Jeep Strokers

Hello all, not sure where to put this, but this seems like a good enough place.

I recently built a 4.5 (ish) stroker. Used a 98 block (bored .020 over), 94 head (machined for flatness only), 2000 intake manifold, mild Comp Cam (252 grind?), and a late 80's 4.2L crank (.020 under) and rods (.010 under). The crank and rods may be backwards on cleanup grind. I reused my 92's stock exhaust and I believe the stock oil pump from the 98 block (out of Grand Cherokee).

I finally got everything in and ran it through the 30 minute 2000-2500 RPM break-in in the cam instructions. The pressure stayed somewhere between 60 and 80 PSI on the gauge. I changed the oil and filter and have driven it about 130 miles to this point. I'd like to know what you guys have seen as your oil pressure on a freshly built engine. My gauge is reading above 60 PSI under load and around 40 PSI at idle running conventional 10w30 oil.

I have a rear main leak as well. I'm positive it is the rear main as the oil is coming out between the back plate and transmission bell housing and the back and sides of the engine are bone dry and clean, including the back of the head where it meets the block. It wasn't leaking right away, I checked under the Jeep a few times during the break-in when checking to make sure the new radiator's coolant level was correct and the electric cooling fans were working. I'm guessing it happened after the 20 minute mark. I'm not sure if I rolled the lip on the seal or if high pressure caused it to fail. Either way, I've already lost at least a quart of oil.

Sounds like everything is OK you just need to reseal it.

Pull the rear main cap and make sure the factory brooch marks aren’t too deep. While you’re in there if you think the rear main seal got compromised he could roll a new one in. Break clean everything really good and lay in real thin layer of silicone in between the cap and block. Silicone on both sides of the rear lip oil pan gasket (i’m assuming you’re using the good Fel-Pro one piece silicone gasket OS34308R) and make sure the factory metal strap goes back on.

Good luck

Thanks. I figured as long as it was inside the gauge limits the pressure was probably okay seeing as everything was machined.

What are the factory brooch marks and what would qualify as too deep? I'm not familiar with the term.

The block and cap surfaces typically aren’t a problem but you should at least be aware of a potential surface mating irregularity. That’s why I like to put a little dab of silicone on my finger tip and just give the mating surface a slight coat of the sealer. The excess will just squirt out when you’re torquing the rear cap. I always figured it wouldn’t hurt.
Oil leaks are my pet peeve.