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A new method of timing the cam shaft


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Recently, I had to time the camshaft.    You may know my enthusiasm for “Equal Lift on Overlap” (QV https://sideways-technologies.co.uk/forums/index.php?/topic/7770-equal-lift-on-overlap-the-other-cam-timing-method/#comment-102165 ) whereby setting the cam to that point in its rotation, at TDC, puts the timing in correctly.        Previously, I have labouriously set up dial gauges to measure the lift:

image.png.c326c5a9855bddba6b326d2481cdaa3e.png

So, I got out my dummy cam followers, the wooden dowels seen in the above photo.    They are tape-wrapped at the lower end, so that they are a sliding fit in the cam follower bores, and lightly fire hardened at each end.     They are also exactly, according to my Vernier gauge, equal in length.

That wouldn’t matter with dial gauges, but mean that I might use a spirit level to see them at equal heights!   Problem is that the engine is tilted up towards the front, but there is a tool that can overcome that!

You may have a “Combination square set” a rule with a length adjustable setsquare, and a centre finder on it, as well as an adjustable protractor. 

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Loose the first two, and you can do this with it.

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For ELoO, you set the crank to firing TDC on No.1, and set the camshaft to ELoO on No.6 (see my article, link above, for an explanation).  So first set No.6 to the back of the cams, and level the protractor.     Then turn the camshaft  until it's on overlap, and adjust the position until the protractor is level again.

Job done!

That is a LOT simpler than faffing about with dial gauges!

John

Edited by john.r.davies
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4 hours ago, BlueTR3A-5EKT said:

Good trick thank you.

You could even go digital!

https://www.manomano.co.uk/cat/digital+inclinometer

 

 

I use one of those for rough settings on my telescope to get aimed close enough to then do a proper alignment. They are useful but not super accurate or repeatable. If I set mine to 52 degrees and look for the north star I’ll be lucky to find it without a fair bit of tweaking. 1 degree error with the valves about 2” apart is 150 thou, so it may not be ideal.

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