99Justin4.0

BREAKTHROUGH!:

I put it up on the ramps and stethoscoped around everywhere underneath, then up above. I found a really loud point right under the 4th (from front) spark plug. I checked into it. Plug was super loose. I'm jumping for joy at this moment. But the big hairy but comes in. Tightened it up and it sounded different, but still ticked.

I decided since I'd come this far I'd do a proper compression check, so I pulled all the plugs. All the plugs looked good. But when examining the plug that was loose compared to one of the other ones, I noticed the little washer gasket was all deformed compared to the other. I'm hoping that it's just not getting a good seal and leaking there creating the tick.

I couldn't do the compression check because my gauge fitting wont go in that far, so I'll figure that out tomorrow. I'm also just gonna replace all the plugs.

One thing I did notice though, is when cranking the engine without compression, there is no ticking or knocking whatsoever. I'm thinking I would have been able to hear a rod knocking if that were the case.

So tomorrow: Compression check, new plugs, and I'll update.

Any suggestions on plugs? Do 4.0's like or dislike anything special?

EZEARL

NGK plugs. Make sure there isn't an old or part of an old compression ring in that 4th cylinder.

CCKen

Spark plug application chart and Chrysler tech tip. The NGK ZFR5N plug is the recommended plug.



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99Justin4.0

Meaning make sure I didn't break a piston ring? I've done that in a boat engine and the whole plug was mangled (including everything else in the combustion chamber). This plug is fine, it was just loose and probably loose for so long in wacked out the plug seal.

I'll look through the plug hole good though.

Probably just gonna go with Champion or NGK. Those E3's look pretty sweet (youtube videos), but this isn't a race car.

EZEARL

"I noticed the little washer gasket was all deformed compared to the other."

I meant to make sure there wasn't an old "washer gasket" in the spark plug seat of the head.

99Justin4.0

Oh, yeah good thinking. It's really dirty down in there. I'm trying to clean them but it's hard without stuff falling into the hole.

salad

Yes NGKs coppers outperform Champions in reliability with the coil rail distributorless ignition in your WJ. (Which is a separate section for Grand Cherokees). E3s are a total waste of monet in these engines.

No need for Lucas oil stabilizer. Really bad idea with 5w40 anyway. Just buy the oil.

Good luck with the compression test!

99Justin4.0

Well compression came out, Back to Front. (Cold Engine):

159, 157, 155, 75, 169, 157

Looks like I got a stuck lifter. That's my best guess anyway. If that's the case, fine by me. It seems to run perfect, so whatever. I'll live with the tick. I've heard of these things freeing themselves too.

Any thoughts?

salad

Confirmed to be valve-related after pouring some oil in yeah?

99Justin4.0

ahh, no I didn't think to seal up the rings with oil. I put it back together. I'll do that tomorrow. to confirm it. I don't know any special tricks to unstick these lifters if that is the case either. All I'm familiar with is DOHC. This whole cam in the block and push rod thing is all new to me. It's got 50 miles on it since I seafoamed it. I think I'm gonna go another 50 and change over to the 5W40 and a new filter.

But If the engine starts, runs, and idles perfect, and it's not going to cease up on me, I'm a lot more comforted. I still haven't ruled out flexplate for the noise either.

I drove it all around town today and when I got home I put the infrared gun all over it. Here's how it went:

Front rotors: 104F
Frong hubs: 95F
Front drive shaft U-Joint: 98F
Rear drive shaft U-Joint: 110F
Pumpkin: 95F
Rear Rotor: 150F
Rear Rotor: 150F

It kinda seems like my very first thought is correct. It sounds like the rear brakes are constantly grinding away. My 97 Dakota sounded the same way when the brake pads were down to metal. Only difference is these aren't down to metal. But I can't see why the rear rotors would be hotter than the fronts regardless, they take way less of the load.

HEY STORM: PM me about those engines!

PS: Salad, is your signature a Kerouac quote? Sounds like something from "On the Road"...

salad

A couple guys on here swear by Marvel Mystery Oil for dissolving gunk that causes stuck lifters. I'd definitely follow up with the wet test, though.

That is odd that the rear rotors are toasty. Parking brake maladjusted?

Hunter S. Thompson, actually

99Justin4.0

Dude, I was gonna edit that post and say "or Hunter S. Thompson?". He was a little later than most of the stuff I used to read like crazy (Kerouac, Burroughs, Ginsberg), but fell into the same category kinda. I haven't read his work, but I've seen the movies. I have "Generation of Swine" but haven't read it yet.

Yeah, wet test later. When I do the oil change I'm gonna pull the pan. Maybe I'm slappin. Funny thing is, by the time I'd driven it home I'd already nicknamed her "slappy", and I hadn't even heard of the piston slap problem yet...

I read about 20 pages of past threads on guys who had it and just put in a new set of pistons. Some just let it go. If that's the case I'd like to get to it sooner than later.

I'm also pulling the access to flexplate after work. So once again, update later.

99Justin4.0

Just tested all the same points after a 10 minute drive home, and all are about the same but the rear rotors.

Rear Driver: 180F
Rear Pass: 270F

That's gotta be it...

s346k

I don't see how a collapsed lifter would cause low compression. a collapsed lifter wont open valves, not vice versa.

a leakdown test will pinpoint the problem.

CCKen

^^^ This for sure.