Timing guide rail screw put hole in cover

[Leumas]

Has anyone seen this before? It looks like this bolt came loose and put a hole through the cover... The threads are pretty bad and it didn't want to screw back in. I'm also afraid the threads going into the head are probably about the same...

'91 318 with 258k

Anyone know where I can get this bolt?



The bolt was near the top of the rail.


You can see the hole and wear marks in the upper timing cover.

[bmwman91]

I had the exact same thing happen to me, except for it wearing all the way through. I could hear an awful rattling coming from the engine at around 3000RPM and opened it up to find that the threads in the head were stripped and the hex cap screw was almost through the cover.

Sadly, there is not really any way to replace that threaded thing. It is an M12x0.75 thread, and the die for cutting that thread costs as much as a new guide rail & timing case gaskets!

What I did was use a fine triangular file to clean the threads, although I also have a lathe that I was able to chuck it up in while filing it. I was also able to drill out the bad threads in the head and install a helicoil without removing the guide rail. That involved a shop vac with some rubber hose duct taped to it to catch the drill chips.

[bmwman91]

Here's the thread I made about my issue. Hope it helps.

http://www.m42club.com/forums/showthread.php?t=13720

[masduro]

Wow! This happened to me too. The previous owner JB'd it, then it came loose and got stuck in the timing chain, then the motor blew up. Awesome.

[RobertC]

When you replace the new timing rail you are required to use a new longer bolt.
The original bolt is 5mm too short when using the new style guide rail.

The bolt is torqued to 89 in lbs. Use a dab of blue lok-tite. I have done about a dozen m42 guide replacements, that bolt should never back out. If it did then a mistake was made somewhere in the process.


06 GUIDE RAIL 1311247470 $53.24
only in conjunction with
Fillister-head screw M6X45 07119919629 $0.62

http://realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_4367&hg=11&fg=25