Jeep Strokers

I purchased a 2000 XJ not quite two years ago and the previous owner claimed to have stroked it 60 over with a new crank. By the numbers I calculate it at 4.7 after his mods. Although after owning the vehicle for a few months I began to question his mechanical prowess and am now doubting whether it was truly stroked at all. He claimed that he had repalced the heads and for the more reliable "less prone to warping" heads when they did the motor work, but of course I am questioning that now too. Engine also seems to be suffering from extremely low oil pressure at hot idle, off the bottom end of the factory gages and between 4-10 psi on a mechanical gauge. But the motor runs quiet, no clanky, grinding noises yet and I hope to keep it that way.

Question 1 - Is there an easy way to tell the good head from the bad head without tearing everything off the engine?
Question 2 - She seems to have an appetite for coolant. I never hear or see it steaming out the coolant bottle so I don't think its blowing combustion gases into the water jacket. It also has good clean oil, no foam or brown nasty stuff, like I would have thought. So I suspect coolant is burning up and steaming out the exhaust. Will a simple head gasket fix the issue or am I getting into a much bigger project?
Question 3 - Once I pull the head, confirming the stroker should be easy? Measuring between BDC-TDC will should confirm the stroke and measuring the diameter and a little bit of math should tell me what I bought.
Question 4 - If I pull the head, and it's warped, or the bad head, where can I get a new one that won't break, crack or leak in the future.
Question 5 - I live north of detroit so If I need to have machining rebuiling or fixing the motor, are there any fellow michiganders that can recommend a good machine and Dyno shop in the area.

Cerveja wrote:Question 1 - Is there an easy way to tell the good head from the bad head without tearing everything off the engine?

Pull the oil fill cap and look down to the head. Teh better heads have TUPY on them. Earlier heads weren't prone to warping, but to cracking in that area.

Question 2 - She seems to have an appetite for coolant. I never hear or see it steaming out the coolant bottle so I don't think its blowing combustion gases into the water jacket. It also has good clean oil, no foam or brown nasty stuff, like I would have thought. So I suspect coolant is burning up and steaming out the exhaust. Will a simple head gasket fix the issue or am I getting into a much bigger project?

Check all your hose clamps even those constant tension factor ones. Rent a coolant pressure tester. Since it has low oil pressure I wouldn't waste money on a head gasket replacement.

Question 3 - Once I pull the head, confirming the stroker should be easy? Measuring between BDC-TDC will should confirm the stroke and measuring the diameter and a little bit of math should tell me what I bought.

The difference in stroke between a stroker and a 4.0l is .482"

Question 4 - If I pull the head, and it's warped, or the bad head, where can I get a new one that won't break, crack or leak in the future.

2003+ head or alabama cylinder head reinforced head.

However, since you have low oil pressure I would pull the whole engine and fix it correctly. Most likely the PO had a head crack and leak coolant into the oil. Which damaged the bearings, which is giving you the low oil pressure. Replacing the head will not fix your low oil pressure.

I fear that the head has probably cracked and because coolant has been leaking into the crankcase for some time, it's contaminated the oil and wiped out the bearings.
If the engine wasn't already built into a stroker, now's your chance. A good used OEM head from '03+ with TUPY stamped on the top should prevent that from ever happening again. Alabama Cylinder Heads and Clearwater Cylinder Heads also have new reinforced castings.

Okay, so I guess I forgot to mention that, it is due for an oil change, but I checked it and there is no milky brown gunk like I would have expected on the dipstick or under the fill cap. It's not a daily driver so it spends most of its days sitting in the garage and I have never seen puddles or anything under the vehicle.

Its still possible that it is leaking coolant externally.. just evaporating or burning off before it hits the ground.

I like the way you think. That sounds like a nice cheap solution, I will keep an eye open for drippage before diving into the motor.

To locate an external leak, you can add a dye to the coolant....then inspect the engine and cooling system with a black light. It'll make leaks much easier to find.

I'd be concerned about that low oil pressure. 10-15 psi should be enough to keep it alive at idle, but no lower.
I'd be tempted to throw a high-volume pump on there to see if it helps. And take a look at the bearings while you're down there.

Oh I am very concerned about the low oil pressure. I hate leaving it idle ever, it's a PITA. That was the first thing got me wondering if he had ever built/stroked it. In the time frame he claimed to have rebuilt it and the amount of miles he claimed it had on since the build, there is no way the engine should have loosened up that much that quickly.... I have nearly 200,000 on a GMC inline with zero motor work and the oil pressure is rock solid since day one.