63 ignition timing F/I 327 360 hp
06-07-2008, 04:31 PM
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63 ignition timing F/I 327 360 hp
I have a few questions concerning vacuum and ignition timing for the F/I engine.
What should the vacuum be out of the metering unit to vacuum advance?]
I am getting 10in. at idle. Increasing the rpm to about 1500 it reads 20 in.
With the vacuum advance hose off I have ignition timing at 5 deg. With it connected I have 11 deg.
I am familiar with carbed engines procedures but not the F/I engines. I am assuming that loosening the hold down bolt on the distributor is not the way to change the timing since the two drive units (tach) and (F/I) prohibit any turning of the distributor.
What should the timing be with the vacuum line disconnected?
How is the timing adjusted?
The advance is all in at 37 deg at 2000 rpm. Seems rather steep.
What should the vacuum be out of the metering unit to vacuum advance?]
I am getting 10in. at idle. Increasing the rpm to about 1500 it reads 20 in.
With the vacuum advance hose off I have ignition timing at 5 deg. With it connected I have 11 deg.
I am familiar with carbed engines procedures but not the F/I engines. I am assuming that loosening the hold down bolt on the distributor is not the way to change the timing since the two drive units (tach) and (F/I) prohibit any turning of the distributor.
What should the timing be with the vacuum line disconnected?
How is the timing adjusted?
The advance is all in at 37 deg at 2000 rpm. Seems rather steep.
06-07-2008, 05:56 PM
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St. Jude Donor '07
the top of the distributor is rotated, not the whole distributor. there is a 'band' (kind of like a very special hose clamp) between the bowl (top) and the base (where the tach and injection pump drive is) with a slotted screw that you loosen/tighten. loosen this clamp and rotate the top of the distributor as needed to set your timing, then tighten the band back up... 
Bill
Bill
06-07-2008, 08:11 PM
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The way I have mine set up is to use the stock mechanical advance curve as Delco built it for late '63. It's a little slow mechanically but I am using the '64 vacuum cannister which comes in with about 8" of vacuum which means it's all the way in at idle. I have my vacuum advance sourced off the fitting at the rear of the plenum for full manifold vacuum at idle. If yours is stock, it's tapping off the venturi vacuum at the air meter.
I set my initial at 12* with the vacuum plugged. This gives me 15" vacuum at idle @ 750 rpm with the vacuum connected. I run the engine on 89 octane fuel with the .125 domed factory replacement pistons.
Some will tell you the '63 mechanical curve is too slow and you should have all the mechanical in by 2800. That's fine if you want to do that but you can probably forget about using 89 octane gas.
Your mechanical advance is too fast for a street engine and it sounds like your vacuum can doesn't pull enough degrees in. Maybe they work ok together. I don't know.
I set my initial at 12* with the vacuum plugged. This gives me 15" vacuum at idle @ 750 rpm with the vacuum connected. I run the engine on 89 octane fuel with the .125 domed factory replacement pistons.
Some will tell you the '63 mechanical curve is too slow and you should have all the mechanical in by 2800. That's fine if you want to do that but you can probably forget about using 89 octane gas.
Your mechanical advance is too fast for a street engine and it sounds like your vacuum can doesn't pull enough degrees in. Maybe they work ok together. I don't know.
Last edited by MikeM; 06-07-2008 at 10:08 PM.
