Bad vacuum leak ansen intake

Vanspeed

Vanspeed

Well-known member
Hi guys,

I bought my old roadster back and at some point somebody did some hot rodding to the engine. It backfires very badly while idling so I shot some brake clean on it and I have a terrible vacuum leak at the back. It looks like homemade gaskets. What are you guys with downdraft intakes running for gaskets? It also has a reds header. Any help appreciated.
 
Vanspeed said:
Hi guys,

I bought my old roadster back and at some point somebody did some hot rodding to the engine. It backfires very badly while idling so I shot some brake clean on it and I have a terrible vacuum leak at the back. It looks like homemade gaskets. What are you guys with downdraft intakes running for gaskets? It also has a reds header. Any help appreciated.
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The best gasket for Model A intake/exhaust manifolds I have ever used is the Remflex #3040 Gasket.

But first, check for cracks as suggested.
 
My car has a Weber carburetor and the aluminum intake manifold that comes with it in kit form. The intake and exhaust manifolds are separate and not bolted together like in the original manifolds for the Model A. I use the standard conical washers that act as a bridge so that both manifolds are pushed against the block with about equal force. I torque to 55 foot-pounds and then check the torque after the engine cools after the first heat cycle and then at the 100 and 1,000 mile intervals. I use the 1931 original style gaskets, see https://www.snydersantiqueauto.com/product.htm?pid=979403&cat=0.

Even with separate manifolds, they individually must be flat and have about the same ear heights.

Check for broken ears or cracks as mentioned above. Check to make sure your manifolds are flat and have about the same ear heights. Use the copper clad gasket per the link above. Check for fit up to make sure that the holes in the manifolds are lining up with the holes in the block.

I know nothing about the Reds header. Some photos would help. If the intake and exhaust manifolds are bolted together they must both be flat and in the same plane.
 
Last edited:
nkaminar said:
My car has a Weber carburetor and the aluminum intake manifold that comes with it in kit form. The intake and exhaust manifolds are separate and not bolted together like in the original manifolds for the Model A. I use the standard conical washers that act as a bridge so that both manifolds are pushed against the block with about equal force. I torque to 55 foot-pounds and then check the torque after the engine cools after the first heat cycle and then at the 100 and 1,000 mile intervals. I use the 1931 original style gaskets, see https://www.snydersantiqueauto.com/product.htm?pid=979403&cat=0.

Even with separate manifolds, they individually must be flat and have about the same ear heights.

Check for broken ears or cracks as mentioned above. Check to make sure your manifolds are flat and have about the same ear heights. Use the copper clad gasket per the link above. Check for fit up to make sure that the holes in the manifolds are lining up with the holes in the block.

I know nothing about the Reds header. Some photos would help. If the intake and exhaust manifolds are bolted together they must both be flat and in the same plane.
Click to expand...

Yes sorry I was a little vague. Reds headers are a full length header, the intake bolts to that directly so the header takes a gasket as well as the intake because it mounts to the header flange, on top of it if that makes sense. I would just love to know how to properly mate them. Lots of pics I have found and it seems like everybody does it different. I want the best method of anybody knows.
 
Call Red's and ask them. They have always been helpful when I have called them in the past.
 
Zax40 said:
Call Red's and ask them. They have always been helpful when I have called them in the past.
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How do you get Red's to answer the phone? I have called many tines recently and left messages, but have gotten no reply or answer. I wanted to place an order for an OHV header for my Miller engine. I think they may be closed up, except the phone still takes messages.
 
midgetracer said:
How do you get Red's to answer the phone? I have called many tines recently and left messages, but have gotten no reply or answer. I wanted to place an order for an OHV header for my Miller engine. I think they may be closed up, except the phone still takes messages.
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It's been about 2 years since I ordered anything from Red's. At the time they were very responsive. I'm sad to hear they don't seem to be very responsive anymore. Hopefully it's a temporary staffing or technology issue and not a sign Red's is struggling as a business.
 
Vanspeed said:
Hi guys,

I bought my old roadster back and at some point somebody did some hot rodding to the engine. It backfires very badly while idling so I shot some brake clean on it and I have a terrible vacuum leak at the back. It looks like homemade gaskets. What are you guys with downdraft intakes running for gaskets? It also has a reds header. Any help appreciated.
Click to expand...

Stock gaskets to the block and homemade gaskets under the manifold. Check for clearance between the manifold and the header.
 
By the way, I had a set of headers on my car like Red's but a different brand, and a straight through exhaust system. It was too noisy so I switched to the stock Model A exhaust manifold and an Ares performance steel muffler and exhaust pipe. I did not notice any loss of performance with the stock manifold and Ares system. I think the headers may be better if you are really reving the engine, but I never go above 3,000 rpm. To take advantage of the headers you have to have the whole exhaust system tuned and the cam timing appropriate too.
 
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