Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Best way to find true TDC on an single cam (8 valves)

How to Degree a Cam

Relevant Module: Practical Skills > Finding True TDC

Forum Posts



Tech Articles

Discussion and questions related to the course How to Degree a Cam

= Resolved threads


Hi, what would be the best way to find true TDC on a single cam engine, when the cylinderhead is already fitted?

Is this even possible? Because unlike a twin cam engine i dont have a spark plug hole directly above the piston.

On my engine the spark plug holes are above the injector holes so theyre abit under an angle if that makes any sence.

So it would be hard to measure the top of the piston.


Hey Niels,

With a piston stop it won't matter where the spark plug hole is as it takes the average of the measured angle you get in both direction. In other words, the piston will hit the stop at the same spot in both direction.

With a dial gauge, there's a risk that the tip would slide on top of the piston as it's on a angle so I wouldn't recommend this method.

Just what Frank said.

If you buy an adjustable one - different engines will use different 'plug positions and angles - I'd suggest grinding or filing the end so the threads can't mar the piston top.

Mine was made from an old spark plug I gutted and brazed a stop into.

Hey guys, thanks for the replies! i didnt think of the piston stop! Cheers

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?