You're just getting old /ubbthreads/images/graemlins/grin.gif Yeah, it does appear those are machine marks, but had assumed that'd how the oem heads are? It's possible the PO had some head work, as he put a lot of $$$ into that engine. I did notice #4 (? closest to pass. side) exhaust seal is a little messed up, as some oil witness marks and need to replace those someday (have them, but just want this to get running). Otherwise, it looks new still.
Anyhow, thanks guys for the compliments and I think this ought to work out great. As for what it is, I ended up finding a flat cookie sheet that had a cool texture on the top side, which to me looked sort of what a heat shield would. I originally bought the sheet for my CTS-V as I was going to build an intake box/shield, but sold the car. So, had this sitting around, already bent up for that box and it had flats large enough to trim out this piece.
Well, most sheets have an air pocket in it and some are insulated, which I thought this one was, but it wasn't. I have a bunch of silica wrap leftover, so figured I may as well stuff some in bewteen.
One thing about that area is you cannot really use a flat piece, since the alternator wiring/harness plug would hit and I didn't want it touching there. I suppose you could if you used a spacer at the top, but I didn't want to do that, either.
The way I made it was just trial and error, as far as trimming (you have to clear the IC piping, the coolant hose at the bottom and transfer tube at the side, along with the wiring, as I mentioned. The aluminum is pretty thin and was already crimped on one end (where the factory put the two pieces together) and for the other end, I simply bent it back over itself and sort of hammered it closed. Real easy to work with, but what you can't see is part of it is bent at a 90 degree in the rear, so this thing is really stout.
It's obviously not finished, but another thing I need to point at is at the top where there wasn't enough meat to bend it back over (in retrospect, I'd have cut it longer there to be able to do that), I just put some jb weld there, mostly just to seal and not as a structural aspect...same thing on the rear (where the bent back "crimps" are), I just used it to flattend it out.
Wouldn't mind making another, although it is something that is pretty simple to make with common tools and some patience. The trickiest part (and not difficult, just trial and error) was making it so I could slide it from the top and it just come down easy without hitting anything. I wanted to make it in such a way that everything could be on there, yet I could still pull it out. I think on any future units though, it may be just as easy to start with some raw aluminum (or stainless) and do it like thta...However, for the price, you cannot beat a cookie sheet. Just don't get the kind with the sides on it though, since you'd not have a pre-crimped side, if that makes sense. IIRC, I picked this up at a garage sale or something and paid $1. I have an all-clad ($$ new) SS flat sheet sitting around somewhere too, but it's much thicker and not sure it even has an air pocket, but mentioned that as some sheets are stainless steel.
Also, wouldn't mind making one that looked even nicer, but this one doesn't look bad and I like the texture that makes it look sort of oem-ish...what I don't like is that ugly hex head bolt, but that's all I had on hand (it's M10-1.25, which is sort of an oddball) and I cut the bolt down on the lathe; there is a thru-hole there, so the 40 mm length would've worked, but why have extra and it'd be that much harder topull the screw out with the manifold and stuff on there. The top bolt is M8-1.25 and is pretty short (< 20 mm) and has a blind thread, so don't go too long.
sorry I didn't take any status pics, so to speak, but if you have any questions...
