doing another FI conversion here... HG and intake surface of the heads plus both ends of the Intake runner were all milled...for whatever reason, now the intake does not sit perfectly flat on the head with a "slight rock" to it... makes sealing up the intake to the head impossible even with subaru gaskets...(very, very small amount of coolant leaking into the inside )..I thought about doubling up on the gaskets or useing the permatex product "the right stuff" , but don't I know from experience how well this will hold up being near atomized gas flowing thru the runner...any ideas..

Actually, that is what I was going to suggest. However, you may want to wait for someone with more experience to comment. Otherwise, I have heard of people using fine grit sandpaper to mill their own heads and stuff, maybe you could use that technique to get the surfaces flat for the intake manifold to sit on.

use ultra grey

Actually, that is what I was going to suggest. However, you may want to wait for someone with more experience to comment. Otherwise, I have heard of people using fine grit sandpaper to mill their own heads and stuff, maybe you could use that technique to get the surfaces flat for the intake manifold to sit on.

..I did go back to the machine shop and the intake runner is perfectly flat with no twist.. the problem is with the intake side of the head and the way it was placed in the cnc machine..can't do anything now since everything is bolted up..no hand sanding here since we are only talking about a few thousands,..but just large enough not to seal completely..

Make a spacer from aluminium (thin) and put an OEM gasket on either side of it.

 

GD

Make a spacer from aluminium (thin) and put an OEM gasket on either side of it.

 

GD

..makes sense..soft material for one side to dig in a little deeper..I was just about to order some new gaskets before reading this...

Yeah the gaskets are designed to seal on aluminium. Some thin aluminium sheet (1/8" or so) would make the gaskets seal well and it should work without much fuss. A little time spent making the spacers but they aren't terribly complicated.

 

GD

Could be hanging up on the centerline of the engine halves also.

 

Have an intake here that's been on 3 different enginges counting the orginal one.. Had an issue with that area on this last engine.

Little bit of grinding at that seam area, and it sat down like it should. And I do mean "a Little bit" of grinding.

Could be hanging up on the centerline of the engine halves also.

 

Have an intake here that's been on 3 different enginges counting the orginal one.. Had an issue with that area on this last engine.

Little bit of grinding at that seam area, and it sat down like it should. And I do mean "a Little bit" of grinding.

..I will check this out.. the intake, block and heads are a combination of 4 engines with no way of knowing how many times each mating surface has been milled...