99Justin4.0

Yeah, they have the Mahle rings at Rock Auto, and they'll save me money. I think they're like $40 cheaper actually. I was hoping to get the whole order from Summit because who knows how different the shipping arrival dates will be.

It sucks having nothing to do but wait for the parts. I guess I'll just have to detail everything.

dave1123

99Justin4.0

My dad had a really bad experience with Moly rings on a freshly bored 302 for is 68 Cougar XR7 back in the mid 80's. He said they never seated. I'm noticing most of the ring sets have a moly top ring. Should I be concerned about this?

99Justin4.0

Well, everything is OFFICIALLY ready and waiting for the parts now. Now I know, everyone hates the 0331. Everyone knows it's gonna crack someday. Maybe. But mine is as clean as I've ever seen. There isn't the slightest bit of gunk anywhere whatsoever.

It says 0331 on the outside of the valve cover right over the 4th cylinder. It says NHI in between 1 and 2, 1999 between 2 and 3, and WJ between 3 and 4.

I just ended up putting a jack under the exhaust and it just moved right over to the side.

I don't know how on Earth I'm gonna get that head back on... I'll figure it out though.

dave1123

My friend the mechanic used an engine crane! That Clearwater head weighed 85 lbs! He's an old guy like me. You may need to insert the 2 rear bolts into the head first because of cowl clearance. It made the job a lot easier.

99Justin4.0

I watched a vid of a guy taking the head out of his XJ, his rear driver side bolt couldn't come out or go in with it in place. But I had plenty of room. I realized after the pistons are installed I can put it back on the ground for a bit to install the head. That should make it about 7 or 8 inches easier.

I really didn't run into anything too difficult tearing it down that I had heard about or seen in vids. Like I mentioned before, the plastic clips and hose holders where the only things that gave me a lot difficulty. It's like they never planned on people needing them off. There must be a specialty tool or something...

Fred/N0AZZ

My young friend I have read the whole thread and have one small piece of advice if the WJ is as nice as you say it is, I have an 04 WJ that is spotless also.


At this point you should stop and save more money then remove the engine and take it to a machine shop and have it prepped. Then have a builder build it and balance the new rotating assy then install the new head on the completed short block.


With that done you will get many trouble free yrs form it knowing you did it all right the first time, with the knowledge by doing it that way you saved yourself a lot of money in the long run.

99Justin4.0

Well guys, as always I went back and forth in my head waaayy too long in the parts ordering process. But I did it! It's final! And all I can tell you is I used my absolute best educated judgement in my final decisions.

I really appreciate your tips. I'm feeling a warm welcome from the Jeep community. And I'm happy to be a "Jeep Guy" now.

Estimated ship date is Tuesday.

So I guess all that really matters now is how she runs and how she sounds when it's all said and done.

I'll probably ask for some more specific advise during installation and break in. But for now, I guess I'll wait for Tuesday.

dave1123

Have you got the ridges cut and the bores honed to break the glaze? If not, there's something to do while you're waiting! Don't forget the new pistons need to be fitted to the rods. Make sure you don't mix them up so they go back in the cylinder they were already in.

Does anybody know if the pins are a press fit or are they full-floating?

CobraMarty

Press fit.

99Justin4.0

I've never used a Ridge Reamer before. Are they a pretty safe tool? I watched a vid on it where the guy used the one they rent out at O'reilly's. Doesn't look too hard, but I'd hate to do more damage than good...

My head guy is going through the 0331 tomorrow. The guy's done all mine and my dad's heads since the 80's. He did my 944S 16V head after the timing belt broke and bent all 8 exhaust valves.

Here's a good one for you guys: My old Volvo 240 Turbo just stopped running right out of no where. I pulled the head to find an old bolt wedged in a valve. It had been in there so long that it had to wear the threads off the bolt before it finally slipped through. Surprisingly enough there was no damage. He just pulled it out, re surfaced it, and back on it went... He said he'd only seen that one other time in his entire lifetime of doing nothing but heads (and he's like 70).

So long story short, despite it still being the 0331, it will be as good as it can be when it goes back on. Oh yeah, turns out he's a 4.0L guy too! So he knows these particularly well.

dave1123

Ridge reamer are made with a shoe on the bottom below the cutting blade so you don't cut too deep. As long as you keep it square to the bore, you'll be fine. Most I've seen have an overhang on top that rides on the block deck surface anyway. Don't turn it backwards because you can break the cutting blade that way. It's going to take several turns to complete the cut unless it's not that deep. 6s are pretty easy, V8s tend to have more of a ridge on the lower side. Well, any V engine that is.

Be sure to wash all the crap out of the bottom after the hone job as well. Abrasive sand can ruin bearings!

99Justin4.0

Well I took my head in to the head guy. He told me within 30 seconds it had been over heated and the gasket had blown between cylinders 3 and 4. It has one leaky valve that needs a grind. Other than that it's perfect.

Some of you are going to **** frisbees (and it will probably start a war when you read this), but when I asked him about his knowledge of the 0331 he had a lot to say about it.

He said sure some have cracked but it's probably 1 in every 100,000 (I'm sure that was an exaggeration). He says the internet has hyped it up way out of proportion. He said he's seen them cracked, but it's never in the typical spot you see in all the pics and videos, it's actually in the valve ports. The subject kinda erked him from what I gathered. He's got the one of biggest machine shops in Tacoma, WA backing this stuff too.

He also told me the only real problem with the high mileage Jeeps is no one ever has the automatic transmission serviced. So he recommended a guy who will go through it for $100.

The first thing he did was pulled the middle two valves, dusted them, and told me I'm A okay. Then he pressure checked every port and found the leaky valve. Well he found two, but the second he said there might just be something stuck in it, so he tapped it with the hammer and found that to be true.

Anyway, It's getting a grind, resurfaced, tanked, and (when my gasket set gets here) new valve seals.

$60

And I got a good reference to a guy that'll get my wrist pins in within a day. I guess I get to cut the line...

Sorry if this snowballs, but I just had to spread the word of a guy that's done Nothing But Heads since 1974.

PS: He said Mercedes ruined Jeep.

dave1123

Yes, Mercedes and Fiat both had their hands in that!

What he said about the 0331 MAY be true because mine waited until 155K miles, then cracked in the valve ports. I think a lot has to do with the stresses we off-roaders put on them, more so than street driven jeeps. High temperature situations may have a lot to do with it as well. Sitting in stalled traffic at 90+* temps are hard on any engine. The thing is, this engine has been bullet-proof until the 0331 head made it's appearance. It was an attempt to get more power out of an engine that was already topped out for performance. The head porting, new designed intake, cam profile change, and the low restriction water pump added only 10 hp! Hardly worth the effort!

The REAL reasons for the demise of the 4.0 was it's physical size and weight. It was too long and tall to fit the new body designs, besides having problems with emission compliance.

Rant over. Have a nice day.

andrewmp6

100k-150k is the range most of the heads cracked.Some followed the maintenance to the T and the head still cracked.And jeep used that head on the 99-02 wj the 00-01 xj and tj had it 99-02 and for the tj and wj it was mid 02 when they changed to the upgraded head.Some get lucky like you and blow the head gasket and not crack the head.But the head still can crack its a design problem same reason jeep replaced it in mid 02.As far as his numbers it might be just what hes seen but hes just from one part of the country.And some people rather replace a head then try to repair it which wouldn't be in his numbers.