[Trevor]

Originally Posted by SVXRide

Trevor,
In response to your request, here's what Harvey PM'ed me:

Checking valve timing, and lobe center.

This is the method I would use to check the valve timing and find the inlet lobe center.
I use a plastic degree wheel stuck, to the harmonic balancer, with double sided tape, with the TDC marks aligned. Set up a wire pointer on one of the bolts on the front of the engine, so that it is in line with the 0 degrees on the degree disc.
Zeroing the degree disc to the crank.
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AGREED, Provided "Zeroing the disc to the crank" clearly means at TDC.

The following in appears to be made up from words lifted from a US publication, which is fair enough.
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Set up a dial indicator through the plug hole, and zero it while the piston is at TDC. Rotate the engine( always turning the engine forwards,NEVER TURN IT BACKWARDS) till the dial ind. shows the piston has dropped 0.050". read the degrees the crank has turned pass TDC. Say it is 12*. Turn the engine over till the piston is 0.050" from the TDC. Read the degrees, say it is 8*, that means that the wire pointer is too far to the 12* side, so we half the difference 4*, and move the wire pointer 2* to the 8* side, so that the pointer is aligned with 10* BTDC. This zeros the degree wheel to the crank, it will now read the same 10* at 0.050" before and after TDC.
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AGREED AS A WAY OF CONFIRMING TDC, if this can not be established from reliable marks. This method can be simplified by using a probe and educated feel, to establish that the piston is rockiong over TDC, if a dial gauge is not available. The "never turn the engine backwards", suggests the possibility of excessive big end clearance, which should become obvious while rocking the crank shaft. However this instruction should be carried forward regarding cam measurements, as here tolerances in the camshaft drive must be taken into account.
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Measuring the valve timing.
Set up the dial indicator on the top of the valve follower, zero the needle. There is two different ways to show duration figures, the US way is to start the measurement at 0.050" lift, and end 0.050" from the fully closed position. The other which everyone else uses, is from seat to seat. Turn the engine till the dial shows the first movement, of the valve opening, read off the degrees BTDC. (This is the start of the seat to seat duration.) Keep turning till the follower has moved 0.050", read off the degrees, (this is the start of the US duration). Turn the engine over till the valve is 0.050" from closing, (US closing point), keep turning till the valve has stopped. (end of the s to s duration)

The book quotes the timing to be ;Inlet 2* BTDC, 54* ABDC 236* Duration. Exhaust 55* BBDC, 9* ATDC. 244* Duration.
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AGREED.

Finding the lobe center.
Turn the engine till the valve is fully open, zero the dial needle. Turn the engine till the dial shows 0.050" from fully open, read the degrees, keep turning till the valve has closed 0.050", read the degrees. Add the two degree readings together divide by two. This is the inlet lobe center.
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READING THE PROTRACTOR when the valve is established to be at full lift will give the exact lobe centre in practical terms, without any calculations. But do not rock the shaft without thought, unless absolutely no play is present in the cam drive.

Although it is desirable to use a dial gauge in making all of these measurements, the eye and feel can be very accurate if used sensibly .
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If you can find what the factory lobe center is, and what the new cam duration and lobe center is. We will know where we stand.
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AGREED --- N.B. we already know the factory lobe centre if we accept published figure, but a check would be worthwhile and could also varify other mearsurement methods have been reliable

-Bill (aka "Fountain of Cam Knowledge" )

Please be sure that my intention is not to be smart by adding the above comments and that most of all I simply wish to assist.