Ops checking Fuel pump

[Dale C.]

I am replacing a leaking fuel pump with a #'s correct used pump. Is there a way to bench check it prior to installing? It is a pain to get on and off, with C60 I have to go from underneath and not much room. I was thinking of putting some vacuum on it to dry leak check it. It would be nice to know if it works before I put it on.
Thanks
Dale

[Michael J.]

Re: Ops checking Fuel pump

You might try this procedure. Scroll down to "checking the pump operation":

https://www.howacarworks.com/fuel-systems/checking-a-mechanical-fuel-pump

[Duke W.]

Re: Ops checking Fuel pump

Slip on a foot or two of 3/8" ID tubing to each nipple. Clear vinyl if fine. Place the inlet hose into a gallon jug of mineral spirits and the outlet hose into a clean container. Cycle the rocker arm at about 2 Hz and see if the liquid flows.

Duke

[Joe L.]

Re: Ops checking Fuel pump

I am replacing a leaking fuel pump with a #'s correct used pump. Is there a way to bench check it prior to installing? It is a pain to get on and off, with C60 I have to go from underneath and not much room. I was thinking of putting some vacuum on it to dry leak check it. It would be nice to know if it works before I put it on.
Thanks
Dale

Dale------


I wouldn't be using ANY used fuel pump just to get correct numbers. I'd use only a brand new fuel pump. Even if the used fuel pump is OK now, how do you know how much life it has in it? This is a major safety item.

[Dale C.]

Re: Ops checking Fuel pump

Thanks, I'll try in the AM.

[Dale C.]

Re: Ops checking Fuel pump

Thanks for the heads up Joe.

[Troy P.]

Re: Ops checking Fuel pump

I had a WCFB carb rebuilt/restored from one of the best in the country. Upon installation had trouble running right, flooding, rough idle. Carb guy suspects fuel pump.

It is obvious that the pump does pump lots of fuel, which is what you propose to check for. But in my case the suspected issue is an incorrect spring inside the pump. I'm being told when the fuel bowl is full the pump is supposed to go into sort of a bypass mode. If the internal parts are not calibrated correctly the pump will continue to send too much fuel to the carb. This is all news to me.

To resolve this I am sending my pump to the world's number one, 89 year old, fuel pump guru to have him rebuild the already rebuilt pump and to test the pump.

The specs for my pump call for a minimum output of 4 psi with a max of 5 psi, a very narrow range. Also be aware that you need to know if that measurement is supposed to be wet or dry. In other words bench testing with fuel flow or with air flow.

In summary, my point is there is more to determining if you should use the pump than just seeing if it does pump some fuel.

[Dale C.]

Re: Ops checking Fuel pump

Troy, who is the Guru and how might one contact him?
Dale

[Frank D.]

Re: Ops checking Fuel pump

Personally, I'd rebuild any used pump before installation as you don't know what's going on inside. The procedure is not that hard .
Especially if its that difficult to install on the OP's car as he states.

Its such a straight forward job I'm surprised anybody doing it is referred to as a 'guru'...

[Joe L.]

Re: Ops checking Fuel pump

Personally, I'd rebuild any used pump before installation as you don't know what's going on inside. The procedure is not that hard .
Especially if its that difficult to install on the OP's car as he states.

Its such a straight forward job I'm surprised anybody doing it is referred to as a 'guru'...

Frank-----


1967 and later fuel pumps are not rebuildable. At least, not like screw-type pumps.

[Troy P.]

Re: Ops checking Fuel pump

I have rebuilt a dozen or so fuel pumps. That includes 8-10 of the complicated double diaphragm 53-55 vacuum/fuel pumps. But the point of my story is there is sometimes more to it than rebuilding. There is testing and a calibration process that was news to me. Find me a rebuilder that does that.

I'm a rebuilder but not a guru. One thing the typical rebuilder will not know is if the kit he uses really has the correct springs. It is common to fudge and to make the kits usable for multiple pumps. Also it may not be obvious that the pump has been modified in an attempt to improve engine performance over the years.

The guy I sent my pump to is a retired mechanical engineer that designed and tested fuel pumps for 60 years. Fuel pumps for everything from cars to heavy construction equipment to aircraft. He deserves the guru moniker.

He is very selective about who he works with. Because his services are in high demand and he does not want to work much he'll only take on a job for someone he knows and if the task is interesting to him. I had to be introduced to him by someone he is close to.

[Frank D.]

Re: Ops checking Fuel pump

Frank-----


1967 and later fuel pumps are not rebuildable. At least, not like screw-type pumps.

Right. My 63 had a crimped together pump (incorrect) when I bought it...worked great and still have it on the shelf...
It'll most likely never see duty again..

[Frank D.]

Re: Ops checking Fuel pump

I have rebuilt a dozen or so fuel pumps. That includes 8-10 of the complicated double diaphragm 53-55 vacuum/fuel pumps. But the point of my story is there is sometimes more to it than rebuilding. There is testing and a calibration process that was news to me. Find me a rebuilder that does that.

I'm a rebuilder but not a guru. One thing the typical rebuilder will not know is if the kit he uses really has the correct springs. It is common to fudge and to make the kits usable for multiple pumps. Also it may not be obvious that the pump has been modified in an attempt to improve engine performance over the years.

The guy I sent my pump to is a retired mechanical engineer that designed and tested fuel pumps for 60 years. Fuel pumps for everything from cars to heavy construction equipment to aircraft. He deserves the guru moniker.

He is very selective about who he works with. Because his services are in high demand and he does not want to work much he'll only take on a job for someone he knows and if the task is interesting to him. I had to be introduced to him by someone he is close to.

If you're happy with your choice of expertise I am too.

I've found that the problem with the rebuilds is not so much the process as the kits...some of them cause overpressure and the WCFBs (and other carbs) can get unhappy when that happens.

[Duke W.]

Re: Ops checking Fuel pump

Dale------


I wouldn't be using ANY used fuel pump just to get correct numbers. I'd use only a brand new fuel pump. Even if the used fuel pump is OK now, how do you know how much life it has in it? This is a major safety item.

That thought crossed my mind, too. Case in point. I accompanied John Seely to the 2016 Tuscon Regional for a PV on his low miles unrestored '65 FI Coupe. Don Hooper and he had gone through the PV about three times and had it nailed.

Upon startup for the PV a little geyser of fuel shot up from the right front of the engine. The main diaphragm in the clearly original pump failed. We found a pump, jack, jackstands, and had tools, and Casey gave us more than the allotted time to swap it out, but we finally had to throw in the towel.

Dale needs to weigh the risk of installing a used fuel pump against the point loss of a quality OE replacement.

Duke

[Joe L.]

Re: Ops checking Fuel pump

That thought crossed my mind, too. Case in point. I accompanied John Seely to the 2016 Tuscon Regional for a PV on his low miles unrestored '65 FI Coupe. Don Hooper and he had gone through the PV about three times and had it nailed.

Upon startup for the PV a little geyser of fuel shot up from the right front of the engine. The main diaphragm in the clearly original pump failed. We found a pump, jack, jackstands, and had tools, and Casey gave us more than the allotted time to swap it out, but we finally had to throw in the towel.

Dale needs to weigh the risk of installing a used fuel pump against the point loss of a quality OE replacement.

Duke

Duke------


As I've reported previously, many years ago I awoke one morning to the strong odor of gasoline in the house. My Mother was frantic. The garage floor was covered with gasoline. When a Corvette fuel pump fails, all of the gas in the tank can flow out and that's what happened to me. NEVER AGAIN. I consider fuel pumps to be a regular maintenance item. Replace them BEFORE they fail.