exhaust manifold analysis paralysis

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parsok

exhaust manifold analysis paralysis

Post by parsok »

Folks;

I've reached exhaust manifold analysis paralysis. I've studied this thing until I can't make a decision and would appreciate some help and guidance. I have an '80 carbed with the regrettable 4-1 exhaust, nuff said there. I have a 2-1 down pipe off of a '74 that has a 4 bolt flange. What I can't figure out or decide is what to buy and from where for the exhaust manifold. For the time being I will keep the 2L cylinder head. Therefore I need to get a manifold that connects to the head with 6 bolts and has a 4 bolt down pipe connector. Seems this does not exist???? But I've read numerous threads where you guys have converted the exhaust to 1 4-2-1. There must be a solution. But what is it? Do I buy a new 4-2-1 setup? But from where? I can't afford the expensive performance solution. is there a medium cost solution?

Help!

D
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manoa matt
Posts: 3442
Joined: Thu Oct 26, 2006 4:28 pm
Your car is a: 1978 Fiat 124 Spider 1800
Location: Honolulu, Hawaii

Re: exhaust manifold analysis paralysis

Post by manoa matt »

D,

1968 through 1974 cars had a 4-2-1 manifold and down pipe with 4 bolts connecting the manifold to down pipe
1981 through 1985 cars also has a 4-2-1 manifold and down pipe with 6 bolts connecting the manifold to down pipe.

What you need is the exhaust manifold from a 68-74 car. They are not available new through the vendors, although midwest bayless may have one. Possible other sources are ebay, the parts wanted section, anyone parting out a 68-74 car. On ebay you may do a general search for "Fiat 124 exhaust manifold" or there is a used parts store/dealer "Matthew's foreign auto parts" that routinely has good used fiat parts at good prices.
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: exhaust manifold analysis paralysis

Post by narfire »

I'd goto the parts for sale section here. Looks like plenty of cars being parted out,perhaps some are close to you. The exhaust manifold no matter what year is heavy (shipping) but the 4-2-1 is the way to go I believe.The 79 onwards were 6 bolt on the 4-2-1 here in Canada , the three I've seen are anyway. Snoop around for used parts and be patient,there will be someone going to headers and will unload the chunk of cast and downpipe very reasonably.
Chris
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
parsok

Re: exhaust manifold analysis paralysis

Post by parsok »

correct me if i'm wrong here. The 2L exhaust has 6 bolts that hold it onto the head. The '68-'74 exhasut manifold has 5 bolts that hold it on to the head. I'm assuming, as I have not yet taken the manifold off, that the pre '75 will not fit the 2L. If i look at the gaskets they don't align either. Am I wrong?
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124JOE
Posts: 3141
Joined: Fri Jun 24, 2011 7:11 pm
Your car is a: 1978 124 fiat spider sport 1800
Location: SO. WI

Re: exhaust manifold analysis paralysis

Post by 124JOE »

i think your wrong
your telling me you have a 2 into 1 DP but are wanting a 4 bolt not a 6 to the DP




and the exhaust ports are all the same "just difertent hights as the deck hight changed 6 bolts
your gasket must be the wrong one.joe



i dont mean any thing bad "just confused?"
when you do everything correct people arent sure youve done anything at all (futurama)
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fiat218
Posts: 5745
Joined: Fri May 16, 2008 5:06 pm
Your car is a: 1969 124 AS spider

Re: exhaust manifold analysis paralysis

Post by fiat218 »

i got a 74 exhaust manifold
Jim
East Grand Forks MN
1970 Fiat Spider BS1 ( FOR SALE
1969 124 AS Spider
2017 Abrath
2018 Alfa Romeo 4c Spider
lanciahf

Re: exhaust manifold analysis paralysis

Post by lanciahf »

parsok

Some 79/80 carb cars come with 4-2-1 exhaust manifold and correct 2-1 downpipe. Just need to find one.
parsok wrote:Folks;

I've reached exhaust manifold analysis paralysis. I've studied this thing until I can't make a decision and would appreciate some help and guidance. I have an '80 carbed with the regrettable 4-1 exhaust, nuff said there. I have a 2-1 down pipe off of a '74 that has a 4 bolt flange. What I can't figure out or decide is what to buy and from where for the exhaust manifold. For the time being I will keep the 2L cylinder head. Therefore I need to get a manifold that connects to the head with 6 bolts and has a 4 bolt down pipe connector. Seems this does not exist???? But I've read numerous threads where you guys have converted the exhaust to 1 4-2-1. There must be a solution. But what is it? Do I buy a new 4-2-1 setup? But from where? I can't afford the expensive performance solution. is there a medium cost solution?

