Jeep Strokers

The easiest way without even bothering to look for a number is count the counter weights. The 4.0L crank has 8. 4 in the middle, two at each end. Rod journal #2 and #5 don't have any. The 258 crank has 4 or 12 weights. Either two in the middle and one at each end, or 2 for every crank throw.

Mine dropped out on my at 98,000 miles. Always had a oil leak between 3 and 4 also. The oil leaked on the drain side.

215,000 on mine out of a 2000 WJ and she is still strong. I will start looking for a TUPY as soon as I get her running.

i have 2 heads both off WJ. 1 has 179k and the other is 129k still are fine yet can't say much for the blocks nor the pistons..hehe

20,000 miles on my ported 0331 head. And i only ported it after the 220,000 miles it did before stroking it. Since stroking its been running aprox 9.5/1 compression as well. It even over headed once real bad at about 190,000. Is this the best flowing head jeep ever made? This guy thinks so. Id love to flow it and see some numbers.

akadeutsch wrote:20,000 miles on my ported 0331 head. And i only ported it after the 220,000 miles it did before stroking it. Since stroking its been running aprox 9.5/1 compression as well. It even over headed once real bad at about 190,000. Is this the best flowing head jeep ever made? This guy thinks so. Id love to flow it and see some numbers.

I've found that the exhaust port on the 0331 fully ported with a 1.550 valve will outflow a similarly ported 7120 or a 0630 head up to .175 to .200 lift, but will fall off after that because the port is just too small.

So I'm buying a buddies 02 WJ Special Edition, went to check it out today and of course its the 0331 but it's a TUPY, yet date of manufacture is 04/02.

I've been scouring the forums for the past couple days in regards to the dreaded 0331 but this is the earliest TUPY revision I've seen/read of. Has anyone else seen or heard of a TUPY from this early in 2002?

EDIT: For clarification, I found the TUPY when I removed the oil cap

If you have a 0331 head with TUPY cast into it and passes Mag you should be good to go.

The TUPY Head was manufactured in Brazil as a remedy to the earlier crack proned 0331 castings.
My understanding they came out in late 2001 and were in production until at least 2005.

My first stock 0331 head cracked same place about 240,000 Miles due to overheating. This my 2nd cracked at 193,000 no overheating.

I don't know I wouldn't trust any 0331 stock head unless it's Tupy stamped. My first head cracked around 240,000 Miles simply because I overheated. But I had another head at 193,000 crack also. I had just replaced the manifold gasket because of a loud ass whistle. I drove it 10-15 miles went down a trail a straight trail and came back out . Turned the engine off waited for a friend turned it back on and it didn't start up clear bogged carried on . I gassed the pedal a coupe times then it ran fine. Well we went on a trail anyway . I couldn't make it up a slippery dug up hill and I really didn't gas the shit out of it I was watching what I was doing because I don't have enough tire clearance yet and didn't want to rip off my fender flares. So I backed up and went a different way. Met up with friend turned jeep off , talked turned it back on with same idleing bogging problem. So I revved it again a coupe times now it's running. Needless to say I run a two row aluminim radiator it's been a great radiator I run a 80 thermostat I believe and only run the engine fan. I have no overheating issues yet. After the engine idled correctly we went up two decent hills . Turned jeep off and then talked and started again. It started just fine. Then we went on a 2 hour trail ride . Afterwards got out turned it off and talked got back in and it started fine then drove 10-15 miles home. Next morning I'm on my way to work to realize I have 10 -0 oil pressure. It's a 15 , 20 min ride. On way home I had 10-20 oil pressure. Question does the oil regulator stop or only allow a certain amount ofoil from going into the engine or does it just tell my tac what to read. Again no overheating I thought I was lucky cuz this head had so many miles with no crack. I get home I open oil cap and there's a huge crack. Now if the regulator which to regulate means to me is it monitors or controls oil flow into the engine. So if that's true which I don't know. Please correct me. I'm here thinking a lousy regulator cracked my head . Or should I be thinking the head cracked for no apparent reason maybe to much throttle stuck on the hill maybe? If that's the case the head doesn't deserve to be in the jeep. Now I then put on my spare tupy head that i used out of my last jeep when that head cracked at about 240,000 because I didn't know my jeep. Tupy heads run strong. I didn't go with the 0633 head or I think 7120 head I think that's the # . Because I don't have a distributor. I thought long and hard about this conversion to do it or not and I chose not to. So I then went to junkyard and got another tupy head. It's currently at Simpson Machine Shop in Muncey Pa being reseated and ported. They are waiting and we are both looking for a 12 counterweight crankshaft. But I'm gonna build this stroker with a tupy 0331 head. Any comments? Info? Ideas? . Thanks for listening guys.

I got lost a little with all the info going back and forth. I have a after market 331 head that was ported and polished my Russ. from what I have read and seat of the pants feel, is the 331 with its longer runners will add quite a bit of torque. more so then with the earlier head. has anyone gotten a 331 after market head that has cracked on them ? what do you think about the 331 will produce more torque down low where we need it?

The 0331 head doesn't have longer runners. It merely has smaller exhaust ports to help light up the cats quicker.
The heads to avoid are the '00-'01. Later TUPY heads are fine, and I believe the aftermarket only uses those.

Posting a picture of my 2000 XJ head casting 0331. It was rebuilt back in 2018 when I purchased the jeep with a blown head gasket. No cracks to date with 240,000 KM.

Picture shows all the markings... hope this helps.