I purchased a Chevy261 which had been removed from vehicle before purchase. It was locked up at the time. I have since torn it down, cleaned it up and installed new rings. Getting ready to try to fire it up and noticed that the right hand bolt on the fuel pump (double action type) has a special bolt that includes a tube that runs all the way through to the crankcase. I can't seem to figure out if this is for some type of oil line return or something else. Anyone ever see this before. My 261 is set up for running without an oil filter - I've checked that the dow pin is in correct position to bypass filter and still lubricate the engine.
Any idea what this special bolt/tube is on my fuel pump?
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
found a couple other threads that suggest it may have been connected in some way to the vacuum pump on the fuel filter - but no one seems to know why. I think I'll leave it and just put a plug over the top of it to keep it clean and open in case I ever figure out the purpose for it.
I have a pic of it but having trouble figuring out how to post pics. I'll see if I can figure it out and post pic later.
Last edited by Clark6400; 02/25/20183:40 AM. Reason: add photo
That location is not where the a vacuum pump fitting would attach on a dual action fuel pump (that I have seen). I have several dual-action fuel pumps (but they are for the 47-55st truck - maybe your pump was for/from some other type of vehicle)?
This is just a guess. Could it be a weep hole for the fuel side? It appears to be between the fuel diaphragm and the vacuum diaphragm. Or a vent between the two diaphragms to prevent pressure build up?
Just a guess. Don
1967 GMC 9500 Fire Ladder Truck "The Flag Pole" In the Stovebolt Gallery 1946 2-Ton grain truck 1946 3/4-ton pickup, 1953 1-ton pickup 1957 1-ton flatbed dually, 1954 Pontiac Straight Eight Of all the things I've lost in my life, I miss my mind the most!
whats the numbers on the metal tag that is attached to the fuel pump ?
Tim
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Is there a possibility that the engine is from a former military application? I had a M-151 Jeep once that had what appeared to be a vacuum boosted fuel pump which was actually a small air pump. Its purpose was to keep a slight amount of positive pressure in the crankcase when a snorkel and a high exhaust pipe was attached for deep water fording- - - -keeping water out of the engine while it was totally submerged. Pressure lines also went from that pump to the distributor and the alternator. As long as the driver could keep his head above water, moderate-depth flooded roads could be negotiated. Jerry
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