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Engine timing, 1979, 400, manual


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5 replies to this topic

#1 ron1

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Posted 21 May 2011 - 05:11 AM

Just finished assembling the engine. The book states the timing to be 18 degrees BTDC, which seems quite a bit to me. Is this actually the setting, and is it with the vacuum advance disconnected? I question the number because the timing marks on the timing gear cover only indicate to 15 degrees. Thanks.

#2 cwi inspector

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Posted 21 May 2011 - 05:27 AM

I have a 79 403 and the timing is 18 BTDC not sure about the 400.
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#3 joeq

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Posted 21 May 2011 - 06:01 AM

!8 degrees is correct, Ron. That's with the vac adv disconnected.

#4 Glenn Lever

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Posted 21 May 2011 - 10:59 AM

What you really want is a total advance of 30 degrees.

That is static advance,
Vacuum advance,
and mechanical advance all added together.
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#5 ron1

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Posted 22 May 2011 - 03:35 AM

What you really want is a total advance of 30 degrees.

That is static advance,
Vacuum advance,
and mechanical advance all added together.


Thanks all. Hoping to drop the engine in today, will be a while before I get to start it. Wanted to paint the timing marks so it will be easier to see.

#6 72 blackbird

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Posted 22 May 2011 - 06:20 AM

18 degrees is alot of initial lead timing for any Poncho- I normally never have to set more than 15 degrees, and that's with small chamber (72cc) heads. I like to run about 32 degrees total advance, but that also depends on tune and available gas- 30 degrees total is definitely a safe point and shouldn't ping w/ 91 octane if you have 9:1 SCR.




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