The Stovebolt Site Forums The Shop Area Engine Shop Carburetors for 235

This is long-winded so my apologies, but maybe someone can learn from it. This is for my 1956 210 Sedan with 235. The car had a worn out Rochester 1BBL that leaked like a sieve from just about everywhere. The old Rochester ran pretty well and the car would run 75 mph with no trouble, but leaked everywhere. I talked to Tom Langdon about several upgrades including carburetor. I bought a Weber-style 32/36 kit from him and installed it. It started and idled very well out of the box, with very minor adjustments. Vacuum is a steady 17 at idle. Took the car for a test drive and it ran pretty decent but I "ran out of throttle pedal" at about 50mph. I talked to Tom and he thought the jets may be clogged with some debris. So I opened it up and the jets were clean. I jotted down the jet numbers to do more investigating. The jets were 140 primary and 150 secondary. So doing more research on the various forums, most people recommend much bigger jets for a 6 cylinder. So I ordered a variety of larger jets and test drove with a 170/180 set. Test drive reveals the car accelerates much better but I still top out at about 50-55 mph. The car runs very well, with acceptable power and acceleration for the 235s I've owned, but the pedal is on the floor at 50-55mph. It accelerates very well all the way to wide open throttle and it just "runs out of pedal". I triple-checked that the linkage is wide open at full pedal and it is.

I have read on here that the 32/36 is just too small and I am starting to believe it. Tom Langdon disagrees, but something is wrong. So I am debating between either a 38/38 or a suitable 1BBL. I do like the Weber style 2bbl performance otherwise. Has anyone ran a 38/38?

I have run them both but always in dual carb form. The 32/36 Weber is a progressive two bbl with a small primary and a larger secondary. The Holly/Weber 5200 is nearly identical and was actually the 32/36 design licensed to Holly for the Ford Pinto and for the Chevy Vega and others, all small four cylinders. So I have always thought they were too small to run as a single carb on a 235. They run great I agree but it does not surprise me it runs out of steam at some point.

The 38/38 is not progressive. It dumps both bbls at the same time which is probably not what you need with a stock motor. Those 38s are really a higher performance carb then what you need or should want and aI don't know that the bigger is better option is going to work out all that well.

The problem is, as you may have discovered, is that the Rochesters can be problematic as 60 plus year old carbs. Between being rebuilt by who knows how many people in the past, with who knows what level of skill or attention, and the warping, and throttle shaft wear and the power piston sticking issue for example. Couple that with the fact that there are just not that many people left that can really rebuild/remanufacture one correctly. I am absolutely not one of those people so I am in the same boat as you when I am building a stock motor.

A carter YF, which could be purchased as a replacement back in the day is an excellent alternative but finding a correct version is getting harder to do these days and you still have to find someone when can do a really good job of redoing one. Those carbs also have some similar problems, but not nearly as many as the Rochesters have.

I for one would love to find a replacement option that is available, reasonable and reliable but that seems unlikely. But to answer your question, I dont think the 38/38 is going to be the answer to your issue.

As best I can tell, that Model B is 1-9/16" throttle disc, 1-11/32" venturi flowing about 200 CFM @ 3.0 Hg".
The Ford 32/36 is about 270 at the same vacuum.
Something is wrong, but it's not too small.

I see you checked the linkage position; are you sure the secondary throttle is actually WOT?
Are you sure the power valve is open?

Should you desire to go to the Carter YF, as Mike mentioned, the correct YF(s) would be:

Automatic transmission (auto choke) - Carter 2101s
Standard transmission (manual choke) - Carter 2100s

A major issue with the YF can be the neoprene (diaphragm) accelerator pump.

If a daily driver, one has few issues.

For a "monthly" driver, failure of the diaphragm will occur as the neoprene tends to harden once it has been in fuel, then allowed to dry. Using ethanol-laced fuel makes the problem worse.

I would expect failure on a monthly driver maybe every 3 years, more often if ethanol is used.

Jon.

Thank you all for the responses.

Tom Langdon questioned my fuel pump pressure under load. That could be a thing, but the car had a lot more top end with the Rochester so I doubt that is the issue. I do need to find a way to run a remote guage.

DragSix- a friend of mine bought a Daytona brand single barrel carburetor and had good luck with it. So that is an option. I do realize it is foreign made, etc. I appreciate your thoughts. There is so much differing opinion from people.

Panic- I came up with about the same CFM calculations you did, which is why I chose the 32/36. I read a LOT of people saying the carb was too small but the CFM calculations say differently. It runs very well until roughly 2,800 rpm or so. The power valve definitely opens at roughly 90% throttle, it really came to life at that point. Just need 2 more inches of throttle pedal so to speak.

Carbking- I did some searching last fall when I was shopping for a carburetor and looked around for a YF2101, but didn't have luck other than Chinese clones. I had bad luck with one a couple years back, the casting was so bad on a brand new one that it had a pinhole in the fuel bowl. So I am debating between a Daytona brand,
the Holley fuel injection system or figure out what is wrong with this 32/36.

