Hello club members
I am busy working to my Model 9 1936. I am currently assembling the rockerbox. After measuring the light height of the pushrods I measure a difference between the Inlet and the Exhaust from >2 mm resp. 7.1 mm to 9.3 mm.
Question is there a major difference between the cam shaft Inl./Exh? Or is my camshaft worn-out?
Hi Cees, do the two pushrods have the same length? Cheers, Thomas
Hello Thomas
Yes original they are. However they added a ring of 2 mm in the exhaust pushrod to make him longer.
I try to adjust the rockerbox corectly, so the angle from the rocker to the valve from both valve, in open and close position, is correct. Just as the contactpoint of the rocker on the valve is correct.
During that I measure the open and close trave from both valves. the inlet has +/- 7 mm trave and the exhaust valve 9. 5 mm. The valve diameter are the same. I would imagine there is a difference in light height because the inlet diameter is 27 mm and the exhaust 38. (The valve diameter is the same) Also the volume of intake air is smaller than the exhaust. On the other hand the inlet suks and the exhaust has overpressure.
Hi Cees!
QuoteHowever they added a ring of 2 mm ... Just as the contactpoint of the rocker on the valve is correct.
I once had to lengthen my exhaust pushrod with a ring out of silver steel to adjust the rocker arm geometry. That is a reasonable adjustment because the rocker-valve geometry should be symmetric between open and close positions.
QuoteDuring that I measure the open and close trave from both valves. the inlet has +/- 7 mm trave and the exhaust valve 9. 5 mm.
This in turn depends on the pushrod length and the correct geometry. I believe without guarantee that this is ok and 2.5mm difference is not crucial.
Cheers, Thomas