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Correct distributor for 3.4 carb swap by stewnew
Started on: 06-05-2013 06:07 AM
Replies: 19
Last post by: Hudini on 06-13-2013 06:59 PM
stewnew
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Report this Post06-05-2013 06:07 AM Click Here to See the Profile for stewnewSend a Private Message to stewnewDirect Link to This Post
After experiencing many problems with the fuel injection set up on my 2.8 I have manage to purchase a good 3.4 from a Firebird, no easy feat here in the UK as they aint that common. I have decided I am going for a rebuild aswell as carbing it over the summer then swap the engine out over the winter.

Reading numerous threads I can see for the most part what I need, the intake manifold, adaptor and 390 cfm 4 barrel carb I can get off the shelf from summit (easy option as they ship to the UK at a reasonable cost) although I may be able to get a used carb here in the UK from ebay as they do come up quite regularly.

I can either swap the current V6 fuel pump to the I4 version or purchase the Mallory pressure regulator, again I think summit sell these.

My main concern is the ignition system, what distributor should I be on the look out for. I could go used from ebay.com if the seller is willing to post to the UK or the expense of new again from summit. I have read about vacuum advance, mechanical advance, contact breaker points, electronic modules, coils and aftermarket electronic ignition sytem but not sure which way to go. I dont want to purchase the wrong distributor as there would be very little chance of me reselling here. I understand early 80's S10 2.8 are the most likely doner.

Any info on the distributor would be appreciated.
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lateFormula
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Report this Post06-05-2013 07:08 AM Click Here to See the Profile for lateFormulaSend a Private Message to lateFormulaDirect Link to This Post
If you go salvage yarding, any distributor off of a 60° V6 (2.8/3.1) will work, or you can buy a remanufactured Cardone or AC Delco unit: http://www.rockauto.com/cat...249208,parttype,7108
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Arns85GT
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Report this Post06-05-2013 08:07 AM Click Here to See the Profile for Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
I recently parted out my 2.8 carb'd setup. The 3.4 is pretty much the same. If you look up threads by Oreif, he had a really nice carb'd 3.4 setup dyno'd out at, if I recall correctly, 234 hp.

To answer your question on the dizzy, you are looking for an early 80's S10/Blazer distributor with the vacuum advance module on it.

If you can find one, get an Offenhauser intake manifold. They are dual plane, and lower profile than the Edelbrock.

If you use an Edelbrock, you'll need a scoop for clearance purposes.

While you are at it, have a look at the 500cfm Holley 2300. You don't have to play around with the secondaries with that and they flow really well.

You can get a rebuild from National Carburetor cheaper than the 4 barrel, and the center hung float does not react to hard right corners like the side hung float.

Good luck with the build

Arn

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[This message has been edited by Arns85GT (edited 06-05-2013).]

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woodyhere
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Report this Post06-05-2013 09:38 AM Click Here to See the Profile for woodyhereSend a Private Message to woodyhereDirect Link to This Post
One thing easily overlooked when changing to a carb and using an off the shelf manifold is the angle of the carb flange surface. Aftermarket manifolds are made for front wheel drive cars. Motors in front wheel cars are angled back and sit lower in the back than front. Fieros motors (any swap or stock) sit dead level. It is easy to make a wedge to correct this "out of level" carb mount. It may not seem like much but the carb flange on an Edelbrock manifold is about 3/16s higher on the bell housing side on a 4 bbl flange. Float level changes of 1/16th make a big difference on A/F ratios. If you need some help on making a wedge for making the carb sit level, send me a PM and I'll be glad to help. The aforementioned distributor is a good choice.

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woodys 427

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stewnew
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Report this Post06-05-2013 10:17 AM Click Here to See the Profile for stewnewSend a Private Message to stewnewDirect Link to This Post
Many thanks for the replies to date.

Checking the link to Rock Auto brings me to Fiero distributors, I assume these are for the standard electronic ignition used in the Fiero rather than the basic vacuum advance one I am looking for from the early 80's 2.8 engines.

Is the S10/Blazer distributor a straightforward contact breaker points unit with condensor, that just requires a coil and a vacuum connection for advance/retarding. If so is it wise to change this to an aftermarket electronic module and coil set up. I read in one post about using a Crane Fireball unit.

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Arns85GT
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Report this Post06-05-2013 10:32 AM Click Here to See the Profile for Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
If you are looking for a Fiero dizzy, it will need the ECM to run and it will still be looking for the MAP sensor etc.

