XJ Stock Replacement Camshaft

If it isn't a performance upgrade, the only suggestionI've seen was Autozone. I'll happily live the rest of my life without walking into another one of those "places" again. I talked to my machinist, and they can order me one through Engine Tech for about $207. Bearings are $23. Lifters come out to about $41. I'd get everything next day.

Here's my problem: Engine Tech is not a manufacturer, so point of origin is a mystery. Also, lifters come separately, perhaps even from a different manufacturer. In my experience, lifters are supposed to be matched to the cam, as far as materials are concerned. Thus, buying cam from one place and lifters elsewhere is not a good idea. That's what they offer.

O'Reilly's doesn't carry one. I only called for laughs. Presently waiting on a call back from my regular parts store, I'm sure they're going to offer me some bulk discount special from China. I'm willing to pay for a quality camshaft, just not the Chrysler premium, if it's even still available.

I let the bearings go for too long, and they seem to have nosedived on the return end of a 1700 mile road trip. Engine is running great as it approaches 300k. I had considered checking and reusing the original cam, but with the noise it's making now, I can't see it looking all that great.

This is a 96 4.0, and I'd love to get another 300k out of it. Any suggestions?

Comp Cams has several to choose from, one is supposedly near stock, and they have the lifters too.

Hmm, unavailable through my usual parts provider. He recommended the machine shop. Going to stop in today and compare specs. I'd like to avoid close enough, or mild performance, as I'm not planning on doing anything on top. In fact, if I can remove the lifters without taking the head off, that's how they'll come out.

The way I see it, just replacing the bearings restores a bit of lift, which by slowly decreasing over a lot of miles would produce a tapered shoulder on the valve stem. Suddenly the factory lift is restored, plus whatever wear on the lobes, so that the shoulder is now entering the guide. I don't see this as a good thing.

If I can't minimize the impact on the head, I should just pull it and rebuild it with new valves and guides. As the second owner, I know it's as it left the factory, and it hasn't had a head problem yet.

This would be a good time for someone to chime in with their high mileage chain of events.

I yanked out my 340k mile engine and replaced it with a clean one from a 99 XJ with 50k miles. Once you start messing with any of the innards you'll need to fix the rest of them to get the full benefit (piston rings, valve seats, etc). Easier to just yank and swap.

Here's my problem: Engine Tech is not a manufacturer, so point of origin is a mystery. Also, lifters come separately, perhaps even from a different manufacturer. In my experience, lifters are supposed to be matched to the cam, as far as materials are concerned. Thus, buying cam from one place and lifters elsewhere is not a good idea. That's what they offer.

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Untrue. The only time you need to worry about matching is when you are reusing the cam and lifters. The lifter and lobe "match" during break-in, and the lifter must be re-installed to the same bore it came out of on reassembly.

Also, the head will have to be removed. there is no way to remove the lifters otherwise.

Shoulder on the valve stem? nah. If there is, you have more serious problems to deal with. valve and guide replacement will be needed. If it's off, get the work done, especially if you are doing the rest of the engine. Be wary if you are not re-ringing. Sealing up the top end without freshening the lower end can induce oil consumption, especially on high mileage engines.

Rockauto.com shows the engine tech cam for $165. pair it with a set of clevite, melling or sealed power lifters and you'll be golden. I see they have engine tech lifters as well if you're that worried about mixing brands.

ehall said:

I yanked out my 340k mile engine and replaced it with a clean one from a 99 XJ with 50k miles. Once you start messing with any of the innards you'll need to fix the rest of them to get the full benefit (piston rings, valve seats, etc). Easier to just yank and swap.

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This.

Less work too.

All of my extra engines are high mileage, Renix, or both. Late models are pretty well unheard of in the salvage yards, and here they equate Jeep with Wrangler so almost everything which might swap is premium. I know of one 94, with an engine in it, and the guy said it ran. I bought the cluster out of it, was missing the check engine light. I wonder why?

I feel I'd be buying something someone else has already flogged, overheated, ran out of oil, etc. Besides, the sentimental value of this engine far exceeds anything I could purchase around town.

