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How to make your four- barrel carb work
Posted by: DrMike ()
Date: October 14, 2010 12:54PM

A couple of issues ago an article was written in Corsa about the four barrel carb application. A lot of problems and solutions weren't addressed, so I wrote to the editor, and the final answer was that they stated this was a complex issue, and most folks couldn't do what I did anyway....

I'm here to tell you that it can and does work, and I'll help you if you need it...So here's my letter, since they obviously aren't going to print it in CORSA:


Dear Larry,
I found the four barrel manifold article interesting, but what always gets me is that no one, VW, GM, etc. has ever made a remote carb work well without applying heat to the manifold. Remember the Grand National....they had to plumb the turbo intake manifold to accept heated water from the radiator. There is a very simple answer which I provide, and solves these problems. The bottom of the four barrel intake manifold is machined away, and an aluminum box is fabricated and tig welded in place to carry engine oil. The oil comes from the oil filter log which I machine off....A remote filter is then used on the return line from the heater box. This system not only heats the plenum, it cools the oil as well. The oil leaving the manifold is generally 10-12* cooler.
Exhaust could be used for heat if one wants to replumb an AIR exhaust manifold. The perfect example is the single carburetor V W engine.
All carburetors become refrigeration systems, due to the Fuel/Air (F/A) compression in the venturi and idle systems and later expansion in the plenum. All modern engines compensate for this phenomenon by locating the carburetors over the oil valley in a V-8-6, or over an exhaust manifold in inline engines. Corvair engineers wisely mated the intake manifolds directly to the head, keeping the F/A mixture warm, and in suspension. The lack of heat to the remote 4-barrel manifolds we use allows the F/A mixture to condense on the sides of the frozen plenum, creating a very lean situation, and resultant hesitation (lean skips). Winter operation becomes almost impossible due to carburetor ice formation with resultant frozen idle circuits. Most folks compensate for the problem by using the 50 cc accelerator pump and fire-hose nozzles. The result being poor gas mileage and extreme dilution of the oil at the top compression ring. With my system, one can use the stock Holley accelerator pump and normal nozzles.
My suggestion for initial carburetor settings in the Holley 390, 4160 series is as follows:

Stock accelerator pump (NOT the 50cc)
.031 Accelerator pump nozzles
.057 primary jets
.059 Secondary plate jets
75 power valve
Electric choke
Purple secondary diaphragm springs


Best wishes, Mike McCrae
619-466-0014

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Re: How to make your four- barrel carb work
Posted by: Phil Dally ()
Date: October 14, 2010 01:19PM

Nicely done...you should post this on all the blogs.

[corvairforum.com]
[groups.yahoo.com] (key word fastvair)
[vv.corvair.org]
[v8vairs.com]

And your right...it isn't vairy hard to build that.

The metal work could easily be done with hand tools. cool smiley

Any good welding shop could TIG and/or heli-arc it for a nominal fee.


Paso Robles CA-Unsafe at Any Landspeed-Sidewinders (SCTA Charter Member 1934)-CORSA Member-Central Coast Corsa-Ventura County Corvair-V8 Registry-Corvanatics-California Angels Fan Since 1978...World Series Champions 2002 & 9 AL West Division Titles-So Cal Gas Since 1974 (Now Retired Again) Rehired as Contractor Seasonally-Baddest Street Legal Corvair on the Planet is SuperVair (AKA Vairy V8) ADE 506 Cube BBC/PG/QC L/M Coupe-1963 Deluxe Rampside (AKA PhilSide2)-148.253 MPH Landspeed F/BGALT Late Model Coupe-B&M Blown Methanol 3.1L Mid Engine Funco Sandrail-1965 Ugly Duck 110/PG Monza Coupe Parts Car-2013 Ford F250 Super Duty XLT Four Door Crew Cab Short Bed 6.7 Powerstroke-Grand Design Momuntum 350M Luxury Toy Hauler-When I Grow Up I'm Selling Everything and Buying a Vintage Triple Weber 911S Because I'll Never be Able to Afford the Miura!!!

