: Aaaaagh! I should'v know better,



Rob Benham
01-05-05, 04:15 AM
I should know better, but I didn't note the location of the short screws of the 12 on the top cover. Please advise if you can call it from memory...save me fishing around with a vernier tomorrow.

Also, I was surprised to see that it was sealed with a ‘gasgate' of red silicone or some such. How critical is the seal on that cover. Thanks in anticipation. RB 94 SLS

BeelzeBob
01-05-05, 07:33 PM
I am not sure what you mean... I remember that all the perimeter row of screws holding the top cover to the lower manifold were the same length.... There are the 4 inner, recessed bolts that are about 6 inches long that hold the intake to the cylinder heads but I thought all the perimeter screws were the same length...

Do yours have the large rubber grommets under them?? They should if they are the OEM bolts. The factory hold down bolts had an oval washer under the head of the bolt with a thick rubber grommet isolating the bolt from the cover.

If the bolts have been replaced for some reason without the rubber grommets the length shouldn't be too critical as I remember that the tapped holes in the lower manifold are all thru holes so the bolts will not bottom out. If the rubber grommets are missing you should spring for the set of them at the dealer. There is a service kit that includes all the bolts, washers and grommets as the kit was a retrofit kit for the early 93 Allante intake manifolds that had plain screws originally. The grommets were added as a running change in early 93 model year to allow the cover to "burp" excess pressure in the event of an intake manifold overpressurization event....i.e..back fire.

The manifold cover is sealed with a silicon beaded gasket that is integrated into the upper manifold assembly as a wire loom, mount for the MAP sensor and FPR, etc... If there is RTV sealing the cover that was added by someone after the engine left the factory.

an01sts
01-05-05, 08:07 PM
This is an engineering feature you can almost always bet money on. (Notice I said ALMOST? because Murphy's Law always plays a role in evertying.)

With like diamater screws bolts, insert all fasteners into , meaning that they will all stick, let's say, a 1/2 inch out of the holes. There are no blanket garuntees--because the logic behind some engineering defies common sense, with zero foundation to justify the differences---but as a rule of thumb, this way usually works for sorting out various lenght fastners.

Rob Benham
01-06-05, 03:49 AM
Thanks again. Yes there are oval washers on the rubber. I noticed that two of them were being squashed when I put the twelve back. Sure enough, they were slightly shorter than the other ten and at a quick guess they will go into the rear or left two holes, but I'll get to it in good light before pulling them down again. RB