Carb upgrade procedures? Definitive Guide?

[jaubine]

Hi all,

I have a '79 spider with stock "everything" under the hood, I've made the [relatively easy] decision to do some upgrades.. I've been searching for a 34 ADF carb (but may settle for the 32/36 DFEV if I cant find one for a *reasonable* price), and have a lead on an intake manifold. At this time, I'm probably not going to swap the exhaust out quite yet due to budget (probably next year), as I have a few other things to address with the car. I'm also going to yank all the emissions [except the cat, as I dont have anything to replace it with] as well. After reading a ton of message threads, I'm wondering if someone's got a fairly detailed, step-by-step procedure for doing the carb/manifold swap for ether the ADF or the DFEV that would include all the little things I've been catching here and there that I'm not entirely positive of whether some changes are required or not - e.g. What ports (on where) to plug, what ports to keep, things to re-route, brackets, linkage, gaskets, etc needed (e.g. I saw one thread about having to change to a different mount for the dipstick tube when bolting on the 1800 intake?)

If anyone's got this written down, or if folks could contribute to even a quick ordered list of things to do, let me know. I've seen a ton of people on this board looking to do the similar conversion, and I think it would help if a doc exists for future n00b's like me

Thanks!!

[mbouse]

if you are willing to document and share the resulting procedure, i am willing to walk you through it via email. T'ain't difficult, but i am not the handiest with the pictures.

[jaubine]

if you are willing to document and share the resulting procedure, i am willing to walk you through it via email. T'ain't difficult, but i am not the handiest with the pictures.

"most definitely"

hell, perhaps we could convince Mr. Artigue to post it up on his site in a nice format once completed? It'd be a nice compliment to his other guides he has there...

[bradartigue]

Well...one could argue that the only car you need detailed instructions for is the CS2 Spider, the 79-80 carb models. But really the instructions aren't going to do much good on the installation side, since what you are really doing is removing everything connected to that old carb and intake manifold and throwing it out...everything that is except for the brake booster, charcoal canister, and distributor vacuum.

There are a lot of ways to upgrade to the ADF. And you can upgrade to the 32 or 34 - both are big compared to the pitiful ADHA. One way is to find or make a 1/2" or so spacer (Bayless used to provide them when you bought the 34) and just swap out the carb. You still have the EGR and stuff installed but you've made your carburetor bigger and motor happier.

The next approach is to replace the manifold and carburetor. When you do this you will take the entire gang of vacuum lines and do away with it. The 1800 manifold will connect to the booster only; everything else is blocked out (the carb connects to the distributor vacuum and charcoal canister). This little upgrade really puts some zing back into your Spider, but you still have a lousy head and exhaust to contend with.

The final approach really gives you the most bang for your buck. Replace the exhaust with a 4-2-1 type from an FI Spider, replace the head with a very early 1800 head or any 2000 FI head - they have no emissions controls junk and no EGR ports, put on an 1800 intake manifold, and a 34 ADF. Its also a good time to yank out the block and clean it, reseal/gasket, check the bores, replace the rings, bearings, and washers. A lot of work but you're going to gain a lot of HP. Enough power to bust those old U-joints to pieces.

I've done all of these at some point and all improved the 2000 Spider tremendously from the sad 81 HP stock configuration. Pick what you are comfortable with and go for it. Keep in mind that a 32 ADFA on the stock 2000 manifold isn't ideal but is cheap and improves the car. A 32 ADFA on an 1800 manifold is better, maybe $75 more expensive, and really improves the car. After that start thinking 34 ADF and throwing that hog of a head in the trash with the exhaust.

If I can help let me know.

http://www.artigue.com/fiat <- lots of carby info there

[mbouse]

great thoughts Brad.

the thing that makes the written instructions difficult is the variety of choices and approaches to the individual steps involved.

person A limits the budget to only the intake side...what to do about the EGR port?
person B throws on a 1800 head

person C wants electric choke
Person D wants water choke

lots of variables, and good luck putting them all in writing.

don't forget.... you must do something about that oil dipstick tube mount when you yank the stock '79-80 intake from the head.

[jaubine]

Agreed, this is probably going to be a rather large undertaking to document, but I figure that there are a probably a lot of other spider fans out there who havent taken up the wrench because they really dont have a good plan for doing so... Brad - your docs on the carbs, wiring diags, etc have done wonders for many, myself included.. I'd like to compliment that with the beginnings of *how* one would go about cracking that first nut.

As for me, I plan to swap the carb with the 34 ADF, replace the intake manifold (need to find one now since Brad yanked the one I was going to buy from him <grin>), and replace the exhaust manifold / downpipe (need to find these too). I'm not quite ready to tackle pulling the whole block out yet for a rebuild or replacing the head - just looking to get a little more "fun" out of the car for now. Perhaps next year I can start looking at that size of a project...