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Re: How to make your four- barrel carb work
Posted by: B-Vair ()
Date: October 14, 2010 01:33PM

Vairy nice Mike, I think I will try this this winter. thumbs up

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Re: How to make your four- barrel carb work
Posted by: lgoodwin ()
Date: October 14, 2010 01:50PM

As an alternative, how about wrapping the intake pipes with a 12v pipe wrap run off the 12v electrical system? These guys have 2 12v products that might work (did not show any closeups of the actual product):
FreezeSentry.pdf

1962 Corvair 900 sedan1967 Corvair Monza 140/4-speed1968 Corvair 500 coupe1983 Mexican Mustang 5.0
1962 900 sedan needs a home1967 Monza 140/4-spd1968 500 coupe (now my son's)1983 Mexican Mustang 5.0

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Re: How to make your four- barrel carb work
Posted by: PGrommes ()
Date: October 14, 2010 02:53PM

A well written article. But does the box you put in the manifold affect the A/F mixture as it goes down the runners?

__________________________________________________________________________
Phil Grommes
Hanover, IL
The car is 48, I'm 25, I guess it makes the decisions
1965 110HP Powerglide Monza Coupe

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Re: How to make your four- barrel carb work
Posted by: Phil Dally ()
Date: October 14, 2010 03:09PM

"But does the box you put in the manifold affect the A/F mixture as it goes down the runners?"

Good question...the "box" might not need to be so deep in the manifold???

I also remembered a picture of my 500 manifold with this style set-up.

I don't use the oil fittings and interestingly enough with:

Carb manifold
foot of 3" pipe
water injection
ice water intercooler
another foot of 3" intake
6x6x6 plenum
4 leg plenum
4 runners

I never have any icing...must be the turbo heat.

Plus it might not have time to ice...only has to run for 5 minutes.

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Re: How to make your four- barrel carb work
Posted by: Phil Dally ()
Date: October 14, 2010 03:13PM

Haven't run the cool can yet...next Sunday October 24.

Maybe that will make it ice up...we will see.

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Re: How to make your four- barrel carb work
Posted by: DrMike ()
Date: October 14, 2010 04:09PM

The depth of the manifold box is due to interference with the blower bearing if you don't. There doen't seem to be any problem, and all my cars sport high performance engines. One could make spacers under the manifold ends, but this is simple, and it works. That Holley two barrel manifold shown above (Phil Dally Post) has a chamber for oil...notice the two holes on the bottom.....

I've machined 12 of these for customers, and no one has complained yet.

Mike McCrae

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Re: How to make your four- barrel carb work
Posted by: DrMike ()
Date: October 14, 2010 04:13PM

You want the plenum hot where the acceleerator pump shot and A/F mixture initially strike, otherwise it condenses immediately....

Mike

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Re: How to make your four- barrel carb work
Posted by: Phil Dally ()
Date: October 14, 2010 04:20PM

"I've machined 12 of these for customers, and no one has complained yet."

That's the kind of real world pragmatism I like!!!! cool smiley

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Re: How to make your four- barrel carb work
Posted by: firevair66 ()
Date: October 14, 2010 05:50PM

I was thinking on mine to Shroud the air cleaner and feed hot air from the winter/summer outlet. Any merit on trying that?

John Shoemaker,Riegelsville,PA.
1958 Impala Sport Cp. 348 ,pg/ac
61 Rampside full custom show truck
65 Monza 110/4 vert driver
65 Full Custom Monza 140 Cp
66 Monza 110/PG Vert
66 Corsa FITCH SPRINT Documented ( in Process,recondition)
66 CorV8 350 "firevair"Custom Show




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Re: How to make your four- barrel carb work
Posted by: VegasVair ()
Date: October 14, 2010 06:14PM

I had a 3 inch metal flex hose from the right top cover hole to a shroud
that covered a third of a 9 or 10 inch aftermarket air cleaner.

