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How does one cope without timing marks?

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Luegolover Avatar
Luegolover Steve L
London, London, UK   GBR
My engine doesn't have any timing marks and I'm at a bit of a loss on how to proceed. I don't think I am unique on this front so I wonder what people do to overcome the issue?

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San Jose, CA, USA   USA
You'll want to invest in an 'advance meter,' similar to this (not endorsing this particular one, just for example):

There should be a small arrow either embossed or tacked on the timing cover (think the 100s have embossed, and the 6-cyl cars have one tacked-on). There is a notch on the crank pulley that will align with the arrow's head at TDC of the #1 cylinder. With the engine running, you turn the knob on the meter until the arrow and notch align, then read advance off the meter, or set the desired advance on the meter and rotate the distributor until the arrows align. You can set static timing with a small lightbulb, and a couple of leads to see when the points open; I think 5/8" on the pulley gives an approximate start. BJ8s have an initial advance of 15deg BTDC at 600RPM with the vacuum advance disconnected and plugged; I think 100s and the earlier sixes have a bit less.

Edited 1 time(s). Last edit at 2019-02-09 01:34 PM by Bob Spidell.

O, ON, Canada   CAN
1967 MG MGB GT "Maggie (GT From Hell)"
Create your own. TDC is easy enough to find. Then use the dial back light to make a 10 degree mark ( bit of trial and error ).

I find that if you use a vacuum gauge and set your timing to whatever gives you the highest vacuum signal, and them make sure your total timing is about 32 degrees at 32-3500 rpm, you should be pretty good to go. Set the valve clearances first before you do timing with a vacuum gauge.


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AlasCrag Avatar
AlasCrag A Campbell
Suggest downloading

which has an article on making a timing mark and many other useful tips on 100's

O, ON, Canada   CAN
1967 MG MGB GT "Maggie (GT From Hell)"
If you must have a timing mark, the easy way is to create it while you are degreeing the cam and make marks on the balancer

If you are not going to degree the cam, then find TDC on the compression stroke and make a mark on the balancer. Of course, you need to make a pointer to correspond to the mark! Use a dial-back timing light to get the degrees of advance.

If you know a bit of geometry, you can easily mark TDC and them make marks on a tape that correspond to the diameter of the balancer to give you degree increments.

If you are not too worried about the whole thing, then get a vacuum gauge and after getting the engine running simply rotate the timing until you get max vacuum signal. Sometimes you have to go back and forth between the carbs and the ignition to max out the vacuum and get both spot-on. Make sure the valve clearances are set first if doing this.


PAN Avatar
PAN Alwyn Keepence
Ipswich, Queensland, Australia   AUS
It it a fact that the 100 did not have a timing mark on the pulley ot the timing cover. The workshop manual refers to the ignition timing on page D/15: “the spark should occur on cylinders one and four, 6 degrees before “top dead centre” or a quarter of an inch before the 1/4 mark on the flywheel.” It then goes on to describe the procedure for checking the timing statically, using the piston and valves.
I presume the timing light had not been adopted in 1953. I believe some BN2s do have an arrow embossed on the timing cover.

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