My first stroker build for my 2001 XJ is well underway at this point (after breaking a piston skirt at 240,000 miles)... Below is the recipe I've used thus far:
- Stock/original 4.0 block, bored .040 over.
- Stock/original non-TUPY 0331 head (hey, it made it 240k, and I'm a masochist - let's just call it an experiment).
- Silv-O-Lite UEM 2229 pistons (+.040) (11cc dish is what Silv-O-Lite told me).
- Comp Cams 68-115-4 camshaft and lifters.
- AMC 232 crank (apparently the one I received is .020" undersized, with matching bearings).
- Stock valvetrain and valve springs (fresh valve job though - new seats and seals, ground, etc).
I took the block and head back to the machine shop for a test assembly to determine how much the block needed to be decked to hit a .030-.045 quench height with a Mopar Performance gasket (.043 compressed). Based on the mini-stroker recipe thread here, I anticipated up to .020 needing to be removed...
Turns out that with NO changes to the deck height, I'm already sitting .004-.005 out of the hole?! Between this and the fact that they needed to take .010 off the head while working it over, I'm starting to worry about my resulting static compression ratio.
This leaves me with a few questions:
- How much did that .010 affect my combustion chamber volume? I know stock is ~58cc.
- Given that the 68-115-4 cam only adds .002 of lift on exhaust (and brings the intake lift up to match), I should be fine sticking with my stock valve springs, right? The shop tested them and verified they're still within factory spec (but I don't have the exact numbers).
- With .010 having come off the head, but the block being at stock/original deck height, I *should* be able to re-use my original pushrods (provided I can find a head gasket in the ~.053 territory), right?
Pic for attention: