View original topic: Lining up intake runners to plenum
airkooledchris Wed Aug 20, 2014 12:55 pm

79CA Bus, just had the motor out for misc seals and other cleanups/upgrades/replacements...

Putting it back together and the #1/2 intake runner doesn't appear to be matching up to the intake plenum. Im not sure what the hell im doing wrong, but im hoping someone here will notice my mistake or know what the issue may be...

The 1/2 side seems to sit too low to match up to the plenum, where the 3/4 side looks fine.

Here is how far off the 1/2 side is from lining up:

Here is the 3/4 side, which seems to match up a lot better:

That said, they still aren't pointing straight to the plenum:

I can probably get the sleeves to match up if I work at it enough, but should I be trying to somehow bend these things to point directly at the plenum, and why is the 1/2 sitting so low compared to 3/4?

EDITED TO ADD: Yes, the intake runner gaskets are in place.

aeromech Wed Aug 20, 2014 1:07 pm

I just had a similar problem but it turned out that I had purchased two right side runners instead of a left and a right. Are these the same parts you removed or new? They sure look good.

airkooledchris Wed Aug 20, 2014 1:42 pm

Thanks aeromech

I don't remember doing it, but i must have mixed up the old intake runners with some spares I had. (before cleaning and painting)

Also - im starting to think there are more than just RIGHT/LEFT options for them.

If you look closely under the right side runner, there is a number. On the left of all of them is the capital letter N, but on the right one there is a number.

I have two 3's, one 4 and one 2.

The one marked 2 best fits on the 3/4 side and the one marked 4 best fits the 1/2 side.

Neither of the ones I have marked 3 line up well on either side.

Perhaps there are different orientations of runners for variances in the plenum's over the years?

You could force most any of them to work, but there are absolutely more ideal matches.

aeromech Wed Aug 20, 2014 2:01 pm

Once I aquired the correct left side intake runner everything lined up well. No need to bend anything.

airkooledchris Wed Aug 20, 2014 2:07 pm

The one that seems to line up best with my #1/2 side was the one marked 4:

Still not perfect, but the closest of them all:

marked with a 3:

marked with a 2:

tristessa Wed Aug 20, 2014 2:12 pm

Is this with or without the phenolic spacer/gaskets installed on the intake ports?

airkooledchris Wed Aug 20, 2014 3:04 pm

tristessa wrote: Is this with or without the phenolic spacer/gaskets installed on the intake ports?

with the spacers/gaskets in place.

Wildthings Wed Aug 20, 2014 3:11 pm

I haven't found that they always match up all that well. Always attributed it to shoddy manufacturing. :cry:

raygreenwood Wed Aug 20, 2014 7:47 pm

Quite a bit can be the actual mounting tangs on the plenum where they bolt to the case.
Invariably if you bump the plenum hard enough taking the engine out....or lean on the runners or plen um...or pull on the plenum while moving the can twist things around .a little. It twists the runners a bit and the mounting tabs a bit at the same time so they look really off when you get ready to put it back together.

Do yourself a favor. Get rid of the stock injector seals and get some green CIS injector seals. They fit tighter and better and seal far better...and are viton. Ray

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