pgtr

Which Distributor for 2.8L V6 (1984)?

I have a 1984 Firebird with 2.8L V6. It has an ECM which controls carb mixture and distributor ignition advance. After 200k mi - the original carb is tired and the emissions equipment has simply gotten too tempermental to hold a tune. I have a replacement VaraJet that I'll be rebuilding out of an S10 which is a bit simpler than the original.

In addition to installing the carb (and removing the check engine bulb) I believe I'll need to replace the entire distributor with a vacuum advance version.

If so any recommendations on which distributor I should go for?

A distributor from a mid 1980s S10 with 2.8L also has vacuum advance - should I go with one of those?

The car/engine is stock, dependably gets 25mpg currently - just want good overall driveability and gas mileage.

thanks.

pgtr

Just noticed that in 84 some S10 V6 2.8Ls came w/ and some w/o vac advance. What's up with that? Will my Firebird work OK with the orig ECM hooked up to the distributor (check engine light will go off when the TPS and Mixture Solenoids are disconnected forcing an open or closed loop mode I'm guessing).

Should I find an '84 S10 Distributor WITH vac advance?

84silverS/C

this is the best bang for the money


http://www.summitracing.com/parts/PR...4925143+400405
can be found here. It will fit 2.8L to 3.4L with carb and no puter. If you gasket match your intake and heads it will give you most of what the Eddy intake at the cost of a few sandpaper rolls and a grinder set.

If only there was a manifold to use this and 3500 heads on a 3.4L rwd block!

good luck,

b

Scorpner

iTrader: (4)

Huh, I didn't know they made an HEI for these.

Awesome-X

Early 2.8 S-10's and Jeeps were carbed so they were HEI, so I'm sure this is Summits updated version of GM's original design.

Gumby

85 was last year for no computer in the s10/s15 line

You can get one for $100 from rock auto, google em to find discount codes.
Nice place to get parts.

http://www.rockauto.com/catalog/x,ca...,parttype,7108

pgtr

Couple of Questions here.

The HEI type distributor is considerably shorter height than the OE distributor currently in there or the one pictured at RockAuto.

Q: Are there not any clearance issues? I want to say the 2.8L intake manifold and maybe the EGR valve etc...(?) required some height in the shaft between the hold down and the distributor housing...?

Q: Wiring for the coil? The OE setup has the coil on a bracket over the right valve cover - any issues or tricks I should be aware of if I move to an integral HEI style setup?

OE type distributor:



HEI Type Distributor:


Coincidentally I looked at the very same distributor at the very same website (Rock). Also - do you recommend WITH or WITHOUT (using ECM) vacuum on the OE type distributor? I'm assuming WITH vacuum but wasn't sure if the ECM offered some advantages to controlling vacuum over a hose...? (and remember I'll be losing the TPS with the new carb install)

Gumby

Why would it not fit, the carb 2.8 engines are all the same.
Some just used a computer to control the carb.


you either need a vacuum one or a computer controled one.
That is up to you.


w/Module; w/Vacuum is the one you want, it you want vacuum control

The WO ones mean you gotta buy them extra parts if you don't have them.

pgtr

Look at the pictures above. The HEI posted by 84silverS/C appears to place the flange on the shaft housing MUCH higher - perhaps 4 or 5 inches than the OE style distributor. Thus my question above about fit...

Not quite sure how to interpret this answer but it sorta sounds like it's just 'personal preference'. That's rather odd... So once the carb is swapped to a non-emissions version of the Varajet (w/o TPS etc) - I'm curious - How does the ECM control the vac advance on the OE distributor w/o vacuum advance when there is no TPS input to the ECM?

I have the OE distributor on my '84 Firebird 2.8L V6. It has no vacuum advance. What extra parts are you talking about?

84silverS/C

ok the dissy i posted up is an upgrade to the oe hei offered on some , not many us rwd, 2.8L 660. I have found them on fwd in crapped out 4door eco boxes in the local junkyards.

It goes on and replaces the oe coil. It is both a high volt multi spark and uses adjustable vac advance. I use in conjunction with a real carb, weber. to get a lot more than what the rated power was for 84's. The power was lower from 83 and 84 to make the fi cars look better. The 2.8L went from 125 hp to 102 hp with a combonation of smog and to prove fi was helping make power. With a better cam and some mild port work you can push well past 125+hp.

If you jump to a computer controlled carb with a vac/computer dissy you will not get the benifit of the vac advance. if you walk away from the computer controled carb all together there is a good bit of power being left on the table. I cought/still catch a lot of crap for not wanting to "upgrade" to fi but my car did not have it and I am happy with the what it is putting out.