Help!

D
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tartan18
Posts: 505
Joined: Sun Mar 13, 2011 10:58 pm
Your car is a: 1975 Fiat 124 Spider
Location: Lebanon, Oregon

Re: exhaust manifold analysis paralysis

Post by tartan18 »

I have a 1975 exhaust manifold. What should I be looking for ??
Jim MacKenzie
1975 Fiat Spider
Finest Italian Automotive Technology
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: exhaust manifold analysis paralysis

Post by bradartigue »

Easiest path: go stock. Consider that 79/80 had two manifolds that fit perfectly:

The 4-1. You have this one. It is not great.
The 4-2-1. For two years only - 79/80 - the 4-2-1 was manufactured with the EGR port to match your head

Other options:

With minor modifications you can block off the EGR port and use the 4-2-1 from the 1980-85 carbureted Spider.
You can use an 1800cc 4-2-1 setup as described above; if interference occurs you can either have a spacer fabricated or have a muffler shop modify the bend.
A header.
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124JOE
Posts: 3141
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Your car is a: 1978 124 fiat spider sport 1800
Location: SO. WI

Re: exhaust manifold analysis paralysis

Post by 124JOE »

i have a spare 4-2-1 manifold with 6 bolts
the guys on here want the 4 bolt one
wouldnt the 6 bolt one be more secure?
why wont they want the 6 bolt?
when you do everything correct people arent sure youve done anything at all (futurama)
ul1joe@yahoo.com 124joe@gmail.com
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: exhaust manifold analysis paralysis

Post by bradartigue »

124JOE wrote:i have a spare 4-2-1 manifold with 6 bolts
the guys on here want the 4 bolt one
wouldnt the 6 bolt one be more secure?
why wont they want the 6 bolt?
I never found either one to be more or less secure than the other. The older ones have 4 bolts, the newer ones have 6.
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124JOE
Posts: 3141
Joined: Fri Jun 24, 2011 7:11 pm
Your car is a: 1978 124 fiat spider sport 1800
Location: SO. WI

Re: exhaust manifold analysis paralysis

Post by 124JOE »

i still dont know why people dont want these?
mabey it cuse it has a hole on top?for the air reciculator.
and the early ones didnt.

and can i use thie hole for a o2 sencer?------------------------------------------------brads my hero
when you do everything correct people arent sure youve done anything at all (futurama)
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geno58

Re: exhaust manifold analysis paralysis

Post by geno58 »

I used a early 4-2 manifold on my 1980 Carbed Spider, the extra bolt is for the exhaust flow thru to the intake manifold.
I removed all of the Emision stuff, pluged all the vacume lines, and made a block of plate where the EGR valve used to be.
When you block of the EGR valve you no longer need the extra part of the flange that is on the 1980 Manifold, but not on the Early Manifold. Is the conversion worth it, yes, especially when combined with one of Marks Empi Carbs.
By the way, I bought my manifold,from one of the advertizers in the parts for sale section, shipping to Missouri from
New Jersy was about ten bucks I think.
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: exhaust manifold analysis paralysis

Post by bradartigue »

Hole on top? Sounds like a 4-1 manifold, not 4-2-1. 4-1 had a heat exchanger thing on top to provide hot air to the carburetor when the "winter" flap was turned on.

You can't put an O2 sensor that high up.
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124JOE
Posts: 3141
Joined: Fri Jun 24, 2011 7:11 pm
Your car is a: 1978 124 fiat spider sport 1800
Location: SO. WI

Re: exhaust manifold analysis paralysis

Post by 124JOE »

Image
2 holes/6 bolts
when you do everything correct people arent sure youve done anything at all (futurama)
ul1joe@yahoo.com 124joe@gmail.com
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