The Stovebolt Site Forums The Shop Area Engine Shop Fuel Line Probs

We have a ‘49 3100 AD Chevy PU with a 235. We ordered new tank and stainless steel fuel lines from classic parts. The fuel lines that arrived are a different diameter even though I ordered the ones for a ‘47-‘50 Chevy Truck. (See pics). The old line from the carb is 3/16” inside diameter and new one is 1/4” inside diameter. The one coming out of the carb seems fixed, and not removable. Is this an easy fix or do we need to order a different fuel line? Thanks!

Larger ID fuel line is always a plus. Different fittings required.

Ed

Great! Thank you.

I have another question regarding the new fuel tank. There seems to be a bolt at the bottom instead of a metal fitting/plug that was in the bottom of the original one. See pics please. What is required to get the fuel line attached? Thanks again!

That's just a plug to keep crap out of it while it sits in the warehouse.

The npt nipple and petcock thread into it. The fuel line threads into the petcock.

Ok thank you, had no idea!! 😁 Don’t know what we’d do without you guys’ help!

SuziQ

SuziQ,

Without knowing which tank (brand and part number) you ordered, first guess on the "bolt" at the bottom instead of a metal fitting make me think the bolt is just there to act as a plug to keep debris out of the tank before installation. There is a fitting there, just not same as original design and installed differently than the way your old tank was constructed.

From your new tank/old tank pictures, it's clear that the new tank fitting was applied on the inside of the tank and spot welded (4 visible weld dots) and sealed on the inner part of the tank instead of the way the original tank was made with the bulk of the fitting on the outer face of the tank.

Removing that bolt should leave you with a threaded hole to accept the bottom of the tank fuel line fitting/shut-off valve assembly from your original tank (assuming of course they used the proper fitting on the new tank).

A word of caution on this threaded fitting hole. Double check the thread and hole size against your existing fitting/valve if transferring from the original tank. I have seen it posted in here sometime in the past that some reproduction tanks (don't remember brand) use a metric threaded opening instead of the us standard size. Will cause you some grief trying to get your fuel line connection/shut-off valve installed into the new tank if they aren't a match.

We may be able to offer more info if you can post the brand and part number of the new tank.

Dan

EDIT: Otto beat me to the punch with a shorter but accurate answer. Still wouldn't hurt to confirm your hole and thread size before trying to install the fitting.

Hi Dan. Thanks so much for the info! II ordered off classic parts. I don’t see a brand but part # is 23-923.

SuziQ,

Although off-shore made, I read good review comments on the product.

One review did specify that the fuel fitting threaded hole was correct for US original standard fittings. A very positive sign.

When you install yours, maybe you could provide some pics and your observations???

Glad the info is helpful!

I ordered a Canadian made Spectra tank from NPD. I wonder if the Classic Parts tank is also Canadian?

Spectra tanks are good quality.

Yes. I think the new tank is actually superior to the original. Even the straps I bought with it were better quality than the factory straps.

Larger fuel lines are often required for racing, especially on vehicles where the engines can be modified for much higher RPM.

Larger fuel lines on a street driven or even more so, a parade vehicle contribute to "heat soak" issues, and hard starting hot issues. The larger diameter slows the fuel velocity causing the fuel to run hotter, or even vaporize in the lines. The additional capacity allows for more fuel to be dumped into the carburetor on a hot engine at shutdown.

The stock line size is sufficient for a stock vehicle. Billions of miles were driven using stock sizes. My opinion, one of the worse fuel system modifications which can be made for a stock or mostly stock vehicle.

Jon

One other possible issue, at least to be aware of, stainless lines.

A long time ago, maybe 25~30 years?, we custom-bent fuel lines. We no longer do, so the following is not a conflict of interest post. In fact, I still have a commercial Di-Acro machine that I no longer use.

As our focus for the lines, were lines for GM tripowers (Chevy and Caddy used steel, Olds used copper, steel and aluminum, and Pontiac used steel and aluminum. Buick did not have a tripower, but used steel for the dual quads. So we ordered a large amount of tubing, mostly steel and aluminum, in 5/16 and 3/8.

About this time, stainless became the "rage". I never liked the stuff, but try to give the customers what they like. Went back to the manufacturer to order some stainless. The guy on the other end of the line asked "do you wish to order any of the special fittings?" I replied no, I could buy fittings at any auto parts store. He said just a minute, and put me on hold. A couple of minutes passed, and another guy came on the line, and identified himself as one of the company engineers. He asked what I was doing, and I explained. He then asked "you do know that stainless CANNOT be flared at greater and 37 degrees, and automotive fittings are 45 degree?". I said no, I did not know that. We talked for awhile longer, and he finally said "to protect you, we are going to refuse your order!"

So, summing up the above:

(1) This is NOT my field
(2) This was a long time ago, perhaps a different stainless alloy exists today that can be flared 45 degrees, I don't know.
(3) When an engineer tells me something is unsafe, I tend to listen
(4) WHEN A COMPANY REFUSES AN ORDER BECAUSE THEY BELIEVE THE APPLICATION IS UNSAFE, I REALLY TEND TO LISTEN. With many companies, it is all about the money!

Food for thought!

Jon

Wow! Thank you Jon for the information! I am printing it off for my husband to read and digest.

Suzette

I thought I'd post a picture of the old vs new fuel tanks!

Suzette

That looks like the Spectra tank. Are you sure it wasn't made in Canada?

It has the same oblong dimples in the indented portions and the same vent tube (different from original design).

In your situation, the stainless steel line is a solution looking for a nonexistent problem. The plain old butt-ugly dark green copper/nickel generic fuel lines that are available at the corner parts store would be a much better choice, at a fraction of the price of stainless. That line is durable, rust resistant, and much easier to bend and shape to the correct form than stainless. Win/win/win!
Jerry

Gosh....as they say, "Hind-sight is 20/20!" I think it's a lot like rearing kids, we'll be much smarter the next time around!

SuziQ

We aspire to get to the point you are Otto in your pics of your Spectra tank. Ours is just like you see it in the above photo, unfortunately! I didn't know I'd have to say, "Hurry up and wait so many times!" lol

The only fuel tank I've every removed and installed that was easier than this AD Chevy is the first generation Mustang.

You'll have that tank installed in no time. Did you buy new straps?

You can purchase pre-bent fuel lines from a variety of sources. You'll need to purchase a new petcock for the bottom of the tank, too. In stock configuration, all the new parts will bolt right it and fit without any fuss.

I got my tank, petcock, and tank-to-pump fuel line from NPD.

What's your fuel pump situation? Don't buy a new one if you have an original. Have it rebuilt.

Post a photo of it.