I'm a big fan of running alot of initial but not locked out at total.
Necessary to lock out your distributor for boost?
Thread Starter
Melting Slicks
Joined: Sep 2004
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Necessary to lock out your distributor for boost?
I just got off the phone with a Procharger tech. He told me that I needed to have my distributor locked out (so there is no advance, mechanical or vacuum) and have 26 degrees of timing to start and 32 when I get it tuned.
Is this true?! I can't imagine having 26 or better yet 32 degrees of timing at idle!
And is this necessary or is there a better way to do it?
Is this true?! I can't imagine having 26 or better yet 32 degrees of timing at idle!
And is this necessary or is there a better way to do it?
Drifting
Joined: Sep 2004
Posts: 1,959
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From: North Bend Ohio
You're not going to have any vacuum advance under boost so you don't need to worry about that. As far as the rest of it goes, put the initial at about 12 BTDC and put in a slow mechanical advance curve. Like all in at about 4000 RPM. You can also limit the amount of mechanical to hold the total down at first. Tune from there.
BigBlockk
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BigBlockk
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Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
The tech support advice doesn't make any sense to me. At a single advance number (26* or 32* or whatever), you are running at an inefficient point for 99% of your driving. It might be tuned right for when you are at one level of boost, but the rest of the time your fuel economy, drivability, and exhaust valves are going to suffer. His recommendation will work, but it is brute force crude. Put some time and effort into it, and you can get a system that will give you driveability and performance.
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
You know I run a 8-71 and this year I am running it 27% overdrive.
I set initial timing at 24 degrees, have a short 12 degree advance curve, all in my 3000 and another 16 degrees of vacuum advance.
Blower motors like advance. I also believe in vacuum advance.
I get great mileage and the motor runs great.
I set initial timing at 24 degrees, have a short 12 degree advance curve, all in my 3000 and another 16 degrees of vacuum advance.
Blower motors like advance. I also believe in vacuum advance.
I get great mileage and the motor runs great.
Thread Starter
Melting Slicks
Joined: Sep 2004
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Are roots blowers different than centrifugal superchargers when it comes to vacuum? Could I simply leave my vacuum advance attached? Do I have to modify something to make it work properly? I will be going with a centrifugal supercharger by the way.
Drifting
Joined: Sep 2004
Posts: 1,959
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From: North Bend Ohio
Vacuum advance only works when the intake manifold is under vacuum. When the intake manifold sees positive pressure (boost) there is no vacuum to cause the canister to advance. If you are running a blow through system hook the vacuum advance to the "manifold" tap on the carburetor. If you are running a draw through system you'll want to get the vacuum signal from the intake manifold not the carburetor.
BigBlockk
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BigBlockk
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Tech Contributor
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I've been curious about the same thing. Does anyone know if there is anything internal to the vacuum canister that would prevent it from moving the opposite direction when pressure is applied to the port?
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
This will tell if you can push a vacuum advance into retart.
Vacuum operates against a spring in the housing so maybe pushing it with positive pressure will just cause it to retart.
I sent this question to mallory twice and both times they ignored me.
While I run a mallory ignition I am not a fan of the company.
Melting Slicks
Joined: Dec 2005
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It works good with the right mechanism, I did it on a Ford Capri that I fitted with a turbo many moons ago (German V6). The distributor didn't require mods on this application. Got the idea from Ak Miller who sold turbo kits in the early '70s. You should be able to pull the cap and watch the advance plate as you apply pressure for a quick check.
Last edited by shafrs3; Nov 22, 2007 at 07:25 PM.
Race Director
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From: Waterloo ontario Canada
Thread Starter
Melting Slicks
Joined: Sep 2004
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Sounds like a possible cheap substitute for a boost retard box. You've sparked my interest... 
Couldn't I just stick an oral syringe in the vacuum hose going to the distributor advance and apply pressure? Then watch the idle with a timing light...
Couldn't I just stick an oral syringe in the vacuum hose going to the distributor advance and apply pressure? Then watch the idle with a timing light...
Last edited by enkeivette; Nov 23, 2007 at 06:54 AM.
Race Director
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From: central FL, near the beach.
u will have to take it apart and re-design it.they did sell them in '73. not cheap either, i passed over it due to cost
Last edited by Matt Gruber; Nov 23, 2007 at 09:00 AM.
Thread Starter
Melting Slicks
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Le Mans Master
Joined: Apr 2000
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From: cincinnati ohio
St. Jude Donor '09
Nope, no worky.
I just tried it on my accel adjustable canister. When no vacuum is applied the diaphram is bottomed out against the back of the can and can only move one way.
I just tried it on my accel adjustable canister. When no vacuum is applied the diaphram is bottomed out against the back of the can and can only move one way.
