Question : '91 Z34 LQ1 Clacking Above 2,000 RPM - Lifter?

[Patrick Keller]

Hello everyone. Although I've just become a member of the site I've been here many times since I bought my car back in 2001. I bought my performance chip from WOT-TECH and I'm very thankful it was made available. It's my first car and I love it, but when it hit 215,000 miles it started to have serious problems. Two top-end rebuilds and one bottom-end rebuild later and I have a new noise. Mechanics either won't touch it or they don't know what it is so they recommend a fresh rebuild at thousands more than I've already spent.

So I've decided to go it alone... plus three friends of mine that love the car and to turn wrenches with me. Plus all of you.

Here's what happened. This past May, I started to hear a bit of a ticking noise. It got worse until it became very loud Memorial Day weekend. I parked it at first, then limped it to the dealership that had been working on it (because no one else would) and they said rod bearings and they wanted to replace the motor. I limped it back home.

Eventually I borrowed a hoist and had my neighbor pull the engine and replace the rod bearings. We thought the sound was coming from cylinder #1, and that rod did have the worst bearing. All of them were bad though. When he got it all back together (he did it from the bottom of the engine and didn't touch the top-end) it made a loud clacking noise at idle. It appeared to be coming from cylinder #1. Different than the rod bearing noise, and we used a scope to determine it was a cam carrier noise, but vibrations are tricky so we could be wrong.

I asked what oil my neighbor used and he said 10W-30 so I got some 5W-30 and we put that in. No noise at idle anymore, but now when you rev it past 2,000 RPM it starts clacking loudly (it only gets faster with more gas, not louder or quieter) and up around 2,500 RPM it will also bog down a little bit and the exhaust smells like gas. I put Seafoam (half a can as recommended) into the crankcase and half into the gas tank and there was no difference.

I took it to a local shop that said they would look at it and it made the 8-mile trip there and back without any change. They wanted to pull it and send it somewhere to rebuild again so I just said no.

I hear no valve plinking off the piston, it still has the same timing it had before, and the rod bearings are new. My friends and I believe it is a dead lifter on the exhaust valves of cylinder #1. The dealership mixed old GM lifters with new aftermarket ones to make a complete set and I think one of the old ones may have gone. No, I didn't have a choice in the matter. They had to send back so many bad lifters that the aftermarket company they were using refused to send any more.

Are you able to tell by my tale of woe what is wrong? If it's not obvious I can get a video posted. Thanks very much.

[1988GTU]

You are probably hearing the piston smacking the head/valves.

Pull the entire motor, and have at rebuilding the entire engine. A machine shop will be needed at minimum to check and correct parts bringing them hopefully back in tolerances.

Before going all that rebuilding route, look for a crate engine on the flea bay markets that someone is offing with zero miles. There were a few here and there popping up not long ago.

[robertisaar]

certainly could be a lifter.

http://wot-tech.com/shop/gm-60v6/91-96-3-4-dohc-lightweight-lifters/prod_276.html

Ben still has the lightweight upgrades listed.... the only stock replacement lifters i'm seeing are the clevite 213-1784 pieces(and there aren't that many sets still out there)... the acdelco p/n is 17108288, but those are going to be difficult/impossible to locate.

$300 for stock replacement lifters(the one auction on ebay i can see for those clevite parts) vs $320 for the ones Ben lists....

[Patrick Keller]

To 1988GTU: Thanks for the quick reply. One concern my neighbor did express (well actually his dad) was that the heads were machined down too far during the second rebuild. I have had it where the valves were plinking against the cylinders when I lost the timing tensioner a couple of years ago on the way home from work. This isn't that sound at all, but I never considered the piston smacking the head itself. It's a NY car and although I love it, if it's not this engine I'll have a tough time justifying even to myself replacing it with another after having spent so much already. This would be my last resort, but I do appreciate the feedback.

To robertisaar: Thanks also for the quick reply. I did order a set of those lifters about a year and a half ago and installed them with a friend in the garage. They were so loud, all of them, that we abandoned that idea and I went back to factory. Thank you for the part numbers. I did see the Clevite and I saw where I could get 1 each for $25, so that was exciting. I may have the last few of the ACDelco ones under my hood from last year. I also have the original lifters from my car somewhere in oil. Not all of them, since some were bad. I have the ones that were still good, but over 20 years old. I could try them just as a free and available basis for comparison to see if there is any change in the noise - to verify that it is in fact lifters and not a piston smacking the head/valves.

It looks like this isn't as cut and dry as I was thinking, so I'll try to get some video with sound posted soon. Thanks again!

