Lifter Noise 258 with 4.0L head - does the head need to be pulled??

MomoJeep

Basic User
CJ-8.com Member
City
Seattle
State
WA
#1
Backstory:

OEM 258 block was rebuilt. I did the 4.0L head conversion and brought in the MPI/computer. Valves/Lifters were quiet for first 25k miles. On a long summer road trip one day, after driving a few long days in the heat, with a full load in the jeep, up and down mountains from Sequoia NP to Moab area to Yellowstone, it started tapping.

COLD
It'll tap continuously on cold starts, then go away once engine warms a bit. So you'd think it was an issue when cold. However...

HOT
It will also tap when hot and running for a few hours. But this tapping is not continuous. It goes in and out of tapping every few seconds. Like: tap tap tap tap tap tap tap tap / quiet quiet quiet quiet quiet quiet quiet / tap tap tap tap tap tap tap tap / quiet quiet quiet quiet quiet quiet quiet / etc.

THINGS I'VE TRIED:
I tried different oil weights. I tried multiple motor flushes. I ran diesel oil (high detergent) for a while. These things seem to make a little difference, but ultimately it comes back to the same tapping pattern.

Valve work: I had a shop makes sure the pushrods and valves were all good. They made a few little adjustments. it was quiet for awhile, but then the same tapping pattern eventually came back within a few weeks.

QUESTIONS:

LIFTER BORE
(1) If a lifter bore is damaged, am I just SOL? Look for a new block? Or have it machined over size?

(2a) Bad lifter. If this is the case, does the head have to be pulled to do the job?
(2b) A mechanic told me even a new set of lifters is a risk, because it's hard to find high quality ones. Anyone have experience with this?
 

MomoJeep

Basic User
CJ-8.com Member
City
Seattle
State
WA
#2
OK, simplified version of my question: Does the 4.0L head need to be pulled to change the lifters?
 

CJ-8_Jim

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
NW Chicago Suburb
State
IL
#3
OK, simplified version of my question: Does the 4.0L head need to be pulled to change the lifters?
Yes.
But note: If you think your lifters are bad, what about the cam? If the cam's lobes (sp?) are bad, you are just putting good lifters on a bad cam -- you might still have some degree of a problem immediately or in the near future.

BTW... your engine was rebuilt... correct? Have you ruled out piston slap?

It's a tough call on whether to spend time (and money) trying to fix it.
Engine noise is annoying to listen to.
But what if you don't hear it while driving (especially topless) and performance is not suffering?
Life is short.

The 4.0/258 takes a lot of abuse.

Do you have a car hauler and tow vehicle to carry your CJ, gear and some cots to sleep on during your adventures across our great Western U.S.?
 

MomoJeep

Basic User
CJ-8.com Member
City
Seattle
State
WA
#4
There was no noise for the first 25,000-30,000 after rebuild. It started during a long drive, heavily loaded, over mountains, in the summer. I think the engine got abused a bit that day. There has been no metal in the oil, and my mechanic listened and said he thinks a lifter is having an issue, but that the cam is ok. I also believe it's a lifter because it comes and goes: tap tap tap tap tap tap tap ..quiet quiet quiet quiet quiet quiet.. tap tap tap.... etc.

It seems to be noisier in the summer. Yet thicker oil does not necessarily make it go away.

You're so right: it IS annoying. And life IS short! I'm going to keep experimenting with oils and additives before dropping the coin.
 

93_Fummins

CJ-8 Member
CJ-8.com Member
City
Edmond
State
OK
#5
Have you tried adding Sea Foam to your oil? I've had good luck with it silencing ticks. It's supposed to loosen up carbon buildup. Add it to your oil about 500 miles before an oil change.
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
#7
Pull the valve cover, look for a bent pushrod, maybe, since you said you were abusing it?
He said he had a shop look at the pushrods to verify they were ok, but a bent one was my first thought too.

However, I'm curious about the detail on the "...few little adjustments" that were made by that shop because there are no adjustments to be made to anything inside the head on these. Nothing is adjustable. I'm a tad confused.
 

CJ-8_Jim

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
NW Chicago Suburb
State
IL
#8
Pull the valve cover, look for a bent pushrod, maybe, since you said you were abusing it?
He said he had a shop look at the pushrods to verify they were ok, but a bent one was my first thought too.

However, I'm curious about the detail on the "...few little adjustments" that were made by that shop because there are no adjustments to be made to anything inside the head on these. Nothing is adjustable. I'm a tad confused.
X2 - on bent push rods
X2 - on 4.0/258 not having any adjustments (i.e., no valve lash adjustment)

MomoJeep - Since you are well-into taking a "Trial and Error" approach spending time and $$$ on oil additives, maybe replacing the push rods is the next step -- only $2/each ($24) + valve cover gasket (good time to upgrade to a reusable Fel-pro).

BUT.... Before you loosen the rocker arm bolts, check the torque of each. Maybe the "... few little adjustments" the shop did were tightening down the rocker arm bolts.

Rotate each cylinder to TDC before checking torque. Before my stoker, I did the 4.0HO head swap and I recall the 4.0HO rocker arm bolts to be the same spec as the 258 head, BUT double check a '94 YJ/XJ shop manual for torque spec since I do know at least one other torque spec is different (headbolts).

If a rocker arm bolt is less than torque spec, I can't guess why a rocker arm bolt has worked its way loose after a shop (other than the engine rebuilder) just made a "... few little adjustments".

If you a find a loose one and are able to re-torque (i.e., the threads are not stripped), you could try some Loc-tite thread locker (carefully degrease the threads and use Loctite thread locker).

Loctite threadlocker - there are two versions of Blue: 242 and 243 (better oil resistence... use 243).
I also hear there are Loctite Blue stick and Loctite Blue Tape versions.

If a rocker arm bolt is stripped, then time for a helicoil.. stop by NAPA and they'll explain what to do.
 
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