Bad head / gasket - HELP

[bummininca]

In have a 92 e34 m50 with a bad head. I replaced the head gasket myself but did something wrong. Now when I try to start it there is a mechanical banging sound. My mechanic wants $3000 to do a top end job. I cannot afford to spend that money on this car. Do I have other options? Please help. I love this car and want to drive it again.

[repenttokyo]

buy a used head, or a used engine. you should be able to get a used engine for under 1k.

[Ross]

Valve timing wrong?

[Dave M]

Why does your mech think you need a top end job? What else does he 'know'?
Does the engine fire?
Did you crank the engine over before you re-assembled and started it?
Did you follow a repair manual?

If you did the gasket yourself, you're capable of removing the head again (rather quickly if you've done it before) and inspect the valves and pistons. If they aren't damaged, go through the timing procedure again (making sure piston # 1 is at TDC this time ;) -just pokin fun) and hope for the best. That way, you're only out a head gasket and bolts. $hit, for investigative purposes, I would just re-assemble with the same garket and bolts, then re-do if it works.

Dave M

[632 Regal]

Id guess the valve timing was off and it bent some valves. Like Dave says pull the head off, replace the bent valves and put it back together but do the timing thing correctly.


Why does your mech think you need a top end job? What else does he 'know'?
Does the engine fire?
Did you crank the engine over before you re-assembled and started it?
Did you follow a repair manual?

If you did the gasket yourself, you're capable of removing the head again (rather quickly if you've done it before) and inspect the valves and pistons. If they aren't damaged, go through the timing procedure again (making sure piston # 1 is at TDC this time ;) -just pokin fun) and hope for the best. That way, you're only out a head gasket and bolts. $hit, for investigative purposes, I would just re-assemble with the same garket and bolts, then re-do if it works.

Dave M

[Phatty5BMW]

This sounds like a post im going to post when and if my head gasket blows ... (hopefully not) Good luck man

[Ferret]

An interesting point - the first M50 I did, I knocked one of the cams out by a tiny amount and it wouldnt start properly - and banged terribly - despite the fact the valves werent striking.

You might be getting detonation while the valves are still open, or the valves opening while under high compression.

[bummininca]

Thank you to all. With regard to post by Ferret... Did you just pull the head back off and do a visual inspect of the valves, then re-time and it worked?







An interesting point - the first M50 I did, I knocked one of the cams out by a tiny amount and it wouldnt start properly - and banged terribly - despite the fact the valves werent striking.

You might be getting detonation while the valves are still open, or the valves opening while under high compression.

[Dave M]

Thank you to all. With regard to post by Ferret... Did you just pull the head back off and do a visual inspect of the valves, then re-time and it worked?

I'm not Ferret, but.......

If your cam alignment is out a bit (not sure about the banging noise), you can just pull the head cover, remove the secondary timing chain/sprockets, and adjust the cams accordingly. No need to pull the head IF you're sure you have #1 at TDC (check the OT mark on the harmonic balancer ;) )

Dave M

[Zeuk in Oz]

Thank you to all. With regard to post by Ferret... Did you just pull the head back off and do a visual inspect of the valves, then re-time and it worked?
May I suggest that you have nothing to lose by removing the head again - it sounds as though that is where you will find the solution to the problem, whatever it is. You can then perhaps diagnose what the problem is.

If at that stage you think you can fix it or correct it, well and good. If you need to get another engine or take it to a professional, then you can decide.

First get the head off and see if you can't see what is going on.