New Air Grabber Setup, Faulty Switch/Low Vacuum

[SixBarrelBill]

I've spent too much money and invested too much time for my Air Grabber not to function. For the sake of argument, I'm going to refer to the toggle valve with the red handle as the switch here.

I've got a 1970 Roadrunner 440+6 that I have converted to an Air Grabber car. All new pieces and parts. Yesterday my dad and I installed all the components and spent all day diagnosing issues. At the end of the day we were finally able to get the Air Grabber to work on its own by bypassing the switch but the vacuum is too low to fully raise the door.

I want to keep the original look so I believe I have a couple solutions but wanted to see if any of you have done the same and what parts you used.

1) It seems my engine will not produce the vacuum necessary to fully open the door because of the cam I'm using. When we first hooked up the vacuum gauge I was getting about 12in. After advancing the timing a lot we were able to get close to 15in but I can't run that kind of timing normally so that's a no go.

The solution for this seems to be an electric vacuum pump. I have never used one and just guessing to successfully operate the lift on the door I would need 18-22in.

Have any of you used these types of pumps for this kind of solution?

2) I have 2 brand new switches and both of them leak so the door would barley raise. I have taken them apart, greased them up and now one doesn't work and one kind of works. I'm done with those.

The solution I would like to use is to keep one of the switches in the dash as a dummy, it wouldn't function but will look the part and mount a brass valve under the dash.

A while back I read an article (I think it was one here and wish I would have book marked it) where someone used a Clippard valve to overcome the leaking issue. I think it may have been a Clippard MJTV-5 but for the life of me I cannot find the article. Does anyone happen to have that link or have used one of these brass valves to accomplish what the original switch does?

Thanks, Bill

 

[Photon440]

You would think that somewhere in the engine's operating range there would be some vacuum, such as high revs and closed throttle. The vacuum canister should retain that vacuum even when the engine isn't at a vacuum state. My 'grabber would raise and lower two or three times even with the engine off just with the vacuum stored in the canister.

 

[SixBarrelBill]

You would think that somewhere in the engine's operating range there would be some vacuum, such as high revs and closed throttle. The vacuum canister should retain that vacuum even when the engine isn't at a vacuum state. My 'grabber would raise and lower two or three times even with the engine off just with the vacuum stored in the canister.

And maybe that could be an issue. I'm running an after market vacuum canister that is close to the original but not the same. It has a large nipple on the bottom and a smaller one at the top that I believe is used for things like running A/C. I've switched the hoses around and found the bottom larger nipple is correct for attaching manifold vacuum. By switching manifold vacuum to the smaller top nipple it will not function at all.

I guess the first thing I need to fix is the switch with one like the Clippard valve. Gotta tighten up the system first so there is no leaks.

And I guess I'm a little surprised at how small the vacuum port is on the manifold, seems pretty restrictive on the volume. I'm using a vacuum port that is supposed to be specific for Air Grabber or A/C, it's like an 1/8 or so.

 

[440+6]

Are you using the solenoid valve, if so is it energized?

Should work with the vacuum you have.

 

[kiwigtx]

I've spent too much money and invested too much time for my Air Grabber not to function. For the sake of argument, I'm going to refer to the toggle valve with the red handle as the switch here.

I've got a 1970 Roadrunner 440+6 that I have converted to an Air Grabber car. All new pieces and parts. Yesterday my dad and I installed all the components and spent all day diagnosing issues. At the end of the day we were finally able to get the Air Grabber to work on its own by bypassing the switch but the vacuum is too low to fully raise the door.

I want to keep the original look so I believe I have a couple solutions but wanted to see if any of you have done the same and what parts you used.

1) It seems my engine will not produce the vacuum necessary to fully open the door because of the cam I'm using. When we first hooked up the vacuum gauge I was getting about 12in. After advancing the timing a lot we were able to get close to 15in but I can't run that kind of timing normally so that's a no go.