[1988GTU]

It could be a worthwhile engine change while upgrading to the 97 TDC engine. Slight increase in efficiency, most likely cheaper cost, & parts that are dated not as far back as yours.

[SappySE107]

The lightweight lifters are a little noisier than stock but not that bad. How long did you run them? Sounds like you may have worn out cam carrier bores for the lifters if you gave them all enough time to fill with oil and work properly. Fresh lifters should be bled down so they give. It will clack like a son of a bitch for about 5 min before it smooths out.

I run 20w50 in mine and it works great. Mostly noticable after a 20 min session on the track but even on the street, I noticed it was quiete.

[pocket-rocket]

I would recommend the oil Ben suggested as well.

I ran 5w30 Mobil 1 and Lucas and while it was fine putting around town if I kept my foot out of it, if I got on it a good bit or did some good distance driving down the highway it would clatter pretty bad too.

This was in my 92 with the lighter lifters and a factory replacement engine for the original that had the oil pump fail under warranty, and I do not believe it had the top end oiling update.

[robertisaar]

so, even with a stock engine(and being an early one at that, should be with the radiator-based oil cooler), xW-30 isn't sufficient for a LQ1?

[pocket-rocket]

If it lacks the oiling update, I would say no (at least from my experience).

It's something I battled in both cars, especially in the 92 and more so after the lighter lifters.

I forgot what year it was, but Ben had told me that engines produced after a certain year (I want to say 95, but don't quote me) had the oiling revision from the factory.

The LQ1 may have a larger oil pump and an oil cooler, but it also has twice the lifters and valve springs.

Nothing for me was as embarrassing at the track as returning from a run only to have to hold a high idle to pump those stupid things back up, just to have the clatter return again, lol. That's why I tried the Lucas. Then when I drove it to the last meet I actually had a car at, when I got there it was clattering like a banshee despite driving like any sane person on the highway and having a fresh oil change with 5w30 Mobil 1 and Lucas in the crank case.

[robertisaar]

alldata is showing the TSB for the oiling update(57-61-09, dated november of 95) applies to all 94-earlier engines and only 95 lumina/monte carlo built prior to VIN S9148603.

mine is from a 95 GTP, so it should have the factory update... i'm still considering a 5W or 0W-40 though if it's that close to the edge of being unsuitable.

[Schurkey]

http://60degreev6.com/forum/showthread.php/49738-LQ1-Service-Bulletin-57-61-09-Lifter-tick-%28cold%29

The lifter-tick bulletin was for clatter especially when cold. Goes away when warm. The bulletin is easy to perform if the cam carriers are off the engine. Do-able "on the vehicle" but not near as much fun. Most difficult part is finding (or making) the thinner cam retainer plates.

"I" would clean the lifters before I blew ~$300 on new ones. Again, not hard, but something of a PITA.

http://60degreev6.com/forum/showthread.php/49680-1993-3-4-DOHC-quot-Lifters-quot

Therefore, I suspect other problems if your lifters clatter when the engine is run hard. The first thing that comes to mind is air entrained in the oil leading to foamy oil and therefore compressible. I'd be wondering about oil level--specifically, if running a quart low would reduce windage and promote non-frothy oil. Ever checked the dipstick to verify it's providing a correct level measurement?

Lucas oil additive is known for creating a froth--foam problem. Seems it' won't let-go of the air that gets whipped into the oil. I'd drop the Lucas like a broken rubber.

I'm also very suspicious of the need for thick oil. Maybe that's my bias. How hot do you get the oil? Ever verified oil temperature? First guess: Plain ol' 5W30 with NO LUCAS is better than the thick stuff you're running.

[Patrick Keller]

For some reason I stopped getting emails that people were replying. Sorry it's been a while since I was on. I had a lot going on.

The other day I recorded the noise in a video. I couldn't get it to upload here so I made it a public Facebook video. Let me know what you think. Also let me know if the video doesn't work. I'll try YouTube next I guess. As far as the type of oil, I've had no problems at all with lifter noise using 5W-30. Even now it's only that one spot on Cylinder 1. I would think I'd get all lifters making noise if oil was to blame. It had thicker oil in it when my neighbor first finished the rod bearings and that was louder.

Sorry this video is awful. The sound is out of sync and cuts out near the end, but I think it's enough to get the point. I'll be getting a better phone in a couple of months.

Let me know what you think it is please.

https://www.facebook.com/video.php?v=781735259327&l=8716667650498289014

[SappySE107]

I haven't heard a lifter sound like that yet.