Vacuum source / brake booster hose

[MildSeven]

thanks but I think I'm more confused now

 

Simeon are you suggesting that I use the vac advance signal from the brake booster hose, check pressure with a gauge, then program the 123 distributor taking the difference in to consideration? currently my only vacuum source is the brake booster hose.

 

thanks again.

 

 

 

 

 

 

Edited February 3, 2017 by MildSeven

[Simeon]

3 hours ago, MildSeven said:

thanks but I think I'm more confused now

 

Simeon are you suggesting that I use the vac advance signal from the brake booster hose, check pressure with a gauge, then program the 123 distributor taking the difference in to consideration? currently my only vacuum source is the brake booster hose.

 

thanks again.

 

 

 

 

 

 

 

Basically, give it a go with what you have first. As long as the 123 can distinguish between the vacuum at idle, part throttle and WOT then you can take that into account in your programming. 

 

As I said before, the 123 MAP sensor may not be able to react fast enough to the pulses so it may see a lower but consistent vacuum signal. If you imagine your vac signal going between 20"hg and 0 over the course of one revolution and it is doing this somewhere between 1,000 and 6,500 times a minute. When the 123 samples this signal periodically it won't see 20"Hg but it might consistently see 15 or 12 rather than something hammering back and forth from 0 to 20. 

 

Connect it up, run it without a vacuum curve and make a note of what you see when driving in various states. Report back and we will see what we can put in your curve. 

[antares242]

I've a Bosch electronic distributor and I've been wanting to connect my vacuum lines ever since I switched to side drafts. After reading this posts and some info online, this is how far I've come:

Removed the 4 vacuum port screws and got m5 barbed fittings off eBay

Installed 3 tee M5 connectors and sent everything to the back of the Dizzy.

Now my questions are:

Is the Anti Pulse Ignition valve supposed to go on the blue hose of my setup (between the Dizzy and the carbs)?

Where do I plug the line that's on front of the dizzy?

Please see pictures for reference.

Thanks!!

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[antares242]

Is it a good idea to get one of these brake booster check valves and connect the front line of the dizzy to the small port?

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[Simeon]

Your distributor has an advance / retard vacuum capsule. The retard function (I forget which side is which) should be left disconnected. The retard function was part of the original emissions system and was controlled by solenoid valves to be cut in under certain circumstances. You definitely don’t need it to run with your Webers. 

['76mintgrün'02]

4 hours ago, Simeon said:

Your distributor has an advance / retard vacuum capsule. The retard function (I forget which side is which) should be left disconnected. The retard function was part of the original emissions system and was controlled by solenoid valves to be cut in under certain circumstances. You definitely don’t need it to run with your Webers. 

 

This is the first combination-style vacuum pod I have seen with it on the retard side of the distributor.  I am guessing it must have been an e21 model.  Some of those spun counter-clockwise and had a camshaft with a 'backwards' gear to match.  It would be possible to swap a 2002 type gear onto the distributor shaft, but it would not work properly.  The early e21 distributors spun clockwise though.  Which way does the little arrow under the part number point?

 

The later e21 distributors did not use points.  Does yours use Pertronix, or something similar in place of the points; or is it the later style that came with 'electronic ignition' from the factory?  More photos of the distributor might be helpful.  One of the numbers and another showing what's under the cap.

 

Assuming it was a clockwise spinning unit, the nipple on the backside would be the vac advance feature and the one you've connected to on the front would be vac retard.  As Simeon mentioned, you don't want to use vacuum retard.

 

The brake booster fitting with an extra nipple will be manifold vacuum.  That will pull full advance in at idle, which will be an additional twelve degrees or so.  The way you have it connected now is also manifold vacuum.  The ported signal needs to come from in front of the throttle plates. 

 

I'd only connect to the pod if I had a ported vacuum signal to work with and I don't believe side drafts have that option.  I suppose you could possibly drill and tap the carbs to accept those cool little barbed fittings you have, but I've never read of anyone doing that.

