Distributor lock out

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1972ho
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Distributor lock out

Post by 1972ho »

Just need to double check this question when you want to use a timing high speed timing retard doesn’t the distributor need to be locked out are can you retard timing with the advance mechanism still attached.
barnym17
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Re: Distributor lock out

Post by barnym17 »

Locked would be better,with the advance mechanism being variable you could be pulling say 10 degrees from 20 or 30 or whatever just probably not as predictable.
F-BIRD'88
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Re: Distributor lock out

Post by F-BIRD'88 »

Be aware that with locked out timing the spark timing tends to self retard at high rpm. VS what you set at idle..

EG:. A locked out GM HEI tends to retard about 4+/- degrees by itself at 6000+ rpm.
1972ho
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Re: Distributor lock out

Post by 1972ho »

Are you guys saying that with the distributor not locked out that I can still retard the timing use a switch to retard the timing back a few degrees it just will not be as accurate as it would if it was locked out.
1980RS
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Re: Distributor lock out

Post by 1980RS »

One time I rigged up my nitrous retard so I could turn it on in high gear, with the distributor locked out it picked up very little when I took 6°out of it.
barnym17
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Re: Distributor lock out

Post by barnym17 »

yes you can use the timing retard with a variable advance distributor.
F-BIRD'88
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Re: Distributor lock out

Post by F-BIRD'88 »

Yes you can use a retard box on distributirs with and without a mechanical advance system.
Be aware that the action of a retard box. DOES have an effect on diz cap-rotor phasing alignment.
You want to verify the cap:rotor phasing alignment with and without the retard box active.
If it is or becomes to far out of wack you can get spark scatter, missfire or crossfire between cylinders.

The more amount of retard (degrees of) used and the more powerful your ignition box is (eg: a CD ignition system) the more critical cap-rotor phasing alignment is.
Check the cap:rotor phasing alignment.
1972ho
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Re: Distributor lock out

Post by 1972ho »

Thanks for the responses I kind of had feeling it was possible but needed to verify before I had hooked it up,and also thanks for the rotor phasing I’ll check that also.I really had thought for years that it had to be locked out I even have another engine where I did lock out out the distributor but I didn’t want to lock out this distributor seeing how it’s already perfectly set up with the advance curve.
F-BIRD'88
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Re: Distributor lock out

Post by F-BIRD'88 »

If this is a street motor keep the vacuum advance either way.
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