If you are looking on Rockauto, look for a 1984 Chevy Blazer.

BTW, I did not correct the Edelbrock lean and I had no ill effects. Also, the Mallory bypass fuel regulator is the way to go.

Arn
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Report this Post06-05-2013 10:58 AM Click Here to See the Profile for woodyhereSend a Private Message to woodyhereDirect Link to This Post
It's not just Edelbrock manifolds that have the flange made for rear wheel drive, it's any brand made for rear wheel drive. To ignore good advice because you didn't notice any ill affects isn't very scientific. Any carb is designed to sit level. The wider the carb the more the out of level effects performance. I would suggest that you have no basis for your opinion. You haven't corrected your flange tilt to see if there is a difference. I have. Holley 4bbls aren't as sensitive as the Edelbrock 4 bbls but still need to be level. The small Holley 4 bbl is a better choice than the 2 bbl. Small primarys make for great throttle response and good mileage. Secondary opening rates are easy to set with such a small 4 bbl carb. A non-computer controlled dist will be realible, simple and run like a thief in the night.

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Arns85GT
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Report this Post06-05-2013 11:15 AM Click Here to See the Profile for Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
Woody, the 390 cfm without an adjustable float might be a problem, but the adjustable float takes care of your issue.

Moreover, if it was the big deal you seem to think it is, cars would malfunction going up hill?

The bigger issue with the 390 cfm 4 barrel, which I have hands on experience with, is the side hung float.

When turning right you can get fuel starvation when you don't want it.

For this reason the 4150 upgrade to center hung float bowls is a good idea for a Fiero.

Of course I did not do this because I was not autocrossing or the like.

I can tell you that the 350 cfm 2 barrel performed equally well and was simpler to install and use.

If you order a rebuilt one from National Carb, or a new one from Holley, they come flow benched and ready to go either way.

I do not disagree in theory that the smaller venturi at lower rpm can be an advantage, but, I have not found practically that it makes any difference.

In fact, for years, the stock cars at the local track were using single barrel Holleys.

Arn
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Report this Post06-05-2013 06:26 PM Click Here to See the Profile for woodyhereSend a Private Message to woodyhereDirect Link to This Post
I have noticed a difference. If a car was constantly climbing a hill you can bet there would be a problem. Why not do the right thing and have this fellow mill the flange flat before it goes on the engine. It is simple to do. If the engine is together, make a wedge. I don't like 390 either. I'm not wild about Holleys in general but have used them a lot in the last 40 years. Whenyou need a 1050 no one else makes one. I like the (AFB) Edelbrock, especially the redisgned new series. I can easily get a 16 or 17 to 1 F/A for cruise and, depending on the motors likes, a 12.5 for performance. The holley is much better at accepting a slant due to it's narrow fuel bowls. The Edelbrock and other similar layout fuel bowls really hunt around on the A/F meter. If you have one handy take a look at the fuel bowl. The floor slants up to the secondary jets. It was made that way to have an even fuel level and not flood on excelleration. My 800 Edelbrock avs varied several ratios when it sat at an angle. Leveling it made a surprising change. The F/A ratio now only varies by tenths. It would stumble on hard lefthand corners and doesn't do that anymore It's not like it costs a bunch or is difficult to do.

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stewnew
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Report this Post06-06-2013 06:01 AM Click Here to See the Profile for stewnewSend a Private Message to stewnewDirect Link to This Post
Many thanks for the info so far.

I am going to try and keep it simple as that was the purpose of moving away from the FI system.

Based on the recommendations

I will start my search for the offenhauser intake (is there a part number) as this sounds like its going to be tough to track down. Where should I be looking, please bear in mind I am in the UK, not everyone is willing to ship overseas. I can try the Mall here, ebay.com, plus I read about people using craigslist although I have no experience of this as it does not exist here. If no luck the edelbrock one is off the shelf but this may cause clearance issues.

A choice of a 500 cfm 2 barrel or 390 cfm 4 barrel (vacuum secondaries). The manufacturer appears to be important as the design of each has potential flaws with float and bowl positions.

The use of wedged spacer to ensure the carb is level if max carb performance is critical, will work without.

The Mallory pressure reducing regulator.

An early 80's S10/Blazer distributor, found one on ebay.com in Florida but its in poor condition and missing parts, no others listed from my search criteria.

A suitable ignition coil, either a replacement or OEM performance unit.

I am looking at a camshaft and roller tip rockers upgrade but will not cover that in this post as I just want to get these fuel and ignition items correct.