I will add this to stop the flames I can smell in the air. FI is very good if it is working properly and you want it. A carb is more user friendly and shade tree tunable and rebuildable. I keep a rebuild kit in the upper drawer of my box. I have never found a fi setup that is rebuildable in under an hour for under 30 bucks. I can find any problems with out a scan tool and only hand tools.

I have 4 trucks, 1 van and a linc town car with fi. they are great as long as they are working. I have the camaro with a carb and a 77 ford bigblock with a carb both of these are toys and are only inop when I wear my dumbass hat and do something to make them not work... like run through a fence or get stuck in the lake.


sorry for the hijack,

so simple end word hei dissy good thing, with a better non computer carb = very good. do not be scared of the instal it is not bad at all. and u can put lighter springs to get a faster ramp up to full advance!

b

sorry for the spelling had to make my cannuck friends happy and had a good boxing day! i hate molsen!

Maverick H1L

iTrader: (8)

I believe that is a generic picture of an HEI dizzy, possibly for the 3.8 or early 4.3 engines or even more possibly for a V8...


Simple. Lose computer control altogether. You said your system was pretty much fried anyways, so you're probably better off. However, if you were to go the route the guy above is suggesting, I would still at least go to the FI crossover exhaust pipe (or headers, but then you might have to block off the EGR fitting as well)... It's bigger than your OE. (I accidentally got one as a replacement for my broken one a while ago and had to take it back and swap it for a different one because it didn't have the O2S fitting and was .25" smaller in diameter) You'll just have to find a way to plug the O2S fitting.

:edit: This is, of course, assuming you don't live in an area that requires you to keep computer control to stay state emissions compliant...

I believe there is at least a spark delay valve among others. Not entirely sure, though.

pgtr

Hmmm... I thought choosing a distributor to go w/ a carb swap would have been trivial but this thread seems to suggest otherwise...

1) Baseline: I have a 1984 F-Body with original 2.8L Vara-Jet E2SE CARBURATED V6 which includes full emissions.

2) I AM going to be replacing the original E2SE carb with a re-conditioned Vara-Jet 2SE from a non-emissions '85 S10. Essentially the same carb configured and jetted somewhat different and (IMPORTANT!) LACKING in a TPS or M/C solenoid. Otherwise largely identical externally.

3) WHEN I swap in this carb, among other things the ECM will no longer receive any inputs from the TPS. This (along with the M/C solenoid being absent) will immediately cause the ECM to set the ENGINE LIGHT and go into closed or open loop or whatever. I strongly 'believe' this will impact ignition advance control but not certain...? - which is why I'm posing this question here...

4) The current OE distributor (NOT an HEI) in the 1984 2.8L F-Body has an advance that is FULLY controlled by the ECM. It does NOT have centrifugal or vacuum advance. It does NOT have an integrated coil. Coil is mounted on a bracket over the RH valve cover. It DOES have a 4 wire harness connector. It is mounted on the original carburetor intake manifold. Here is a picture of the OE type 1984 2.8L V6 distributor (note the lack of vacuum and centrifugal advance provisions and it's relatively small size and different height from an HEI:


===========================

Now to my question which I will simplify as:

Given the upcoming carb swap and ignition described above do I need to:

A) Replace the OE distributor with an early ('83-'85) S10 2.8L V6 OE type distributor with vacuum and centrifugal advance? One can easily be purchased from a junkyard or reman from a parts supplier and be similar to the carb shown above except w/ mech/vac advance provision (CARDONE p/n #301630 for example).

or

B) Leave the current ECM controlled distributor and let the ECM control advance even though it will be lacking TPS input?

or

C) Other... (and yes I'm certainly open to an aftermarket HEI retro-fit IF it will really fit but not interested in more power per se - just preserving good all around driveability and gas mileage is all)

pgtr

As for the HEI retrofit recommendation - riddle me this: HOW do you get it to fit a 1984 2.8L w/ original carb and original intake? I've positioned and alligned the JPEGs for the two distributors side by side such that the mounting flange is on the same plane. The HEI is on the left and the OE is on the right. The shaft length on the HEI below the mounting flange is considerably LONGER. The lack of space above the mounting flange would likely cause interference with my intake runners and EGR valve possibly...? Also shown is a 3 wire harness connector - I'd have to figure out how to cross that over to a 4-wire flat OE style connector on my '84.

Just eyeballing it - I don't see how an HEI distributor would come close to fitting into my 2.8L.

