Replacing Hydraulic Lifters

[RockyMtnYJ]

Well my lifters are definitely worn. Rat...tat....tat....etc.

I want to replace them on my 2.5L this weekend. I was reading in a Haynes manual and it says that ANYTIME lifters are replaced, the cam shaft also MUST be replaced.

This is first time I've ever heard this. I would think that with hydraulic lifters this wouldn't be too big a deal.

What do you think?

[dillonjm]

Not sure about how it works on the 2.5 as I haven't gone through that yet with mine. However, on my older 304 in my CJ you can replace just the lifters.

Just a thing to think about though, the 2.5's lifters are notoriously noisy even when they are still in decent shape.

[OhioYJ]

The 2.5 does have roller lifters right? I can't imagine it doesn't. If its rollers I wouldn't touch the cam, I don't see any sense in it.

Anyways like dillonjm, its not uncommon for a Jeep to make a little racket.

[mrbeerbaitnammo]

i have read the same thing for my 4.0 in the same book and in the jeep engine book, i have never heard that before, but to answer your question ohio they are hydraulic just like the 4.0l, in my opinion i would pull the cam and look at all the lobes and make your decision from that, so that way you dnt put in new lifters with an overly worn cam.

[Slowride]

You have a hydraulic flat tappet cam and lifter set so..........yes you have to replace your cam when you replace the lifters and vice versa. Why? It's because flat tappet lifters and cam lobes individually wear to each other. Each lifter and cam lobe are thus unique in the fact that one is not like the other after the wear patterns are established. Once the cam lobes and lifters are broken in, they're "married" for the life of either component. Put in a fresh set of lifters without changing the cam or swap the cam and reuse the old lifters and you will either wipe the cam lobes out, wreck the lifters or both. This isn't something you want to have happen because all that metal will make it's way into the cam, rod and main bearings pretty quickly and then you are looking at a full rebuild. When you put that new cam and lifter set in, apply a lot of cam lube to the cam lobes and the lifters. Change the oil and filter out after the cam breaks in, which will be after about half an hour of running it at ~2000 rpm at a varying pace. Change the oil and filter again after you put ~500 miles on it. While you have it all apart, change out the timing chain and timing cover/crank seal as well.

Now if you had a roller cam, which you or anyone else with a factory stock Jeep 2.5 or 4.0 for that matter doesn't have, you could just replace the lifters and leave the cam alone and vice versa. Roller lifters and roller cam lobes do not wear themselves to each other like a flat tappet cam setup. That's why you can reuse a roller cam or roller lifters individually. This is a real nice fringe benefit of running a roller cam. I highly doubt anyone makes a roller cam and lifter set for a Jeep inline engine though.

[dillonjm]

I stand corrected on the replacing of lifters and cam on the 2.5. Thanks for the good info Slowride. I still reiterate that the 2.5 is notorious for noisey ticking lifters that really don't need replacing.

[RockyMtnYJ]

Hmmm....interesting information! Thank you so much. I am not an engineer, but my brain can't reason out how new lifters would "increase" cam lobe wear? I can understand how worn lifter and a worn cam must remain "married" to eachother because BOTH surfaces are worn together into a "custom" fit. However, if one replaces just the lifters, then one is causing an even, flat surface to ride against worn cam lobes, soooooo....

....how can this "increase" wear between the cam lobes and lifter faces? I would think that, at worst, the two facings would once again marry themselves together over time. Of course, some wear would occur, as is normal over time, but the concept of "increased" wear just eludes my simple brain.

Can someone please explain to me, in simple terms, why wear would be accelerated by replacing the lifters with new ones? I truly want to understand the dynamics that would come into play by replacing the lifters.

[OhioYJ]

What happens if the cam is worn more than the lifters, giving you the play in the pushrods?