[mbouse]

i applaud your willingness to document your procedure. hopefully, it will be well written and clear to most that read it. we'll help you all the way, if you choose.

[jaubine]

I've done a fair amount of technical writing in my previous life as a software support guy, so I'll certainly give it a shot.. Mind you, it'll probably start out as a living document, as I think both you and Brad clearly pointed out, there's many more ways to do this beyond what I'm planning on doing to my own car.. I'll at least build the framework for the doc in a way that other "optional" methods could be plugged in later on by others...

[racydave]

I have a 4-2-1 manifold and down pipe. I imagine shipping is expensive? PM me if interested...

[bradartigue]

Somehow this didn't post the first time.

I created a small diagram of the combinations.

http://www.artigue.com/fiat/Pubs/Select ... r-2000.pdf

[stefhahn]

Hi-
Ken Dickson has written a fantastic guide re the IDF upgrade - this guide is covering many of the aspects when you want to upgrade w/ a single carb - you can find it here: http://www.kendickson.com/car/idf/index.html

ciao,
Stefan

[jaubine]

Somehow this didn't post the first time.

I created a small diagram of the combinations.

http://www.artigue.com/fiat/Pubs/Select ... r-2000.pdf

Brad, do you have this diag in a word or visio format? I'd like to use this is as part of the guide - it'd be a great addition to the introuction, and perhaps a means for selecting the "type of install" procedures to follow...

[jaubine]

so I pulled the carb, intake and exhaust off yesterday, taking pictures and notes along the way... I have a few questions...

Would a 4-2-1 exhaust setup ever be "stock" on a '79? I ask because after taking mine off, it appears to be just that... Downside is that I just bought a 4-2-1 setup from Mark last week, so looks like I'll have a spare to sell

Also, on the subject of replacing the head... A few of you suggested to do so, and I'm now contemplating this since I've got it all torn apart, and this would appear to be the time to do it.. A few questions:

- Brad, you mentioned replacing with an "early" 1800 head - define "early", or more specifically, what should I be looking for?
- Assuming I find one, should I have it rebuilt? What sort of [estimated] cost is involved with this?
- Are there any parts on the 2L head that should be swapped onto the 1800 head, or should the 1800 stay intact?
- What's the going rate for an 1800 head these days?
- lastly, if I decide not to replace it, will there still be a noticeable gain by swapping out the carb, intake, and exhaust?

Thanks!

[racydave]

The answer is yes. My 79 had the 4-2-1 set-up. Yes another carb and intake does wonders. You will think its a different car. I would do this before I worried about doin the head.

[bradartigue]

so I pulled the carb, intake and exhaust off yesterday, taking pictures and notes along the way... I have a few questions...

Would a 4-2-1 exhaust setup ever be "stock" on a '79? I ask because after taking mine off, it appears to be just that... Downside is that I just bought a 4-2-1 setup from Mark last week, so looks like I'll have a spare to sell

Also, on the subject of replacing the head... A few of you suggested to do so, and I'm now contemplating this since I've got it all torn apart, and this would appear to be the time to do it.. A few questions:

- Brad, you mentioned replacing with an "early" 1800 head - define "early", or more specifically, what should I be looking for?
- Assuming I find one, should I have it rebuilt? What sort of [estimated] cost is involved with this?
- Are there any parts on the 2L head that should be swapped onto the 1800 head, or should the 1800 stay intact?
- What's the going rate for an 1800 head these days?
- lastly, if I decide not to replace it, will there still be a noticeable gain by swapping out the carb, intake, and exhaust?

Thanks!

Yes - federal (non CA) 79's had a 4-2-1. 79's also had a 140 MPH speedometer, never seen again on a FIAT Spider.

For starters, ANY 1800 head is good, early heads did not have the holes for the smog pump valves. You simply block those holes off if you have them. You can also use a 2000 FI head. The 1800 head gives a little CR increase but both heads are superior to the stock 2000 carbureted head.

Most heads don't need the valve guides replaced. Disassemble the head yourself (sears sells valve spring compressors for about $20) and bring it to a machine shop to have cleaned and inspected. Then make a decision. I spent $75 on my last head, the surfaces were recut and it was cleaned and bead blasted. I installed all new valves, seals, reused the springs, etc. I lap valves myself (a kit is about $12), some people don't lap them at all.

You can use your cam boxes if you want and you definitely want to keep the cam box mounted accelerator - the old rod type sucked. If you have a phelonic cam gear on the 1800 then swap it with the metal gears from your 2l head. The cams are otherwise the same.

Last 1800 head I bought cost me $8.00. The one before that was $60. Same condition. There is no real line for the market.

If you keep the 2000 carb head and put the intake, exhaust, and carb on it then it will still kick some ass. The head replacement gives you an extra few percent. They make a difference, especially when you're talking about going from 81 HP to 104 HP or so.