Resize jets?

[JD 1931]

I have the drill bits to resize jets if they are too small but what is the proper way to resize them if they are to large?

Thank you, JD

[Pete]

Solder it up and re-drill.
It is best to drill under size and ream to final size.
It is best to do it in a lathe or drill press.

[JD 1931]

thanks for the nice explanation , do you have the correct lengths for all of the jets in the zenith? Hope I am not asking too much...

[Mike V. Florida]

You can also "cheat" and buy them already tested from Renners.

[H. L. Chauvin]

Possible questions one may want to think about and consider when buying new jets?

1. At the price of gasoline today, and considering miles per gallon, and miles driven per year over a period of a few years, is it sometimes cost effective to pay for "perfect" carburetor jets offered by Renner's as opposed to paying for the same cheaper "imperfect" jets offered by Model A Parts supply houses?

2. Anybody ever wonder why some may consider the perfectly sized "solid" brass jets sold by Renner's to be superior to the new "imperfect" jets offered by Model A Parts Suppliers after testing flow through jets?

3. Anybody ever wonder why some may consider the perfectly sized "solid" brass jets sold by Renner's to be superior to the new "imperfect" jets which are soldered "closed" then re-drilled under one's oak or persimmon tree?

4. FWIW: Heard that Renner's buys "undersized" jets made of "solid" brass; and under very strict quality control, has the proper equipment to drill orifices to "exact" sizes every time without using softer solder.

5. One Example to maybe consider:

a. Joe's jets were bought new, soldered, drilled with a hand drill, and he gets 15 mpg with 5,000 miles per year; hence he uses 333 gallons per year, and with gas at $2.75 per gallon = $916.00 per year he spends on gas.

b. Joe's wife's jets were bought new with carburetor jets from Renner's, and she gets 21 mpg with 5,000 miles per year; hence, she uses 238 gallons per year, and with gas at $2.75 per gallon = $655.00 per year that she spent on gas ........ and with Joe's $916.00 - $655.00 = $261.00 savings per year by her, and $1,305.00 savings by her over five (5) years.

c. Moral of the Story:

(1) Joe had fun soldering and using his hand drill while under his oak or persimmon tree.

(2) Joe's wife saved enough money to buy five (5) new "Whitewall" tires and take a vacation "alone", with her rich neighbor, in her Model A, while Joe fixed his worn out flat tires.

There has to be an added: ...... "Rest of this Story." LOL

[mrtexas]

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Jet size in engine won't reduce mileage significantly. That is why the GAV is there.

[BILL WILLIAMSON]

How in the world do they make a .021" drill bit, amazing!!---I CAN'T even sharpen a BIG bit. I "lost" mine in the carpet ! ! Buster T. found it for me, GOOD DOG!
Bill W.

[Rowdy]

Used to use bits every day down to #62 bits for drilling the bleed holes in shock pistons. Ran a 3 machines that drilled up to 16 holes at a times. Ran close to 10,000 pistons per shift when all 3 were running right. Rod

[H. L. Chauvin]

Just differences of opinions of Model A owners based on their past experiences:

1. Any Model A owners having several carburetors ever experience a big difference in mpg, idling, pickup, between these different carburetors, and ask why?

2. Steve Pargeter the author of Zenith Model “A” Carburetor Restoration Guidelines made the following statement in his restoration manual.

“The operation of the Zenith Model A carburetor can be affected by the way it was rebuilt and by the use of the correct parts. Of all the parts in the Zenith, the jets (which are more accurately called orifices) are key to making it operate as well as when it was new.”

2. Performance Tuning (Mr. Steve Partager)

We can take the level of carburetor rebuilding to the next level for those of you that want specific performance from your car. It is possible to achieve 25 miles per gallon fuel economy with a well maintained Model A Town Sedan (a heavy car) with little loss of top end power by fine tuning your jet selections. We can also get every bit of power out of your engine to help keep up with modern traffic when needed with only a small drop in fuel economy. I like a slow and even idle for my stock ’28 pickup engine, so slow that at times, you barely hear it running. This performance can be achieved with careful carburetor rebuilding, jet selection and final tuning. All of the above described characteristics can be achieved by performance tuning your carburetor.

[Mitch//pa]

Originally Posted by mrtexas

Jet size in engine won't reduce mileage significantly. That is why the GAV is there.

anything in a carb that allows more fuel to pass will affect fuel mileage and also the fuel to air ratio ..
put a set of jets from the suppliers in ,,, then try a set of flow tested from renners... huge difference

[HoarseWhisperer]

Originally Posted by Mitch//pa

anything in a carb that allows more fuel to pass will affect fuel mileage and also the fuel to air ratio ..
put a set of jets from the suppliers in ,,, then try a set of flow tested from renners... huge difference

Just installed a set of David Renner's flow tested jets. Package included documented flow rates. Great performance!

Will be tracking fuel mileage.

[Mitch//pa]

Originally Posted by HoarseWhisperer

Just installed a set of David Renner's flow tested jets. Package included documented flow rates. Great performance!

Will be tracking fuel mileage.

Don't beat it when checking the mileage drive it normal

Personally I don't give a squat about mileage... As long as I get a good burn on the plugs and it runs to my expectations I'm getting the best I can.