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I have been working on the 66 L79 AC Coupe I bought in November, steering, dash, electrical issues, etc. The last few weeks, I have been smelling gas when I go out to the garage after the doors have been closed for a while. Looking on the vehicle on the lift, I saw what is in the attached picture. There is a big drop of gas pooling on the bottom of the fuel pump. I wiped it off a couple days ago and it comes back. The engine hasn't been run in 3 months with the dash out. So, I am guessing that the leaking fuel means it is time to replace the fuel pump? The pump is not an original AC pump, a 40083, it is aftermarket. It also doesn't appear that the current fuel pump is even the correct L79 pump, as the inlet/outlet are not 180 opposite. Because of this, it doesn't seem even worth trying to rebuild it. I can get a Spectra Premium 350 hp pump on Parts Geek for $41.00. Seems this would be the best way to get the car running without hopefully risking a fire. Not going to be a judged car. Thoughts?
If you are not chasing the NCRS certification, the 67 and later style crimped pumps will work fine. The main thing is the pressure must be around 5 - 7 psi. and of course the clocking for the lines. You can get one at your FLAPS if you make sure it fits a 67 Corvette. They are cheap and less problematic IMHO.
Ron
Check your oil for a gas smell. The pump may have leaked fuel into the crankcase. Also, the control arm bushing looks like it should be replaced because of fuel leak on it. Jerry
I thought about a Holley pump. I did order the Spectra Premium pump as it was the only one that I found that said it was for a 350hp 327, and would have the correct 180 inlet/outlet. I figured for $41.00 I could give it a try. Has anyone purchased or tried one of these? If it isn't great, at least it could be a back-up, and I can go with a Holley. I have had nothing but trouble with the mechanical fuel pumps available for my Corvairs, so those have both been converted to electric. I don't smell any gas in the oil right now, but I plan on changing the oil anyway as soon as I get the car fired up again, as I have only driven it about 200 miles since I bought it at Mecum in November, but not sure when the last oil change was. Most of the 67 pumps I have seen show a hose fitting, not a screw in. Is that correct? Good call on the control arm bushings, I will probably end up changing those too.
It appears the leak is at the bottom cover??? Have you tried tightening the screws on the bottom cover and also around the upper body connection? If he pump is working properly, it could be just loose screws due to gasket shrinkage.
Holley carburetor bowls have a habit of leaking over time due to vibration and gasket shrinkage. Or at least the Holleys I have.
I did try to tighten the screws a little, some moved, some didn't. I did that a few weeks ago, and the leak continues. I am guessing that since the previous owner said he only put about 500 miles on the car in 15 years, that the gaskets have just given up. I don't know when it was replaced, but it could have been in 2014 when they appear to have put the different Holley carburetor on, probably also when they installed the Mallory Unilite, removed the PVC system, and removed the Vacuum Advance....
I will share some recent fuel pump experience. I had some serious carburetor fuel leaks dues to stripped screws and a warped metering plate. Thus I sent the carburetor off for a professional rebuild. Once the rebuilt carb was installed and float levels verified, I was still experiencing fuel leaks. Some testing of the fuel pump discharge pressure confirmed it was too high at 9.5 psi. The fuel pump worked fine so it was a shame to remove from service but I was not going to tolerate fuel leaks. I tried two other pumps and both had a discharge pressure that exceeded the spec for my L36. I ended up purchasing an Edelbrock unit that had a guaranteed discharge pressure of 6 psi and that resolved the issue. The Edelbrock unit was not cheap but I now have zero fuel leaks. My advice would be to verify the replacement fuel pump discharge pressure is within the specification for your carburetor to prevent overwhelming the carburetor needle/seat and seals.
I am literally going through this on my 66 L79.... Links to few threads on that pump.
Seems to be its hard to get a rebuild kit, and the replacement pumps some carry are made by Keen. I have Keen pump and now I think I have too much pressure. Testing it today actually. I am working with them on a rebuilt hit as well, as the other one they had did not work for the 40083 pump.
I also have a regulator coming to back down pressure to verify everything as well.
L79 New Fuel Pump Time?
