Upper timing chain cover removal

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ytr1903
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Joined: Wed Sep 14, 2016 10:38 pm
Location: Southern Illinois

Upper timing chain cover removal

Post by ytr1903 »

I have a leak at the bottom of my upper timing chain cover and finally decided to replace the gaskets, etc. I have removed the distributor cap and rotor and now see that there is an "adapter" that attaches the rotor to the camshaft. In order to remove the chain cover to replace the gaskets this adapter has to be removed. It is held in with an allen head bolt. I have put quite a bit of torque on the bolt but it won't budge. So instead of just blundering forward, I better ask whether this bolt is a normal thread or a reverse thread. Any other suggestions are welcome. Thanks in advance for any help.
Tom
1989 BMW 635Csi Automatic 3268183
2006 3.0 Z4 Convertible 6 speed
Pod
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Re: Upper timing chain cover removal

Post by Pod »

I’ve removed these on many occasions and don’t recall there being a left-hand thread (but don’t blame me if I’m wrong!). Possibly it’s been “Loctited” in which could account for the problem. Have you tried using a little heat on it?
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hornhospital
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Re: Upper timing chain cover removal

Post by hornhospital »

According to the parts breakdown, it's a M8X40-8.8-ZNS3, part number 07119902984. No mention of it being left hand thread. I have one apart at my shop I could check, but it'll be a little while. I don't recall any LHT bolts associated with the head/cam.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
ytr1903
Posts: 21
Joined: Wed Sep 14, 2016 10:38 pm
Location: Southern Illinois

Re: Upper timing chain cover removal

Post by ytr1903 »

Thanks so much for the replies. I just got in from a successful trip to the garage. The bolt is definitely right handed. I was able to get a small butane torch in the recess, put some heat on it and the bolt broke loose! I will now move forward to repair the leak and put it in a new distributor cap and rotor.
1989 BMW 635Csi Automatic 3268183
2006 3.0 Z4 Convertible 6 speed
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