 

If you do not have a variable advance timing light, I'd suggest ordering the Innova 5568, for around $100 delivered to your door.  I'll also suggest adding a WB 02 sensor, if  you have not already done so.  

 

Tom

[antares242]

 
This is the first combination-style vacuum pod I have seen with it on the retard side of the distributor.  I am guessing it must have been an e21 model.  Some of those spun counter-clockwise and had a camshaft with a 'backwards' gear to match.  It would be possible to swap a 2002 type gear onto the distributor shaft, but it would not work properly.  The early e21 distributors spun clockwise though.  Which way does the little arrow under the part number point?
 
The later e21 distributors did not use points.  Does yours use Pertronix, or something similar in place of the points; or is it the later style that came with 'electronic ignition' from the factory?  More photos of the distributor might be helpful.  One of the numbers and another showing what's under the cap.
 
Assuming it was a clockwise spinning unit, the nipple on the backside would be the vac advance feature and the one you've connected to on the front would be vac retard.  As Simeon mentioned, you don't want to use vacuum retard.
 
The brake booster fitting with an extra nipple will be manifold vacuum.  That will pull full advance in at idle, which will be an additional twelve degrees or so.  The way you have it connected now is also manifold vacuum.  The ported signal needs to come from in front of the throttle plates. 
 
I'd only connect to the pod if I had a ported vacuum signal to work with and I don't believe side drafts have that option.  I suppose you could possibly drill and tap the carbs to accept those cool little barbed fittings you have, but I've never read of anyone doing that.
 
If you do not have a variable advance timing light, I'd suggest ordering the Innova 5568, for around $100 delivered to your door.  I'll also suggest adding a WB 02 sensor, if  you have not already done so.  
 
Tom

Hi Tom,

To answer your questions in order:

1) Yes, my cam and distributor turn counter clockwise. I have an early E30.
2) It's an electronic distributor from the factory (check picture for reference)

Considering my distributor spins counter clockwise does that mean the nipple on the back is actually vacuum retard and I should connect it the other way around?

When you say the signal needs to come from "in front of the throttle plates" does that mean that taking it from the vacuum ports of the Weber's as I have it right now is no good?

I'm not a fan of drilling my intake manifolds either

Also, what are your thoughts about getting the APV001?

Thanks for your recommendation about the timing light, I'll definitely check it out.

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[antares242]

Your distributor has an advance / retard vacuum capsule. The retard function (I forget which side is which) should be left disconnected. The retard function was part of the original emissions system and was controlled by solenoid valves to be cut in under certain circumstances. You definitely don’t need it to run with your Webers. 

Thanks Simeon, after I'm certain about which side is which, would you say just plug the nipple on the vacuum retard side or just leave it unplugged?

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['76mintgrün'02]

Well, Hell.  E30?  I don't know about those.

[Simeon]

3 hours ago, '76mintgrün'02 said:

Well, Hell.  E30?  I don't know about those.

 

They still have weights and springs!

 

?

['76mintgrün'02]

6 hours ago, Simeon said:

They still have weights and springs!

 

Let's see 'em!

 

I've never seen one taken apart.  Have you?

 

I looked through a few of the previous posts about this setup and it has MSD... and stuff.  @Dudeland did not have good luck with that Innova light with his MSD, iirc.

 

My knowledge is limited to cars I've owned/worked on and even then, it is quite limited.  I could guess about pod pulling direction/advance/retard, based on the ones in our cars and what seems like common sense... if it's pulling against the direction of rotation it is advancing.  Just leave the retard side open, or cap it if you want to.  I'd leave them both unplugged, unless I could provide a ported vacuum signal.

 

As for vacuum signal sources, it is an easy googling search to learn the difference between ported and manifold vacuum.

 

It's an easy search to learn about vacuum signals on side draft carbs too.  Having never owned them, I'm only so confident in my answer and I already typed that.  The current setup is using manifold vacuum, since it's coming from behind the throttle plates.

 

The curve that's built into that distributor was for a fuel injected engine, which has different timing needs than one with carbs.  I'd be interested in seeing what the factory curve was when it was new.

