Anyone running an NOS AC or original AC mechanical fuel pump?
 

I have a couple of NOS AC fuel pumps for my pair of 68 cars and avoided running them thinking the diaphragms inside might be dry rotted or not compatible with the fuels of today. Are any of you running those without them failing early?

Thanks
Old Joe

they will not mesh well with todays fuels, and can only assume they are dry rottedby now.

these guys make kits to rebuild them with new internals.

https://www.then-now-auto.com/produc...uel-pump-kits/

My bird has an AC pump on it that I installed back in 98 or 99 when you could still buy them. I've logged over 100k miles on it since then and it's still kickin'. Nothing but 10 percent ethanol mixed pump gas.

I run a repop AC pump on the 69 Z and that one has over 60,000 miles on it, same gas, still flawless.

I’m using an old stock AC pump that was given to me over 30 years ago. I installed it about 7 years and 10k miles ago. No issues and minimum 10% ethanol here in California.

I put a nOS on my 78, got an extra in the box. No problems.

Thanks for the input. I, have heard lots of stories about how these NOS and original to the car pumps are likely dead meat in today's fuel. That said, I have yet to hear anyone that tried one and it actually was DOA, or had a short life. My biggest fear is installing it and having it pee gas all over due to a bad diaphragm. If anyone out there has actually encountered a failure of the like, I'd be interested in hearing that as well.

I'm sure their are failure stories with nos stuff but I tend to think it's few and far between.

My failure stories are with new pumps you buy today from places like Napa, AutoZone etc... Ive had 2 Carter's fail the same day. First one a block from the house, Napa swapped it and the second one died a few miles from the house. The third time they just gave me my money back. The AC, airtechs, and Carter's are all the same pumps now. AC doesn't even have "AC" cast in the pump anymore and the 3 pumps side by side with their corresponding boxes I took a photo of and posted on this site, you couldn't tell them apart. The AC I mentioned I have on my bird I bought way back in the late 90's, actually has AC cast in the pump. Back when you could still buy a real AC pump.

I find today's stuff way more unreliable today. I'd rather take my chances with an nos pump to be perfectly honest. And if I were worried about numbers and date codes I'd send my original out for rebuild. There are a couple good places that offer that service. Just be prepared to wait.

Yup, I'm living your "their all crap" nightmare right now.............

I have an NOS pump from the late 1970's for this SD-455 I am getting back on the road. I am going to try and use it. For the same reason others have mentioned, the available aftermarket junk may have a new, alcohol compatible diaphragm, but the valves are junk and the pressure produced is generally too low or too high, the pivot and pin are poorly made, have too much clearance and are noisy. Also the arm is soft material, shaped incorrectly, and wears fast. It's a no win situation. I am going to do my best to find zero alcohol fuel and keep an eye out for oil dilution from a diaphragm leak.

I heard the Napa pumps in Canada look just like the AC ones here.

I grabbed a NOS 40607 pump for my 68 back in 2016 and have been running it since. Hasn't crapped the bed yet, knock on wood.

I ran a NOS AC fuel pump on my '79 T/A for around a year before I was experiencing fuel starvation symptoms, and so I replaced it with a Carter just as a guess to see if that was the issue. Wasn't. Was just a clogged fuel filter because I dumped Berryman B-12 into the fuel tank almost raw lol. I never did put the NOS fuel pump back because the Carter works fine, but I didn't have any issues with the NOS one, either. I used REC-90 fuel exclusively because the diaphragm in it probably wasn't made to withstand Ethanol gas.

I appreciate the comments about running non-ethanol gas. I live in an area where premium is available without ethanol so that's what I run anyway. I'm going to run a test on one of my NOS pumps to see what kind of PSI it's putting out. If it turns out good, I may just install it and run it for a while and see what happens. So far I haven't seen any actual bad comments from those of you who actually run NOS pumps.

Earlier quadrajets with the larger floats ran at much lower pressures than the later 70's units with the smaller nitrophyl floats. The factory service manual for my particularly engine family has the fuel pressure at the carb spec between 7.5-8.5 PSI. My Carter I put on falls right within spec.