That setup eventually warmed the Holley 390 carb body, but took forever
to warm the aluminum manifold. That was in mild Las Vegas winters.

Back in the day I think somebody marketed 4 barrel manifolds with
an oil reservoir on the bottom. Hot oil is probably the way to go.

65 Corsa 140/4 A/C convert.
CORSA+Vegas Vairs

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Re: How to make your four- barrel carb work
Posted by: Richard ()
Date: October 14, 2010 06:17PM

Not exactly a new idea. My brother put this oil plate on his sand rail in the mid '70s. He was never sure if the foam rubber on the runners helped, but he thought maybe a little. The hot oil plate did help, but running around Pismo late at night the air is really damp and carries a lot of moisture. The water in the air, the humidity is what freezes.

In the mid '70s you could buy VW kits with Weber or Dellorto's, linkage, air cleaners and dual port manifolds for a couple of hundred bucks. That was cheaper than two carbs by them self. Enough guys bought the VW kits for Corvairs that they would re-jet them before shipping and my brothers ran perfect right out of the box.

Day and night above the center mount Holley.

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Re: How to make your four- barrel carb work
Posted by: DrMike ()
Date: October 14, 2010 06:39PM

Remember....hot air has fewer molecules to burn, so lower total horsepower output. That's how we check to see that the carb heat is working on an aircraft...we pull it on and watch the RPM's go down.....V W uses hot exhaust under the plenum and is very fast, but they loose the dual effect of cooling the oil. The V W plenums will also fill with carbon deposits, and the car almost won't run as a result. I'm not saying this is new....just saying I did something about it and it worked.

Mike

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Re: How to make your four- barrel carb work
Posted by: corvairmonza63 ()
Date: October 14, 2010 09:13PM

The only question I have is why does the carb set-up put the carb directly over the fan? You would think that would cause it to freeze up as well.

I had the same problem with my Mini and the twin webbers were mounted over the Exhaust. We would wrap the exhaust manifold with heat wrap and during the "winter" months unwrap the exhaust and wrap the intake and exhaust together(ish) If you wrapped it to much you would almost boil the fuel in the carbs.

I would imagine if you mounted the carb closer to the sides like 2 2 barrels that the intakes point toward the fan but it was heated by a small heat port off the exhaust. Just a thought.

Oh and I am new to Corvairs, so these are just thoughts running threw my head.

V/R

Kendall
USAF

'63 Corvair
'76 Leyland Mini Clubman Estate
'03 Celica

Some people are like slinkies, worthless until you push them down the stairs!!

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Re: How to make your four- barrel carb work
Posted by: MattNall ()
Date: October 14, 2010 09:23PM

63.... Vair's fans stall at higher rpms...so this is actually good for performance...





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: How to make your four- barrel carb work
Posted by: davemotohead ()
Date: October 14, 2010 11:30PM

I saw one where the manifold was drilled and had a steel pipe bent in a U going in and out and think it was hooked up to the oil presure switch hole and drained back in the filter housing that was taped with a fitting,,looked simple to do,,dont know how well it worked?





Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)

-----------------------------------
Rust Free Lancaster Ca

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Re: How to make your four- barrel carb work
Posted by: slow61 ()
Date: October 15, 2010 05:09AM

I have an Induction Engineering manifold made for a 2 carb engine. It appears to have two holes cut in it for oil circulation. Looks factory to me, but I don't know, it just showed up in a horde of parts.

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Re: How to make your four- barrel carb work
Posted by: Phil Dally ()
Date: October 15, 2010 05:45AM

slow61...how about pictures? cool smiley

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Re: How to make your four- barrel carb work
Posted by: slow61 ()
Date: October 15, 2010 06:26AM

Ask and ye shall receive.

Its a little dusty, I just yanked it off a bedroom shelf.

The holes are definitely threaded for something.

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