Lets discuss wrist pins and the sounds they can make.

NYSpeed Automotive
1

Trying to diagnose a persistent tick/knocking sound from the top end. I have eliminated the head from being the issue by changing lifters and the actual head itself.

The noise is from the bottom end, but the sound is the loudest from up top towards the exhaust side of the engine.

Possible issues:

Rod bearing - Doesn’t sound like it
Wrist pin - Could be
Arcing plug wire - have been removed and installed many times and are new
Exhaust leak - New manifold, new gaskets

The engine has been bored to a 2.9L with forged pistons/rods. Has about 100 miles on it since work was done. These type of pistons are known to slap until warm, but then go away. My tick/knock is loud and persistent all the time and at all rpm’s.

Discuss…

http://i26.photobucket.com/albums/c136/jxaxexgxexr/HPIM2722.jpg

2

You aren’t comsuming any oil, right?

EDIT, can you take off the oil pan to inspect each bearing?

3

I know you said persistant all the time, it ticks with and without load on the engine? Right?

I would guess wrist pin. Do the cylinder walls look like there is any scoring?

4

I broke a wrist pin in my grand prix back in the day…sounded like lifter tick, only it wasnt in time with revs.

5

no oil consumption, no smoking.

It is a persistent tick that increases with rev’s. SOunds like someone is tapping the head with a small hammer.

I would swear that it was a lifter or in the head, but I changed lifters, and then heads.

6

EGR valve gasket leaking?

Sounds funny but the exact thing just happened to me. I changed my lifters and thought I was done, but that elf was still hidden under my hood hitting my block with a hammer. Then I hit him with my intake, and put a gasket on.

7

Can’t be the EGR valve gasket, because I no longer have one.

I just had the service manager from Autohaus VW come over and liisten to it. He says there is no way it is in the bottom end. Confusing part to him is that it is the same identical noise with both heads and new lifters.

One possible thing to check is an oil restrictor in the block feed passage to the head. Could be clogged or broken. Longshot though.

8

Did you check for a piston that has too much piston to bore clearance?

9

Wrist pins will make a double knock one at TDC and one at BDC. If you short the cylinder out it will go away if it goes away it is moot as the cylinder head and oil pan need to be removed. Check your oil restrictor for sure. Was there engine oil in the cylinder head when you pulled the valve cover off? Did you ever get a spec sheet from the guy who built it? Did you call him and what did he seem to think?

10

Found the problem…

A piston was just barely touching the head. Seems like the block being decked, in conjunction with the thin copper HG, caused the piston to literally be just barely touching the head.

I had a spacer from an old engine, which I put in. No more sound. So now I have the copper HG, SS spacer on top of that, then a very thin part of the OEM HG. I plan to run this for a while to check for any bugs, then have a thicker copper HG cut.

Thanks for the help guys.

11

lol, werent we talking about that too when we saw the copper HG. Balls. Good to hear the noise is gone. Was there any damage.

12

I don’t believe so…

13

helllllll yea, very good to hear man

14

:tup: