Resolved 420a cylinder bore question

[jonathanfl]

Does anyone know the maximum bore size a 420a on a 98 eclipse can handle? Got some things organized that had been messed up Friday with my ordering so my pistons will be 88.5 8.5:1 but the company I'm having make me sleeves is unsure they can make the sleeves now. So my question is can the block handle a bore with The walls of the sleeve have to be .80 over / 3.32in I believe my math is correct on that bore size.

I'm asking because I don't have my block out yet to measure and hoped someone here would be able to help.

 

[Terrancep7]

If I'm not mistaken the stock bore is 3.44. I'm almost positive about that and to answer your question no the block can't handle an .080 over bore. The bore you have listed is only a .040 over bore stock is 87.5. You don't need sleeves with a .040 bore the block is safe with this bore size.

To clarify everything bore it .040 over don't worry about sleeves you're safe. Although I would just bore it .020 over and get pistons to fit unless you're stroking the engine. Let me know if you need to know anything else.

 

[jonathanfl]

Thanks, I figured I was hitting the max limit with this piston size, I wanted to have sleeves in case anything happened I could just swap the sleeves as well as strengthening the block. Looks like its block only on this build.

 

[Terrancep7]

If you start off with .020 over then if anything happens which it shouldn't with forged internals you would be able to bore it .040 over

 

[Fotowntalon]

I know I have seen people do .060 over, never seen a .080 over, really is going to come down to your cylinder wall thickness., and application. You could probably get away with a .080 (once again depending on the wall thickness) depending on application, but the thinner the walls, the harder it is to dissipate heat, among other things.