All my life experience with 4 cycle engines have been based on this
theory ...
Intake Stroke: piston is going down intake valve open
Compression Stroke: piston is going up both valves closed
Power Stroke: piston going down both valves closed
Exhaust Stroke: piston going up exhaust valve open
Now it seems to me that TDC is very close to either the end
of the compression stroke or the beginning of the power
stroke, with both valves closed this should be when they can be
correctly adjusted. My new TDC indicator (neat whistle the
screws into spark plug hole) allows me to determine TDC (I
think).
If my theory is wrong ... I am willing to listen to the
combined intellectual experience of this extremely august group
...
>
>cheers
>Scott
>
>PS. a few misinformed individuals seem to think that "on the rock"
>refers to the crank position when the exhaust valve of the cylinder
>in question are just about to close and the intake valve of the same
>cylinder are just in the process of opening, hence both rocker arms
>are applying pressure to the valves. The cylinder 360 crank degrees
>(180 cam degrees) from the cylinder "on the rock" will thus be on
>the opposite side (non lifting) of the cam and both its valves will
>be fully seated. As any true TR mechanic who has used the true "on
>the rock" method will clearly recognize, this latter definition is
>obviously utter poppycock and will not produce nearly as effective a
>result.
--
Bill Pugh
1957 TR3 TS16765L
aka
Casper
1970 TR6 CC59179L
aka
Rosey
Wallace, CA
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