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Boyer advance curve

Submitted by david_evans on Sun, 03/03/2013
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Commando

I'm reluctant to take my "new" engine to 5000 RPM to set the ignition timing of my old analogue Boyer. I've looked up the diagram of the advance curve on "Dyno Dave's" website and working back from 31 degrees at 5000RPM I reckon I should set to give 21 degrees at 2000 and 25 at 3000. Anybody see any holes in that theory? (and not in my pistons)

Submitted by alan_dawes on Mon, 04/03/2013

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Nothing wrong with 5000 rpm on a new build. There is no load when you are setting up an ignition. If she cannot take 5000 rpm in that situation, she won't last long on the road!

Submitted by david_evans on Tue, 05/03/2013

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What difference does the load/no load make to the engine with regard to running in? The newly ground journals and new shells along with honed bores and new rings would probably benefit from a little bedding in before taking up a notch throttle/RPM wise. I have heard of engines being assembled dry and run straight up to full power for a couple of minutes and considered "run in" most likely race engines that only have a short life span.

Maybe Mick Hemmings or Norman White will read this and give us their opinion.

Submitted by george_farenden on Wed, 06/03/2013

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Hi David,

Whilst not exactly an 'apples to apples' comparison, I have seen at Ford that everyengineproduced (and that was 600,000 a year in the plant I visited) gets run before it leaves the engine plant. they are run at idle for a few minutes followed by something like 30 seconds at peak power speed. Doesn't appear to cause problems with lots of blown up, oil burningengines in their cars!

Your engine will be fine.

George

Submitted by norman_lorton on Wed, 06/03/2013

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I agree with George. With very little petrol going in the loads on pistons, big ends, etc. are much reduced.

For a brand new engine I would run it at 1,000 - 2,000 RPM for a few minutes until it was slightly warm - it will not matter where the timing is if it seems to run reasonably. Spend the time watching the oil flow back to the tank. Then momentarily up to 3,000 - 4,000 to see if the timing is heading up towards 20-25 degrees, and you only need a few more seconds to take it to 5,000 and 28-30 degrees. I have always timed my Mk3 to that because the Boyer will carry on advancing past 5,000.

 


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