timing.......veryconfused

[ninjadave1400]

hi guys ive been running some tests as im trying to avoid pulling the head im going to have to as my compression is low and my valve clearances although to tight,dont explain why my compression is from no.4 at 150psi down to no.2 at 95psi any why my question is this, the manual says to use the t marks in the crank as number 1 and 4 at tdc how ever when timing the engine it says both should be at tdc and now im very confused about timing it up when i rebuild.

i posted the question in my build thread as well so if people read it back they will see the issues i hit.

[cargo]

When timing the camshafts for rebuilding.................1 and 4 cylinders are at TDC................as per the timing mark...............see the manual for picture

a cylinder reaches TDC twice per cycle..............once on compression and again on exhaust

[Mori Man]

You need your valve clearances to be within spec to get pressure readings to compare with service limits.

[ninjadave1400]

Valve clearance I have re checked now I understand the cycle I got mixed up all are within tolerance so I will press ahead and pull the head.