The solution for this seems to be an electric vacuum pump. I have never used one and just guessing to successfully operate the lift on the door I would need 18-22in.

Have any of you used these types of pumps for this kind of solution?

2) I have 2 brand new switches and both of them leak so the door would barley raise. I have taken them apart, greased them up and now one doesn't work and one kind of works. I'm done with those.

The solution I would like to use is to keep one of the switches in the dash as a dummy, it wouldn't function but will look the part and mount a brass valve under the dash.

A while back I read an article (I think it was one here and wish I would have book marked it) where someone used a Clippard valve to overcome the leaking issue. I think it may have been a Clippard MJTV-5 but for the life of me I cannot find the article. Does anyone happen to have that link or have used one of these brass valves to accomplish what the original switch does?
View attachment 1096156

Thanks, Bill

Did you check to see if the hoses on the Vacuum Canister are the correct way around first?
(I saw your later reply after posting that)

There was talk a while back of faulty switches, but they were primarily reproduction ones from the same dubious source.

If your engine has a severe lack of vacuum, and that indeed turns out to be the problem, you 'could' get a vacuum accumulator tank and mount it under the battery tray. But I doubt that anything but a highly tuned race car would have that low a vacuum to warrant such a modification.

 

[kiwigtx]

And I guess I'm a little surprised at how small the vacuum port is on the manifold, seems pretty restrictive on the volume. I'm using a vacuum port that is supposed to be specific for Air Grabber or A/C, it's like an 1/8 or so.

You probably need to get a multi-port fitting that replaces where the brake booster feeds from on the rear of the manifold. These have a 1/8" fitting as well as a 3/8" fitting for the brakes. Taking off the carb port will be restrictive, and not accumulate enough vacuum to fill the canister.

Example:

Block off unnecessary port, or buy appropriate two port fitting.

 

[SixBarrelBill]

Are you using the solenoid valve, if so is it energized?

Should work with the vacuum you have.

We found with with the brand new solenoid valve connected with 12v ignition power, it would not even attempt to raise the scoop. Once we bypassed that solenoid it actually tried to lift the door.

 

[SixBarrelBill]

You probably need to get a multi-port fitting that replaces where the brake booster feeds from on the rear of the manifold. These have a 1/8" fitting as well as a 3/8" fitting for the brakes. Taking off the carb port will be restrictive, and not accumulate enough vacuum to fill the canister.

Example:
View attachment 1096278

Block off unnecessary port, or buy appropriate two port fitting.

So I was wondering about that small 1/8" port not having enough volume, seems small but according to everything I've seen it's correct. Maybe I will try and buy the vacuum port you suggested with the larger diameter options.

Here's what's on the back of the intake manifold now where I'm drawing vacuum.

 

[440+6]

Eighth inch is plenty.
I would start at the manifold with a vacuum guage and work my wall all the way to the two lines on the door actuator, should have the same vacuum everywhere.
Sounds like something is plumbed wrong or bad parts.

 

[440+6]

 

[SixBarrelBill]

One thing I forgot to mention is that when the hood is open the scoop will open all the way. Once it's closed it opens almost all the way, the top of the teeth on the bottom jaw of the decal are barely showing. Because of course gravity is in play so if I give the scoop a little bump up it will raise and stay all the way up.

Well, I'm going to start with replacing the switch with a new brass valve and then look at the vacuum canister and actuator to see if one of them is the culprit.

 

[SixBarrelBill]

Well I think I probably found the main issue. With a hand pump directly connected to the brand new actuator, I cannot get it to hold vacuum on either side of the pod. The nipple closest to the front of the car which closes the scoop, bleeds off quickly without removing the hand pump from it. The nipple closest to the engine which pushes the rod out to lift the scoop does not hold any vacuum at all. With a squeeze of the handle the gauge quickly jumps to about 15 and then immediately falls to zero. Without continually trying with the hand pump, the scoop will not stay up.

I would think that actuator should hold pressure in either direction and not bleed off until the hand pump is removed. The vacuum canister itself seems to hold vacuum pretty good.

