M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: BoostedEverything on February 03, 2009, 06:40:55 PM

Title: Bent valve stems?
Post by: BoostedEverything on February 03, 2009, 06:40:55 PM

I have two M42's I am tearing down... on one of them, with the head off and the cams out the valves look a little uneven in the head and not flat with the edges. About 8 of the 16 are sticking out further than the rest... should all the valves be pulled in, flat against the top of the combustion chamber when there are no cams in?

Title: Bent valve stems?
Post by: colin86325 on February 03, 2009, 07:11:22 PM

Yes.

Sounds like the valves are bent.

Title: Bent valve stems?
Post by: BoostedEverything on February 03, 2009, 07:37:43 PM

Yeah, that's what I figured... the pistons are perfect through, must have *just* tapped the carbon on them. Damn. Oh well.

Title: Bent valve stems?
Post by: nomad on February 03, 2009, 07:52:41 PM

A finished head in good shape will have the valves just barely protrude past the surface of the head. They have to remove the valves to resurface these heads properly.

If it is 8 random ones that are not seated correctly in the valve seats then yes they are bent.

Got pics?

Title: Bent valve stems?
Post by: nomad on February 03, 2009, 07:53:46 PM

Or, drip a little oil in the ports with the head sitting flat ona piece of cardboard. This will show if there is a poor seal.

Title: Bent valve stems?
Post by: BoostedEverything on February 03, 2009, 11:25:41 PM

Upon closer inspection, the poor bastards are CLEARLY bent, I was hoping for... I don't know. I'll snap some pics, just in case there arent enough pictures of damaged valves in these timing chain eating interference motors.

Title: Bent valve stems?
Post by: CCE30 on September 06, 2009, 12:34:46 PM

A little late, but did you ever get a chance to snap some pics?