Vacuum gauge on Performer 440

[YY1]

Hey folks-

I just purchased a vacuum gauge to help me tune the 440 in my D150.

The only vacuum port on the Performer intake is in use by the PCV valve.

Do I have to put a "T" in that, or can I use one of the EGR ports that already have the correct threaded hole?

Might be a silly question, but I'm not sure exactly where those EGR ports go.

I suppose another alternative might be to reroute the PCV to the big unused port on the base of the TQ carb, and then use the intake port for the gauge.

Thanks.

 

[A383Wing]

you cannot use the PCV "T" because you will not get full vacuum. You cannot use EGR port because that is ported vacuum.

There should be a vacuum port on the carb...you can "T" into the choke pull-off hose if need be

 

[YY1]

I think I got it...

the PCV is supposed to be on the big port on the front of the TQ.

That frees up the port on the back of the intake.

I already had an adapter fitting for the intake (1/2"?) to what came with the gauge (7/16"?).


So... the EGR passage(s) doesn't get full manifold vacuum at idle?

 

[Meep-Meep]

The back of the intake is for power brakes and you can Tee into that. Or better yet just use a manifold port on the TQ.

 

[A383Wing]

EGR ports do not get vacuum at idle...

you want a more "centralized" port on the carb for the gauge instead of one of the runners on the intake...

 

[Meep-Meep]

The EGR passages as cast into the intake, with one end of the passage in the plenum floor of the intake and the other end at the EGR valve mounting pad, would get vacuum at the pad. You will need a block off plate on the pad or an EGR valve that doesn't leak. One port on the pad goes to the intake floor and the other to the exhaust heat cross over. You can get a manifold vacuum signal from the floor of the intake but much easier to use the back of the intake or a port on the carb.

 

[bigmanjbmopar]

Your carb does not have a pvc port? The port on the manifold is for the brake booster. On my carb I use the full vacuum port in the front for the A/C heat controls this could be used for a gauge. you should have two ports one for full and one for the distributor advance.

 

[YY1]

This particular TQ (I can't read the number as hard as I try) has one huge port on the front, that I am fairly sure is for the PCV. It was blocked off by the PO.

It only has one smaller port on the front, which I assume is the dist vac advance.

My intake has threaded plugs in the EGR Pad, so if I'm getting this...I could use the one that goes to the plenum, and just leave the plug in the other one.

I didn't figure the EGR could be timed (ported) as there is nothing to control it (like ball/valves in the carb), except the actual EGR valve.

Come to think of it...the brakes are awfully hard to push. I hadn't gotten that far in checking that out yet.
Maybe I'll get more fixed than I thought with this project.

 

[bigmanjbmopar]

Pics?

what ever is in the intake use for brakes and or any vacuum gauge if you don't have a full vac from your carb. PVC should go to carb. Dizzy vac advance from carb if you have that. So you could T the intake port for your new gauge & brakes. Sounds like you have it backwards now. Are you sure you only have one small vac fitting on carb? What carb is it I'll look it up.

 

[YY1]

OK, here's a pic from when I got it.

It shows:

Red- vacuum for brake booster CLEARLY not hooked up.

Yellow- PCV hooked to rear intake port.

Blue- plugged port at front base of TQ and dist advance hookup.

Green- threaded plugs in EGR pad.


The PCV has been re-routed to the front.

I think I'll be OK for testing the way it is. then I'll hook that brake booster back up.

Anyone know which port on the EGR pad goes where?

- - - Updated - - -

I'm going to try taking a pic of the left front of the carb base, to see if I can decipher the numbers under magnification.

It's a 1969 motor, so I'm sure it's not a 69 TQ

- - - Updated - - -

Judging from some pics I've found, I'm gonna guess the front most EGR hole goes to the plenum, based on the observation that the rear most port is centered above the heat riser.

 

[bigmanjbmopar]

I have been scouring the net for info on those erg ports and all I can find is edelbrock saying to block them off like you have it. This would bug me too since you have a gauge can you take a vac fitting and use it on each of those ports and see what the vac output is? I'm would guess the same and low.

looking at that carter thermo quad carb I'm surprised you don't have to small vac ports one on either side of the PVC port. So I guess unless you upgrade carbs that's all you have to work with.

On the back of the carb is a large port like the PVC port in front that should be used for your brakes since it is full vac.... If it does not the you have a bigger problem. First things first fix the PVC port.

 

[A383Wing]

YY1, if you take PCV and route it to front nipple on carb, the rear nipple will now go to booster..you can "T" off of that for vac gauge or get the other booster nipple that has the large nipple for brake hose and smaller nipple for accessories.

I would be leery of taking a vacuum port off the EGR plate...it's gonna get very hot there and rubber hose will melt or crack with heat.

 

[Meep-Meep]

I'd have to look at my TQ to remember which port does what. You have a pretty late model carb so will have extra ports.

There is probably a little brass tube coming out of the plastic body on the primary on the pass side. This goes to the vacuum amplifier, which I'm sure you don't have, so just plug it. This is venturi vacuum.

You also want to find the ported signal for the vac advance. If you currently have the vac advance hooked to manifold vacuum that is wrong.

PCV to the 3/8" nipple on the front of the carb.

There may be one or two manifold vacuum pots at the rear of the carb.

Leave the EGR plugs alone but fix them if they leak.

Power brakes go to vac port on rear of intake.

 

[67 coronet]

you mat want to make sure that your vac booster dosnt leak before you hook it up.that may be why it is not hooked up now and will cause a vac leak if bad.just make sure it holds any vac applied to it.