aspirator tube

UNKIE

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I bought this 1978 Caravelle on eBay well I've e found a few problems with the car. Like I've replaced all the weather stripping cap, wires, rotor, and plugs along with master cylinder brake lines and power brake booster. The kid had no relays or fuses in the fuse box. I bought a nice set of mufflers Hush thrush mufflers just like the sound. The problem is the aspirator tube and the hole in the manifold. So now looking for headers only place was Walmart. Also, does anyone have an idea on adjusting the driver's door hinges?
 

Duke5A

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The manifolds are easy to plug if you don't want the headaches of headers. It's a single bolt that holds the tube in place on the backside of the manifold. Cut the tube an inch of so from the flange, pinch it closed in a vice, then fold it over and pinch it again. Problem solved. I did this one a few smog era 318's.

The problem you're going to have with headers besides ground clearance (unless you buy very pricey headers) is the air injection holes in the heads themselves. These will have to be drilled, tapped and plugged. If you stick with the manifolds then those holes stay covered. The manifolds are good up to about 300HP.

Are the doors drooping when opening them? The hinge pin is probably worn. Common issue. I just used a hardened bolt in place of the factory pin on my hinge.
 

SRTMirada

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I've pinched off the aspirator tube as Duke suggests and it works......until the bolt breaks and the flange falls off. A better solution is to tap the hole in the manifold for a threaded plug. Much more reliable.
 

BudW

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Your cylinder heads have A.I.R. ports drilled into them:
AIR Ports.png


Also, your exhaust manifolds have ports cast into them as well"
3870055 E Manifold.jpg

The exhaust manifolds have a passageway and flange at rear of manifold which the aspirator valve (or air pump) lines attach to.

The picture above, someone cut that line about two inches (5 cm) out, flattened, then bent over and flattened again to crimp off the tube - which is something I see a lot of (in non-emissions states or cities). DO NOT do this if you live in an emissions state or city! In my state, Oklahoma, they don't care what you do.

Other options are:
Find or make a metal plate to bolt to rear of exhaust manifold. The factory plates are very hard to find.
AIR EM B.Plate.jpg

Here is a picture of a new engine with one installed:
New 318 engine, rear A.jpg

A person can also make a plate as well. The hard part is finding a gasket - but it wouldn't take much to make a gasket using header gasket sheets.

If you plan on using headers then the only other way is to tap the holes on cylinder heads and insert metal plugs in the holes. This method is the best way - but there is limited space with engine in car to perform this operation.

The last option is to find mid/late '70's/early '80's exhaust manifolds that have no provision for A.I.R. holes:
3870337 E Manifold.jpg

See earlier manifold to see the differences.

BudW
 

Aspen500

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Alternative to a block off plate gasket is high temp rtv such as Ultra Copper.

I must be getting old. Remember getting the block off plates from the dealer. The Dodge dealer here usually had them in stock, along with the bolt and gasket. When the aspirator tube rusted out or the aspirator valve failed, a block off plate was the common repair. No emission testing here.
 

Duke5A

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Couldn't they be welded shut, or filled with JB Weld? just throwing out ideas.

Probably, but why? Use my method and I didn't even have to remove the manifolds from the car. There actually is enough room to get to them.
 

BudW

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A lazy attempt to crimp off is all you need. It is not under pressure.
After a bit, the small ports will carbon up (stop up), which means there will be 0 pressure at that time (as opposed to maybe 2 PSI on a good day at WOT). You can see in the above photo # two (on post # four), the Left most port is almost stopped up.
 

SRTMirada

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Here's my manifold with the bolt broken off and my threaded plug repair. Apparently having the bolt break isn't a common problem.

20220529_131240(0).jpg
 

LSM360

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I've pinched off the aspirator tube as Duke suggests and it works......until the bolt breaks and the flange falls off. A better solution is to tap the hole in the manifold for a threaded plug. Much more reliable.
Much better solution. I did the same. BUT, you can always start off crimping and be prepared for the other. Oh, and when I write "I did the same" it means my mechanic did the same and I paid him lol..
 

UNKIE

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I bought this 1978 Caravelle on eBay well I've e found a few problems with the car. Like I've replaced all the weather stripping cap, wires, rotor, and plugs along with master cylinder brake lines and power brake booster. The kid had no relays or fuses in the fuse box. I bought a nice set of mufflers Hush thrush mufflers just like the sound. The problem is the aspirator tube and the hole in the manifold. So now looking for headers only place was Walmart. Also, does anyone have an idea on adjusting the driver's door hinges?
I know what you mean about the door hinge. That's how I repaired my 73 Charger doors. I still have it have to do a lot of patching on the car. I finally have all the shocks on the car and now I had to use a reciprocating saw to cut the shock bolt R?R. which leaves me with the driver's door window regulator and bottom hinge he put one on but the door alinement is off. I guess that I'll remove the tube and do the do and make a gasket for it.
 

Aspen500

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Cars with pulse air only had one tube to the right manifold. With an air pump, they had 2. My '78 Cordoba (no air pump) had just thr one. They use exhaust pulses to draw the air in.

Of course when I had it, if you needed a new tube, you went to the parts store or dealer and bought one. Same with the block off plates. Ah, the good old days. :)
 

BudW

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My '77 has what @Aspen500 refers to pulse air. Chrysler calls it an aspirator valve. The valve blocks off the exhaust pulse then opens with the exhaust suction, allowing fresh air into the exhaust.
It uses the hose that attaches to bottom side of air cleaner (which is VERY noisy when disconnected).

People don't see it that way, but each exhaust valve opening creates a pulse wave, with a suction afterwards.
it is like finding a large diameter length of PCV pipe and mounting it at a small angle downwards. Then filling some water balloons slightly smaller than inside pipe diameter. Then have someone start putting those water balloons down the pipe. One end will be under (slight) pressure as the balloons rolls downwards and other side will have a slight vacuum.
Aftermarket exhaust headers work the same way by using amplifying the pulses and vacuum effect to move more air.

high end drag race engines also use an aspirator valve with a hose hooked to the valve cover. It uses the vacuum pulses to help keep the crankcase under vacuum:
Exhaust Crankcase Vent.jpg

BudW
 

UNKIE

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there are tubes on both manifolds correct?
No, it looks like just the one side if I remember right. I had taken it to the local muffler shop that did my 73 Charger but he said it was leaking and never let me see it right. So I'm assuming that it's the gasket on the aspirator tube I tightened the bolt that was leaking already and wielded the upper pipe closed. I noticed that later and earlier manifolds don't have this as they don't have the lean-burn on them. If I were still in Ga I would have had this done by now. In Ga. I have friends and parts yards that like to help you and for free. I know it's funny but where I was they try to help people just to help and parts discounts are plenty around Ft. Gordon for retired people. now a lot of the stuff that I got was rock auto or believed it or not Amazon and Walmart online. Walmart surprised me that they had headers mufflers along with other things they have links to speed shops like amazon has links to dealerships and speed shops. Sorry for rambling on. s-l1600 (2).jpg
 

BudW

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Actually Fel-Pro makes the gasket - BUT it is only available as part of a head gasket kit - so, yea (sigh).
BudW
 
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