The Stovebolt Site Forums The Shop Area Engine Shop Rochester jets

Anyone know where I can get #50 jets for my single rochester C?

putting a set of Rods on a 235 and want to take the Main jet from 58 down to 50!

I tried .51 jet on a 235 and it was too lean to start on a cold morning. Went to a .55 and it worked fine.

I don't think the main jets have anything to do with start up and idle, they work at cruising speed!

Where did you get them, I need a source to buy them from!

mark

Here you go...The carb shop .

WOW, Called this place, ten minutes and I can't recommend anyone using him, can't stand someone who talks down to me!

I've never used them but based on your experience with them, I won't recommend them anymore .

BTW if you have extra jets, you could go to any machine shop and have them chuck them up to a lathe and drill it larger.

bodiman - tell the whole story.

You called and asked for jets for a Rochester model C - right so far?

We have virtually every page that Rochester ever printed for the aftermarket. There is no reference to a model C.

I asked you for a tag number - you had none - right?

You told me the application was a 1949 Chevrolet truck. Well, the 1949 Chevrolet truck used a Carter; Rochester's first one-barrel came out in 1950.

So we have absolutely no idea what it is that you have but you want jets. Assuming (always bad, but in this case we will) that you have some form of the Rochester B (not the C) there are at least 3 DIFFERENT series of main jets, NOT interchangeable.

We ended the conversation with me suggesting that you take one of the jets you have to a local machine shop (if its what you have, it should hopefully be correct for your carb) and have it duplicated in the orifice size you require.

I am sorry if you felt I was "talking down to you".

I was trying to explain that you did not offer sufficient information for me to know what you have.

Oh, and a little free information. Generally, when one wishes to drop from a 0.058 jet to a 0.050 jet in a Rochester B it is because the airhorn is warped, the power valve is always open, and the mixture is much too rich at high vacuum. Installing a jet that is 0.008 smaller may solve the high vacuum rich condition, but will probably cause detonation under wide-open throttle.

Again, my apologies if it came across that I was "talking down to you". Please, review this post from our standpoint as a supplier, and see if you still feel the same way.

Jon.

My experience with the Carb shop was just the opposite. I called with questios about the carb in my '54 3600 and they were extremely helpful in pointing me in the right direction.

We talked about what to do in the short term to get the truck running decent and then what to do in the long run to get extra performance out of the engine.

I would highly recommend them as they were very helpful. I did not feel talked down to at all.

Just my 2 cents...

Jon has helped many of us on this site,,,one of the best.............................Fred

CarbKing,

You may not know it but that's exactly what you did, your post is correct but if your handle is correct you should be able to talk to anyone and come up with the solution, I have 5 rochesters here and the jets interchange with all of them but none of them have what I want, you never asked me what I was doing to make a conclusion as you have in your post!

I have no tags on these carbs, so from your prospective you can't help me! I told you it was a 49 truck, but you were insistant that I couldn't have such a carb you never gave me the chance to say anything else, "Talking down" the motor I said was a 235, and you would then know it's a post 50, infact it's a 56-58 motor, you also won't just sell what I want, I have to buy a kit, that isn't a problem but I needed to know that I could have two of the Jets I wanted, because, I'm putting them on a elderbrock atop the 235! The Jets I have are #58s I want to drop the jets down to give it better milage at cruising speed!

Thread size and all can be checked with a thread gauge and that can be solved!

Believe me I'm no amature, I have been working on cars for well ove 25 yrs, but when your insistent that no Tag no help, that perturbs me!

By the way it was 1500 carbs not three! your words!


Talking Down is when your more concerned in being right then helping or coming up with a viable salution! I will appoligize but my post was what I got from Our convesation!

Mark

Mark - why didn't you tell him the application is a 56-58 motor w/ dual carbs? sounds like a little lack of communication on your part, is he supposed to make the assumption that you have a non-49 motor because you have a Rochester carb in your hand?

carb parts are very specific, and the tag is important as 5 different B's may all be different, and tagged so, and if you're convinced you have C's when the carb expert says there is no such animal, how can he be expected to know what you need?

as others say, I've found carbking very informative and helpful and had you presented the complete information, he no doubt would have had a viable solution

Bill

It never got that far, he was just concerned that there was no way I had a "C" Rochester and no way I had one for a "49" and without a Tag no way he could help me!

