Metal on metal tap tap tappy!

Mountainman · **Posted:** Mon Apr 28, 2014 10:24 am

So, I finished pulling CRD 2 home with CRD 1 last night (about 5 hour drive with tow dolly), and now I've got a metal on metal "tick or tap sound", that sounds like when the marble inside a can of spray paint strikes the can when shaking, but at just the right interval for a rocker.... It comes and goes, with a second or two delay in strikes, but it was late and I didn't put a screwdriver to my ear to pinpoint, but sure sounds like upper left of valve cover. I pushed the old beast to about 27-2800 rpms on a handful of the hills, but that's pretty mild treatment isn't it?
EDIT: The delay of a second or two is after a few taps that really sound like a "loose rocker", and this is all in park at an idle.
Sounds like a set of rockers is in my near future? 164k miles

Any advice is greatly appreciated :JEEPIN:

geordi · **Posted:** Mon Apr 28, 2014 1:35 pm

DON'T DRIVE IT. STOP RUNNING IT NOW.

Tapping noises are very very bad, and *might* be rockers (I hope it is for your sake!) but that wasn't my experience with 2 motors. First step is you will need to take the timing components off and get down to the top of the head and have a look. Hopefully you find the problem.

IF NOT - The most likely source is the rod bearings, and that means the bottom will need to come apart. Whether you choose to do this with the engine in the vehicle or pull it, that is a decision that I cannot offer much help with. I haven't taken one of these engines that far apart, so you are kinda on your own. What I can say is that this is a "tunnel block" design and supposedly the crankshaft can be serviced with the block in the vehicle. I don't know how accurate that information is.

SargeIndustries · **Posted:** Mon Apr 28, 2014 3:35 pm

I would pull the motor if it is bottom end. You do not want to take the whole front axle and steering loose to be able to remove the oil pan in my opinion.

Mountainman · **Posted:** Mon Apr 28, 2014 6:13 pm

Well, being that it's not constant on every revolution, and sounds like a tapping rocker, I've got my fingers crossed that it's top end. I've heard a bottom end knock before, and it doesn't sound like that, but rod, heck if I know.
Thanks for the caution Geordi! I'm hitching a ride to enterprise and getting a month rental as a precaution. I'm not chancing a 5k repair. I was thinking of doing rockers and studs soon anyhow.
Anyone else get a nice tick when they had a rocker giving out? Maybe I got lucky and caught it right before it dropped a valve...?

racertracer · **Posted:** Mon Apr 28, 2014 7:05 pm

How about a YouTube clip of the noise?

lars0247 · **Joined:** Sat Oct 12, 2013 12:09 am **Posts:** 98

You might try a mechanic's stethoscope. I just ran mine at idle and moved all around the cam cover area with a stethoscope, and the tapping sounds consistent everywhere and free from and grinding sounds (stuck roller) or louder tapping (bad rocker pivot). Whether this is a definitive test or not, I cannot say. Perhaps someone else might have additional insight?

car0430a · **Posted:** Mon Apr 28, 2014 9:29 pm

Well @151k I would say I have a similar tap,tap sound but not noticeable at idle. Kicks in around 2000 rpm I'd say and stays for a couple hundred rpms then goes away after higher rpm. Only notice it on medium to hard acceleration? I'm sure everything will go at once, experienced some good TC shutter a week ago when getting on it to pass some a-hole on the freeway. Had to stop shift in neutral shut engine off restarted it and it had been pretty good ever since, but I haven't driven it hard.

Mountainman · **Posted:** Tue Apr 29, 2014 6:49 pm

There's a first time for everything. I started to pull things apart, and found the serpentine belt partially seperate, which was apparently slapping a metal pulley making a sound similar to a rocker that's loose... I pulled belt, started, and sure enough, he sound was gone. The belt was two weeks old! Anyhow, all bearings seems smooth, so I put on the spare, and started the 3 hour round trip with the wife to return the rental :5SHOTS:

She's back on the road! Thanks for all the advice :rockon:

geordi · **Posted:** Tue Apr 29, 2014 8:11 pm

*whew!*

Mountainman · **Posted:** Tue Apr 29, 2014 9:42 pm

That's what I'm saying! I still think the rockers tap a little (slight tick like old adjustables that need tightened), but I'm no diesel expert. Do they tick slightly with new rockers, or do I have some worn parts?
I'm planning on new rockers in about six months just to be safe, along with studs

thermorex · **Posted:** Tue Apr 29, 2014 11:48 pm

I think all crds have that tapping noise, that made me replace mine as a matter of fact... If you have an ehm or provent, you could add oil till max on the dipstick, which is not recommended but the engine will spit it out anyways. When I do that, the engine quiets down and those "tick-tick-tick" noises can't be heard. With new rockers, engine sounds very close with the original rockers. Glad everything is good with your jeep!

Mountainman · **Posted:** Wed Apr 30, 2014 10:21 am

Thanks for the specifics! I know my old 22RE's are notorious for tapping loud, but they run forever, so I didn't know what to think of these. I guess I'll trust my MAF readings until I tear into it to get the intake cleaned properly. I'll probably do studs and rockers then, even though my HG seems to be good ripping another CRD uphill at 65 :pepper:

Maybe that way I can avoid ever having to do a HG.

I've read quite a bit on the rocker threads, but havn't seen anyone mention a certain way to measure the rockers tolerances. Everyone talks about play or slop in them, but I guess I'll have to get hands on before I get the idea, I mean, if they are all worn, where's your reference for worn vs new? Maybe I'll order one new one :dizzy:

geordi · **Posted:** Wed Apr 30, 2014 11:35 am

The main way to know if they are bad is if the roller isn't "raised" in its position between the two sides of stamped steel.

If it is level or just about level, then it has either worn the needle bearings or the roller itself has worn. There should be about a 1/16" difference between the top of the stamped steel and the top of the roller.

Now, if the rollers are wobbly or any of the steel carriers appear cracked or bent or scored, or the lifters come apart when you wiggle them out of their wells (they just sit in there, but they are closely machined) then that is a bad one too.

Mountainman · **Posted:** Wed Apr 30, 2014 12:32 pm

Many thanks, you guys are the best :rockon:

I guess they will have 170k on them by the time I get in there, so maybe I should just change them as cheap insurance. I also hate to drop another $400 on studs, but if it saves the head in another 100k, then I guess it's a no brainer :BINGO:

Metal on metal tap tap tappy!

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