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Old 11-04-2007, 07:23 PM   #1
Richard Dobson
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396 engine timing?

I tried the engine & drivetrain section, does anyone here know what the timing should be on a stock 396 with HEI would be? Thanks
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Old 11-04-2007, 08:46 PM   #2
kwmech
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Re: 396 engine timing?

I've got mine set at 6 btc.
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Old 11-04-2007, 09:23 PM   #3
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Re: 396 engine timing?

6 sounds good to me but alot of engines vary a little so play with and see where yours runs best at. If it runs great at 8 or so keep it there, if you hear it pinging, back it off a bit. I usually never put a light on my truck, I just crank on the dizzy til it runs good and starts up without putting a load on the starter. I did put a light on it a few months ago to see where it was out of curiosity and it was at 9 but it runs good so I leave it there.
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Old 11-05-2007, 12:55 AM   #4
72armyswbtruck
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Re: 396 engine timing?

Takes practice for us newbies to do it off of sound
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Old 11-05-2007, 07:29 AM   #5
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Re: 396 engine timing?

I've always been too cheap to buy a light so that's why I just do it by ear, if I was doing it for someone else i'd probably use a light so I could tell them where it was exactly but since I only work on my stuff I don't need one.
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Old 11-05-2007, 04:58 PM   #6
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Re: 396 engine timing?

BBC's in general don't take (like) quite as much initial or total timing as SBCs.

6-10 degrees before TDC initial is fine as long as the total timing doesn't go beyond about 35-37.

(initial+centrifugal=total)

What I usually do is plug the vacuum advance hose then rev the engine to about 3000 RPMs and set my total at about 37 degrees. With 30 degrees of centrifugal, that means my initial is about 7 degrees. If you're running less centrifugal, then your initial will be a little higher than 7 by the same amount.

I mounted a timing tape on my harmonic balancer so I could tell where 37 degrees was, but you can do the same with an adjustable advance timing light (set it on 37 then time it until the marks line up i.e. = zero advance).
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Old 11-06-2007, 07:38 AM   #7
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Re: 396 engine timing?

Book or factory spec's call for 8 degrees before top dead center. Start there and see hoe it runs. Mnuun is correct about the total timing, or advance curve. Hope this helps. danny
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Old 11-06-2007, 05:48 PM   #8
Richard Dobson
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Re: 396 engine timing?

I got the timing adjusted to 6 deg before TDC but, it would backfire out the exhaust when reving it to about 3 grand. It was hard to start when I shut it off which means it is too far retarded right? I advanced the dist to where the engine would not backfire and start better and sounded like it was more responsive when reving up the engine and it quit backfiring. OK, I got a vacuum gage adjusted the carb to to highest reading I could get while it was ideling. The vacuum gage needle didn't fluctuate much at all at 20 hg which indicates no mechanical problems from what I understand. I didn't check to see what the timing was after these adjustments. What if it is off from 6 deg, I'll let you know what the timing is set at (with the new adjustments made by ear) with my timing light when I check it again tomorrow. Thanks for all the input from you more experienced engine guys, please let me know if I am going in the right direction.
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Old 11-06-2007, 07:23 PM   #9
Jtrux
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Re: 396 engine timing?

Actually if it's too far advanced it'll be hard to start. If you turn the dizzy clockwise then your retarding it, counter clockwise and you're advancing it (on a chevy anyways)
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Old 11-07-2007, 05:47 AM   #10
Richard Dobson
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Re: 396 engine timing?

Thanks Jtruks, you're right. Any other inputs?
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