Sleeve vs rebore

[Greg W]

I have a Lehman 120 which is in good condition other than a marring in cylinder 6 which needs repair. Question for the forum is would it be better to put sleeves in or rebore the cylinders? It is cast now (no sleeves).

 

[O C Diver]

Pretty sure you have to rebore the cylinder to press a sleeve in. If you have torn it down to that point, no reason to go half way, sleeve it.

Ted

 

[jleonard]

No need to bore or sleeve all cylinders if they are not broken.

 

[rslifkin]

It depends on how deep the damage is. Many cast iron block engines that don't have factory sleeves are designed to be over-bored up to a certain limit and have a couple sizes of oversize pistons available to accommodate. For engines that have factory sleeves with a coating (like most aluminum block engines) you would have to replace the sleeve, but I don't think the FL120 has any limitations like that.

If the damage is minor enough that going to the first available over-bore will remove the damage, I'd go for that route as it's likely to be cheaper and will return a perfectly good result. If the damage is too deep to clean up with an over-bore, then you have no choice but to bore it and sleeve it.

 

[Greg W]

Great feedback everyone (although no consensus). I believe the FL 120’s have plenty of iron to be over bored (.020) a couple times. I don’t think the damage is too severe but it has slightly changed the cylinder to something less than perfectly circular.

 

[rslifkin]

although no consensus

Beyond whatever opinions you get here, it would be a good idea to talk to the machine shop that will be doing the work and see what they think. They'll have a good idea of what's involved with each route and what they recommend based on the damage, maximum allowable overbore, and what sizes of oversize pistons are available for the FL120.

 

[Comodave]

I would call Brian at American Diesel ask his opinion.