Replacing hydraulic lifters is a 4.0 liter Jeep

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I've put new lifters on an old cam plenty of times... never had a problem with it.

I agree with others here that an oil pump might make as much difference as lifters- but PLEASE don't put a high-volume oil pump in that perfectly good engine. HV pumps do stock engines no favors and cause more problems than they mitigate.
 
Originally Posted By: mechtech2
I'd lube everything well with engine assembly lube, and overfill the crankcase with 1/2 qt extra. Be prepared for scary clacking when you start it up!


Never start an engine with cam/lifter work without pre-oiling.
It will cause premature wear.

Originally Posted By: onion
I've put new lifters on an old cam plenty of times... never had a problem with it.

I agree with others here that an oil pump might make as much difference as lifters- but PLEASE don't put a high-volume oil pump in that perfectly good engine. HV pumps do stock engines no favors and cause more problems than they mitigate.


I've been Jeep'n for many years and never had any issues at all with installing Melling high volume oil pumps in my Jeeps. In my trail rig, I can sit on my side waiting to get pushed back over with 40 psi of pressure at idle.
 
I've changed lifters w/o a cam, technically its a no no but on a 193,000 mile engine you'd be fine. I would make sure I primed the lifters, and coated the cam and lifter bottoms with some kind of assembly lube. A new oil pump wouldn't hurt either.

IIRC I would stand the lifters up in a clean tin can filled with oil, and worked the pushrod by hand to pre-fill them. This way they are not dry on the inside when you fire it back up.

HTH
Frank D
 
Quote:

I've been Jeep'n for many years and never had any issues at all with installing Melling high volume oil pumps in my Jeeps.


Yet.

The extra oil pressure from high volume oil pumps is NOT good for the bearings... this is not a 'more is better' situation. In fact, I've read that bearings can be damaged by excessive oil pressure (never seen this personally, but it's generally referred to as the bearings being "washed"- it's covered in most engine manuals). HV oil pumps also tend to wear out the gears on both camshafts and distributors (seen this several times). They unnecessarily rob power. I've even seen them pop oil filter cans on a cold morning.

So I've seen them cause lots of problems, and I can't name a single benefit. Except maybe if you want to run your engine while your jeep is laying on its side? That's gotta be great for the engine.
 
As a kid working in an auto parts store I would talk to the guys in the machine shop all the time. I asked about hi volume oil pumps and they told me basically the same thing you're saying. Stick with a stock replacement pump in any stock engine, or you're asking for trouble.

Frank D
 
Thanks to all for the input. Looks like a toss-up at this point. Benefits vs. risk, etc. I will probably go with new pre-filled lifters and plenty of assembly lube. I just don`t want to get it all back together and have an old, collapsed, noisy lifter to deal with in the near future.
 
Originally Posted By: onion
Quote:

I've been Jeep'n for many years and never had any issues at all with installing Melling high volume oil pumps in my Jeeps.


Yet.


Well, I guess we'll just have to see what happens in the next 20+ years of wheel'n.

Originally Posted By: onion
The extra oil pressure from high volume oil pumps is NOT good for the bearings... this is not a 'more is better' situation. In fact, I've read that bearings can be damaged by excessive oil pressure (never seen this personally, but it's generally referred to as the bearings being "washed"- it's covered in most engine manuals). HV oil pumps also tend to wear out the gears on both camshafts and distributors (seen this several times). They unnecessarily rob power. I've even seen them pop oil filter cans on a cold morning.

So I've seen them cause lots of problems, and I can't name a single benefit. Except maybe if you want to run your engine while your jeep is laying on its side? That's gotta be great for the engine.


