How much can we bore these things without overheating problems?

Frank
CPT

 

IIRC the max is .060 but that might be pushing it. I also think youd need to sonic the block to verify it can go to that limit. I'll let someone else chime in though since Im not an expert.

 

safest is .040" over without hitting the jackets. I have heard of some going .060" over but they had the block filled.

 

The extra cubes are not worth the loss of stability in the cylinder walls and the resultant loss of power.

Overbores on stock blocks should be kept to the minimum required for bore straightening/cleanup.

 

Maybe I should've explained everythuing a little more. This is a "fresh" .030" motor that I screwed something up putting it together. A few of the cylinders are scratched up more than I like. The block already has a "half fill" of Hard Blok.
I have my original block that I can have taken to .030", but the one in question has been line bored, decked, new cam bearings and brass freeze plugs.

Frank

 

How far out are the cyl.?

What piston to wall clearance do you want?

 

I have been pretty scared of these blocks due to their extremely thin walls and even going .030" - I have seen several at .090" @ STD bore, between cylinders which we would consider paper thin.

You need to have the block sonic tested to be safe.

Like mdacton asked - what is the bore clearance at now, what pistons are you using, etc...

 

40 over is probably ok.

Rich