troubleshooting the terrible tick

[alpineG]

Hi guys, so glad to be back after a long hiatus. I bought my e30 back from the guy I sold it to, and we have some problems...

Most issues I can fix (tails, seats, general maintenance) but I am wracking my brain over this one and praying it isn't a rod.

Been experiencing a terrible knock, that is constant (not intermittent) that gets louder as I rev the engine. I feel like it happens too quick to be just one cylinder so I'm hoping it's something simpler than I'm assuming, or I could need a new engine (darn :D)
I did a valve adjustment hoping that was the problem. The knocking seemed to get quieter but not by much. All the rocker arms are fine, nothing seems damaged that I can see in the valvetrain.

Here is a video of the knock.

https://www.youtube.com/watch?v=OIOo6Jd ... e=youtu.be

And here is a shot of spark plug from Cyl #2.

http://imgur.com/NTStWjh

All of the plugs looked like this and the inside of the wires on cylinders 2 and 5 looked pretty foul.

Any help is greatly appreciated.

Nice to be back, y'all :)

[crappycoco]

Link to the video is broken =)

[alpineG]

sorry about that. here is a link that works hopefully.

http://youtu.be/OIOo6JdV1a4

[dnguyen1963]

Does not sound good at all. Open up the valve cover to see if anything broken. Use a stethoscope to see where the noise is coming from...most likely the bottom end.

[jeffnhiscars]

I vote wrist pin although I would rule out a very bad lifter first.

[Ether-D]

Mine sounded like that when it had a valve that was bent and sticking in the open position until the piston forcibly closed it as it slammed into it on the up stroke each revolution. That's definitely a real bad noise. Sorry bout your luck.

[alpineG]

Like I said in the original post, I opened up the valve cover because that's what I thought it was in the beginning. Did a valve adjustment and went over everything under the cover and nothing seems bent or broken in there. I cannot of course see the valves so it very well could be a bent valve.

[TobyB]

Yick.
Roll it over slowly and see if any rocker gets a lot of lash,
otherwise, wristpin.
Or a spark plug falling out of it, or a hole in an exhaust manifold.

Mechanic's stethoscope for $8.99 might help a lot.

t

[Som]

http://youtu.be/5Aiq2TQq-S8

That's a video of knocking I had when I swapped my head. The second half of the video is me rattling the timing belt cover to hear the comparison -- my hope, at the time, being that maybe the knocking was the cover rattling and not piston-to-head clearance.

Turned out to be a clearance issue. Machine shop over-decked my head and my pistons were hitting the head. Took the head off, put on a thicker gasket, and the sound went away.

It sounds like the same sound to me (though yours is louder). My guess would be the piston hitting the head. If there was no head work done prior to this sound, though, then something like the wrist pin makes more sense. Full disclaimer, though, I don't know what a valve to piston impact would sound like, so maybe it would sound the same, too.

Good luck!

Som

[razo-s.supra]

I bought a junker e30 that sounded just like this. It was rod knock. Try getting a stethoscope from harbor freight to listen closer or as its running iirc disconnect and reconnect each plug wire one at a time. If the noise gets quieter than that's your problem cylinder.