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Intake leak problem


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Slowly figuring out the problems with my engine... Had a bad cooling issue and figured out that is was cavitation in the water pump due to water leaking out of the intake into the valley inside the engine (I'm sure my cam LOVES that!).

 

So anyway onto my question. I have a 400 block, Canfield heads, and a VicJr intake. I had the block decked .021 as well. I found that the angle between the heads and the intake was wrong (about .008 larger at the bottom), so I took the intake to the machinest and he set the angles right for me. It fit a lot better, but the @!*$&%&%&!!!! thing is still leaking! Either the intake is cracked or I'm thinking that the distance between the head and the intake may be a little to large for it to seal.

 

So my questions are... has anyone had intake problems like this? Can I put 2 intake gaskets together on one side? I'm not sure what else to do about it.

 

 

Thanks!!

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When you deck the block, the intake sides of the heads actually get closer together not further away, however they are lower. In some instances of severe head milling it is necessary to elongate the intake bolt holes, just to get the bolts in. I have found that the intake bolts need to be retightened after running it awhile. Sealer around the ports helps as well.

 

This may be a dumb question, but how do you know that the intake is still leaking? Is the intake bottoming out on the block at the ends of the manifold? Could use alittle more information.

 

I don't think I have heard of anyone running two intake gaskets, may work, I don't know. Seems the problem is elsewhere in surface angles to me.

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No it's not bottoming out, definately sits lower now though. I've had problems with this since I built the engine. From what my machinest said the intake was not at all flat(on the surface that mates to the head). Lots of high/low points.

 

A little more info... When I first built the engine the intake was very difficult to bolt up, I needed to elongate the holes to get it to match. It did leak at the time. I then had to pull everything apart and had the deck milled. When I put it back together I saw how far off the intake angle to head was (.008 on both sides. So I had the intake machined to match the head angle. When I put it together everything fit very well, the bolts lined up etc.. I used gasket sealer when I put it together to help if there was any space between the head and the intake. When I bolted it on it squeezed out some of the sealer so I thought I had a good seal.

 

As far as the leak, it's easy to know since I pull it off and there is very lovely goo covering the underside of the intake where the water is dripping down inside and mixing with the oil the only place with the goo is under the water passage.

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Are you using the rubber seals that come with the intake gaskets? When a block has been milled sometimes they can hold the intake up enought to cause leaks. If so, throw them away and run a big bead of silicone across both end rails of the block. Also clean all surfaces with ether (starting fluid) before applying sealer. I use silicone or Hylomar, can't tell much difference.

 

John

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Yeah, I've never used the rubber end gaskets either. When using AFR heads, it's the opposite, the end gaps open up to about 1/2 inch.

 

So, it's the water that's leaking (for sure) or intake plenum leaks or both?

 

If it's wate the corners need more huckypucky as do both ends and tighten the crap out of it. Almost sounds like the manifold isn't quite right, is there porosity showing on the corners where the water passages are?

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Well.. definately water. I can't really say about any vaccum leak. I think with the problems I've had with it I in no way would be surprised.

 

Heh.. yeah the manifold really isn't right. When my machinist was changing the angle he couldn't believe how poorly it was made... it really was very uneven. I just put it on after being machined so I know it at least appears to be in good shape at the water manifold!

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Yes I had the same problem, but I was mounting a blower intake to Eldebrock Victor Jr aluminium heads, The ports on the heads were a lot bigger than the intake. Take a look at my site www.jnjdragracing.com under engine photo's. You will see that I used plates that went between the intake and heads. I used a big gasket on the head side and a smaller gasket on the intake side. This cured my problem. You will have to make the end pieces for the front and back of the inatke to seal it. Take a look at my photo's and you will see what I did. You can by the plates from Dart. They are called transzitian Plates / spacer plates.

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Ok this was really dumb... While I did have a leak from the intake. I did end up fixing it. Getting the angles machined right on the intake did fix it. I found what the bad leak problem was....

 

The plate on the back of my water pump was coming loose. It finally came loose enough to have a puddle under the car, so I was able to find it. I NEVER would have thought about looking there. Sheesh...you'd think on a new water pump (only about 2000 miles on it!) that kind of thing wouldn't happen. Well it does seem to be fixed!!! No wonder I was having problems with cavitation!!

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