Sorry about the repost, but I need some help on this:
I recently had the head rebuilt on my 1993 M40 Touring. (new cam, lifters, rocker arms, valve guides , etc.)
When I got the cylinder head back, the the cam was separate from the tooth belt gear wheel. ( the one that the belt rides on to turn the cam)
When I put the pulley on the cam, I found that I can rotate the tooth belt gear wheel back and forth several degrees! The slot on the cam is larger than the key on the tooth belt gear wheel!
The cam is not worn, because it is new. The key on the gear wheel doesn't seem to be worn either.
It appears that the only way the timing is maintained on this engine is because of the bolt that holds the gear wheel on the cam provides friction.
Is this correct?
M40 Cam Pulley on Cam problem?
Moderator: martauto
It's been ages since I did mine but have a vague memory of this. I've just had a quick google and....quote from https://www.bimmerforums.co.uk/threads/ ... nt.115363/
When refitting the cam pulley, leave the centre bolt finger tight until the belt is on. Fit the cam locking tool (it's a steel plate that locks the cam at TDC), fit the new cambelt, tension it and then tighten the centre bolt. This is because the cam pulley has a few degrees of movement, essential because the cam is locked solid.
Hope that helps.
When refitting the cam pulley, leave the centre bolt finger tight until the belt is on. Fit the cam locking tool (it's a steel plate that locks the cam at TDC), fit the new cambelt, tension it and then tighten the centre bolt. This is because the cam pulley has a few degrees of movement, essential because the cam is locked solid.
Hope that helps.
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twright
- E30 Zone Newbie
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- Joined: Tue Sep 01, 2020 11:21 am
- Location: Indianapolis, Indiana USA
"When refitting the cam pulley, leave the centre bolt finger tight until the belt is on. Fit the cam locking tool (it's a steel plate that locks the cam at TDC), fit the new cambelt, tension it and then tighten the centre bolt. This is because the cam pulley has a few degrees of movement, essential because the cam is locked solid."
I put the engine back together, using the flywheel lock and the cam locking tool. After that I tightened the bolt on the gear wheel. It is working fine, but I am worried that the bolt torque alone is not enough to hold the gear in the correct location.
Won't it move?
I put the engine back together, using the flywheel lock and the cam locking tool. After that I tightened the bolt on the gear wheel. It is working fine, but I am worried that the bolt torque alone is not enough to hold the gear in the correct location.
Won't it move?