Tecumseh 2.5 hp cylinder honing

[boat21]

I’m working on a Tecumseh AH520-1602 engine, bad compression. I’ve never done this before, my cylinder walls have vertical scoring on the walls but they still feel smooth.

1.When is the scoring too rough to hone out?
2. How much can be honed out?
3. I've read aluminum cylinders are hardened inside
3. Is a honing stone ok to use and what grit what kind of oil to hone with? (I've read 400 grit or do you start out with heavier grit work to 400 grit)
3. What’s the proper lube to use when honing? (I also read go in and out to get cross-hatching. Also read after bar honing/crosshatching to then use the ball type honing which its supposed to knock down edges of the new crosshatching so rings seat better Is both recommended if so what grit on ball honer.
4. Looking into the cylinder you cant pass the honing stone to far past bottom on cylinder wall being the sides of the casting juts inward right below bottom of cylinder. Will this be a problem for honing? I’m worried the stone will bounce and catch while going in and out and screw up the process, any thoughts here?
5 When installing loose needle bearings on piston rod half’s what’s the trick to keep them in place to put bottom-bearing cap. I tried a dry run and they fall off cap.. (very thick oil?)

Need advice weather this is even worth it. I’m already onto a New Coil, Points, and Condenser, Carb rebuild. Then found out compression was too low. Crap did things backwards..

[bobodu]

Use bearing grease on the bearings......you can wash it out afterward if you are concerned about lubrication.

[Deere2me]

It's prolly trashed. If you can snag your fingernail on a groove, its usually not gonna hone out. There are exceptions, but that motor ain't one of em. Are you familiar with the term " pi$$in' in the wind"?

[KE4AVB]

Been there before, just rebuilt a Briggs 171400 series that had a broken rod. It nearly six months of searching just the find the part and then found out I had only 25 PSI compression. It would went .010 over but the only left on the market was .020 over.

Tecumseh has been out of business for some time now. There is a new Tecumseh Power Group but they are not making parts for the older engines.

Kinda bad news here from what I can find. There is no oversized pistons available to rebuild these engines. Even if there was then the cylinders if needed are not available either; unless, you're lucky enough find in NOS (New Old Stock) on Ebay. We would need one the fellows that is experience in Tecumseh to chime in on this as they would be more familiar with these engines and know where these older parts.

As honing aluminum cylinders it depends construction. Plain cylinders that are use in engines like Briggs can hone fairly easily with around 300 grit using a ridge hone setup. Even with Briggs there is a Cool Bore version that requires a different setup. The plated versions are not usually honed as the plating is fairly thin. In larger engines where plating is thick enough then they use things like diamond hones or similar.

[bgsengine]

Dude, its a ported 2-stroke..block is aluminum, with a cylinder liner. you DONT hone cylinders on them - you'd need a machine shop that can do a re-sleeve and by the time they get done, it'll cost you more than replacing the whole machine. Maybe you can find a NOS, or if the scoring is less than a fingernail catcher, you COULD just sandpaper the edges of the scoring smooth and re-ring 'er. Honing stones will catch in the ports and make your problem worse. That's why they don't do oversize piston kits for them - you would have to get a whole jug and piston kit or short block.


Needle bearings - A gob of vaseline or very light white lithium grease on the crank and stick the bearings one by one to it and then install rod and cap, wipe away as much excess as possible. vaseline will melt and wash away and burn off little by little as the mix oil takes over lubrication.

[KE4AVB]

That what I was thinking from my 2C work here but haven't even seen a Tecumseh 2C here so I had no idea on how the cylinder was setup. I have only been at this for 5 years now. I do know that the cylinders are machined or at least that is how the NCC cylinder I just installed on Poulan 4218AVX was done and it looked rough to the eye but I had 165 PSI after the rebuild so I not going argue with the looks.

Here the customers are only willing to rebuild is some of the larger chainsaws. When comes to it most will just buy a new machine with good warranty. The cost to rebuild vs replacement cost is what kills most engines here. The saw I just did for my myself as training exercise cost nearly 90 USD in parts alone plus shc and saw only sold for 119 USD. The customer still had his sales receipt.

[boat21]

Thank for all the quick reply fellas.. Just fir kicks and giggles I will clean up piston and hone out cyl walls.. What’s too loose 11 bucks for rings and s5 bucks for gaskets, call me crazy but it will be instructing

PS: you all did save me from spending MORE money on a piston valve reeds ect