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Timing
Posted: Wed Oct 14, 2009 5:53 am
by David53
Just tried to adjust the timing as per Mike Perry's technique of turning dizzie body for smoothest idle. Unfortunately i stupidly didn't tippex the body before i started so lost my original point of refence. The plan was to advance until it "pinked" then retard it slightly.
What I found was that turning clockwise gave a faster idle but the car ran worse under load. After a dozen or so road tests the best setting was turning back anti-clockwise a little (ie: Retarded). By advancing it I could not get it to "pink", it just ran lumpy under load. Retarding it again made for a smoother run...Does this sound right?
Posted: Wed Oct 14, 2009 9:42 am
by mike.perry
Check the points gap and set the dizzy where the car runs best. You only have 30 horses so you don't want any having a rest
Posted: Wed Oct 14, 2009 1:35 pm
by David53
Points gap is spot on (Dwell angle of 60). i was just curious why advancing the timing made it run worse...I thought advancing would give more power and you just had to watch out for pinking?
Posted: Wed Oct 14, 2009 3:58 pm
by bmcecosse
Have you checked if the vacuum advance is working correctly yet ?
Posted: Wed Oct 14, 2009 10:53 pm
by David53
Good point will have a suck and see

Posted: Thu Oct 15, 2009 12:44 am
by mike.perry
If the advance is too early it can try to push the piston back down the bore before it has reached the top especially on a low powered engine and you might not hear any pinking.
I found that my side valve engine would run over a wide range of timings but there seemed to be a critical point where it went best so the easiest way to set it up was to go for fastest tickover then road test it up the nearby hill with small adjustments until I was happy with it. It was imporant to mark the starting point as a reference particularly as the s/v dizzy tends to wind itself out of the head when the clamp is slackened
Posted: Thu Oct 15, 2009 2:24 am
by David53
Yes will have to have another tinker this weekend.
Initially turned slightly to the right and idle speed increased substantially. "Brilliant" I thought and took it for a short run but the accleration was lumpy she ran badly - power greatly diminsihed under load. So I am wondering about the vacuum advance as BMC says.
For now have turned it back anticlockwise and it is running better, but idle still a little lumpy. Kicking myself for not marking the original position!
Posted: Thu Oct 15, 2009 8:37 am
by David53
Actually, I'm REALLY kicking myself for fiddling about with it when she was running quite well

When will I learn.......?
Posted: Thu Oct 15, 2009 8:41 am
by alanworland
Surely you can reset the timing to its 'correct' position as you must have done when you rebuilt it - then mark it up and start again?
Posted: Thu Oct 15, 2009 8:45 am
by David53
Well, yes I guess I could by doing static timing but my engine has no timing marks so would need to pull rocker cover off, watch the valves, hook up a light bulb etc. Was trying to go for the "twist it and see" method
What I meant was I should have marked it before I moved it as it was actually running very well
Posted: Thu Oct 15, 2009 9:32 am
by mike.perry
You should have a notch in the crankshaft pulley and an arrow on the timing chain cover at 12 o'clock. Later engines had the 3 pointers below the timing cover. I guess it is important not to mix up pulleys and covers or you could be 180 deg out!
Posted: Thu Oct 15, 2009 10:29 pm
by David53
Actually no arrow which is strange....not that you could see the thing if it was there anyway!! Just about to replace the timing cover with a Mini one so I can have the better seal.
Posted: Thu Oct 15, 2009 10:37 pm
by mike.perry
The Mini cover will probably have the 3 pointers at the bottom which could be confusing. Could you mark the crankshaft pulley 180 deg out? Possibly with a notch on the back rim of of the pulley if the original is on the front rim. It would need to be accurate.
Posted: Thu Oct 15, 2009 11:02 pm
by cormorant
I must admit I couldn't get my engine to pink either no matter how much I advanced the ignition - it just ran worse eventually and I ended up setting to 3 degrees btdc static (1098) was a bit miffed as I liked the idea of trying this method
Posted: Thu Oct 15, 2009 11:40 pm
by David53
Ahh so I'm not alone then
I think I'll start from scratch - fit the new timing cover, find TDC and then mark the cover and pulley, set the timing using the static method, mark the dizzie body and go from there.
But first I will check the vacuum advance - I have a feeling this might not be working...
Posted: Fri Oct 16, 2009 9:00 am
by bmcecosse
If very low/poor compression I suppose it may not be possible to induce pinking!
Posted: Fri Oct 16, 2009 10:18 am
by mike.perry
If the vacuum unit diaphram is damaged it can allow petrol vapour to be sucked into the distributor, ignited by the points and shatter the dizzy. Unlikely but it happened to me.