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Mechanical Fuel Pump, gas in oil after 9 months use?
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Author:  60 Plymouth [ Mon Sep 22, 2008 2:22 am ]
Post subject:  Mechanical Fuel Pump, gas in oil after 9 months use?
Hi guys,

After about 9 months of use, my carter mechanical pump seems to be flagging again. Oil smells a little of gas and the engine has died a few times whilst driving (electrics stayed on). Im guessing that it's the fuel pump (screwed diaphragm), and the 2/3 empty fuel filter seems to suggest that also, but as always I am open to suggestions of those more knowledgeable than me :)

Any opinions on my dying car and gas-in-oil problem welcome.

If it is the pump, can anyone recommend a good make of fuel pump? I'd prefer to avoid electric pumps, I like the current system, and my Carter didn't last very long (the previous pump was replaced a year earlier by the car's former owner, and that was a Carter also, discarded for the same reason)

Also, if anyone could recommend a supplier who may be willing to ship to the UK that would be excellent, I can somtimes undercut UK dealer prices.

Lastly, out of interest, is there a simple, easy way to test a fuel pump without the use of compressors etc? Mostly to check if the diaphragm has failed.

Thanks alot,
60Ply
Author:  65Dodge100 [ Mon Sep 22, 2008 9:59 am ]
Post subject: 
Author:  Ed Mullen [ Mon Sep 22, 2008 10:00 am ]
Post subject: 
I had just replaced my fuel pump this weekend with a NOS Carter I had picked up 10 years ago when I had misdiagnosed a fuel system problem as the pump, only to find the pump was fine.

My Carter was made in USA. I don't know if the newer ones are. (I hope not, since I'd like to think that is why your two failed, and not that Carters are just problematic in gerneral.)

I noticed on both the new and old pump, there is a drain hole below the diaphram. I'd assume if the diaphram leaks, that gas trickles out of that hole. (I havn't cleaned off the old pump enough to know what brand it is, but it's original)

As far as testing: if you have a fuel pressure gauge, hook it up to the outlet of the pump and turn the motor with a remote starter or the key with the coil unplugged. Let pressure build, then stop and see if the guage maintains the pressure it had built up to, or if it drops off fast.

If you have no gauge, I guess you could pinch off the hose of the pump outlet and check that drain hole for leaking gas. (of course watch out for hoses popping off in other places when the pressure is building.)

Also, mechancal fuel pumps are at such low pressure, you could use a football or bike pump for whatever you were going to attempt with a compressor.
Author:  60 Plymouth [ Mon Sep 22, 2008 10:25 am ]
Post subject: 
Hi guys,

Thanks for the replies. I have had the leaking pump problem before, and picked up on it by sniffing the dip stick. I have that again now, though not quite so pronounced. I am really not keen on the idea of petrol (sorry, gas) trickling down the pump's arm and onto the cam lobe, then dripping into the oil to be honest.
Neither of my pumps have the drain hole that Ed mentions. I know the fuel pumps on Russian Zil trucks had these drain holes, it would make life much easier when diaphrams went.
My Carter pump was bought from RockAuto, I have no idea who made it. :roll:
Author:  65Dodge100 [ Mon Sep 22, 2008 4:49 pm ]
Post subject: 
I’m not sure the hole is intended as a drain – it’s a vent. Fuel may trickle out of it or not when the diaphragm breaks, but I think the vent is just to let air in. Either way, fuel can leak into the crankcase, even with a vent hole.

Danny
Author:  terrylittlejohn [ Mon Sep 22, 2008 6:19 pm ]
Post subject: 
why not try a bb dodge carter pump and switch the pump arms, just use a small drill to weaken the narled edges over the pin then pop out the arm and pin ,then epoxy the bb arm and pin in place.
Author:  SlantSixDan [ Mon Sep 22, 2008 8:22 pm ]
Post subject: 
Using a big-block pump will create large problems: the pressure and volume will both be much too high. Overly-rich running and godawful driveability and fuel economy will result. The (anywhere close to stock) slant-6 wants 3½ to 5 pounds of fuel pressure (this is the spec from the first '60 engine clear through to the last ones made in the '80s), not the much higher pressure of the V8 pumps. The only reason to adapt a V8 pump to your slant-6 is because you've got a very high performance engine with a very large carburetor.

You got a defective new pump, which sucks. The previous pump failed because it was an old one (the "O" in "NOS" means "old") made out of old materials. These would be short-lived due to their age even with 1960s gasoline formulations; with today's formulas they get eaten up in short order. You can toss on another current-production (crimped-together) slant-6 pump if you want, though I like the '60-'63 bolt-together pumps myself. You've got to put in a fresh rebuild kit made out of modern materials. Get the kit here. Kit consists of new pump diaphragm & spring, new air dome diaphragm, new valves with covers and springs, new pump mounting gasket, new pivot pin plug, and might even have a new pivot pin. It's not costly, and once you've removed the pump it should take you about 20 minutes to install the kit. The key is to compress the pump arm and retract the diaphragm (in a bench vise if you have one, with arm muscle against a hard surface if you don't) before installing the screws. If you fail to do that, you'll tear the diaphragm immediately upon installing the pump and operating the starter.
Author:  60 Plymouth [ Tue Sep 23, 2008 2:52 am ]
Post subject: 
Hi,

I have heard about these bolt together pumps, but I do not have one (all my old pumps were crimped together). I understand they haven't been made in 20 years or so. Are they still in stock somewhere, or is this an eBay scouting time? I like the idea of anything that is rebuildable rather than replaceable, it's nice to know exactly how it has gone together.

Thanks alot,
60Ply
Author:  SlantSixDan [ Tue Sep 23, 2008 6:13 am ]
Post subject: 
Ah, sorry, I misread and thought you already had a bolt-together pump (kidney stone flared up yesterday, so yesterday involved mostly drugs and bed). Those pumps show up on eBay from time to time. I've stockpiled a few myself. But no sense waiting on one to appear; I'd say just chalk it up to bad luck and get another current-production item.
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