Thread: Cam Pulley Markings

after a massive responce from the forum.....

I decided to find a cam sprocket matching the manual which I got very cheap second hand from the breakers. they did also have one sprocket that matched mine but the manual I have does not cover that type.
I just hope the chain won't complain about the new wear pattern if any on the teeth - looks still good in my opinion.
Let's hope I can get the marks in lign such that the drive side tesion is sufficient. If not I still don't understand the concept of selecting the next keyway but then the mark ligning up with the bolt hole in the block is no longer in place?
Hope someone who is familiar can share their experience with me.
Cheers James

There are six keyways in the cam gear for a reason. They will each give you slightly different timing. You need to select the best one. I don't know if SIII engines are different, but on a SII/SIIA engine, you time the cam via the exhaust peak mark on the flywheel. This is meant to align when the number one exhaust valve is open at it's maximum. This is found while using a dial indicator. When I rebulit my engine, it took me nearly two hours to get the camshaft timing perfect, as it happened to have the best timing on the sixth keyway that I tried.

The 180 deg out would mean that you would have been timing the cam to number four instead of number one. Rotate the crank 360 deg and the cam will be back on number one.

Aaron.

Thanks mate.
I don't have an inspection cover on my flywheel so I will have to use the correct cam pulley rather than looking on the flywheel.
How tight did the chain have to be on the drive side without pulling back the crank?

Regards James

There is a tensioner in the system, so there is no slack anywhere. When timing an engine, only rotate the engine forwards, to get rid of any backlash.

Did you get a new timing chain? They do stretch. To check for stretch, wrap the timing chain around the cam gear. Pinch it tight at the bottom. If you can get any movement at the top of the cam gear, the timing chain is stretched.

Aaron.

I decided to make another plan so I first fitted the correct sprocket and set the cam to correct position. I then refitted the original sproket with the strange marks and turned onto each of the 6 keys until I found the tightest fit, marked the key, removed and rechecked with the other sprocket that nothing had shifted and then finally refitted the old sproket, chain and tensioner.
After all that I had a stiff whisky and off to bed to dream of a more powerful series