freeing up a '79/80 carburetor 2L Spider 2000

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cgranju
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freeing up a '79/80 carburetor 2L Spider 2000

Post by cgranju » Sat Feb 24, 2018 10:17 am

Hi folks. I've done this in numerous iterations, timeframes, etc in the past, but I've also slept a few times since then. I offered to help a friend free up the basic ability of his 1980 stock Spider 2000 (carb model) by swapping the major intake/exhaust parts readily available from a 1974 124 Spider parts car he just bought. The 1980 is amazingly stock & complete. The basic plan is to install the 74 1800 intake & carburetor (34 DMSA) and replace the 4-1 exhaust with a 4-2-1 exhaust (unless he buys a header, which would be rather wasteful on the otherwise stock engine). Hoping to be able to do this in a bit of a 'house call' format w/o a lot of back & forth for parts from my basement or waiting on something to be shipped, I wanted to run this checklist by the group's knowledge base to see what I'm forgetting. (plus, this is probably universally good information).

1. carb gasket kit & pump diaphram- 34 DMSA (vendors carry this, I presume?)
2. maybe base gasket, maybe not? (the donor is in decent running condition thanks to a seller who didn't realize its a parts car)
3. plug auto choke nipples (one is at the heater/return tube, where is the other?)
4. threaded rod/weber ends/joints for linkage from bell crank to carb
5. install choke cable (extra points if the cable from the '74 is used)
6. Plugs for reed valves (16mnx1.5?)
7. intake/exhaust gasket (will the 74/1800 exhaust manifold work? this head has EGR plumbing)
8. assuming, we have the right manifold, new 2L downpipe (which should line up more or less with what is there? the height difference is made up with the downpipe not the manifold, right?)

I guess the only part I'm having trouble fully imagining is what we'll get into with the exhaust manifold. This could also creep into a new timing belt if that's not been done on this car, but anyway, feedback & thoughts on the approach & bits to be sure to bring in my traveling tool box will be appreciated. Hopefully, someone who's just bought a '79 Spider 2000 will see this & it will be helpful also.
Chris Granju
sunny East TN
owner of a number of Fiats built prior to 1986
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vandor
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Re: freeing up a '79/80 carburetor 2L Spider 2000

Post by vandor » Sat Feb 24, 2018 1:07 pm

>1. carb gasket kit & pump diaphram- 34 DMSA (vendors carry this, I presume?)

Yes.

>2. maybe base gasket, maybe not? (the donor is in decent running condition thanks to a seller who didn't realize its a parts car)

Carb kit should come with base gasket.

> 3. plug auto choke nipples (one is at the heater/return tube, where is the other?)

The other was in the 79 manifold, but the 74 manifold will not have this. So only one nipple to plug. I usually do a piece of hose with a bolt in it, it looks trashy, but is more reliable than some cheapo cap that will rupture in a year or two.

> 4. threaded rod/weber ends/joints for linkage from bell crank to carb

The stock 79 linkage should work, you may have to adjust the length of the rod.

>5. install choke cable (extra points if the cable from the '74 is used)

Yup.

>6. Plugs for reed valves (16mnx1.5?)

There were 2 different sizes, so you'll have to measure and then go to auto parts store and hopefully they will have oil drain plugs in that size.

>7. intake/exhaust gasket (will the 74/1800 exhaust manifold work? this head has EGR plumbing)

Yes, use the common int/ex gaskets. If you use the 74 manifold int/ex then the EGR passage at the front will be open on both ends, which won't bother anything.

>8. assuming, we have the right manifold, new 2L downpipe

You need a downpipe from a 49-State 1979 Spider, which is a two into one design. The 1980 carbureted (and 79 California) Spider has a single pipe. The 79 type pipe is not available new.
Only thing you can get new is the Fuel Injection type pie, but then you'd need a FI type exhaust manifold, and the flange at the cat end would be 4-bolt, instead of the carb type 3-bolt.

>(which should line up more or less with what is there? the height difference is made up with the downpipe not the manifold, right?)

Yes, the carbureted two outlet manifolds are all the same height.
Csaba
Parts: http://www.autoricambi.us
Cars: http://italiancarclub.com/csaba/Fiat.html
'71 124 Spider, much modified
'72 124 Coupe, new project, ex-Pete, ex-Eli, ex-Jack car (all Mira members)
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cgranju
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Re: freeing up a '79/80 carburetor 2L Spider 2000

Post by cgranju » Sat Feb 24, 2018 3:41 pm

Thanks Csaba!

It's nice when I remember some stuff!

The FI downpipe is different in shape AND has a different flange,'or is it just a different flange? I need to see what he has after the downpipe, but I'm guessing the original cat. A full AR system would be the way to go, but it's his call.
Chris Granju
sunny East TN
owner of a number of Fiats built prior to 1986
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vandor
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Re: freeing up a '79/80 carburetor 2L Spider 2000

Post by vandor » Fri Mar 02, 2018 10:11 pm

I don't know what difference is other than the flanges, since they are not interchangeable, so it can't be tried easily :-)

It seems like the FI manifold is lower than carb one, but I never measured.
Csaba
Parts: http://www.autoricambi.us
Cars: http://italiancarclub.com/csaba/Fiat.html
'71 124 Spider, much modified
'72 124 Coupe, new project, ex-Pete, ex-Eli, ex-Jack car (all Mira members)
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friedman
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Re: freeing up a '79/80 carburetor 2L Spider 2000

Post by friedman » Sat Mar 03, 2018 10:58 am

Yea, I don't think a carb downpipe will work on an FI manifold for that very reason, the FI manifold extends further down I think. Also the FI manifold I six stud and the carb ones are four stud.
Carl in Virginia
75 spider
86 Bertone
77 X1/9
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