If this is a 'stock' photo and they do fit - has anyone actually fit one to an early 2.8L 2 bbl carbureted V6? Where can I see an image of one that really fits? Do they come w/ 4 wire harness adapters?

Maverick H1L

iTrader: (8)

1. Like I said before, the pic that was posted was for a generic HEI distibutor, probably for either a 3.8 or 4.3 (here's one from an 85 C1500 pickup with a 4.3: http://www.rockauto.com/catalog/x,ca...,parttype,7108 if you want proof of this), so it obviously won't match. Try looking for a dizzy from a late-70s to early-80s Chevette or something that had the way-early 2.8's.
2. Technically, our distributor-type ignition systems are STILL the HEI, just computer controlled. Heck, the same coil design was in use for select HEI engines back in the 70's.
3. It IS possible to retain emissions control without the computer. It requires coolant-temperature controlled valves (EGR delay valve) and other things. Besides, you already know you're losing computer control over the primary part of regulating the emissions... the mixture control solenoid. That is how it was done in the 70's before GM and other companies switched to computer controlled carburetion and fuel injection.
4. And yes, I know the dizzy you currently have... I worked on an '84 2.5 that had that system (albeit with TBI). Like was said before, try looking for one from an S10 or something with the very early 2.8, as it will more than likely have vacuum advance.

1980 Citation, 2BBL 2.8 dizzy... HEI without CCC system: http://www.rockauto.com/catalog/x,ca...,parttype,7108 Notice this one has vacuum advance and is for the 2.8.

(I can get some more data on this later, as I have a manual that has data in it for most makes/models up to 1980/81 that also has a complete repair guide for the HEI system)

84silverS/C

if you don't want to up grade and or update what you have that is cool. do not choose not to based on pics of parts. The parts stores and the web designers are in a big a$$ hurry to fill the blanks and do not take the care to have a real image of each part.

I thought the question was what would work.?. unless you are gonna photo shop a 660* together a pic of a part is almost useless... or am I missing something?

and this replaces the coil and cleans up the under hood area.

hope you find what you are looking for

b

84silverS/C

and so you know it comes with the 4 pin quick plug! you can get the matching male end or cut into and splice.

b

Maverick H1L

iTrader: (8)

The plug you see in the dizzy pics in the links and in the pics above actually plugs into the dizzy cap and the ignition coil. All you would need to do to swap over to HEI is find power and a tach signal (if you currently have a tach, otherwise, just run the ignition-controlled +12V power to the cap). There is no computer control, no ignition advance bypass wire, no wiring to have an interference thing going on with, just cool classic tuning using weights, springs, and, of course, dizzy body timing (and for cheap, too... no scantool or tuning software required). You can delete most of the wiring in the engine bay if you do this.

To run the EGR and the canister, all you really need to do is find the ported vacuum connection on the carb and hook them to that... Neither will operate until you open the throttle plate. As for the spark control, same deal, but you might want to use the 4th gear switch in the transmission to control a solenoid such as the canister solenoid for better control.

Although, I do understand what you are saying in that you need some way to also control the torque converter clutch for 4th gear. You could retrofit a relay or something to control both the TCC and the vacuum spark control off of the 4th gear switch, I suppose. You might try asking around to find out how others who have deleted their CCC (Computer Command Control) have dealt with this.

Gumby

Get a vac advance dizzy for a 84-85 s10-s15 like the link I posted and it will fit.

http://www.rockauto.com/catalog/x,ca...,parttype,7108

A-1 CARDONE Part # 301630 {Reman.}
w/Module; w/Vacuum

it will fit, it will fit, it will fit. End of story, its what you need if you are ditching the computer.

pgtr

Thanks 84Silver and Maverick.

There are several solutions to address 700R4 TCC to go along with the carb swap. Actually some good threads here on these forums on this very topic.

Making the carb swap carries some baggage with it.

thx

Maverick H1L

iTrader: (8)

Let us know how it turns out. There aren't too many guys on here who have a carbed 2.8, but I'm sure they would like to have some tips on waking up their engines.

ericknight

To answer the original question, I would use a distributor for a 1985 S10. I have one, and it's not a HEI (has a separate coil mounted on a bracket on the passenger side).

Each vacuum port on the Varajet carb has a corresponding letter, I connected mine like this.
Port A - connect to primary vacuum break.
Port B - connect to vacuum advance and TCC switch if equipped (not needed with manual transmission).
Port C - capped.
Port D - capped.
Port E - connect to PCV valve.
Port F - capped.
Port G - connect to secondary vacuum break.

I have removed the AIR pump, EGR valve, EFE grid, and charcoal cannister with no ill effects. If you have AC, you may need to run a vacuum line to the selector switch for the air valves to work.