Fuel pressure is critical with the Weber’s. Not so much with the pinto 5200. The Weber’s need a steady 3 pounds or so of pressure. If using a mechanical pump, the pulsing prevents a steady pressure. I am not saying that is the issue, but it’s certainly in the mix. As to flow, I have the same calculations as you and while theoretically they should be large enough, in practice, I still think they are a little too small and a lot of people who have run that carb at higher rpm and mph like you are have had the same issue.

Anything is possible at this point. On my truck I installed an electric pump and a pressure regulator. Maybe I should do the same on this car to be sure there is constant pressure no matter what else happens.

The other thing I question is timing. I adjusted it for the best idle and starting. Maybe it needs advanced a couple degrees? The car does not ping at all even under heavy load. Turn the distributor counter-clockwise?

There's an alternative to all the exotic dual carb and progressive 2 barrel setups, but it's only available to someone with the machining and welding skills needed to modify a stovebolt intake manifold. The Rochester small bore 2 barrel that was used on the 265 and 283 V8's can be fitted to a 235, and it's probably the best carburetor Rochester ever made prior to the Quadrajet. It really wakes up a stovebolt six when it's jetted and tuned properly. Simply adapting one to the 1-barrel flange won't work, however.
Jerry

Here's my 2 cents worth. I also had a holley/ weber 32/36 from Tom Langdon on my 261. It ran great, except it went flat around 2500 rpm. I drove it for a couple years like that and then just got tired of praying I didn't get run over on the highway going to a cruise somewhere. I replaced it with a Later model Rochester Monojet from a 250 cu.in. engine. I guess you could call it a new improved Model B. They were on just about every Chevy 6 for 20 years or so. I know some of you will belittle this choice, Because You Know Better than everyone else. But it works for me and has for many years now. direct bolt on, linkage fits like it was made for this application. Just My 2 cents worth.

Chadm Will give 2 cents worth of propane !! My 6 outfits that are all on propane run fine. Ihave learned to use forklift LP parts Amazon has plenty of it. Imostly run used stuff is as easy to fix as any i-barrel. Never cold natured,is safe follow the rules,all bolt-on. Am winning right now with 04 GMC injected propane/gasoline 1/2 ton !! My 2 cents worth.

Chad - one way one could tell the imitations (by definition, a clone is an exact replica, so they are definitely NOT clones ) of the YF's used by Willys on the Jeep, was the imitation had an aluminum (or what appears to be aluminum, who knows for sure) throttle body. Carter used cast iron.

Other than quality control on the imitations, which is, at best, questionable; they are two major reasons NOT to buy the imitations:

(1) Calibration specifications
(2) Availability of parts (ever get a tank of bad gas, and have to clean your carburetor?)

Fixite7 - as to the propane conversion, if you are happy with them, then I am happy for you. Locally, even the propane companies that could buy propane at cost gave them up as too costly when compared to gasoline or diesel about 20 years ago, right after propane conversions broke nearly every school district in the area! But the engine rebuilders and machine shops were never happier!!!!!!!!!!!!!!!!!!!

EDIT: Fixite7 - nice one! You got me! I didn't realize today's date!

Jon

Good point. Those would be easy to find compared to the proper versions of the YF. I suppose some of the later iterations of the Monojet have some weird smog control stuff on them?

I think you implied it, but I assume this solved your flat spot issue?

Tommy thanks for your feedback I appreciate it!

JW51, Yes it did . The truck runs much better with this versus the 32/36. The one I use is an early one off of a early 70's c-10.

Tommy I ordered one. How did you run your vacuum lines?

Well to put closure on this, I bought a new (reproduction) Rochester Monojet from an early 1970s application and bolted it on. Adjusted the air/fuel screw by vacuum guage.
Runs like a champ. Idles at 20 inches of vacuum. Ran it home from the cruise-in at 75 mph. Needs a large air cleaner for high throttle operation. I put on a 6-1/2 x 1-1/2 cleaner due to hood clearance but it needs more. So I ordered a 12" x 2" oval, which the longer dimension can run front to back and follow the crown of the hood. K&N filters website has a calculator to explain air filter size by cubic inch and RPM. Read that! You need more air than the normal little single filters you see. There is also the 3/8" vent on the bowl to contend with. I bought a small crankcase filter with 3/8" inlet for it. That seems to help with high throttle airflow as well.

For anyone reading this in the future, a single Weber 32/36 on a stock intake runs like a dream until about 55 mph. I ran 170/180 jets in it. Foot was on the floor and the butterflies wide open. Ran like a modern fuel injected car from 0-55 but thats all it had. Its just not big enough for a 235.

So when my FITech fuel injection died last week. I opted for a 2100 autolite also known as motor craft. I have a clifford intake with an adapter for the standard Holley pattern. Easy to build and dial in. I used the 1.02 Venturi from a v6.

No one has said anything about gear ratio, just saying. What rear end are you running?

Factory, with factory overdrive.