Which carburetor should I use??

azcara11 · Post by **azcara11** » Fri Jun 11, 2004 12:41 pm

I am trying to put a decent carb on my 1972 411. I have a 2 barrel holley for it now and I was told that they aren't the best. I have been referred to the Weber progressive, but I wanted to see if anyone knew any tricks or secrets to make the Holley work better? Thanks!
cara

raygreenwood · Post by **raygreenwood** » Fri Jun 11, 2004 8:05 pm

The weber progressive and the holly 2 barrel are one and the same. Holley/webber is one company. They will give nothing but poor milage and grief. I would look for twin singles. Ray

wildthings · Post by **wildthings** » Fri Jun 11, 2004 8:12 pm

The problem isn't the carburator, it doesn't matter whether it has Holley, Weber, or Motorcraft stamped on it. The problem is the manifold set up. The progressive carb systems for the Type 4 have no manifold heat, so no carb can run right. On the dual carb systems on the vans and some other Type 4 vehicles, the carbs sit almost right on the head and get their heat from there. The progressives just sit out there in the cold and ice up.

If you intend to drive anywhere that the ambient temperature drops below 90 degrees F, you should shy away from the progressive set ups. If some previous owner has already ripped the fuel injection off your engine, you would be way ahead to hit a wrecking yard, find all the parts, and put it back on.

raygreenwood · Post by **raygreenwood** » Fri Jun 11, 2004 9:08 pm

Actually...it is the carb. Manifold heat is a plus...but the idle circuits were designed for short runners and a minimum displacement of about 1.9L. Thats the smallest watercooled engine they put this carb on and it was modified for that. This carb came originally on engines 2.3 and 2.5L. It even came on a few V-6's. The problem is not enough vacuum to run the circuits properly. This carb will either tune out for decent driving at highway speeds...and just barely decent, but hideously rich at idle....or excellent idle and lean at highway speeds. Its hard to strike a balance without extensive work.
It was originally designed for inline 4 cylinders with perhaps 8-10" manifold length...AND heated manifold. Its just not bad runers and no heat...its the wrong carb for the car. Ray

wildthings · Post by **wildthings** » Sat Jun 12, 2004 1:31 am

Ray, I agree that its hard to tune one of these to fit the manifold/engine combo, but it can be done. Its not worth trying though if you don't have manifold heat, so for most its not worth it. I got my '74 van for next to nothing out of a wrecking yard 16 years ago. It ran and looked good so I didn't look the gift horse in the mouth very long. I figured at the time that I could tune anything, but it all but defide me. I eventually built my own heated manifold for it, kind of copying a Type 1. I also suck heated air right out of the heater boxes for the intake air preheat, giving it the quickest possible warm up.

It was still a pain to tune, but I eventually found a jetting combo I liked. I scratched my head over it a lot, until one day I remembered that Holley Bug Spray carbs use a reverse power valve.

Why not take that idea and work with it? I pulled out the power valve plunger, poked tooth picks in the drillings and ports and vola, all the weird characteristics vanished. A little refinement on the main jets and air bleeds and I had it.

I wouldn't recommend that anyone else follow this path however, it would have been far quicker and cheaper to just go back to fuel injection or find a set of duel carbs.

raygreenwood · Post by **raygreenwood** » Sat Jun 12, 2004 7:00 am

Yep..I would agree with that. Without manifold heat its really difficult. The holley bug spray at best...still ran just adequately. I guess thats what I'm trying to get across. These can run smooth with work. But....compared to the HP and torque that say....the original injection ran on the 8.2:1 1.7....or what the twin solexes ran on the 7.3:1....power is down significantly. So....IMHO...saying they run "good"...is a odd comparison.
One thought for heaters....is what they use on some of the audi's andvolvos. The ceramic pincushion heater disc that fits into the manifold and takes the place of water jacket heating. Ray

wildthings · Post by **wildthings** » Sat Jun 12, 2004 8:23 am

I haven't driven enough other Type 4 powered buses to really compare power, but in 16 years of driving mine I don't think that another Type 4 bus has ever taken me on a hill, whereas I've overtaken hundreds. In fact I can remember only once when any air cooled bus ever left me behind unless I was loafing it, and that was a '60 something window van. He pulled up next to me at a toll booth last summer and by the time I got it into third he was long out of sight ahead of me. I pushed it up to 80 for a while to try and catch him, but I never saw him again. Sure like to know what he was running.