Here's a pic for reference. The vacuum hose going to the driver's side is for the TCC switch.

Maverick H1L

iTrader: (8)

Actually, that distributor IS HEI... Up until DIS came out, all GM ran was HEI, from the early to mid 70s when they stopped using the old breaker points (am I the only one who remembers those?) and swapped to the electronic modules. HEI was in 2 major forms: coil-in-cap, and remote coil, depending on how much room the vehicle had for either system. HEI, in fact, was typically coil-in-cap, but the systems were identical except for the diagnosis. The coil in the cap still had 4 wires, power in, ground out, tach, and power to the module. ALL of our thirdgens are HEI. It just doesn't look like the typical coil-in-cap system.

pgtr

I installed a 2SE and distr from an '85 S10 and a 700R4 conversion kit from Summit.

Car starts easily and runs very smooth at cruise, part throttle - better than before. WOT is about the same.

I set timing to 84 or 85 S10 specs give or take - don't recall offhand what now. It's quite a bit more advanced than the original settings with the CCC distributor. What's a safe initial setting given a distr from an S10?

Back when the car was new got as much as 27+mpg. (course we had double nickel back then too). For the last 5+ years it was running 25mpg. Maybe a year ago it dropped to 23mpg. After the conversion I did above - it's still in the 23ish range - occasionally 24 maybe. I was hoping for a return to 25 but it's at least as good as it was before the conversion.

The tranny kit locks it in 4th but not in 2nd or 3rd. I think the OE setup with the ECM locked all 3 upper gears under the right conditions.

Overall it's a nice smooth runner and no more need to tweak adjustments or chase ECM gremlins with various aging senders and subsystems - much simpler.

Maverick H1L

iTrader: (8)

How's the engine's compression and what not? Is it running slightly rich? There is a kit available for tuning the older GM Rochester carbs if you don't already have one.

The ECM setup typically locked the TCC in 4th, but it could lock it in 3rd if it deemed doing so necessary to reduce emissions and improve economy. IDK if some vehicles were able to lock in 2nd... Some vehicles had the same switches for 3rd and 2nd as they do for 4th to tell the ECM that the trans is in that particular gear. Their exact functions? Since my 87 and 91 Firebird FSM's don't have info on other vehicles, I couldn't tell you if some 700R4 transmissions could lock in 2nd. I suppose it could be possible for you to rig a switch, or set of switches, that will lock the trans in 2nd, 3rd, and 4th.

Gumby

Stay out of the 2nd barrel and it will be better on gas.
But that means driving granny style.

Its really a nice carb, sort of just a q-jet cut in half, but the 2nd barrel was fixed, if you play with the linkage like on a qjet so you can stab it wide open, there is no bog as the metering is fixed to the air vain proper.

Doug Roe said some really nice things about it in his performance Rochester book.

pgtr

If memory serves I believe it would lock in 3rd and maybe 2nd but I don't think it's that big of a deal - one doesn't spend all that much time in those gears except when accelerating. I'm happy with the kit I installed which just locks in 4th as it's automatic. That has an impact on mileage but I've got to believe it's very small.

It is a very good carb and a world apart from the E2SE. Actually the E2SE in theory is probably OK if the ECM is properly controlling it. Heck my E2SE well for 150,000 and 20 years and then it worked 'OK' for another 50k and 5 yrs. I believe the biggest problem was with the various other sensors aging though perhaps staying (just) within tolerances that the ECM was providing increasingly poor control over the carb. Though I do remain skeptical of the E2SE's M/C solenoid. At any rate the 2SE was a simpler solution both in cost and time over extensive diagnosis of the ECM's other subsystems.

2SE mods: I enlarged the hole to the auxiliary chamber in the float bowl. I made a few tweaks to the linkage for a smooth secondary transition w/o bog and I polished the slide for the spring on the 2ndary air blades as it hesitated some (not anymore).

The only annoyance is the idle kicker solenoid for the A/C. My old E2SE had a vacuum actuated solenoid which worked fine (though it added convolution with extra vac hoses and an electronic solenoid logic circuit to switch vac). The 'new' 2SE came with a seemingly simple electric solenoid. Unfortunately it was underpowered to crack open the throttle even with the springs removed. A brand new solenoid was just as anemic. So for now I just blip the throttle at idle and the solenoid will then 'hold' the higher idle when the AC kicks on but it is underpowered to 'lift' the idle on it's own. I guess I could go back to a vac solenoid but that's convoluted...

Gumby

The electric ones worked fine on the big V8 cars with Qjets????