Got a knocking sound up top. It's only at idle, it disappears as soon as the revs come up. This noise came up recently. The car has been sitting a LONG time (over a year). Don't know if it could be bad gas?

Other changes that may contribute:
- new spark plug wires
- new valve covers and gaskets
- changed oil to synthetic 10w30
- new filter
- new headers and gaskets (though I know it's not a leak, been over 'em like crazy)

Readjusted all the rockers and installed the new posi locks.

The "knock" does not appear instantly, I start it up and after several seconds it comes on and gets louder... if I rev it goes away. You can put your hand on the valve covers or timing cover and "feel" the clicking/knocking. Oil pressure looks good all over...


:scratch: :scratch:

 

It could be pinging from the old gas.

 

collapsed lifter? :scratch:
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LaCremo live

 

I know pinging, it's not that. Pinging is on the high end as far as RPM goes, usually under load and it's not even similar sounding to this situation.

 

I'm gonna go with sticky or bad lifter. We had a similar situation with a *cough*minivan*cough*

Might try a quart of transmission fluid next oil change if you think it might be gummed up. The detergent in tranny fluid will sometimes free things like this up.

 

I'm leaning towards the lifter too since I did just change the oil and went to synthetic for the first time. This may have magnified the issue?

Are there any detergents on the market that anyone has used successfully?

 

ahhhhh, the "s"-word :shock: How many miles on your engine? Syns can start some funny things on engines, esp if they are moderate-to-high miles.....

RE: trans fluid, I've always heard about doing this, but never had the cojones (Mber won't have to look that one up, he hears it at the C. Lodge all the time ) to try it myself. Let me know how it goes
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LIVE SEX WEBSHOWS

 

Around 3,000 miles...

 

I agree with the lifter, sounds like leak down. A small piece of dirt where it shouldn't be. The ATF does do a good job, the safest bet for a cleanup. These is (or was) a product made by Silo called Hydra valve clean. It was also very effective at removing lifter noise.

I do not think the synthetic oil is to blame, it is a 10w30 viscosity, one of the qualities of synthetic is the stability of the viscosity.

 

ah, only 3k...thats not an issue, then.
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WEB SHOWS

 

I have a couple of cans of Rislone in the garage. Dont know if they are still on the market. I have used the ATF before.

Hows the vacumm? Steady? Fluctuation?

 

I put all new gas in and used a product designed to clean and attack noisy lifters. Sounds to me like the tick is not just at idle, but throughout the range (just difficult to hear over the other noise).

I'm letting it run for awhile to see if it gets noisier or quieter.

Looks like I will drive this ZERO days in '04. If it is a collapsed lifter I'm probably going to pull the cam and replace it and the lifters if that is the obvious cause... otherwise I may be building a bigger mess this fall :stubborn:

 

In my experience, a sticky lifter will free itself after the engine warms up, and the symptoms will go away. I guess you're sure it's not valve lash adjustment?

 

Not sure on the valve lash idea. We are gonna do a vacuum test since you can learn a lot from that. Other basic thing I need to check is that all the plugs are tight ... years ago I had a 200ci that the plugs would wiggle loose on and you could watch them dance while the motor was running, looked like the rubber pencil trick.

Anyone think a PCV valve could contribute to this?

P.S. > After running it awhile yesterday it did seem to quiet a bit near the end when it was really hot. Perhaps the detergent started to work through a lifter?

 

My spelling vacuums !

 

Sounds like the car has been sitting for a while. I'd definitely run it some before tearing down - probably just a lifter having a hard time getting "pumped back up".

 

I was thinking the valve lash as well. Pop that valve cover off and see if any of them are loose. My car has solid lifters and I had trouble keeping a few of them adjusted for a while and you did notice it more when the car was at idle....once it bent a pushrod as the rocker arm jumped off to the side and wore into the rocker arm stud and broke it. Evidently the previous owner forgot to mention this problem because I could see where the pushrod had worn a groove in the head :angry: