Chattering noise from head after a track day

[nando]

try taking the belt of the waterpump, start the car and see if it goes away. Another guy just had a 2500 mile Graf water pump fail on him, made some awful noises. Just because it's new doesn't mean it's good!

[Sagaris]

Danger to the manifold?

[jlevie]

Since this could have serious consequences, I'd treat it accordingly and not drive the car until the cause has been found and fixed. A mechanic's stethoscope may help identify the source of the noise. A bad timing belt tensioner or water pump are possibilities. But it is possible that the noise is coming from the head. If so the head and if there's nothing obviously wrong, the head will probably have to come off and be torn down to find the problem. I'm thinking worn cam journals/bearings, rockers, or valve guides.

[briansjacobs]

The car still ran great and pulled fine. I took it out another session and ran my FTD with it.
Any ideas?

well you know they say the motor makes the most power just before it blows up because everything is nice and loose.

Good luck

[JGood]

Bump. Going to do a leak down test this weekend, any ideas of anything else to check?

[JGood]

are any of the clips that hold the rockers in place loose/worn? I had some that were actually so worn I could move the rockers side to side 1/4". it was pretty noisy!

I actually didn't check for that. But when I was moving the rockers around to measure the valve gaps, I would think I'd notice some side to side play, if it was bad. I'll take a look if/when I pull the valve cover again though.

[nando]

are any of the clips that hold the rockers in place loose/worn? I had some that were actually so worn I could move the rockers side to side 1/4". it was pretty noisy!

[JGood]

Car is an 87 325is. Stock m20b25, with a chip and long tube headers. I put this motor in last year (pulled the stock motor because it had 270k miles), and have approximately 6 track days on it. It has about 140k miles. It pulls hard, feels great. Dyno'd 145whp & trq, and has a smooth powerband.

I was at NJMP last weekend, and after one of the sessions, went to go get gas. I noticed some additional valvetrain noise at 2100-2200 on up, along with a higher idle (900-1000). The car still ran great and pulled fine. I took it out another session and ran my FTD with it. But it's still making the noise. Right at 2100 or so, it starts making a loud chattering noise, and it sounds like it's coming from the front of the motor, possibly the head. It's similar to valve tap, but a little different.

I pulled the valve cover and checked all valve clearances. One was a little loose, so I got it back into spec, and ran the motor. It's still doing it. It does NOT seem to do it when cold though.

The water pump does appear to be making some noise at idle, although that, the belt, and tensioner are new from when I put the motor in the car (~1 year and 2k miles / 6 track days).


Any ideas?