Its going to cost me a fair sum and I only want to do it once, so its got to be right. A measurable improvement in performance along with increased simplicity is key, fuel consumption is not. This will not be my daily drive as with most American cars owned in the UK, with fuel at the equivalent of around US$8 per gallon taking in exchange rate and litres to gallon conversion a mortgage is required to run one on a daily basis.

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Arns85GT
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Report this Post06-06-2013 12:59 PM Click Here to See the Profile for Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
The Mallory BYPASS regulator remember, is the safest and best.

The Offenhauser intakes were made for racing. You may well find one in the UK or in Germany.

The Offy has no slant BTW.

Part of the reason the 500 - 2 barrel works so well with the Edelbrock intake is that the float bowl is on the low side of the slant.

Also, the center hung float is superior and less prone to starvation on hard cornering.

It took me a couple of years to find an Offy. Good luck with your search

BTW Rockauto should be able to get you the dizzy.

Arn
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Report this Post06-06-2013 01:58 PM Click Here to See the Profile for trotterlgSend a Private Message to trotterlgDirect Link to This Post
I am thinking that the s-10 distributator is a lot taller than one for a Fiero ? Am I wrong? Larry
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Report this Post06-06-2013 02:23 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Direct Link to This Post
Although you still need that same distributor... have you considered going with an aftermarket fuel injection system? They have self-tuning systems from Holley and others. You sort of get the benefit of a carburetor, but also the benefit of fuel injection, spark, and timing advance (you replace the points in the distributor).

Whenever I get around to my Oldsmobile project, that's what I intend to do on this motor:
http://www.pontiacperforman...A/81TA_455_1_lrg.JPG

I figured it'll be the best of both worlds...
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Arns85GT
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Report this Post06-06-2013 03:20 PM Click Here to See the Profile for Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
Yes the dizzy is a bit taller. Not much though.

Rockauto has the 1984 distributor for $157.18 today.


Jegs has the Holley Avenger TBI system for $2058.99.

Jegs has the Holley 2300 (500cfm) carb for $399.99

(By the way, National Carburetor has them rebuilt and bench tested under $250)

I doubt you would notice any performance difference
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stewnew
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Report this Post06-07-2013 04:27 AM Click Here to See the Profile for stewnewSend a Private Message to stewnewDirect Link to This Post
The Rockauto site looks good, its clever enough to pick up my UK IP address and price everything in sterling. Are they competitive for most items, gaskets, filters. Do they sell perfomance items such as camshafts rockers etc?

I will commence my purchases in the next month or so once I have got my workspace sorted and start tearing down the 3.4. I need to check the condition of the all the internals and compile a parts list.

Bound to be a few more questions once I start.

Thanks
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Arns85GT
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Report this Post06-07-2013 02:09 PM Click Here to See the Profile for Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
Rockauto mostly sells OE replacement parts. Jegs or Summit sell the performance bits.

Arn
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stewnew
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Report this Post06-13-2013 11:21 AM Click Here to See the Profile for stewnewSend a Private Message to stewnewDirect Link to This Post
Just found a distributor from an ebay.com seller ,US$85 plus shipping to the UK is reasonable. The advert says GM Century/Celebrity 173 V6 80 to 88. A quick read of various web pages leads to think this may do the job as these "A bodied" cars had the 2.8 60 deg V6 carb'd engine fitted.

Any comments to confirm this would be greatly appreciated.

Thanks
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Arns85GT
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Report this Post06-13-2013 04:01 PM Click Here to See the Profile for Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
Check the Rockauto part number for the 84 blazer dizzy and then check the Century part number. They should have picks for both. If the Century is correct, it will have the vacuum actuated plunger on it.

Hope this helps

Arn
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Report this Post06-13-2013 06:47 PM Click Here to See the Profile for FFIEROFREDSend a Private Message to FFIEROFREDDirect Link to This Post
A fuel pump for a 1972 vega will be a elec pump for a carb. the 2.5 tbi 84 fiero pump is set for 15 pound. the vega pump is set for 3 to 5. I have one on my 350ci chevy DUELLY. It is a little shorter than the fiero elec pump. a longer hose will fix it.

Gm didn't use "points" after 1973.
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Report this Post06-13-2013 06:59 PM Click Here to See the Profile for HudiniSend a Private Message to HudiniDirect Link to This Post
My 1985 S10 Blazer with 2.8L V6 has a distributor and carb. As FFIEROFRED wrote, the distributor doesn't have points.
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