, is this rubber grommet absolutely necessary?

here is a pic of the rubber grommet that I am missing via ebay:

I wouldn't be surprised if I have a small case leak and understand that I should replace the crank bearings too. I just need to get this 99% leak free so I can get the last 2 remaining logs cut. They are big and worth some money. Then, I can take as much time I want and split the case. I will replace both crank seals. I find it dumb to replace them and then tear down the case later to discard the seals and have to buy new ones again but that's the price I'm willing to pay so I can get the tree job done before July. sigh. I can buy aftermarket seals and then wait to find oem seals after I split the case. I want oem seals. That's important to me. I have 2 more trees in my yard that can be cut down in like 2 years. It's not an emergency like the two trees I had cut down. One of them had a severe lean with ants and was going to take half of the house out. This is my father in-laws house and I'm trying to protect a good house so my wife and I can sell it.

 

[Mad Professor]

I'll continue to work on this saw. I bought it knowing that it's a well built saw and a hot-rodding saw and wanted to learn about saws. I'm pressured to get the leftover trees cut up in my yard. I live in a neighborhood where it's acceptable to do this type of work but I can't let it sit in the yard for too long. I have certification training all this week at work so I won't be able to work more on the saw until next week.

Yesterday, I put the head back on and used the bicycle tire tube again. I had to double up the tube on the exhaust side. 3mm thick. It's still too thin but was able to get it to not leak. I need 5-6mm thick rubber to do this correctly. I found a leak on the clutch side crank seal and a massive leak at the decompression valve so much that I had to take it out and use my finger to seal the hole while pumping. Interestingly, I found that there wasn't a rubber grommet present. Part number 1122 084 1405 Besides the old decomp valve and washer, is this rubber grommet absolutely necessary?

here is a pic of the rubber grommet that I am missing via ebay:

I wouldn't be surprised if I have a small case leak and understand that I should replace the crank bearings too. I just need to get this 99% leak free so I can get the last 2 remaining logs cut. They are big. Then I can take as much time I want and split the case.

The grommet keeps the cooling air from going out the hole.

 

[hacskaroly]

I find it dumb to replace them and then tear down the case later to discard the seals and have to buy new ones again but that's the price I'm willing to pay so I can get the tree job done before July.

Its not dumb to replace them with AM seals and then later swap out to OEM if you want. AM seals should only cost about $5-$8 (sometimes even cheaper) - I use Duke's seals on my saws, no issues.



While 99% leak free may seem like something to shoot for right now (and do the major overhaul later), as the saw heats up through use, air leaks usually get bigger as the parts heat up and expand and then the saw shuts down in the middle of the project with a scored piston and cylinder. I found this out with my 046, found it at the dump, did a rebuild on it, but didn't touch the oil seals. It ended up having an air leak and during the middle of the work, it shut down with a scored piston, a hard lesson learned. Now all of my project saws get the full case split treatment, replace the bearings and oil seals at the least before my first use with them. As for your decomp, I have heard those be called "factory installed air leaks", I tend to plug mine. I have a 100cc saw that doesn't even have a hole for one.

If your saw won't be as close to 100% as you can get it before you tackle your project, I would recommend trying to borrow or rent a saw if possible so you can take the time you need to get your saw in working order.

 

[Junk Meister]

I'll continue to work on this saw. I bought it knowing that it's a well built saw and a hot-rodding saw and wanted to learn about saws. I'm pressured to get the leftover trees cut up in my yard. I live in a neighborhood where it's acceptable to do this type of work but I can't let it sit in the yard for too long. I have certification training all this week at work so I won't be able to work more on the saw until next week.

Yesterday, I put the head back on and used the bicycle tire tube again. I had to double up the tube on the exhaust side. 3mm thick. It's still too thin but was able to get it to not leak. I need 5-6mm thick rubber to do this correctly. I found a leak on the clutch side crank seal and a massive leak at the decompression valve so much that I had to take it out and use my finger to seal the hole while pumping. Interestingly, I found that there wasn't a rubber grommet present. Part number 1122 084 1405 Besides the old decomp valve and washer, is this rubber grommet absolutely necessary?

here is a pic of the rubber grommet that I am missing via ebay:

I wouldn't be surprised if I have a small case leak and understand that I should replace the crank bearings too. I just need to get this 99% leak free so I can get the last 2 remaining logs cut. They are big and worth some money. Then, I can take as much time I want and split the case. I will replace both crank seals. I find it dumb to replace them and then tear down the case later to discard the seals and have to buy new ones again but that's the price I'm willing to pay so I can get the tree job done before July. sigh. I can buy aftermarket seals and then wait to find oem seals after I split the case. I want oem seals. That's important to me. I have 2 more trees in my yard that can be cut down in like 2 years. It's not an emergency like the two trees I had cut down. One of them had a severe lean with ants and was going to take half of the house out. This is my father in-laws house and I'm trying to protect a good house so my wife and I can sell it.

Gonna PM Ya.

 

[echobite]

Awesome. Thanks guys! This is a huge help!