I have a 72 Lemans with a 1977 W72 motor. My questions is what should the initial timing be. The book says 16 to 18 degrees for a W72 but that seems alot compared to the earlier 70s 400 that requires 8 to 10. Also the harmonic balancer's last number is 12 degrees BTDC with several unmarked units after that. Eighteen degrees would almost be off the harmonic balancers's scale. Due I have the correct balancer? Thanks

Phil

I have a 72 Lemans with a 1977 W72 motor. My questions is what should the initial timing be. The book says 16 to 18 degrees for a W72 but that seems alot compared to the earlier 70s 400 that requires 8 to 10. Also the harmonic balancer's last number is 12 degrees BTDC with several unmarked units after that. Eighteen degrees would almost be off the harmonic balancers's scale. Due I have the correct balancer? Thanks

Phil

I run 18 to 20 on my 78 w72. Low compression allows for more initial timing.

Thanks Butch for you reply. Your 18 to 20 must be at the far end of the scale on the balancer, is that correct? Why would the manufacturer not put 18 or 20 Degrees on the balancer. I just find it strange as if they wanted you to put the timing between their marks, around 10 degrees BTDC.

phil

The timing cover tab on my 78 W72 has the numbers 4-0-4-8-12. So, 12 is the last number, but, there are hash marks for 14, 16, 18 and 20. I would think the timing cover for a 77 W72 would be the same. So, you can set the initial timing to 18 if that is what works for the engine.
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I would not be too concerned worried about what an original W72'S initial timing was. I would try and find the best initial timing that works for your combination. Your combination will be affected by many variables: amount of mechanical advance, rate of mechanical advance, amount and rate of vacuum advance, ported vs non ported vacuum advance, compression ratio-head porting, camshaft, exhaust, carb, carb jetting and mods. etc.
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I would experiment with initial timing and see what works best for your combination of parts.

Thanks MFC, I feel better knowing that your timing marks are the same as mine. I was just scared to use the far end of the marks. I will give different settings a try.

Phil

My 455 likes 16 initial too. Timing marks on cover are the same as MFC stated

18 degrees is correct for the 77-79 W72 400s.