Hi All,

I'm in a bit of a pickle with my cylinder heads... I think in a prior life they have been machined to adjust for something. My cylinder heads are missing 0.080" of material from the surface that meets the intake manifold (measured with the intake resting on the china well without any gaskets in place). I've attached a drawing to help clarify. I can't tell if the head has been milled on the chamber side.

The engine block in a standard size 3970010 5.7L (already rebuilt), the heads are ZZ3 aluminum (stock ports, valves), and the intake is a TPI (stock).

I am 100% certain the issue is with the cylinder heads and not any other component.

The solution I think am going to use is a very thick intake gasket and some gasket maker on the china wall.

Any opinions from the folks who know what they are doing before I go ahead and screw it up?

Thanks.

Usually, that means you have to have the intake's "china wall" mating surface machined down, so that the intake will sit farther down between the heads. If there's .080" of gap, you'll need to take about .125" off of the intake; which is no big deal, since you'll be using a bead of silicone anyway, its thickness will just be different.

Look at the blot holes with the intake sitting as it now is, and see if they line up with the ones in the heads. If the holes in the intake are higher up than the ones in the heads, you're in luck, and you can fix it (or at least improve it) by milling the intake ends; if they're already lined up, then you've got a real issue on your hands, and the only way to fix it would be spacers.

RB83L69: The intake to head bolt holes line up perfectly with the intake resting on the china wall. What do you mean by spacers? Extra thick intake gaskets?

Would it be possible to still mill some material from the china wall portion of the intake and use the thick gaskets? That would give some space for the gasket maker to reside would it not?

Thanks.

Problem is, if the bolt holes are already lined up properly, then so are the ports; and milling the intake ends so that it sits down farther will make the ports have a mismatch.

By "spacers", I mean pieces of metal of some appropriate thickness, cut out in the same shape as an intake gasket; and an intake gasket on each side. I know of no such thing being available on the market. However, there's somebody in almost every town of any size that has a high-pressure water jet cutter; and you could take them an intake gasket and have them replicate it in the right thickness of sheet aluminum, for farily cheap usually. Sounds to me like you need about .050" - .060" of spacer, plus the extra set of intake gaskets, plus you need to get the intake ends milled a bit so that the intake doesn't sit directly on the block.

Somebody really fornicated those heads. What a shame.

RB83L69: So... just to kick around my idea of using very thick intake gaskets some more. Would that not accomplish the same thing as spacers and two gasket sets as you suggest? I can buy 0.120" thick intake gaskets, that ought to hold the intake away from the "china wall" shouldn't it? Milling some material off the bottom of the intake would just be a guarantee of sorts to make sure it doesn't contact... or is that even an issue if it did as long as there was a bead of gasket maker to make sure it was sealed?

What about the distributor? How do I check if it is sitting down to low and needs to be shimmed up (if needed)?

Thanks.

There's some stuff called Prussian Blue, it's a pigmented grease basically. You can smear some of that on the dist gear and then give the camshaft a spin, and when you take the dist out again the teeth will show a mark where they meshed.
The stuff is used for aligning the gears in differentials too.
There are shims that can be placed under the dist collar to correct the gear alignment if nessecary. I think they're from Moroso.

Also, you could do a mock up of your intake fit pretty simply by stacking up extra gaskets, or placing shims in there til it gets to the point where things look like they're aligning right.

Been there, done that.

Get the .120 thick intake gaskets from either fel-pro or mr. gasket and run a small bead of rtv on both sides of the gasket and wipe off accordingly after you put it on the head and before you put the intake on and hope for the best.

Dart makes aluminum intake spacers, but they fit their manifolds. Most people I talked to said double the gaskets, use a thicker one, or get the block/intake fixed accordingly.

Good luck.