I was wondering if anyone could assist me with this fuel system question. I have a 77, it had the bladder inside the tank. The new tank that I ordered awhile back has nuts welded to the underside of the sending unit opening so I don't need the old bladder ring (had the nuts built into it). However, there was a charcoal canister and a manual pump, a total of 4 lines. In the states of Nevada and Arizona where I live and drive, I don't need the old emissions equipment. And I would rather not have all these emission items anyways.
My plan was to use a 69' vented cap in order to vent the tank in-lieu of the charcoal canister and hook up a holley electric blue fuel pump. From there I would use a mix of hard steel and hard rubber line up to a check-valve in the engine compartment and run that directly into the carb.
With the check-valve and the electric pump, I was hoping that I would not have to have a return line. Does this sound acceptable for a swap?
there is a post on this site that had some good input into this site, but can't tell you exactly where it is, maybe one of the other members could help you there. I do know that the venting was still a concern with just the cap, and I decided to stick with the four lines, but that is all I remember, good luck with your search.
All I'd say about deleting the return line is how happy is the fuel pump about being dead headed? Once the float bowls on the carb are full and the float valve shuts the fuel pump will be working against a closed valve, if the pump is designed with this in mind then you'll be fine, if not you could have problems with overheating of the fuel trapped in the pump? When your mechanical pump operates against a closed float valve the rocker arm sits away from the cam until more fuel is required then starts pumping again. To be safe i'd keep the return line with a relief valve set to 3-4 psi to maintain a reasonable pressure at the carb but allow a flow of cooling fuel back to the tank. I just discovered my 70 has an unvented cap on the tank and no charcoal canister(never had one) so far the tank hasn't collapsed but the other day when we stopped there was a strange glooping sound from behind us! Regards Graham
Well, I see all 4 lines. They are not under the body, but run along the from between were the body and chassis meet. Unfortunately most of the fuel system diagrams in my 77 corvette manual have been lost by the prior body shop like the vast majority of parts. I don't remember what line does what and how they connect at either end. Can some one help with this? Also how would I connect the lines to a holley electric pump? it only has one inlet and one outlet, there are 4 lines then.
Actually. I was way wrong. I traced those 4 lines back and did some inspection. Those 4 lines are actually the brake lines. The fuel lines I traced back from the tank location. Total of 3 (1) on the left to vent into the canister and (2) on the right side, one send and one return.
They look like they enter the body and attach to the frame with clips all the way down. I am assuming that the body must be removed to replace the lines. Can anyone confirm this? Is there an easier way?
Any ideas on blowing them out, maybe checking for pressure or leaks?
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