Should I do lifters while I'm in there? ?

[IronManche87]

[Keyav8r]

If I had the head off mine I'd do everything I could on the top end and replace the timing chain, the water pump and the balancer. I haven't heard anything about the new lifters/old cam problem but I guess it's theoretically possible there could be some accelerated wear on the cam as the new lifters break in. Absent any strong evidence that the wear would be severe, I would change them.

[Eagle]

The 4.0

 

If I had the head off mine I'd do everything I could on the top end and replace the timing chain, the water pump and the balancer. I haven't heard anything about the new lifters/old cam problem but I guess it's theoretically possible there could be some accelerated wear on the cam as the new lifters break in. Absent any strong evidence that the wear would be severe, I would change them.

 

The 4.0L engine isn't overhead cam, so the front cover doesn't come off to change the head gasket. There is absolutely no need or reason to mess with the timing chain, water pump, or harmonic balancer just to do a head gasket.

 

Valve lifters and cam lobes become work hardened from use. Replacing lifters without replacing the cam at the same time is very risky, and probably means the new lifters won't last very long. 138,000 miles is nothing to a 4.0L Jeep engine. I would just pull the head, maybe clean out any carbon on the combustion chambers, and reassemble. To do it right, you should have the head checked for flatness by a machine shop, and resurfaced if it's not flat. To do that, you'll need to remove the valves and valve train. Be sure to keep the valves, lifters, rockers, and pushrods organized so that everything goes back exactly where it came from.

 

On my '88 XJ, I decided the replace the timing chain at 200,000 miles as a preventive measure, because I remembered that older AMC engines used timing chains with nylon sprockets. Got it open to find that everything was all steel, and there was no evidence of wear, slack, or slop in the chain. I put the new timing set in because I had already bought it, but I saved the old parts and I wouldn't hesitate to put them in a used engine that needed a timing set.

 

Remember: If it ain't broke, don't fix it.

[ParadiseMJ]

I would...and did...replace the valve guide seals.  Easy, cheap, won't hurt a thing.

[IronManche87]

[IronManche87]

[Eagle]

Yes sir! I plan on doing valves, guide seals, push rods, rocker arms+pivots+bridges (found a kit ), and of course cylinder head bolts. Is this still all a good idea?? I know for sure the bridges are a$$holes when removing I bent practically every one on my xj... X.x pivots and rockers probably aren't necessary but might as well?? And figured since it'll all be off might as well do push rods in case the tick was a bent one x.x is there anything else to check or be cautious in?? I've already gone push rod fishing on my xj.... Don't plan on doing that again

 

 

"If it ain't broke, don't fix it."

 

My '88 XJ 4.0L is at 287,000 miles on the original lifters, rockers, and pivot balls. You have less than half that. If you're rich and enjoy wasting money, go ahead and replace everything, but the notion of doing unnecessary work to something you don't need to touch "just because I'm working nearby" doesn't make any sense at all to me. Just replace the guide seals and do the head gasket.

[IronManche87]

 

Yes sir! I plan on doing valves, guide seals, push rods, rocker arms+pivots+bridges (found a kit ), and of course cylinder head bolts. Is this still all a good idea?? I know for sure the bridges are a$$holes when removing I bent practically every one on my xj... X.x pivots and rockers probably aren't necessary but might as well?? And figured since it'll all be off might as well do push rods in case the tick was a bent one x.x is there anything else to check or be cautious in?? I've already gone push rod fishing on my xj.... Don't plan on doing that again

 

"If it ain't broke, don't fix it."

 

My '88 XJ 4.0L is at 287,000 miles on the original lifters, rockers, and pivot balls. You have less than half that. If you're rich and enjoy wasting money, go ahead and replace everything, but the notion of doing unnecessary work to something you don't need to touch "just because I'm working nearby" doesn't make any sense at all to me. Just replace the guide seals and do the head gasket.

Yes sir! I appreciate the knowledge!! I guess I'll just hang on to that stuff for later use! I knew they wouldn't necessarily be needing replacing just found a great deal on the rockers, pivots, and bridges. Last time I removed the rockers I bent every single bridge arm so one rocker would sit funky.. And although I COULD just rebend them, I'm iffy on doing that with something so volatile.. I'd rather just replace them and not worry about a rod slipping off or sending one through my hood lol probably really unlikely but I'm not trying to mess anything up..

 

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