I have got as far as fitting the intake manifold, and it seems I need to mill it. I know some folks say you shouldn't do it, but its not exactly square as is, so I am about to mill my new Blue Thunder MR intake. It is either that or remove and strip my heads and do the intake sides. So I'm electing to do the intake. Hoping some folks can say if they think I'm on the right track to get some figures to pass to the machinist. Believe it or not I've never had to cut an intake before.
As every engine family seems to be different (angles wise) I thought it best to ask from those who have done this on an FE before. The head to intake is at a 90 degree angle, so theoretically it should be 1 for 1 on milled off head to milled off the intake. However as my heads had been cut before I got them I don't know the total to work from. So the best way I figure is to just go from installed measurements rather than guesswork with the maths.
So I trial fitted it with the dizzy as a dowel. Checked the bolt holes etc. First with no gaskets and then with them on. (using the common FEL PRO steel core types, like most they are .060" thick compressed). It actually fitted not too badly without gaskets, all the bolts went in, etc. But the intake wasn't far enough below the heads (rails) to fit any known gasket I could find. (about .012-.015"). So some degree of milling is required to allow it to take a gasket. I've heard of .030" intake gaskets, but not .015". Even if they did sell such a thing, I don't want it to leak and that's not much thickness to cover so many gaps and corners etc.
I then measured the china walls, valve cover rails and all the corners. Clearance numbers wise it came up fairly even with gaskets on, but had some differences with them off. It seems some folks recommend measuring without gaskets and then doing maths based on gasket specs. Using that method what I ended up with was this:
(from drivers seat)
LHS:
Rail Gap: Without gaskets the intake sits .012" BELOW the head (FRONT) and .015" (REAR). And the gap with gaskets is the intake sitting .067" ABOVE the rail both ends. The total gasket lift of .079" & .082" is I figure because the "Print-O-Seal" sections stick up and some minor variations in flatness, from being uncompressed. I measured them at .074-079" across both gaskets, vs. a solid .060" across the gasket's base layer. So I figure that to aim for a zero rail, I subtract the .012" from the .060" (compressed quoted thickness) and get my ideal cuts of .048" & .045" (av .047"). Some have suggested I undershoot that a bit, to allow for further compression and be on the safe side. In truth that's what I'm happier with as if I undercut it by say 5 to 10 thou, for all practical purposes the bolts will still be centred, and the rails flat, with the least amount cut. So I'm thinking I'll ask for .040" off on this side. If its not enough I can go back and ask for more.
RHS:
Doing the same calcs is trickier as the measurements vary more than on the LHS. So the first issue is should I just average the fore and aft rail gaps for one cut figure? Or would it would be better to ask the machinist to angle the cut slightly to square it up. Anyway front gap was .021" below the head rail with no gaskets and .047" above with them. So my front cut should be .039" (60-21). Rear is quite a bit less at .003 below vs. 061"above with gaskets, which would require a cut of .057". If I average them out the cut is .048", similar to the other side. So this is where the experience of others comes in. Cut to those exact figures or take heart from the fact that with the gaskets ON the corner gaps become fairly even? (about .020-025" all around). Perhaps the gaskets pull it all into line a little? In which case just ask for the average to be cut off? Opinions?
To me it seems a pity not to square everything up while I have the chance. I sure as hell don't want water or oil going where it shouldn't.
Is it strange that the corner gaps are fairly even with the gaskets on, but a bit uneven without them? Comments anyone? Seen this before? Or does no one measure corners without gaskets normally?
So being conservative by nature, I'm planning on asking for these amounts to be cut:
LHS .040" flat across the whole side..
RHS .030" at the front, increasing to .047" at the back.
I figure I don't need to touch the China Walls. They had gaps of around .150" with gaskets on, and .045-.060" gaskets off.
So with gaskets on, lifting up the intake, the post cut gap must be more than that. Anyway I'll just use silicone and toss the cork end gaskets. (nearly .200" uncompressed).
Any advice is as usual, much appreciated. Its too late once the planer has done a pass...
BTW the colour came out wrong on the attached photo. Its more like the deeper blue on the lower half of the engine. I think the flash lightens the front blue up a lot. Its VHT OLD FORD BLUE. Closest I could get to the concourse accepted colour for 67/68'. I tossed the POR15. Too dark for 68'.
[url=https://postimages.org/]
[/u
