Series 'A' Single Valve Timing

[kettlrj]

Can the valve timing of an A single be set without the head being in place, assuming no dot markings. The head is not available at this time. I am re-building an engine for a friend and have not done one before.
Regards Richard.

 

[Robert Watson]

I set both my A's with valve = lift at 4 deg BTDC. They both go very well. But that of course requires the head and valve gear all in place....

 

[vibrac]

Can you find equal lift using the followers and some form of push rod? I seem to remember someone on the forum measuring equal lift on a post war via the rockers to save lifting the ufm

 

[Robert Watson]

Actually I recall doing that on a post war Comet by putting longer flat top round bottom "push rods' down to the followers, but still had the head on.

 

[oexing]

While knowing nothing about the A engine, I think placing a ball onto each cam follower and having two dial clocks with flat face "tips" on their stem that should be allright for getting equal lift at TDC or 4 degrees before.

Vic

 

[John Reynolds]

This might be too late to be of assistance, Richard, but I have just faced (and solved) the same problem on my A Rap which I am rebuilding. My timing pinions are thankfully clearly marked but I wanted to check that the valve timings were correct before building up the rest of the engine. As you will be aware, the cams are not accessible once the cam box(es) are in place and trying to take a reliable lift reading with a dial gauge from the upper end of an unrestrained push rod is just not possible. However, if you wind a strip of paper round the upper end of the pushrod, securing it with a piece of adhesive tape when is of a size so that it is a sliding fit inside the pushrod tube, it will then slide up and down inside the pushrod tube rather like a piston in a cylinder. I then clamped the magnetic base of my dial gauge mount onto the top of the cylinder liner and was able to set up the dial gauge to take lift readings. Remember that the valve timings quoted are at 5 thou lift but, as Bob Stafford observed some years ago, do not expect the timings to accord with those given in the manuals. In my case, my Rap has 4X cams and while the inlet opening and closing and the exhaust closing values for both camshafts are near(ish) to spec, both the exhaust opening values are way out. However, on checking the figures on the Works Engine Build Sheet for my engine, I found that this was the case when the engine was first assembled! Hope this helps.

John

 

[kettlrj]

Thanks John
I as waiting for some work to be done on the head so that the valves could be assembled, but with your method I can crack on with the job and get the bottom half finished.
Many thanks Richard