Need advice on mechanical fuel pump

[Jake_S]

I'm with 74 Shortbed. All of the SBC mechanical fuel pumps I've seen have the hose fittings on the bottom.

Jake

 

[74 Shortbed]

Same with big blocks too..

 

[CRM]

Here is a snip from the service manual. Exactly what mine looks like.

 

[chengny]

That's how it should be mounted. It mounts like that on a 292 as well.

Here is the normal set-up:

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And from the GM parts manual:

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Notice also, that these engines don't use a push rod between the cam and the fuel pump actuating arm. The face of the arm rides directly on the cam lobe and is reinforced:

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Can it be installed either way?


I'm not sure but, I would say no. Even though it will bolt up if installed with the fittings on the bottom, will the arm be positioned correctly - in relation to the cam lobe? I don't know.

 

[74 Shortbed]

Yep, 194-292 are on top and can only go on one way..

 

[CRM]

Hmm...The pump I bought from Autozone recently (and took back) didn't have the reinforcement piece on the arm. Looks extremely easy to install though. Can it be replaced without draining the oil?

 

[74 Shortbed]

That's because it's from the Zone,lol.. yep, very easy to change, and no don't need to draining the oil.

 

[Jake_S]

The pump can be changed without changing the oil, but if the pump had a diaphragm failure it's a good idea to change the oil. A failed diaphragm can let fuel into the oil.

Jake

 

[CRM]

I read somewhere that if a vehicle sits for a long time (mine was in the field for 8 years) the ethanol in the gas eats at the rubber diaphragm in the pump. I've been considering replacing it since reading that.

 

[Jake_S]

I read somewhere that if a vehicle sits for a long time (mine was in the field for 8 years) the ethanol in the gas eats at the rubber diaphragm in the pump. I've been considering replacing it since reading that.

I definitely would. It's a quick repair, and will prevent a failure. I was lucky, and mine failed in the driveway. Before changing the fuel pump I did have issues with the engine missing/cutting out if I drove for more than 15 minutes, along with severe pinging under load.

Jake

 

[74 Shortbed]

I read somewhere that if a vehicle sits for a long time (mine was in the field for 8 years) the ethanol in the gas eats at the rubber diaphragm in the pump. I've been considering replacing it since reading that.

Ethanol is the worst $hit there is, not too bad as long as there's fuel there but if it dries up it destroys all rubber and gaskets in no time, sitting that long it's junk and needs to be replaced..

 

[CRM]

I definitely would. It's a quick repair, and will prevent a failure. I was lucky, and mine failed in the driveway. Before changing the fuel pump I did have issues with the engine missing/cutting out if I drove for more than 15 minutes, along with severe pinging under load.

Jake

I'm starting to see some of those symptoms I think. I only drive a little over 2 miles back and forth to work, but when I get out on the freeway I sure notice some small issues I feel are in the fuel system. I think it's time to replace the pump and rebuild the carb.

 

[CRM]

Ethanol is the worst $hit there is, not too bad as long as there's fuel there but if it dries up it destroys all rubber and gaskets in no time, sitting that long it's junk and needs to be replaced..

I filled the gas tank the other day and saw a stream of gas coming out from under the gas tank. When I start pumping it starts running, and when I stop it does. I suspect that the rubber fill tube has degraded from sitting so long. Looks like more work.

 

[74 Shortbed]

I filled the gas tank the other day and saw a stream of gas coming out from under the gas tank. When I start pumping it starts running, and when I stop it does. I suspect that the rubber fill tube has degraded from sitting so long. Looks like more work.

Yep, may as well replace the vent hose too at the same time..

 

[CRM]

Yep, may as well replace the vent hose too at the same time..

I replaced both as you suggested.