 

I read previous posts asking about the 123 for this engine, saying it can spin in either direction; but it will need to have a gear that is skewed to spin ccw.

 

 

[Dudeland]

22 hours ago, '76mintgrün'02 said:

 

 

I looked through a few of the previous posts about this setup and it has MSD... and stuff.  @Dudeland did not have good luck with that Innova light with his MSD, iirc.

 

Actually I recently used my innova light setting up my crank trigger and it worked properly.  A couple things have changed since I used it last.  Shortly after my first use of the the innova, my rotor exploded and I replaced it with the correct no resistor rotor.   Not sure if that is why it seemed to work correctly now. But I am not complaining. 

 

BTW make sure you have the correct wires and rotor if you do a MSD.  Resistances in plug wires and rotors are very very different for a MSD application.  From what I can tell they want little to no resistance in the system. 

 

 

 

 

['76mintgrün'02]

18 minutes ago, Dudeland said:

 

I'm just curious, was that one installed in your 123 distributor?  Was it a 123 ignition rotor?  Their rep visited one of our 123 threads and said that they do not use the standard Bosch rotors.  There is a step in the 123 shaft and Bosch rotors will be wobbly.  He did not give a replacement part number or anything.  He just said you need to buy replacements from them.

[Dudeland]

6 hours ago, '76mintgrün'02 said:

 

I'm just curious, was that one installed in your 123 distributor?  Was it a 123 ignition rotor?  Their rep visited one of our 123 threads and said that they do not use the standard Bosch rotors.  There is a step in the 123 shaft and Bosch rotors will be wobbly.  He did not give a replacement part number or anything.  He just said you need to buy replacements from them.

That actually explains a lot.  I noticed that my solid rotor that I got from I.E would get loose after a while. I eventually solved it by putting a small dab (smear) of Permatex grey to hold it in.   So far it has been rock solid. 

 

The one in the picture is not the original one i got with my 123, it is a resistor based rotor.  This is why it got hot and ... well the picture tells everything.   The thing is you can use a resistor rotor with a MSD 6a, as long as you have resistor wires, and it will work. 

 

if you change your wires to the recommended ones for your MSD, then you must change the rotor. 

 

 

 

 

[Preyupy]

What is the "anti pulse valve" for?  if it is a one way valve (like the one for the brake booster) then the distributor will not see a drop in vacuum when you open the throttle plates.  If you install it so the vacuum pulls the valve open (one way towards the manifold)  the valve will close and hold the vacuum against the sensor in the distributor.  Your diagram should work, just delete the "pulse valve". 

 

I don't really know why you want to run a vacuum "advance" with a set of DCOE's   You should be able to tune a usable advance curve just based on engine RPM (Ti's and early Tii's were centrifugal advance only and they worked just fine, especially with a stock camshaft)  If you are having a stumble at light throttle it could be,  choke size, Aux venturi size, emulsion tubes, accelerator pump jets, inlet valve with exhaust orifice (in the bottom of the float bowl), Idle jets (too small running the mixture screws more than 2-2.5 turns out).

 

You will find if you do install the vacuum lines in the manifold and install a vacuum gauge when you go for a drive the gauge is going to jump around at low engine speeds so the sensor in the distributor is going to have a hard time knowing what to do. And with very little throttle opening you are going to loose just about all of the vacuum so it will be very ON-OFF as far as a signal to the distributor.  What are you going to do with the vacuum signal you are getting?  Are you going to use it to Advance or Retard the timing based on vacuum? 

 

I'll bet if you just went out for a drive and set the maximum advance at 32-34 deg and have it all in by 3000 rpm and then started moving the curve so it comes on sooner and sooner until you start hearing pinging (then backing it off 3-4 deg at that spot) you will come up with a curve that will work.  Your engine (compression ratio, camshaft, combustion chamber design 121,E12, E21 etc, fuel octane, and overall engine health) will make a ton of difference in how you tune your ignition.