BigVaz

I searched Clearwater & Alabama heads, but their websites say they have nothing for a jeep??? Maybe I'll just give a call. Thanks guys!

fishtaconc

You have to look under chrysler on their websites (Alabama)

Boes

I got my head from Alabama Cylinder Heads. They were great to work with and if I remember correctly it wasn't much over $300 w/ the core. I would definitely recommend them.

DFlintstone

I have zero experience with the coil pack bracket adaptation, but I guess it's pretty common. I HAVE had great luck buying used parts though. Finding that "tupy" mark on something smashed would be sweet.

1991Jeep_Man

I didn't see if posted, but I may have overlooked it. I am by no means an expert with the ominous 0331 head, but if it is cracked, make sure it didn't leak too much coolant for too long a period of time into the crankcase. If allowed to do so, coolant eats bearings. How is your oil pressure?

BigVaz

Oil pressure gauge will drop to nothing when the engine is warmed up & at a stop. When I give it some gas from a stop it goes back up. It's been like this for a long time. But now I have the cash to fix it....

1991Jeep_Man

So wait, when it 'goes back up', how high does it go? If at about 2000 rpms it hits 37+ psi, then I would consider the sending unit (notorious for causing whacky oil pressure readings, and cost like $30). Confirm the pressure with a mechanical gauge. When at operating temp, oil psi should be no lower than 13 at idle, and above 35 (or 37, cant remember) at about 2k rpm.

If the mechanical gauge still reads low pressure, it's one of two things. The optmisitic hopeful thing is there is gunk in the passage that goes to the sending unit, which has been known to cause low readings. Just clean/blow it out. Cheap. The worst case scenario is the low oil pressure is due to wearing out of the bearings due to coolant contamination. This requires bearing replacement, which most people just either go with a rebuild or a junk yard engine.

BigVaz

I have the phantom coolant loss to nowhere & I put on a new sending unit last year. Put a mechanical tester in it & it idled around 15lbs. My check engine light is on & my check gauges light comes on when pressure drops at idle.

The coolant loss is what has me thinking new head...

1991Jeep_Man

With what you just told me, and if it's been losing coolant for a while, you might wanna add 'new bottom end' to that list. I bet the low pressure is because of coolant conatmination. Sorry man. Hopefully I am wrong.

BigVaz

I wish there was a way to definitively know. I'd hate to put on a new head & that not fix the problem....

Can you compression test the motor to know if you've got a cracked head?

BigVaz

I should also note that it did overheat once.

Moncheche

BigVaz, reading your last few posts was like reliving 2011. Saying that we had the EXACT experience would be an understatement . I had 'pressure' but at operating temp, idle pressures would tickle zero. Light would come on.

I had a cracked 0331 head . I opted to change my rod bearings (much of your oil pressure is generated there). I did it with the engine still in, but it was a pain. My races looked good and I took an $80 gamble to get another 100,000 out of her. 15,000 later and the gamble has paid so far. 13 psi at hot idle. 40's at 2000 rpm. New Clearwater heAd $450, she's going strong.

Someday I'll pull and rebuild.

Best of luck ,

Moncheche

DFlintstone

Idk myself if a hairline crack would show up on a compression test. I might go the other way at it and have the cooling system pressure checked. Might get those codes read also. I've seen posted a crack can throw a random miss-fire code. Also I've seen posted guys have seen a little line of green coolant along the head down under the oil cap. The 0331 can crack there, right in the middle. I would look after it's been sitting for a bit, hot.
Then any sign of condensation, on the dipstick or on/under the cap, as well as the front CCV tube to the air cleaner would be a sign.

Moncheche

The crack between 3 & 4 was so small it wasn't 'visible' . With the head off, I went looking around that area rubbing my finger through there. Grease stayed where the hairline crack was. The coolant loss was slow, but enough to take out my bearings.

tjwalker

Yup, the cracks can be BIG or they can be SMALL on the 0331. I've seen both.

I generally perform a comprehensive visual inspection for starters, but know that if you don't see a crack does NOT mean that there is not a crack.

A compression test is not a good test to diagnose a cracked 0331 head. You can have good compression and have a cracked 0331 head.

Cooling system pressure test, leakdown tests are both good. I usually start with a "block test" where you sniff the coolant for the presence of hydrocarbons. Any shop can do it or you can buy a DIY test kit from Napa for around $50.