[Nick S]

On my August 1977, CA 78 spider, my factory owners manual states that the timing chain adjustment is done with the engine at idle, loosen the lock bolt, wait a few seconds and tighten the bolt.
Pat Braden's "bible" suggests two other solutions. Pushing the car forward in 5th or taking off the cam cover and doing it "hands on".
Has anyone done as suggested in the owners manual or as Pat suggested?
Thanks,
Nick

 

[ghnl]

If you are sure the locking wedge isn't going to stick, then you can try the 'loosen bolt with engine idling' method. The problem is the locking wedge does often stick. Without removing the cam cover and doing it the 'pry bar' method, how will you know if it tensions properly or not?

BTW, do not remove the locking bolt - just loosen it 1/2 - 3/4 turn. If you loosen it too far the nub on the end of the bolt will no longer be engaged in the locking wedge...

 

[Andrew]

Many of us do not believe in the idle method of chain adjustment. I do it with the engine off, stationary. Remove the cam cover, loosen the lock bolt a bit, "help" the tensioner a small amount with a big screwdriver or crowbar. Don't really push, but just assist the spring in the tensioner. Lock the bolt down, turn the engine over by hand a couple times to ensure no interference, button it up.
While you have the cam cover off, if you're so inclined, you can check the cam timing and valve clearances.
Andrew

 

[Saar]

I don't like doing that kind of work with the engine running.
I think the 5th gear idea is much safer.
Saar.

 

[Andrew]

The spring is not really strong enough to deal with the forces involved with the engine idling. Yes, "rocking" the engine in a high gear and watching for full plunger extension works. I personally would never do this withough removing the cam cover, to ensure that what I think is happening is in fact happening.
Andrew

 

[valvo0]

Can anyone tell me if it is possible to have the chain over tensioned.

I am saying so because my chain has no slack at all and seems quite tight.

Is this normal ?

Thanks,

Robert

 

[Andrew]

Yes, it can be too tight. The result is that the lower half of the exhaust cam front bearing surface starts to wear and gall.
It shouldn't have any slack to speak of though. This isn't a rubber belt.
Andrew