Sleeve vs rebore
- Thread starter Greg W
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O C Diver
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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
Ted
jleonard
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No need to bore or sleeve all cylinders if they are not broken.
rslifkin
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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.
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.
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
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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
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I would call Brian at American Diesel ask his opinion.
I would bore the cylinders for this project. With an over bore you will only buy new pistons and rings. If you sleeve it, you buy sleeves and pistons. It just doesn't make economic sense. That is if it's not at the max bore now.
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