Satoh Beaver, worn engine

[Baggis]

Hi tractor lovers!

I recently bought a Satoh Beaver. It is in need of an engine overhaul as it has worn cylinders at the upper turning points, which might explain why it was hard to start and when it started it smoked blue/gray and ran rather bad. I have found a couple of dealers which supply parts for the engine, a Mitsubishi KE70, but havenｴt seen someone mentioning oversize pistons for that engine. (Havenｴt asked the dealers yet)

So my question is if someone knows if such pistons are available, meaning it is possible to enlarge the cylinders by "drilling"(right word?) them?

Changing just the piston rings would be an cheaper alternative, but guess they will break in no time?

 

[wrenchturner]

I have owned a Beaver for about 15 years which was bought used from the orignial owner. It has proven to be a workhorse for it's size. These tractors are made just like the big boys; I know having disassembled the trans and now the engine. As far as your engine goes, I am sure someone will steer you to the right place for pistons. I definately would not put the orignial pistons back in if the bores are worn more than .003 inch at the top. If your pistons are not worn excessively, then worst case scenario would be sleeving the block and using the orignial pistons if you cannot find oversize pistons.

My engine is now disassembled due to loaning out and having it overheated. The pistons bores were scored slightly and the rings on one piston got galled into the grooves. The grooves cleaned up nicely and the bores had .001 wear. I have not checked the head for cracks but if it is then I will have to part it out.

 

[stripercity]

I have a head that will need cleaned and maybe resurfaced from a beaver. if you need one let me know and make me an offer.

jim
stripercity@live.com

 

[Baggis]

I have owned a Beaver for about 15 years which was bought used from the orignial owner. It has proven to be a workhorse for it's size. These tractors are made just like the big boys; I know having disassembled the trans and now the engine. As far as your engine goes, I am sure someone will steer you to the right place for pistons. I definately would not put the orignial pistons back in if the bores are worn more than .003 inch at the top. If your pistons are not worn excessively, then worst case scenario would be sleeving the block and using the orignial pistons if you cannot find oversize pistons.

My engine is now disassembled due to loaning out and having it overheated. The pistons bores were scored slightly and the rings on one piston got galled into the grooves. The grooves cleaned up nicely and the bores had .001 wear. I have not checked the head for cracks but if it is then I will have to part it out.

After measuring the bores and pistons it seems the engine is heavily worn. The bore is +0.28 mm(0.0110236 inch)! And the piston is -0.20mm(0.007874 inch)! What do you think of that? Is it beyond repair? How much is it possible to enlarge the bore?

 

[Baggis]

I have a head that will need cleaned and maybe resurfaced from a beaver. if you need one let me know and make me an offer.

jim
stripercity@live.com

You don't happen to have an engine block in good shape too? ;-)

 

[wrenchturner]

I would never consider putting and engine back together with that .011 inch cylinder wear. Piston will rock in bore causing blowby and flexing of the rings will eventually cause breakage. You need to find a local engine machine shop that will take an interest in helping you with this project. The block can be bored to whatever oversize pistons are available.

 

[Baggis]

I would never consider putting and engine back together with that .011 inch cylinder wear. Piston will rock in bore causing blowby and flexing of the rings will eventually cause breakage. You need to find a local engine machine shop that will take an interest in helping you with this project. The block can be bored to whatever oversize pistons are available.

That is exactly what I am doing now. And no, it was never an option to put it together with such wear. I have found a dealer who can supply pistons etc, and also a machine shop which will bore the block.

Not sure though if 0.0197 oversize pistons is enough, or if I should go for next over size, 0.0295 to be sure?

 

[wrenchturner]

I would ask my machinist but I believe the bores will clean up. However, you do not want to get stuck with pistons and rings you cannot use. Maybe get the block bored but not honed to make sure it will clean up then buy pistons.

By the way, where did you find your pistons?

 

[Baggis]

I would ask my machinist but I believe the bores will clean up. However, you do not want to get stuck with pistons and rings you cannot use. Maybe get the block bored but not honed to make sure it will clean up then buy pistons.

Hmmm.. The spare parts dealer recommended buying pistons before fixing the bores so that the machinist can measure the pistons in order to make sure what size to use. But I think that sounds a little strange as a piston's dimensions tolerances should be very very small. He also offered me the option to change the pistons and rings to another oversize dimension if needed.

By the way, where did you find your pistons?

I actually found two suppliers in the US and one here in Sweden where I live. Surprisingly enough the local Swedish dealer's prices were lower than the US prices.

 

[wrenchturner]

Yes the machinist will want the pistons so he can bore and hone to fit the piston to bore clearance. This is standard practice since piston size can vary slightly ( + or - .001) I am sure your machinist has bored enough blocks to determine before hand if the surface will clean up but if there is any doubt, he could bore the cylinder and leave a little more for honing than normal then order your pistons. Let me know how your project goes.