Timing

I've lost, misplaced, or more likely put it in a very safe place and cannot remember the dimension of how far the piston is down the bore at 28degs BTDC with a DTI through the plug hole.

Can anyone help?

Cash

I use 5,2 mm setting ignition.

/Per

Thanks Per, that's what I use with the head off but the measurement changes when the DTI isn't directly in line.

Cash

Yes, need to be re-calculated but you need to know the angle first and unfortunately I don't know what it is.
I did a check with my head removed (using the 5,20 mm) and got confirmed the timing mark was correct so I did never need to do any re-calculation.

/Per

I fitted the degree disc and the measurement came to 0.362" for 30deg BTDC. That didn't ring a bell at all and seems way out. The plug adapter I used I bored some years ago at an angle to reduce the plug angle effect and perhaps I didn't have it indext correctly, or the DTI a fairly new one is geared wrongly, I reckon neither would matter finding top dead.

Thanks once again,
Cash

Even with 30 degrees instead of 28 and an angle on the indicator this value seems very high.

When I did my check I did it with the head off, fitted a magnetic stand with flexible arm using an indicator clock to ensure I got a good reading. I then locked the auto advance at fulll advance, set the 5,20 mm piston position and checked that the original ignition marking and it was at approximately 27,5 degree (same at both sides) so I cut a slot at 27,5 (of the same width as the alternator marking) so it would be easy to use with the strobe light. It works fine!

/Per

Hi there , could be interesting to know the variation between degree versus mm/inches at those piston heights ( timing marks), as it seems difficult to read accuratly ten thou through the plug hole..........