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Help timing
Posted: Thu Jul 10, 2025 4:40 pm
by Loadie
Afternoon all, I think I’m going mad. The timing chain was slack and rattling so I upgraded to a new duplex one. Followed all the instructions and lined everything up correctly. When I started the engine it runs like a bag of spanner’s. So I think the timing has been adjusted ( before me ) to make it run with the slack chain…
Pulled it all to bits again just in case I had the dots misaligned but nope. Took rocker cover and distributed cap off to look at checking the timing.
Now it seems to me that when I have the dots lined up no1 should be tdc and the distributor should be about to spark the no1 pot… yet the rotor arm is lined up to no4????
Am I missing something obvious here??
Cheers
Loadie
Re: Help timing
Posted: Thu Jul 10, 2025 4:59 pm
by svenedin
Do you have a strobe? If you do, you can set the timing to the book settings as baseline and then tweak from there. If you don't, it doesn't really matter. Warm up the engine. Slacken the distributor clamp pinch bolt. Rotate the distributor either way until the engine starts to run well. Then road test. If the engine pinks under load you need to stop and retard the ignition a few degrees and try again. The distributor rotor turns anticlockwise so looking from above turning the distributor body clockwise is advancing and anticlockwise is retarding. Fine tuning can be done with the micrometer adjuster on the distributor marked A/R. Before doing anything with the timing, check that anything that could have been disturbed when you were working on the engine is OK especially electrical connections. Firing order 1,3,4,2 anticlockwise round the distributor. I would also check your rocker clearances. Perhaps these have altered too with a new chain and sprockets.
Stephen
Re: Help timing
Posted: Thu Jul 10, 2025 5:42 pm
by Bill_qaz
These engines are valve timed (dots algned) on number 4 cylinder firing not number one.
So if your valve timing is correct rotate engine one full turn of the crank so back to number one firing and then check the distributor for pointing to number one, once confirmed set your ignition timing.
Re: Help timing
Posted: Thu Jul 10, 2025 5:59 pm
by Loadie
Thanks guys . I do have a strobe yes but know its a pain lying underneath to check the marks. So 4 firing when dots align makes more sense, will jiggle it a bit first.
Just wanted to be sure I didnt line anything up wrong when i hit the key.
Re: Help timing
Posted: Thu Jul 10, 2025 7:42 pm
by Bill_qaz
Just static time it on timing mark and points just opening. Its good enough to get it running then set with strobe afterwards.
Mirror on floor to see marks?
Or set by ear if you are confident enough
Re: Help timing
Posted: Fri Jul 11, 2025 8:54 am
by simmitc
The position of the distributor depends on the fitment of the distributor drive shaft, which can be engaged with any of its teeth meshing. NB, the drive shaft, not the shaft on the distributor that engages with the drive shaft in the engine. I take care to ensure that the shaft is fitted so that the distributor has No.1 in the one O'clock position, but not everybody does, amd I have seen plenty oif engines where a different position is effective.
If the dots are aligned correctly, then bring No. 1 to TDC on compression and note where the rotor arm is pointing. That is where the plug lead for No. 1 should be on the cap, then just work round from there with the 1-3-4-2 anti-clockwise.
Once you have checked that, then, as Bill writes, just set the static timing to get the engine running.
With the static marks aligned, you can put a dab of white paint on the pulley and timing chain cover above the crankshaft so that you can use the strobe from above. Masking tape on the cover with the paint on that will allow removal for originality or in case you got the position wrong.
Re: Help timing
Posted: Fri Jul 11, 2025 9:04 am
by svenedin
simmitc wrote: ↑Fri Jul 11, 2025 8:54 am
The position of the distributor depends on the fitment of the distributor drive shaft, which can be engaged with any of its teeth meshing. NB, the drive shaft, not the shaft on the distributor that engages with the drive shaft in the engine. I take care to ensure that the shaft is fitted so that the distributor has No.1 in the one O'clock position, but not everybody does, amd I have seen plenty oif engines where a different position is effective.
If the dots are aligned correctly, then bring No. 1 to TDC on compression and note where the rotor arm is pointing. That is where the plug lead for No. 1 should be on the cap, then just work round from there with the 1-3-4-2 anti-clockwise.
Once you have checked that, then, as Bill writes, just set the static timing to get the engine running.
With the static marks aligned, you can put a dab of white paint on the pulley and timing chain cover above the crankshaft so that you can use the strobe from above. Masking tape on the cover with the paint on that will allow removal for originality or in case you got the position wrong.
This is a very good point. IF the distributor drive shaft has been fitted as per the workshop manual then the distributor does point in the direction of number 1 cylinder when number 1 is at TDC compression stroke. I had an engine rebuilt recently where the distributor drive shaft had NOT been fitted as per the manual. This caught me out and I ended up with a tremendous and unforgettable backfire....
The easiest way to determine TDC compression is to take the spark plug out of number 1 cylinder and then turn the engine over on the starting handle whilst holding your thumb over the spark plug hole. You will feel compression trying to push your thumb away. Then line up the timing marks underneath the car. Then check that the position of the distributor rotor corresponds to number 1 cylinder HT lead in the distributor cap.
Stephen
Re: Help timing
Posted: Fri Jul 11, 2025 10:56 am
by Mervin
I use a mirror, on the floor, directly under the crankshaft pulley, and aim the timing light from above. I also use a dab of white paint on the c/shaft pulley mark and the pointers for T.D.C. and 5deg B.T.D.C.
I posed the same question when I renewed the timing chain, and as has been mentioned, with the dots lined up no. 4 cylinder is at T.D.C. firing stroke. i.e. rotor arm at no. 4.
For initial (static) set up of ignition timing I use a 12v test light in parallel with the points. Crankshaft pulley mark at 3 deg. B.T.D.C. The rotor arm should be pointing to no. 1 cyl..
Then check the dynamic timing using a timing light.
Re: Help timing
Posted: Fri Jul 11, 2025 11:18 am
by Loadie
Re: Help timing
Posted: Fri Jul 11, 2025 11:32 am
by svenedin
Well done! What did you have to do?
Stephen
Re: Help timing
Posted: Fri Jul 11, 2025 7:03 pm
by Loadie
Double checked the chain was right dots aligned rotor arm on no4. Replaced cover and belt, lined up the timing narks tdc minus 3 degrees. Static timed the distributor until I got the test light. Put the front back on the car( again !), fired up first time…
I was just all confused that the dots line up to 4 and I was expecting 1. Then I’m thinking I’m going to break the engine when I hit the starter!!!!!! Self doubts a nightmare