You can't name a single benefit because you probably don't have a Jeep. We're only talking 20%-25% more volume. The UOA's of my 2.5L, with a high volume oil pump, have been stellar for the amount of beatings it sees. Wear metals are excellent. So, maybe a high volume pump could be damaging to another car, who knows. Maybe the vehicle you saw had a bad relief valve. I know Jeeps, and this guys 193K mile 4.0L will be perfectly fine, if not better off, with a high volume oil pump. IMO, the factory oil pump in a Jeep 2.5L or 4.0L(especially Renix) is only marginally up to the task of lubricating the upper end. It also has a typical life expectancy of 100-150K miles. How many "my Jeep ticks" threads are on this forum? I've been there myself with an old Renix 4.0L that had periodic lifter tick (and no, the engine wasn't dirty). I changed the leaking rear main (another 4.0L issue) and installed a high volume oil pump. Guess what? No more tick, ever. I've done 8-9 rear mains/oil pumps/pan gaskets on mine and friends Jeeps (some with a periodic lifter tick) with a 100% success rate. No blown out filters or stripped cam/dist. gears. No noticeable effect on HP on these tractor engines either.

In the end, this guy can go any route he chooses and listen to any advice we offer. I live, breathe, and eat Jeeps. It's a Jeep thing that most wouldn't understand.
thumbsup2.gif
 
Originally Posted By: Cornbread
Thanks to all for the input. Looks like a toss-up at this point. Benefits vs. risk, etc. I will probably go with new pre-filled lifters and plenty of assembly lube. I just don`t want to get it all back together and have an old, collapsed, noisy lifter to deal with in the near future.


Good luck to you man
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this thread's funny...

- that convex surface on a flat tappet lifter is only to help make it spin so it doesn't ride in the same spot and wear itself and the cam lobe out. It does not add to lift at all,

- prefilling the lifters with oil is a waste of time. you will be priming the oiling system one way or another prior to running the engine which will fill the lifters with oil. All you do prior to installing is coat them with oil, and especially their bottoms with moly assembly lube or paste to help protect against initial startup wear against the cam lobe.

- high volume pumps don't generate higher pressure, the reason they're called high volume pumps is they flow more volume. The oil pressure is controlled by the pressure relief spring in the oil pump body, if you install a high volume pump then all you'll be doing is taking that much more oil up through the pickup tube and squirting it out the pressure relief hole in the oil pump back into the pan. You will never pump the pan dry or cause problems with a high volume pump. The high volume pump will do nothing other than rob power unless you had low oil pressure prior to installing it due to large bearing clearances. And if oil pressure was normal before, then there is no reason to think the oil pump is at the end of it's life. washed bearings? please, who makes this stuff up?
 
Having worked for Chrysler for several years, I worked on many of the 4.0L engines. Be sure your not mistaking the clatter for being lifters when the 4.0 was known to have piston clatter especially when cold. We changed lots of piston assemblys under warranty. Funny thing with the 4.0L, we had to order the pistons according to a letter designation depending on the bore size. One engine could have a variety of cylinder bore sizes. As mentioned in another reply, the 4.0L is a very reliable engine that will run for a long time regardless of the noises it makes.
 
Originally Posted By: PeteM
Having worked for Chrysler for several years, I worked on many of the 4.0L engines. Be sure your not mistaking the clatter for being lifters when the 4.0 was known to have piston clatter especially when cold. We changed lots of piston assemblys under warranty. Funny thing with the 4.0L, we had to order the pistons according to a letter designation depending on the bore size. One engine could have a variety of cylinder bore sizes. As mentioned in another reply, the 4.0L is a very reliable engine that will run for a long time regardless of the noises it makes.
Yup my 93 Cherokee has piston slap since day one, still have it, after warm up it gets quieter but still does it, and still runs strong today, one of the best motors ever for torque.
 
Originally Posted By: meep
I miss my 4.0. :-(

The 3.7 just isn't even remotely in the family. :-(

M



Nope. Neither is the 3.8L
 
On this subject of replacement lifters, what is your opinion on aftermarket vs. OEM? There is a price difference of approx. $3 to $17 per lifter.

Seems like better to stick with OEM, but there should be some quality aftermarket available as well.
 
Another thing that makes the engine bullet proof is that it has a timing chain rather than a belt. At least thats that RockAuto's website says for my 2001 Cherokee with the 4.0.

I'd have timing chains in all my cars if I had a choice.
 
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