Intake Manifolds

[FiatBen]

In the process of swapping intake/carb on the '79. Now I'm trying to learn about the intake manifolds and variations from year to year. Thought I'd start this thread so fellow enthusiasts have a resource to ID parts.

For starters, here is the manifold that came of the 2L '79:




and the casting numbers, found on the top next to the head:


Digging thru things in the barn, I have a complete head pulled off a '78 1800. Here is a pic of the casting numbers on the bottom of it:


Then I have these two that I thought were candidates for the swap. At first I didn't realize how much difference there was between the two. In each pic the one I think is the '75-78 is on the left, and I think the one on the right is an earlier model.
Top view: noticeable differences are the shape of the inlet beneath the carb and the screwed in sensor vs. a plug:


Bottom view: early appears to be plugged off on the bottom with simple hose connections off the side whereas the later on has sensors (?) and a tee (similar to the '78 on the complete head).


and the casting numbers for same;
later model


early model


I am open to further insights and clarifications. Anyone wants to contribute correct information or confirm my guesses? Please do! Also, I would like to see pics of other variations here as a reference.

Now i have to go figure out what connects to that darn water tee.....

[MrJD]

nice images. take some of the inlet area of the two single plane manifolds. Are you saying just the uppermost part of the manifold is different?

[FiatBen]

nice images. take some of the inlet area of the two single plane manifolds. Are you saying just the uppermost part of the manifold is different?

Yeah, gotta start remembering to either make smaller pics or leave more area around them because it is cutting off the right side, but:


The "older" manifold has more of an hourglass shape while the "newer" one is more rectangular. There is also a wee bit of difference in the firewall end where it bolts to the block. It occurs to me that I haven't looked real close to see if maybe the one on the right has been modified after the fact.

[vandor]

The 'early' manifold is from a 1438cc engine. You cannot use it on 1800/2000, as you can see in the pic that it is missing the piece behind the #4 runner that covers the water passage at the rear of the head.

[RoyBatty]

So then,
Will the stock 1800 single plane manifold work on the 1600 in my 71 Sport Coupe?
I only ask because I have a newer carb mounted to the one I took off my Spider when I installed the dual IDF's.
Is the 1800 and 1600 manifold the same?
I have not tore into the engine to do a visual comparison as of yet.
Thanks.

[Daniel]

The 1438 manifold will work with the 1608 no problem.

[FiatBen]

The 'early' manifold is from a 1438cc engine. You cannot use it on 1800/2000, as you can see in the pic that it is missing the piece behind the #4 runner that covers the water passage at the rear of the head.

Thought I might put up a couple of pictures that make this clear:


and close up:

[MrJD]

Is that manifold and head set up unique to the pre-1970 1400 then?

[vandor]

> Will the stock 1800 single plane manifold work on the 1600 in my 71 Sport Coupe?

Yes, it will work great, that is what I used on my 1608.

[FiatBen]

I'm sure that somewhere in my manuals I could track down this sensor, but I'm even more sure that someone out there will look at this picture and know immediately what it is, and whether or not I can just plug it off when mounting this 1800 manifold and 32ADFA on my '79 2000.



And, a follow up question. What does that water tee connect to? Or do I plug it off as well?

[bradartigue]

What does that water tee connect to? Or do I plug it off as well?

That T is air. Hook it up to water and your motor will stop. One side went to the brake booster, the other you block off.

[FiatBen]

What does that water tee connect to? Or do I plug it off as well?

That T is air. Hook it up to water and your motor will stop. One side went to the brake booster, the other you block off.

So that is my manifold vacuum for the brake booster, huh? Is there something I can use to replace the tee with a much smaller, simpler connection?

And the sensor/electro-switch on the bottom is?????

[TimpanogosSlim]

And the sensor/electro-switch on the bottom is?????

thermal switch for dual point ignition on late 124 engines.

pretty much everyone deletes that system and goes back to single point. or goes to electronic ignition.

[FiatBen]

So, if the big tee is a vacuum connection, one end to be plugged and the other reconnect to the brake booster, then what is the smaller connector directly above it?



And I'm guessing the big threaded hole that matches it to the left just gets plugged (18x1.5??)

Always helps to go out and handle things instead of doing from memory. When I look in the manifold, it is pretty obvious the tee is a vacuum connection. I suppose the little ell above it is too small to provide adequate vacuum to the brake booster, right?

[FiatBen]

I wanted to pull the plugs out of the '79 manifold (since it will no longer be used# and use them to plug holes on the '78 manifold. I like the flush plug with the recessed hex #12mm). The problem is that the metal is so soft they are rounding off instead of coming off.



Anyone know any tricks to make these come off? Or, does anyone know a source for these plugs or something with a similar low profile. For that matter, doese anyone know what size these are? I thought they were 18x1.5 (thought I read it somewhere), but that is too large.