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Stupid question - lockout dist but have vacuum advance?

Posted By: kick_the_reverb

Stupid question - lockout dist but have vacuum advance? - 11/29/09 04:01 PM

Hi, this might be a pretty stupid question, but I haven't messed with distributors, so here goes:
I bought a used MSD 6530 programmable 6al-2. But reading more into the instructions I realized it has boost retard, but not really vacuum advance.
So, I know there are some workarounds with the programmable map, but was wondering if there's a way to lock out the mechanical advance of a stock distributor, yet retain the vacuum advance capability?

Thanks,
Ran
Posted By: skep419

Re: Stupid question - lockout dist but have vacuum advance? - 11/29/09 05:40 PM

I believe the answer is no. If you lock out your dist. Your full in all the time. Where the vacuum advance would ad timing with less vacuum.

Not for sure but thats my understanding.
Posted By: RapidRobert

Re: Stupid question - lockout dist but have vacuum advance? - 11/29/09 05:41 PM

Quote:

this might be a pretty stupid question, but was wondering if there's a way to lock out the mechanical advance of a stock distributor, yet retain the vacuum advance capability?


(1) there are no stupid Q's only unasked ones. (2) yes weld up the slots & drill a hole in the weld for each pin & locate the holes exactly which will let you get your rotor phasing dead on in conjunction with the range of travel that a particular vac can gives you
Posted By: Evil Spirit

Re: Stupid question - lockout dist but have vacuum advance? - 11/29/09 06:54 PM

Mechanical and vacuum advance are two separate sections in the dist, and can be modified as needed. You can lock out the weight system so it doesn't change with RPM, and use the ported vacuum port of the carb connected to the vacuum pod to get some advance out of the dist. I don't know what exactly you are trying to do, so unless you want to spend a lot of trial and error time, a programmable dist might be a better option for you.

As to stupid questions, I read them here all the time. A "stupid question" is one that is asked without making an attempt to find the answer first. Some people make no attempt to figure things out on their own; instead, they just fire off questions, expecting others to do their thinking for them. IMO, those are "STUPID QUESTIONS".

Posted By: kick_the_reverb

Re: Stupid question - lockout dist but have vacuum advance? - 11/29/09 09:48 PM

Thanks guys.
To further explain:
Street vehicle - I always want to have vacuumm advance.
Will be adding a blower in the future, so I liked the idea of the programmable 6al-2, which already has a boost retard function and a programmable advance curve through software.
BUT - I didn't read enough before buying it, I assumed it had the function of vacuum advance like the programmable E-Curve distributor. Turns out it doesn't.
The unit requires a locked out distributor at full total timing, and you can plot the curve so the unit retards as much as you want according to the curve.
It has the option of using one of three MAP sensors:
1-Bar, for normally aspirated engines, PN 23111
2-Bar, for 2-30 psia, PN 23121
3-Bar, for 2-45 psia, PN 23131

So...I was reading that for N/A one can get the 1-Bar MAP sensor and get some "vacuum advance" - lock out the distributor at say 50-52 degrees, and as less vacuum "more boost" comes in, you retard it.
But, what happens when I add a blower? I'll have to jump to the 2-Bar MAP sensor, and then that function won't really work.
So, if I can lock out the centrifugal advance in the distributor, but retain the vacuum advance, I can basically plot the mechanical advance curve through the program, and keep the vacuum advance simple with the vacuum canister.

So, from the last two replies I'm getting that it is feasible. I'll be happy to hear some more opinions.
Thanks,
Ran
Posted By: Anonymous

Re: Stupid question - lockout dist but have vacuum advance? - 11/29/09 10:30 PM

i don't get why you want vacuum advance. you have a programable msd. either use the preset curves or custom program your own.
but there is no way to lock a dizzy and still use the vacuum advance on the dizzy. you'd hafta get a lean burn for that.
Posted By: aarcuda

Re: Stupid question - lockout dist but have vacuum advance? - 11/30/09 12:36 AM

Quote:

i don't get why you want vacuum advance. you have a programable msd. either use the preset curves or custom program your own.
but there is no way to lock a dizzy and still use the vacuum advance on the dizzy. you'd hafta get a lean burn for that.




heres why. i have the new mopar elctronic distr with the mallory mech advance setup. i can lock the mech timing out at 32 deg so i get a good idle and hook upo the vacuum advance to get better mileage at part throttle. it can be done. they are separate from each other on the mallory or new mopar distr. not sure about the msd though
Posted By: kick_the_reverb

Re: Stupid question - lockout dist but have vacuum advance? - 11/30/09 12:55 AM

Thanks guys...
Ghost, I want vacuum advance because it's not a race vehicle. I have no problem plotting the mechanical advance using the software.
Just to make sure we're clear - I'm talking about an MSD 6al-2 p/n 6530 which is an ignition box, not a distributor.
So if going by what aarcuda says, the Mallory style/new MP should have that capability, and the stock type might not.
I guess I'll find out when I start messing around with the distributor.

Thanks,
Ran
Posted By: aarcuda

Re: Stupid question - lockout dist but have vacuum advance? - 11/30/09 01:08 AM

Quote:

Thanks guys...
Ghost, I want vacuum advance because it's not a race vehicle. I have no problem plotting the mechanical advance using the software.
Just to make sure we're clear - I'm talking about an MSD 6al-2 p/n 6530 which is an ignition box, not a distributor.
So if going by what aarcuda says, the Mallory style/new MP should have that capability, and the stock type might not.
I guess I'll find out when I start messing around with the distributor.

Thanks,
Ran




i just finished playing with my distr this weekend. locked out the mech adv. set total (and initial) to 34 degrees. IF i had the vac diag hooked up, it would have advanced the timing at part throttle but my promax metering plate doesnt have a vac adj port
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