The only time you need to worry about matching is when you are reusing the cam and lifters. The lifter and lobe "match" during break-in, and the lifter must be re-installed to the same bore it came out of on reassembly.

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I understand indexing for proper reassembly, what I'm talking about is the cam/lifter material. The lifters can't be harder than the cam, or vice versa.

Once you start messing with any of the innards you'll need to fix the rest of them to get the full benefit (piston rings, valve seats, etc).

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This is what I was expecting, in the back of my mind, but somehow still hoping to avoid. Now, knowing I'll have to remove the head, I know it'll have to be rebuilt. Valve job at a minimum.

So it's a snowball. Joy. Looks like I'll be in the two door for a while.

I was just speaking with a friend, and he suggested I start with a compression test before ever pulling the engine. I figured I'd go one further, as I happen to own a leak down tester as well. We both agree that putting a rebuilt head on a worn out engine is a bad idea, but I feel mine runs too well to be worn out.

He also felt that while common sense dictates getting cam and lifters from the same manufacturer, mix and match isn't as bad as I'm thinking. The more opinions like this I get, the better I'll feel about it. I guess the worst thing which can happen is I have to pull the engine again.

Buddy, I concur with Digger87XJ. In a friendly way, I think you are over analyzing the situation. New camshaft, new lifters, install correctly with plenty of lube. And yes, remove the head. You have to. This is a durable engine, but not designed with the tolerances of a BMW or Mercedes engine. Thats why it can be very forgiving. I believe the simple solution will work in your case.
Otherwise, do the engine swap. Its pretty straightforward.

Rebuilding an engine is but time and parts for me, plus borrowing space to leave the stand. I just feel the bottom end is good for a lot more miles.

Over analysis is a problem I deal with daily. It's nice to have this armchair analysis before tearing into it, though. I feel inclined to thin out my pile of old junk, and work aggressively to bring in newer junk, in better shape. The $300 100k mile missing a couple of windows and sheltered a few litters over the years still comes up on occasion.

What good is one from an 89? I drove it in years back, not much left of it now, but the engine. Been packaged well enough. Quiet cam, had around 190k if I recall correctly. How much different is it? Could I steal all of the accessories from a 92, including the head, and drop it in?

Might be a little faster, and the original engine can go on the back burner. I'm stuck in a four cylinder XJ at present. Little engine, little tool box. Not happy about that.

I keep wanting to tell you to just use this opportunity to build a stroker 4.6, because thats what I want to do one of these days. But I know thats not what you are after. I recall one of the other guys saying that if you strictly rebuild the top half of the engine and leave the bottom, you may be getting into some trouble. Im a little old school in the way I do things, but I agree with that. Ive seen it happen and would hate for you to go down that road because only one person told you not to do it. Replacing the cam and lifters, no problem by itself. And my guess is that the pushrods and rocker gear are going to be just fine. But of course, now that the head is off, why not freshen it up too! New valve stem seals, maybe have a shop re-do the valve seats, etc. But if you do that, you really almost HAVE to, from a quality standpoint, replace the piston rings at the bare minimum. If the bearings look fine, by all means, re-use them. But remember, bearings are cheap too! And re-honing the cylinder walls to accept a new set of rings wont even take two hours. Aside from the shop work, you can literally do everything else in one afternoon. It really is that simple. And in the long run, you will have an engine that you wont have to worry about. Just pay attention to details, and always put quality into your work, dont rush.

I figure the leak down and compression tests should give a pretty good indication as to head condition. I'm fairly sure I could put the head back on as it is and keep going, but with the mileage, I don't expect it to be stellar. I can always turn it up on the bench and fill the chambers with gasoline, then observe which ones leak down.

I've built several tractor engines. Most of them don't even have cam bearings, they just ride in the block. Knock new liners in and go back standard on the top end, have the crank cut to the next undersize. I rebuild engines with adjustable end thrust, rope seals, and built in governors. Antiques, mostly. Engine building is nothing new to me, only I've never been very deep into a 4.0. I want mine to last as long as I can manage.

I know people here have high mileage experience, and much of what has been said in this topic, I've been hearing from various people for years. It really makes me want to leave the head alone, replace the cam/bearings/lifters, and run it till it starts smoking.