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Question about timing a 69 RR 383

mpro69rr

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I am timing my 69 RR 383 and set the initial at 18 degrees. When I get one of my friends to help me this weekend I am going to do the advanced timing at 36 - 38 degrees. My question is when I do the advanced timing at 36 -38 when I move the distributor to get that, won't that mess up my initial timing of 18 degrees?
 
You might find it to already be there when you check it; it depends on the components, the set-up of
the distributor as it sits now.
Warm the car up, then run it up to 2500rpm or so and see what you have without moving the distributor
first.
 
If you have your mechanical timing limited to 18° and an initial of 18° that gives the all-in of 36°. Do you know for sure how much mechanical advance you're getting from your particular distributor?
 
You need to do some reading.
The distributor has a mechanical mechanism inside weights held by springs these increase the advance amount as the engine speed increases.
You should be checking what your advance amount is at various speeds. Including where it stops advancing which would be your maximum amount of advance. This should be done with the vacuum advance disconnected. 18 for initial may be a good value.
 
It wont matter--let that fall where it will--If you time the engine to 36 degrees with every thing hooked up it will start and run great--you can still change the initial timing by inserting an allen head key into the vaccum advance and dialing it up or down to give the initial timing you want--that is generally not need --dont forget to recheck the total if you change the vacc advance ---whats important is the total advance at 36 degrees to saturate the coil and so theres 9 degress of timing to light the cylinder-that takes up the 45 degrees for each cylinder--45 x 8 =360 degrees hope this helps--Hemidon
 
It wont matter--let that fall where it will--If you time the engine to 36 degrees with every thing hooked up it will start and run great--you can still change the initial timing by inserting an allen head key into the vaccum advance and dialing it up or down to give the initial timing you want--that is generally not need --dont forget to recheck the total if you change the vacc advance ---whats important is the total advance at 36 degrees to saturate the coil and so theres 9 degress of timing to light the cylinder-that takes up the 45 degrees for each cylinder--45 x 8 =360 degrees hope this helps--Hemidon
The vacuum advance adjustment regulates the rate at which it activates, not the amount. The initial timing should always be adjusted with the vacuum advance disconnected, as previously stated.
 
If you have your mechanical timing limited to 18° and an initial of 18° that gives the all-in of 36°. Do you know for sure how much mechanical advance you're getting from your particular distributor?

Hmm good question, I'm reading the pertronix instructions and it says it has 12, 16 and 20 crank shaft degrees.
 
I'm running 16° initial w a pretty decent roller cam in a stroker 496. It idles at 850 RPM @13-14" of vacuum. It allows me to still turn it over pretty easy when hot. Used a mechanical advance limiter to limit to another 16° of timing for now for a total of 32° due to west coast crappy 91 octane max fuel n 10.5:1 compression. A limiter plate has 0, 10, 12, 14, 16 n 18° of advance slots. I don't know a stock distributors max advance, but I'd say more than 18° otherwise they wouldn't need that slot. With your initial timing, have someone rev the engine and watch the timing marks until they stop advancing so you know your total mechanical advance. As said above, with vacuum advance disconnected and line plugged.
 
It wont matter--let that fall where it will--If you time the engine to 36 degrees with every thing hooked up it will start and run great--you can still change the initial timing by inserting an allen head key into the vaccum advance and dialing it up or down to give the initial timing you want--that is generally not need --dont forget to recheck the total if you change the vacc advance ---whats important is the total advance at 36 degrees to saturate the coil and so theres 9 degress of timing to light the cylinder-that takes up the 45 degrees for each cylinder--45 x 8 =360 degrees hope this helps--Hemidon

Yes, this helps, thank you. My distributor comes with the silver springs for default. At 2500 RPM's its says crankshaft degrees is 16? At 3500 its 24 and that's as far as it goes.
 
The vacuum advance adjustment regulates the rate at which it activates, not the amount. The initial timing should always be adjusted with the vacuum advance disconnected, as previously stated.
The vacuum advance has Absolutely Nothing to do with the rate of mechanical advance, the springs do. The hex key fitting inside the vacuum pot adjusts the rate of the vacuum advance for cruising mileage.
 
The vacuum advance has Absolutely Nothing to do with the rate of mechanical advance, the springs do. The hex key fitting inside the vacuum pot adjusts the rate of the vacuum advance for cruising mileage.
Never said it had anything to do with mechanical advance. I was referring to the vacuum advance itself.
 
@hemidon1, your information is only partially correct. For the vacuum to be adjusted to help w initial timing, the vacuum pod must be hooked to manifold vacuum. This best only used w very aggressive cams that need help w more timing at idle.

Other than that instance, the vacuum pod/vacuum advance has Nothing to do with the rate or the amount of mechanical advance.
 
Never said it had anything to do with mechanical advance. I was referring to the vacuum advance itself.
Nowhere was the OP asking about vacuum advance. Nothing to do with the original post.
 
Nowhere was the OP asking about vacuum advance. Nothing to do with the original post.

True, lets stick to timing without vacuum advanced hooked up, when I get this done I will worry about the vacuum advance. Thanks for all the input so far!
 
Nowhere was the OP asking about vacuum advance. Nothing to do with the original post.
Look at post #6 again. Hemidon stated you can adjust the initial using the vac advance. Thus the reason for the clarification.
 
Curious why you need a friend to help set the timing? Run the throttle with your right hand and aim the light with your left.
 
Curious why you need a friend to help set the timing? Run the throttle with your right hand and aim the light with your left.
To see the timing marks on my 383, I have to stand by the right front tire looking over and between the heater hoses and a/c lines. My arms are not long enough to reach the driver side throttle linkage.
 
Curious why you need a friend to help set the timing? Run the throttle with your right hand and aim the light with your left.

Eh, its just easier. If I have someone then I can turn the distributor.
 
Eh, its just easier. If I have someone then I can turn the distributor.
Gotcha. I just always seem to end up all alone when messing with timing.
 
Lots of the older points style distributors have a 9.5 plate or a 19 degree limit.
I found one for mine, saves the welding and fileing .
As far as help when setting timing and total advance ect. It really helps having my better half running the throttle inside watching the tach.
My light is a dial back style , with her help and that light makes setting up a distributor pretty easy.
 
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