Intake leaking 440????!?!?!?!?

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dkbug

dkbug

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Has anyone else had trouble getting the intake to seal on a 440? It is REALLY starting to piss me off that I have to constantly take this intake off to re-gasket it. It's a 78 model block with 516 heads that are fresh from a machine shop and a weiand dual plane aluminum intake.

I had the machine shop check for square on the heads, they said they are fine. I checked the intake for squareness and it is fine as well. I tried using the paper gasket that fail-pro come with and no bueno. I ordered the victor-reinz gasket and it just comes with the valley pan. I tried just the pan, no bueno. For the third time I have taken this intake off to retry and seal it, I used the metal pan gasket with #2 sealer, no bueno. I am about done with it....

Suggestions?
 
I use a metal valley pan , no gaskets , a little RTV around the ports between the heads , the pan and the intake. I use aluminum intakes torqued to 35 lbs. I even reuse the valley pan and have no leaks. it sounds like you may have a bad/milled intake, or you have a leak somewhere else.
 
Was your intake purchased new or used? No locator pins on a big block. If when you set the intake on the engine without gaskets it should touch the heads and not the valley at all. It may have been milled or the deck on your block could be off.
 
73AbodEE said:
I use a metal valley pan , no gaskets , a little RTV around the ports between the heads , the pan and the intake. I use aluminum intakes torqued to 35 lbs. I even reuse the valley pan and have no leaks. it sounds like you may have a bad/milled intake, or you have a leak somewhere else.
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This ^^^^^^^^^^^^^^^^^^

I never used gaskets on the BB intakes before either, just some sealer and I have also reused the valley pan before.
 
There are some aftermarket gaskets out there to address this issue. They are available in various thicknesses and you can also try a gasket on both sides of the valley pan.
 
mguner said:
There are some aftermarket gaskets out there to address this issue. They are available in various thicknesses and you can also try a gasket on both sides of the valley pan.
Click to expand...



The fel-pro gasket set came with 4 paper gaskets and a metal pan. I cant use the 4 gaskets with the pan because i cant get the bolt hold to line up. The bolt holes line up perfect with the paper gaskets with just the metal pan.

I have a hard time believing that fresh heads from a machine would be off square.

The intake I have came off this motor with different heads. I dont believe that the intake has been milled and the heads have not either. With that said, the way i checked the intake for square or warpage was i held a flash light on the opposite side of a straight edge and i looked for light to come through the bottom side of the straight edge while skimming it across the surface. Nothing came to my attention while doing this.

Is there a more appropriate way of doing this? Im trying to stay out of the machine shop as the one i use is VERY credible and wants an arm and a leg to do anything.

I dont want to order a new intake until i am positive thats the problem.
 
With the intake setting on the engine with no gasket have somebody hold a light so you can see how the surfaces match up.
 
I am not 100% sure what exactly is leaking. With the engine running i can spray carb cleaner along the runners on the manifold and it will idle up. So far, im sure its my lack of knowledge and experience, i can not get my air/fuel mixture set right.
 
I know you can get a valley pan for these big blocks to eliminate using them as the intake gasket. I think I am going to try and get on and just use the intake gaskets that the factory style pan comes with.. I see that sealing a lot better than a metal tray... With that being said, If I were to decide to get my intake milled to fix any imperfections, how much should I have them take off?
 
just a note for you. every 383-400-440 produced used a metal valley pan without gaskets, and we are talking ten of thousands of them. I have built 20 or 30 big blocks and never used anything but a valley pan and never had sealing issues with a cast iron or aluminum intake. the gaskets are included in some kits in case you have an intake or heads that have already been milled. if you are not getting an air tight seal with or without sealer and gaskets, I would look hard at having a cracked intake or cracked head port. its possible that one or the other has already been milled but at a funky angle that is causing it to leak that the gaskets wont seal. I would definitely check the intake and head mating surface angles to see if they are the same. if it were me , I would toss another intake on there and see if that cures it, if anything, just to rule that out. you also want to keep the starting fluid or whatever you are using to check for leaks from getting sucked into the carburetor because that will also increase the idle speed. any open vacuum port or a bad carb seal to the intake will also result in the same increase. I don't think ive ever had one intake that sat perfectly flat on the engine that didnt sealed perfectly after torqueing it down. there is a bit of tolerance that can exist but still seal. that's all I can offer at this point.
 
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