[mac10]

Hey guys I am running into a little problem with my rebuild process. I am getting caught up in an area where I have pretty much zero experience so sorry if I have a lot of novice questions on this one.

I pulled a 327 from a family friend's old truck a while back. The motor sat with my uncle for awhile as he worked on getting it ready to run. Through his work he noticed that he had gas leaking in to the oil. He just attributed this to the old carb, however, and we went and got a comepletely rebuilt one like we had been planning on doing in the first place. The new one is a rebuilt rochester q-jet.

We also bought a new edelbrock intake manifold to go with it. We hooked up the two and tried to get it running with no success. After awhile of messing with it we finally got it to run again (the timing seemed to have gotten brutally messed up at some point), although it struggled to idle correctly. Even with adjusting the idle screw and timing it still seemed to just want to die after running for a little bit.

From what I have read this points directly to a stuck float. But, I highly doubt that since we bought the carb rebuilt and it didnt sit any longer than a month, and I am also reluctant to open up the carb and begin tinkering with it myself since I lack any knowledge in this area. Is there any other possibilites that I can check first? I want to fix this myself rather than sending it to a mechanic and never learning how to do it.

Thanks for the help guys, I am learning as I go!

Mac

 

[VinceS427bb]

mechanical fuel pump with a defective diaphragm will leak fuel directly into the engine crankcase...

 

[mac10]

Alright, just clarifying up on this, when I was running the car you could see a steady stream of gas being pumped into the carb. Is that possible and perhaps its just not running with the right pressure anymore since some is leaking? Also I was running the gas line straight from a gas can and for only short periods of time, so would there be enough gas going through the fuel pump to dilute the oil that much to the point where I can clearly smell it and see the thinned out oil?

The fuel pump definitely seems like a possibility to me if it still fits the criteria. Is there any accurate way to test it other then a fuel pressure gauge? Or is that going to be as good as I can get?

 

[mac10]

Also, is it possible for a 350 mechanical pump to fit, or is the 327 one the only one that will work with the motor?

 

[VinceS427bb]

a fuel pump can still provide fuel to the engine and leak a good amount into the crankcase.

the fuel pumps for a 283, 302, 305, 307, 327, 350, 400 all will interchange

 

[Delta]

I put on a Holley mechanical fuel pump a couple months ago that ended up putting out way more pressure than my QJet could handle and flooded the whole thing and put quite a bit of fuel spilling onto my intake. In the process i guess it dumped a lot of fuel down into my oil as well because right after i changed the oil i could smell that strong gas smell.I'm lucky i caught it then.

Who makes the fuel pump and what's it maximum psi? Possible also the Qjet is leaking from the bottom of the plugs?As for the stuck float that did happen to me even after i put in rebuilt components. The movement of the float was not smooth until i cleaned the bar that looks like a "C" that goes through the holes of the float and only then did it operate smoothly.

I was in your shoes before and was not happy about opening and rebuilding a QJet but when you do it once it really is not all that bad. There are even videos on youtube that go along way on explaining it.

 

[Middleagecrisis]

"you could see a steady stream of gas being pumped into the carb."
Eliminate the possibility (does the pump look stock?) that you have an aftermarket, high pressure mechanical fuel pump that's overpressurizing the carb. If not, then you have a stuck needle and seat in the carb. Are you running a fuel filter?

 

[TXCR13]

Eliminate the possibility (does the pump look stock?) that you have an aftermarket, high pressure mechanical fuel pump that's overpressurizing the carb. If not, then you have a stuck needle and seat in the carb.[QUOTE][/QUOTE]

What Middleagecrisis said.

 

[mac10]

So the fuel pump definitely looks aftermarket to me. Is there anyway to check for sure? Codes are markings somewhere? I also pulled the pump off of the motor, so now is there any way to check for a bad diaphragm if that is still an option? Thanks for the help guys.

 

[VinceS427bb]

this site has many different aftermarket pumps with photos
http://pitstopusa.com/c-135109-fuel-system-fuel-pumps-mechanical-fuel-pumps-sb-chevy-fuel-pumps.html

number 3 and #4 on this site look like stock pumps
http://www.ss396.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=chevellecamino&Category_Code=FUELPUMP

is there gas dripping from the lever area?
can you blow air thru the inlet on pump and hear feel air coming out by the lever with the outlet port plugged?

was the steady stream of fuel you saw going into the carburetor at the carburetor or at a clear fuel fuel filter on the fuel line before the carb???

 

[mac10]

Alright it looks like #4 so I am guessing it might actually be a stock one?

And there was a gas/oily mixture at the end of the lever and it smelled pretty strong of gas. However I can't get any air to come out of the lever area. Plugging the outlet port and blowing in to it just creates an air burst when I unplug the outlet port.

And the steady stream was at the carburetor.

 

[70-SS454]

For $17 (& 15 minutes) replace the fuel pump...

 

[Delta]

#4 probably puts out 6.5 psi max but to be on the safe replace it like Frank said.

 

[HKalin]

My first car was a 64 Ford Galaxy 500. It was leaking gas so bad from the back of the fuel pump into the block that the car was dying. They changed the fuel pump and when they drained the oil there was 9 quarts of gas and oil mixed in the crankcase.

 

[mac10]

Alright, well which one do I go with if I replace it?

And just curious how would it be leaking if the diaphragm is fine? Would it be too much pumping into the carb? I guess I am just lost as to how so much of the gas is getting down to the oil.

Thanks again guys.

 

[rocks66ss]

Alright, well which one do I go with if I replace it?

And just curious how would it be leaking if the diaphragm is fine? Would it be too much pumping into the carb? I guess I am just lost as to how so much of the gas is getting down to the oil.

Thanks again guys.

How do you know the diaphragm is good? Just because it's pumping enough to run the car doesn't mean it's not leaking into the cavity, if its leaking it goes into the crankcase. you do realize the actuating arm for the pump goes into the block, and operates from a rod that works off the crank, and all this is internal. so it can operate and leak inside.

As far as what one to go with, go to ANY auto parts store and just tell them you have a 1965 chevy pickup truck with a 327 and you want a fuel pump.

I went to NAPA online and plugged in a 1966 chevy C10 with a 327 a stock fuel pump is $49.00 they all interchange and no reason to buy a high dollar pump that in the links above, Auto Zone, Advance, Pep Boys, probably cheaper.



Rocky

 

[mac10]

Putting a little bit of compressed air into the fuel pump (while it was off the motor) and closing the outake with my finger just created an air bubble. Nothing was coming out by the arm and when I moved my finger off of the outake tube it puffed out with air. Wouldn't this be a clear test that it isn't leaking from a bad fuel pump?

 

[brimac]

I've had two O'Reilly stock mechanical fuel pumps, in the last year, that made well over 6.5 psi, ....if i I recall, closer to 10. They initially worked ok, for awhile, but then the 1850 Holley, began to flood gas. Only after checking everything else, did I finally check the pressure, ...because a stock pump shouldn't produce high psi. Shouldn't, but they did. I installed a regulator/w gauge, just to keep an eye on things.

 

[rocks66ss]

Do the same test underwater and put air to both the inlet and outlet and see what happens.

Rocky

 

[mac10]

Good idea Rocky, didn't even think about that. Should be able to rule out it leaking there at least.

brimac is there any easy test that you can do to check to see if it is putting too much pressure out? Something that can be seen in the carb with the eye, or do I need to actually test the pressure?