Super disappointing to spend a ton of money on parts that don't seem to work.

If the company I bought it from will not exchange it I guess I'll be on the hunt for a different one, but I'm not sure if all the companies use the same manufacturer.

 

[kiwigtx]

One thing I forgot to mention is that when the hood is open the scoop will open all the way. Once it's closed it opens almost all the way, the top of the teeth on the bottom jaw of the decal are barely showing.

Have you got the heavy spring in place on the actuator rod?

 

[SixBarrelBill]

Have you got the heavy spring in place on the actuator rod?

No, I haven't tried it with that spring in place.

 

[440+6]

Well I think I probably found the main issue. With a hand pump directly connected to the brand new actuator, I cannot get it to hold vacuum on either side of the pod. The nipple closest to the front of the car which closes the scoop, bleeds off quickly without removing the hand pump from it. The nipple closest to the engine which pushes the rod out to lift the scoop does not hold any vacuum at all. With a squeeze of the handle the gauge quickly jumps to about 15 and then immediately falls to zero. Without continually trying with the hand pump, the scoop will not stay up.

I would think that actuator should hold pressure in either direction and not bleed off until the hand pump is removed. The vacuum canister itself seems to hold vacuum pretty good.

Super disappointing to spend a ton of money on parts that don't seem to work.

If the company I bought it from will not exchange it I guess I'll be on the hunt for a different one, but I'm not sure if all the companies use the same manufacturer.

Looks like you found the problem, it should stay open using the hand pump.

 

[kiwigtx]

Looks like you found the problem, it should stay open using the hand pump.

He just needs the passenger to keep pumping the flap while they drive along the road.

 

[MoparGuy68]

Have you got the heavy spring in place on the actuator rod?

My air grabber scoop doesn’t want to fully open when the engine is idling and car is not moving. When the engine is under load and car is moving it will fully open. After removing the big spring, at idle, it now opens more, but still not fully. It seems by removing the big spring so the actuator doesn’t have to work against it, that helped to raise the scoop higher at idle.

I read that the spring is supposed to assist in allowing the scoop to close, but mine does not need the spring in place to fully close. It completely closes without the spring. And does so in the same amount of time as it did when the spring was in place.

I want the scoop fully open when the switch is turned ON. When I’m stopped at a traffic light, it is never fully open. That’s annoying..

 

[kiwigtx]

My air grabber scoop doesn’t want to fully open when the engine is idling and car is not moving. When the engine is under load and car is moving it will fully open. After removing the big spring, at idle, it now opens more, but still not fully. It seems by removing the big spring so the actuator doesn’t have to work against it, that helped to raise the scoop higher at idle.

I read that the spring is supposed to assist in allowing the scoop to close, but mine does not need the spring in place to fully close. It completely closes without the spring. And does so in the same amount of time as it did when the spring was in place.

I want the scoop fully open when the switch is turned ON. When I’m stopped at a traffic light, it is never fully open. That’s annoying..

As said on TV a lot ....Results may vary.

Some cars have sloppy holes where the pivot pins go through on the flap. That can cause the flap to 'bounce' around at speed when open. Alignment and good quality parts are helpful.

 

[SixBarrelBill]

Just an update on this...

The brand new actuator came from PG classic and I called them last Monday. They're shipping out a new one. If this one doesn't work I'll deal with them and then figure out how to get one that does work. Maybe ship it off to the n96airgrabber guy that I've seen mentioned on this site. Or if I can just find an original one that works and I need to paint it or something I'll do that.

I feel I have the right solution for the switch inside the car. I'm not using the crappy plastic aftermarket one as they just seem to be garbage. I think I will post a how-to for the solution since I don't see one on this site. This new toggle valve will fit in the factory location and from the outside it will look totally original.

 

[SlinktRR]

I use a canister and I can actuate with 9-10" vacuum. But my replacement repro switch is crap.

Did you make that switch?? I want one!