I here what your saying but did he have what you wanted, if so great, but a little deductive reasoning in my situation we could have found the answers! he was to busy telling me What I didn't have rather then use his experience to help me get what I need, I have no Tags on any of these carbs, one is a rebuilt from a reputable supplier! Am I to believe that without a tag an experieced carb person can't help me, get what I need, I think not!

I'm not saying he's not a good supplier if you have all the right things, but I don't, so if anyone knows of a person who can truely help, let me know!

Mark

What we have here is an attempt to buy an internal part for a Rochester, from a professional who wants to do things the correct way. It must be understood that if they just sold bits and pieces knowing that they could be used incorrectly, the customer could then spread the word that their stuff is garbage because it didn't work.

Tags are a problem and most of the carbs that I have seen didn't have them any longer. There are other references on the carbs that can be helpful and some of that information was detailed in a previous post.

One of the interesting details left out of the discussion here is that although the earlier Chev trucks didn't come with Rochesters, GM provided a replacement Rochester carb for them. Thus it is possible to have a truck earlier than 1950 with a correct replacement Rochester carb.

Mark - we obviously did have a failure to communicate. I have apologized publicly (in this forum) for my part in this (as you have also).

Unfortunately, with most Rochester carburetors produced prior to the 1968 year; identification when the tag is removed is exceedingly difficult.

What I was trying to convey to you, and didn't, was that Rochester probably made some 1500 or so different type B (we are still assuming you have B's and not monojets). These used 3 different series of main metering jets. These metering series or styles of jets differ in height of orifice and internal approach angle. While the three series can physically be interchanged, the metering will not function as designed, if the incorrect style is used.

You are correct that our minimum is a rebuilding kit. We occasionally take some flack for not selling individual parts without the purchase of a kit. However, this was a business decision which allows us to provide a MUCH larger selection of parts, and still stay in business.

But back to trying to help you acquire the jets. One of the problems with the Rochester B series is commercial rebuilders (true with other carb series as well). The commercial rebuilders interchange parts from many different individual carburetors (often with little regard to whether or not they should be interchanged) and then REMOVE the tag.

Each casting of the Rochester has a casting number. This is a number for an unmachined casting, so this is not an absolute identification; but at least one can get a idea of the time period from the casting numbers. Some time ago, I published some of this information concerning some of the early and mid-50's Rochesters used by Chevrolet on these forums. You might look for this in the archives. If you are unable to find it, I will try to locate my notes and post it again. Most of the early and mid 1950's Chevrolet B's all used the same series of jets. The later one's did not.

One thing you can do until you are able to locate jets is to lower the fuel level in the carburetor bowls. Lowering by a 1/16 inch should give you the same result as installing 1 size (.003) leaner main metering jet. I would still suggest looking at the operation of your power valves.

Good luck with your project.

Jon.

Carb king,

Can you cross referance GM part # 7002650 ?
This is a GM main jet part # , I need two of them.I understand I have to buy the kit,can you work with this.

Mark

Carbking,

Is it possible to solder a jet closed, then re-
drill to the desired size...in a pinch!


Stuart

Mark - yes. This is the 0.050 size in the earliest series of the type B jets. No problem.

Stuart - yes, but by the time you have reached the end of the 1/4 mile, the solder is somewhere in your engine, no longer in the jet. Solder is so soft that gasoline will erode it like a river erodes a levee.

Jon.

Where do you find the casting number?

I'm glad to see the two of you setting aside your misunderstanding and still trying to work together.
You'll probably become life long friends because you are each intelligent enough to work through a problem rather than let frustration rule.

I have been frustrated more than once when trying to deal with carburetors and kits. Carbs without tags can be the pits when you don't dink with them enough to know what you really have.