Vehicles with flat tappet lifters come in cam and lifter kits for a reason, I understand you thinking, but its not that much more work to go ahead and replace the cam too. The whole lifter and cam kit from Autozone is $118. Quadratec has it for $109.95 (http://www.quadratec.com/cgi-bin/sgin0101.exe?T1=51001+05&UREQA=1&UREQB=2&UREQC=3&UREQD=4&FNM=00&UID=2006010718492277)

[RockyMtnYJ]

I guess what I REALLY need to do is start saving up for a re-manufactured engine, a new clutch, some headers, etc. I think I'll call Hiperformer on Monday and start planning on getting an engine together to swap out. I think I'll throw the lifters in as a band-aid to keep me going until I can get a new engine in the garage.

My lifters are so noisy right now that the engine could be mistaken for a diesel. I am really concerned about serious damage if I don't address this immediately.

I've never changed a camshaft before, or pulled a head. I'm afraid of too much downtime - missing work, etc.

[dillonjm]

Well, if the experts who know about the flat tappet cams are right, you're going to end up really hurting the engine by doing it the way you plan. So what's the point in even replacing the lifters?

[RockyMtnYJ]

The point is that the old lifters are REALLY bad. I need to do something to get me by for awhile. I am looking into how to change out the cam as well.

The posts on this thread do not constitute the entire league of "experts" I've been soliciting advice from. I respect ALL advice and input - but ultimately, I always make my own decisions and take full responsibility. *smiles*

[Slowride]

Originally posted by RockyMtnYJ:
Hmmm....interesting information! Thank you so much. I am not an engineer, but my brain can't reason out how new lifters would "increase" cam lobe wear? I can understand how worn lifter and a worn cam must remain "married" to eachother because BOTH surfaces are worn together into a "custom" fit. However, if one replaces just the lifters, then one is causing an even, flat surface to ride against worn cam lobes, soooooo....

....how can this "increase" wear between the cam lobes and lifter faces? I would think that, at worst, the two facings would once again marry themselves together over time. Of course, some wear would occur, as is normal over time, but the concept of "increased" wear just eludes my simple brain.

Can someone please explain to me, in simple terms, why wear would be accelerated by replacing the lifters with new ones? I truly want to understand the dynamics that would come into play by replacing the lifters. Don't think too hard about this. When you have a flat tappet cam, you have to change both the lifters and cam out when one or the other requires changing. It's simply due to the way these parts wear to each other. That's the way it is and the way it's always been with these types of cams.

If you need to hear something "more concrete" from a cam company to make it easier to swallow the unexpected added expense and labor involved with changing out the cam, go ahead and give Comp, Crane or Lunati a call. They'll tell you the same thing I did and they'll also tell you to change the springs out too. I didn't mention them because your springs are likely still good enough for a stock replacement cam. Also make sure you keep the rockers and pivots for each particular cylinder/valve in order when removing them because they have to go back onto the same cylinder/valve when putting it all back together. Pre-established wear patterns between these components are the reason.

Most people only like to do a cam swap once due to the labor involved, so they do it right the first time. If you go ahead and just replace the lifters in spite of the information given to you, don't say you weren't warned when you frag the cam and end up with a Jeep that won't run.

Have you tried changing your oil and replacing it with 20W50 or 15W40? A thicker oil can sometimes quiet down noisy lifters that aren't too far gone yet.

Lastly, check out this link from Crane.

http://www.cranecams.com/?show=article&id=2

[RockyMtnYJ]

Haha! Well you're definitely straight to the point! I'm looking into the cam swap to see how long it would take me to do it myself. I want to thank you ALL for the great advice and trying to keep me out of trouble.

When I just switched from whatever the previous owner used for oil to some 5W-30 Valvoline, the clatter definitely got worse, so you're on the mark with thicker oil quieting things down.

[Slowride]

Keeping you out of trouble was the reason I spent 15 minutes of my life typing this stuff for you. Glad to see you got the message.

[edudley]

Believe us it will wear not only the cam but ruin the new lifters as well. I have seen it happen!!