fuel problems

[Alex Blair (RIP)]

Originally Posted by BSHEVLIN

i have discovered that the push rod for pump is not working properly how do i go about fixing this ?

I already explained the push rod fix in this thread..
here it is again..You do not say what the problem with the push rod is but I can guess that it is worn...like most flat head Ford fuel pump rods..


This was a common problem with the old flat heads..I used to braze a layer of brass on top of the push rod..it dosen't take much..an extra 35 to 40 thousands of brass on the push rod will make all the difference in the world..a air leak on the suction side of the pump is another possibility..as previously mentioned.

[Phil Waterman]

Alex is correct about the fuel push rod wearing and not making a full stroke. This was a very common problem with FORD V8s as a kid playing with hot rods we found that it was more often a problem then not. It would often result in fuel starvation at full throttle. It was very common to find push rods had already had the treatment before. We would generally fix the problem by brazing as Alex suggests. However we also generally added an electric fuel pump back by the tank on a separate switch but hooked to the ignition so that the fuel system could be primed without having to crank the engine to get fuel to the carb. Makes a big difference on starting, also helps cure vapor lock as well because the pump down by the tank can push the vapor bubbles through when the mechanical pump is not able to clear them. The reason for the separate switch was because it was hard then (then as now)to find an electric fuel pump with the lower pressure range 3-4 psi instead of the 6-8 psi of most electric pumps. The higher pressure is great from priming or clearing vapor lock but can cause flooding.

[Lynn Eades]

Phil, I have read somewhere recently, that the Ford V8 range of carbs should be delivered a maximum of 2 1/2 psi. there are fuel pressure regulators available. Alfa Romeo use one called a "Fisba' or something like that. I have no personal experience with them. A point to be remembered is that the pump delivery pressure is dictated wholely and soley by the spring in the pump.

[Grant Bowker]

I have just searched Macs Auto Parts web site for "fuel pump push rod" - they list 4 lengths:
60 HP Aluminum intake 5-3/8"
60 HP Iron intake 6-3/8"
All other V8 Aluminum intake 7.87"
All other V8 Iron intake 8.87"
Since the 60HP are measured in fractional inches, I wonder if the others are a truncated measurement since 7/8"=.875".
This should give something to compare your pushrod to to see if it is worn.

[jim sewell]

To check for air leaks in pick up lines and taps , check the vacuum with the engine running at the inlet of the pump and check it again at the outlet from the tanks .
Readings should similar . To carry out the test run the engine off a gravity can.


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Is it sucking air at your change over tap (or anywhere else on the suction side of the pump.)(flexible hose etc) When you say the diaphragm is good, is it O.K. with modern fuel? Wet the valves in your pump and then put a vacuum gauge on it. It should suck about 15" to 18" of mercury. The delivery should be about 2-2 1/2 psi (which is controlled by the spring) If it does that, and holds it, then work back down your lines, as per my first

Regards
Jim S.

[Howard]

I had all sorts of trouble with my fuel pump, I put a full kit through it & it still would'nt suck up from the tank. The problem? The pump housing was cracked. Almost invisible... I replaced housing and away she went. I hope this helps rather than hinders...!

[Keith Webb]

Originally Posted by Howard

I had all sorts of trouble with my fuel pump, I put a full kit through it & still would suck up from the tank. The problem? The pump housing was cracked. Almost invisible... I replaced housing and away she went. I hope this helps rather than hinders...!

Yes, it wouldn't even run the 5 cylinders then available. I have some footage of Tony working on it.