Sprint Cam Timing

[Ministrone]

I posted earlier in the year regarding rough running of my Sprint engine following a a cylinder head rebuild and skim. The forum gurus suggested the cam timing may be at fault and guess what, it is.

After I refitted the head and the timing gear refitted, this is what the cam looked like with the crank at TDC.


This measures around 8 degrees at the crank pulley

I stripped the timing cover off, the chain pulleys are clearly worn and I ordered a replacement kit from Robsport.
In the meantime, I tried moving the cam pulley over one tooth and this is how it sits now.


This is closer at 5 degrees but still not right
My question is, where do I go from here? Do I need a vernier cam sprocket? Would the new chain and sprockets help to correct this (unlikely).

[soe8m]

Are you using dail gauges and have the exact tdc measured etc?

You can't time an engine using some marks. These are just an indication.

Jeroen

[Ministrone]

I checked the factory timing marks with a DTI and they are spot on. I will double check though.
My new chain kit and sprocket kit has arrived so I’ll fit that and see where the marks fall.

[soe8m]

The cheapest way is to fixate the cam at correct timing. Fit the sprocket 90 degrees off and mark when all timed. Then drill new holes in the sprocket and all should be lined up.

Jeroen