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dehbowwez

Ireland
34 Posts

Posted - 30 Oct 2011 :  11:54:31  Show Profile  Reply with Quote
do i still set the timing @ 8 degrees, ie second notch on the pully for unleaded? Using a strobe. Cheers.

Paul

United Kingdom
60 Posts

Posted - 30 Oct 2011 :  19:50:46  Show Profile  Reply with Quote
It's not the lack of lead which means you have to retard the ignition, it's the octane rating and there are other ways of keeping the octane rating up so it depends which octane rating of unleaded you're running. If you have pinking, simply retard a fraction until you get rid of it.

There are other factors too, such as the deposits in the combustion chambers which give hot spots. When I was touring Morocco in my Series V Alpine in '76 I got sold petrol mixed with paraffin by an unscrupulous petrol station owner just as I was about to climb over the High Atlas mountains. The fuel smelled like petrol but the exhaust smelled like old oil lamps!! Even several tanks of fuel later, I still had pinking and eventually I had to resort to a de-coke back in the UK to remove the deposits.

My Alpine won't float! I need one which does!!

Edited by - Paul on 30 Oct 2011 19:55:22
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dehbowwez

Ireland
34 Posts

Posted - 02 Nov 2011 :  14:57:07  Show Profile  Reply with Quote
Sound Paul but I'd still like to know what the start point is for timing with a strobe. I know the static timing is 8 degrees. It's a 1725 roots motor.
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Paul

United Kingdom
60 Posts

Posted - 02 Nov 2011 :  16:01:10  Show Profile  Reply with Quote
Yes but you don't say which grade of unleaded you're running and, as I said, it depends on the octane rating. From memory, 8 is correct as a starting point for 97 octane. If you're setting using a strobe, remember to disconnect the vacuum advance to make sure that it doesn't contribute any advance at tickover. After that, you need to do a road test to determine if you need to change the setting due to other factors.

My Alpine won't float! I need one which does!!

Edited by - Paul on 02 Nov 2011 16:06:26
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dehbowwez

Ireland
34 Posts

Posted - 07 Nov 2011 :  13:08:07  Show Profile  Reply with Quote
Sound Paul. it was the advance I was worried about. This is Ireland so though they say it's 97 I would,nt believe a bit of it. I've also destroyed a Lambretta barrell from what can only have been dodgy fuel.
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Paul

United Kingdom
60 Posts

Posted - 09 Nov 2011 :  22:01:18  Show Profile  Reply with Quote
Bet you didn't have to get back from Morocco with your brand new 14'x7' inch-thick living-room rug strapped to the boot lid!

My Alpine won't float! I need one which does!!
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