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Valve adjustment question
Posted: Sat Dec 16, 2023 12:50 am
by Hugues
Hi guys
I have a 710M and would like to check my valves adjustment gaps.
The Pinz repair manual says that I need to measure the gap on the cylinder 1 valves when the cylinder 4 valves “overlap”.
What is meant by “overlap”?
Re: Valve adjustment question
Posted: Sat Dec 16, 2023 6:29 pm
by compunerdy
Re: Valve adjustment question
Posted: Sun Dec 17, 2023 8:30 am
by pinzinator
Overlap is the position of the cam when both valves are completely closed.
Re: Valve adjustment question
Posted: Sun Dec 17, 2023 1:08 pm
by Hugues
pinzinator wrote: ↑Sun Dec 17, 2023 8:30 am
Overlap is the position of the cam when both valves are completely closed.
Yes, although this situation happens more than once per cycle, i just realised today.
I think the overlap position the Pinz manual is referring to is the following:
"the overlap position for a given cylinder is when its exhaust valve is almost closed, and the intake valve is just starting to open."
This is the position you can see near the beginning of this online simulation:
https://www.geogebra.org/m/fmhfXxu9#material/fCHTsj4R
and pictured below:
- overlap.png (186.27 KiB) Viewed 1333 times
I have managed to adjust my valves today, a few were around 0.3mm rather than the 0.20mm prescribed in the Pinz manual.
And indeed, when you place cylinder 1 at TDC, cylinder 4 valves should overlap, as described above, so exhaust valve is almost closed while intake is starting to open, this is what I observed on my Pinz.