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Replacing pushrods & Lifters

jeepboy381

jeepboy381

NAXJA Forum User
Location
Gresham, Or
I have my head off my 4.0 to replace a snapped exhaust manifold bolt and in the process I bent a pushrod. Long story short this engine has always had a lifter tick that was very bad at startup and got quieter once the oil pressure went up after startup. I have to replace the pushrods but have heard it is not a good idea to only replace the lifters without doing the cam as well, is this ture? Could I run into cam problems installing new lifters on a old cam that is still in perfect condition? The engine only has around 130,000 miles on it and appears to be in awesome shape. Let me know. Josh
 
jeepboy381 said:
I have my head off my 4.0 to replace a snapped exhaust manifold bolt and in the process I bent a pushrod. Long story short this engine has always had a lifter tick that was very bad at startup and got quieter once the oil pressure went up after startup. I have to replace the pushrods but have heard it is not a good idea to only replace the lifters without doing the cam as well, is this ture? Could I run into cam problems installing new lifters on a old cam that is still in perfect condition? The engine only has around 130,000 miles on it and appears to be in awesome shape. Let me know. Josh
Click to expand...

You can replace the lifters in the 4.0 without replacing the cam, but you CANT replace the cam without replacing the lifters. You can also just replace the pushrods without replacing lifters.

Dont expect it to quiet down with new lifters and rods. The valvetrain in these is noisy period.
Best thing to do would be to replace the rods, and then re-assemble. Then run seafoam through the engine till the next change, then at the next change run some MMO (marvell mystery oil). That may quite it down a bit, but not much.

My opinions of course...

BTW how do you bend a pushrod while dissembling???
 
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I am just assuming I have not taken any measurements but when I took the head off the engine I left the pushrods in as I lifted the head out by myself. When I lifted the head I felt as though I put quite a bit of side pressure on the pushrods taking it out. So for $2.79 a piece I am just going to replace them.

I am still iffy on the new lifters though. I talked to a few more people and read online a little more and it seems quite a few think it is a bad idea. I would really hate to take this engine completely apart to replace the cam!
 
jeepboy381 said:
I am just assuming I have not taken any measurements but when I took the head off the engine I left the pushrods in as I lifted the head out by myself. When I lifted the head I felt as though I put quite a bit of side pressure on the pushrods taking it out. So for $2.79 a piece I am just going to replace them.

I am still iffy on the new lifters though. I talked to a few more people and read online a little more and it seems quite a few think it is a bad idea. I would really hate to take this engine completely apart to replace the cam!
Click to expand...

You can definetly replace the lifters without replacing the cam... dont worry about that. Lots of other vehicles you have to replace the cam at the same time as the lifters, but not with the 4.0 Jeep. If you replace the cam, thats when you have to replace the lifters.

I wouldnt worry about the lifters. Mine has 190,000 miles, and i pulled my head for the same reason. I didnt replace the lifters or pushrods, and its a little quiter then before. Maybe some of the engine noise you were hearing was your exhaust leak also!

Easy way to check your pushrods is to roll them on a glass table or slab of glass. If it wobbles its bent. If it rolls evenly its fine.
 
Alright, well maybe I will just clean the ones I have now really really good and instal them again. When I first start the Jeep the tapping is very loud for about 3 seconds and sounds scary, it gets almost unnoticable after that but is still there. I see that you live in Bend, hopefully you go up and play on Mt. Bachelor!
 
I wish! I havent been up there in years!
Good luck! Make sure you roll those pushrods to make sure there not bent (since your already torn into it that far).
I was also able to pull my head by myself, and i almost got it on by myself. Get a helping hand! Its a pain! Use some threaded rod to line the head up with the block so you dont trash your head gasket (i did in my first attempt).
If you dont have local help, ill come up there if you pay for my gas! lol
 
Man that sucks you havnt been up there in a long time but live so close. I have never been to Bachelor, but I go to Meadows at least once a week lately. My friends went all the way to the top of Bachelor and boarded down, they said it was steep as hell and scary but fun.

I am having a friend come over to help me put the head on tonight. I don't think I can do it by myself because I also bolted the intake and exhaust manifolds on so I wouldn't have to do it while it was on the engine. It is damn heavy now!! I went and bought new pushrods on my lunch so I should be good to go now. Thanks for the help!
 
jeepboy381 said:
Man that sucks you havnt been up there in a long time but live so close. I have never been to Bachelor, but I go to Meadows at least once a week lately. My friends went all the way to the top of Bachelor and boarded down, they said it was steep as hell and scary but fun.

I am having a friend come over to help me put the head on tonight. I don't think I can do it by myself because I also bolted the intake and exhaust manifolds on so I wouldn't have to do it while it was on the engine. It is damn heavy now!! I went and bought new pushrods on my lunch so I should be good to go now. Thanks for the help!
Click to expand...

I took it off and put it on with the intake / exhaust manifolds on also. Definetly the better way to do it IMO. It would help x4000000000 if you or your friend has an engine hoist. I ended up using a rope tied around the valve springs to hold up the end towards the firewall, as my buddy held up the other end / aligned everything.
Also, if i remember correctly i believe 5-90 said somewhere to leave the lifters alone unless your going to replace them. (so dont remove them from there bore etc..)

Again good luck!
 
Well you should replace the lifters while you have it apart, as noted that is completely fine to do so. I replaced my lifters, pushrods and all the rockers on my engine at 180k due to very loud lifters that were dirty as hell. the PO did not change oil as often as needed and it had lots of sludge. After the replacement of the listed parts engine is at 240k and is as quite as a new engine. Also it restored lost power after parts were replaced.
I think you would be wise to replace the lifters if your engine has hi miles and the lifters were loud. I don’t subscribe to any of the liquid cures for engine parts. And while you have it apart it a no-brainer
 
Comanchedude said:
Well you should replace the lifters while you have it apart, as noted that is completely fine to do so. I replaced my lifters, pushrods and all the rockers on my engine at 180k due to very loud lifters that were dirty as hell. the PO did not change oil as often as needed and it had lots of sludge. After the replacement of the listed parts engine is at 240k and is as quite as a new engine. Also it restored lost power after parts were replaced.
I think you would be wise to replace the lifters if your engine has hi miles and the lifters were loud. I don’t subscribe to any of the liquid cures for engine parts. And while you have it apart it a no-brainer
Click to expand...

I also originally thought the same thing, but due to the advise of 5-90, i changed my mind and didnt replace the lifters / pushrods. I do still think that its best to replace things "while your in there" but as i said i didnt and everything is super quiet on mine.
I think there are alot of factors here, and i doubt that there is a definitive answer. I do however think that for those of us who are complaining of "top end noise" with broken studs / bolts that hold the exhaust / intake manifold tight are really just hearing exhaust leaks. For those that dont have that issue, then maybe the noise was really from a collapsed / gunked up lifter. Im thinking it was the later in your case.
 
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