I'll keep those ceramic heater in mind. They might add an extra mile or two per gallon of petrol, especially when it drops down into the twenties and my system begins to get inadequate.

raygreenwood · Post by **raygreenwood** » Sat Jun 12, 2004 8:43 am

Its sounds like you keep your bus well tuned. That is usually why the stock systems run poorly....poor tuning. Trust me...drive a few around. The progressive is literally not capable on a same sized and equipped stock engine of producing the same HP. The atomization is just too poor in the runners with or without heat, due to the length and incompatible vacuum signature. Now....if you are running about a 2.0 or above, the progressive is much more tunable than with any engines below 2.0L. Ray

DeathBus · Post by **DeathBus** » Sat Jun 12, 2004 9:04 am

I run a weber progressive on both my vans. One runs pretty well, has a flat spot around 75 to 85 MPH in 4th gear on the hiway. Brand new rebuilt

TYpe 4 engine with progressive carb set up I can do 95 to 100 on flat interstate, 80 up hills. On my Camper I was running a REBUILT Weber progressive on a New rebuilt

2 litre type 4 engine, carb was junk and trashed my motor.

I found some Dual KAdron carbs on the samba cheap, sent them off to AJ SIMMS to be gone through, decked, etc etc, and am going to yank the good one off. The webers are way to unpredictable both in response and lifespan.

wildthings · Post by **wildthings** » Sat Jun 12, 2004 10:25 am

Part of the reason for my success with the progressives is the design of the manifold system I built. Instead of using the individual long runners of the progressive kits, it has a single runner on each side and then Y's at the heads, kind of like the dual port system on a 1600 Type 1. My runners are also somewhat smaller in diameter than stuff that comes with the kits to give a higher air velocity and get less fuel drop out. I probably have a pretty unique vacuum signiture.

I still wouldn't recommend it to anyone.

raygreenwood · Post by **raygreenwood** » Sat Jun 12, 2004 11:47 am

Excellent wilthings! those are exactly the type of mods I would expect would be needed to make a 2 barrel holley webber progressive run well.
I was never implying that they were a bad or poorly built carb...just that they were ill set up for the vacuum signature.
Maybe you should market your manifold. The interesting thing is...at one time in the junkyard...every other car had one of these on it. All of the 4 cylinder mid sized GM's of the 70's and early 80's had one. All of the 2.3 and 2.5L fords had one. Even a few chrysler 4 cylinders had one. You could pick one up for about $25. Most of those cars have been crushed by now. Ray

DeathBus · Post by **DeathBus** » Sat Jun 12, 2004 11:59 am

raygreenwood wrote:Excellent wilthings! those are exactly the type of mods I would expect would be needed to make a 2 barrel holley webber progressive run well.
I was never implying that they were a bad or poorly built carb...just that they were ill set up for the vacuum signature.
Maybe you should market your manifold. The interesting thing is...at one time in the junkyard...every other car had one of these on it. All of the 4 cylinder mid sized GM's of the 70's and early 80's had one. All of the 2.3 and 2.5L fords had one. Even a few chrysler 4 cylinders had one. You could pick one up for about $25. Most of those cars have been crushed by now. Ray

And the reason they were in the junkyard.... WEBER PROGRESSIVE!

azcara11 · Post by **azcara11** » Mon Jun 14, 2004 4:04 pm

Thank you for all the great advice. I am going to search for a fuel injection set to put back on it, but in the meantime I need it to run. I was told to put dual 1-barrel carbs on it, but what about putting dual 2-barrel acrbs on it...too much?

whitesquare · Post by **whitesquare** » Tue Jun 15, 2004 8:41 pm

Hi Cara, congratulations on your first type 4 and glad to see you have found the best place for type 4 advice. Are you saying that your present carb set up is not working at all. If so, can you give more details. Hisham

azcara11 · Post by **azcara11** » Tue Jun 15, 2004 10:06 pm

Hi Hisham. The Holley progressive I have now works about as well as having a cup with a small hole sitting on the manifold. I am getting ready to order a new dual carb conversion kit with the 1-barrel carbs....my question was whether or not I should order the 2-barrel carbs instead, but I am going to go with the 1-barrel carbs for now. Thanks!

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Which carburetor should I use??

Which carburetor should I use??

What about putting dual 2-barrel barbs?