The car I'm working on is an 84 Capri with a 347 stroker. It has a 750 Edelbrock afb carb, ported Typhoon dual plane, ported World Windsor Jr heads, custom roller cam, 1-5/8" long tubes, dual 2-1/2" full exhaust. Has 3/8" tubing and -6 braided hoses from in the tank to the carb. To clarify, the hanger in the tank is essentially stock with a 3/8" tube.
Is anyone running this pump
on a hot small block with any level of success? That is the newer style (Carter?) 1725 fuel pump. Started having a fueling issue with my old 1725 pump which looks like this:
It wasn't keeping up with the fuel demands at wot, and the bowls were emptying out. I could stay in it for a little more than a gear and the fuel bowls would empty and the wideband would swing dangerously lean as the car fell on its face. Get out of the throttle for a couple seconds and get back on it, it would take of screaming again. This seemed to coincide with a hard starting issue that was worsening to the point of me having to pour gas in the carb to start it after a couple days sitting. I disconnected the pressure line and no gas came out, so I was led to believe there were some bad check valves in the pump. I'm going a little out of order here, but before I changed the pump I tried putting the larger needle and seat kit in my 750 and readjusting the float levels thinking that was perhaps a bottle neck. This did nothing. Inspected my fancy fuel filter at the carb as well, it was pretty clean. I wanted to rebuild this pump, but the rebuild kit is discontinued as well so my hand was pretty much forced into buying the new pump. The carb is performing very well in all modes aside from my wot running out of fuel issue.
I bought the new pump in the first picture, and nothing changed. Edelbrock tech support told me there should always be fuel in the pressure line or a valve is bad in the pump. I had the pump warrantied and got a new one. Pulled the valve assemblies off of both new pumps. Pump #1 that was on the car definitely had a check valve on the fuel inlet side that was not sealing up properly. Pump #2 seemed to be good. Got #2 on and gained a little more time in wot, but still emptying the bowls...
So I dropped the gas tank out, and replaced the strainer. Everything looked pretty clean in there. The new strainer is a lot longer than the original, was hoping this would fix the issue but so far there seems to be absolutely no change. Comparing my disassembled old model 1725 to the original, the old one looks like it's a much nicer piece. I'm going to do what I can with the old one, maybe I'lll get lucky and find a rebuild kit for it... but I'm not really sure where to go from here. The lowest portion of the new style pump is the inlet, and my 3/8" fuel lines all the way there feed into a 1/4" passage to the inlet chamber. The bottom floor of the pump outlet chamber (upper hole) is a poorly supported gasket, with the only support coming from a cube of foam stuck by the cast in inlet passage. This is both hard for me to describe and I'm sure hard to comprehend. I may have a picture on my phone...
Have I reached the limitations of this carburetor with this engine combination? Are these fuel pumps just junk and I should try for a refund in full? Does anyone make a good inline fuel pressure gauge I can leave on there? Does anyone think I need to go to a higher pressure pump with a regulator? Should I got to an inline electric pump? Should I dig hard and try to find a rebuild for my old pump? Is it worthwhile to enlarge to aforementioned 1/4" inlet passage up, and epoxy or somehow fill the cavity below the unsupported gasket in the pump outlet chamber in the new pump? Edelbrock claims these 110gph pumps will support 600hp, I'd estimate I'm at least 150hp less than that brake...
I know this is long, and if you're reading this thanks for staying with me. I've been banging my head against the wall trying to figure this out and could really use some help.
Thanks,
Cale
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