level3porkproducer
Well-known member
which one do i use for the ds2 conversion the single vacume advance or the double ????
which distributor
- Thread starter level3porkproducer
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bigcatchdaniel555
Well-known member
Get the single vacuum. The old emissions cars used the dual vac advance for timing retard. No need for it.
Howdy All:
Use a single if you have a choice.
The tap between the cannister and the distributor on the dual vacuum distributors is for vacuum retard, as Daniel said. IF you do have to use a dual vacuum distributor, DO NOT CAP OFF the retard port. Capped off it can limit the function of the advance side if it is sealed off. Best to just leave it open and forget it.
Page62- I'm curious about your experiences with the retard port capped off?
Adios, David
Use a single if you have a choice.
The tap between the cannister and the distributor on the dual vacuum distributors is for vacuum retard, as Daniel said. IF you do have to use a dual vacuum distributor, DO NOT CAP OFF the retard port. Capped off it can limit the function of the advance side if it is sealed off. Best to just leave it open and forget it.
Page62- I'm curious about your experiences with the retard port capped off?
Adios, David
Howdy Back:
Page 62- I, basically, did the same thing, thinking capping it would keep dirt out and look more finished. I noticed something was wrong in my gas mileage. I got checking timing with a dial back timing light at steady cruise rpm. At first I thought I had a bad canister or a wrong one. For some reason I pulled the plastic cap and, abbra- cadabra! Problem solved. Got the good mileage again.
To be clear and exact, my experience was with a '68 point type distributor. When I set up my DS II I used a distributor with a vaccum advance side only.
Thanks for "the rest of the story".
Adios, David
Page 62- I, basically, did the same thing, thinking capping it would keep dirt out and look more finished. I noticed something was wrong in my gas mileage. I got checking timing with a dial back timing light at steady cruise rpm. At first I thought I had a bad canister or a wrong one. For some reason I pulled the plastic cap and, abbra- cadabra! Problem solved. Got the good mileage again.
To be clear and exact, my experience was with a '68 point type distributor. When I set up my DS II I used a distributor with a vaccum advance side only.
Thanks for "the rest of the story".
Adios, David
simon
Famous Member
as far as aesthetics are concerned, you can also route a vacuum hose from the retard port of the vac canister to someplace hidden, like into the air cleaner or beneath it.
looks fairly stock, but won't limit advance travel.
On some dual canisters, the retard port is merely a piece of brass tubing pressed into the canister body. You could pull that port out with some pliers, a simple hole looks less disturbing than an uncapped port.
looks fairly stock, but won't limit advance travel.
On some dual canisters, the retard port is merely a piece of brass tubing pressed into the canister body. You could pull that port out with some pliers, a simple hole looks less disturbing than an uncapped port.
I'm wondering why these dual advance retard mechanisms are so vilified.
My question is born from ignorance, so perhaps someone can enlighten me.
Is their purpose not to retard the advance during deceleration in effort to raise economy, limiting a rich mix of gas getting sucked in to the carb under those conditions. Is this not a good thing?
Do they in any way hinder performance when set up correctly?
My question is born from ignorance, so perhaps someone can enlighten me.
Is their purpose not to retard the advance during deceleration in effort to raise economy, limiting a rich mix of gas getting sucked in to the carb under those conditions. Is this not a good thing?
Do they in any way hinder performance when set up correctly?
Howdy:
Jackfish- The retard function was designed to be part of a multi-function system. It did not work independently. Heat, load, EGR, thermactic air pumps and others worked in sync, in a perfect world. In fact all of those efforts were a crutch that, in some cases, inhibited both economy and performance.
Modern fuel injection has eliminated the need for most of those 70s systems. You'd have to look hard for someone to remember and understand, much less maintain, those systems. So, for most of us, they're gone.
Adios, David
Jackfish- The retard function was designed to be part of a multi-function system. It did not work independently. Heat, load, EGR, thermactic air pumps and others worked in sync, in a perfect world. In fact all of those efforts were a crutch that, in some cases, inhibited both economy and performance.
Modern fuel injection has eliminated the need for most of those 70s systems. You'd have to look hard for someone to remember and understand, much less maintain, those systems. So, for most of us, they're gone.
Adios, David
8) the dual vacuum can on california emission equipped vehicles was use to reduce emissions. it had a vacuum port that was triggered by a temperature switch. as i recall it was designed to reduce ignition timing when the engine warmed up to reduce emissions.
for those of you that are building turboed engines by the way, use the dual diaphram unit, and plug the vacuum line in after the turbo outlet. that way you get a boost retard function automatically. it really works nice to eliminate detonation under boost.
for those of you that are building turboed engines by the way, use the dual diaphram unit, and plug the vacuum line in after the turbo outlet. that way you get a boost retard function automatically. it really works nice to eliminate detonation under boost.
level3porkproducer
Well-known member
well all those answers were more than adaquate. my pig farming military truck driving brain hurts with all that new info 
thanks guys.....or maybe gals too
thanks guys.....or maybe gals toolevel3porkproducer
Well-known member
another question....i bought a mallory 6A ignition module. has anyone used that as a stand alone for the ds2. did it work alright?
Been chewing on this a bit and came across this in an old Chiltons:
It seems to me this a good thing, and if I had a dual diaphragm dizzy I would probably hook it up and use it as it was intended just to test it out. Especially for on and off the gas driving, or anytime you're coming off high speed to a coast, would it not help lean out the mix and improve gas mileage? We have many threads looking at ways to improve economy and this may be an effect option as well.
It seems to me this a good thing, and if I had a dual diaphragm dizzy I would probably hook it up and use it as it was intended just to test it out. Especially for on and off the gas driving, or anytime you're coming off high speed to a coast, would it not help lean out the mix and improve gas mileage? We have many threads looking at ways to improve economy and this may be an effect option as well.
grocery getter
Famous Member
as far as the msd, you can make it easy with: http://store.summitracing.com/partd...t=MSD-8869&N=700+-86055+1002+115&autoview=sku
I am running the DSII w/ a MSD 6AL standalone. Works great.
As far as the dual advance thing, hooking the retard port up to boost would generally cause you get MORE advance under boost, as the pressure would push the diaphragm.
I am going to be re-installing my vacuum advance pretty soon here, and my thought is that, with a dual port canister, the boost applied to the normal advance port will retard timing.
As far as the dual advance thing, hooking the retard port up to boost would generally cause you get MORE advance under boost, as the pressure would push the diaphragm.
I am going to be re-installing my vacuum advance pretty soon here, and my thought is that, with a dual port canister, the boost applied to the normal advance port will retard timing.
