Topic: 85 2.5 head question

[AZDoug]

My first post here! New to the 4 banger world. Son bought a 85 XJ with the 2.5 that had been sitting 10 years. Got it fired up and sounded good. Rear main leaked like there wasn't a seal in it so replaced it.  Fired it up again and ran it a while, getting lots of positive pressure out the oil fill hole. puffs pressure like it's on a piston stroke. Cracked head?? No smoke out the tail pipe, no oil in water or water in oil. Going to pull head. If it's bad what is the year range head we can use? Is there a stock one that will gain us anything more than the others?

[sharpxmen]

won't be a cracked head imo, piston related probably - more like a broken piston ring or seized piston ring (top one or both i'm thinking).

[AZDoug]

Hadn't thought about rings, sounds good. That would account for oil and water not being in the wrong places

[sharpxmen]

Hadn't thought about rings, sounds good. That would account for oil and water not being in the wrong places

that's correct, cracked head would have most likely have oil in water or the other way around or both, and probably build pressure in the cooling system.

I would take a compression first before doing any work, just so you know what you're looking at.

If it's just the rings you can probably get them replaced with about $200 or less (for rings and top/bottom gasket sets + misc) as it sounds like you're doing the work yourself - that is if the cylinders are not scratched and pistons are in good shape (reusable).

[AZDoug]

My weekend is here, so tomorrow a compression check and off with the head.
Been something like 20 years sense I've built a motor. But try to do all my own work.