Hello, hope this is the right forum. I want to replace the electric fuel pump on my 455 engine with a mechanical pump but the only pumps I can find have a inlet, outlet, and what looks like a return line and my question is will it effect the performance of the pump if I block off the return line as there is no return on the fuel tank. Also is there a chrome pump available for the 455 that anyone knows of as most of the parts people i have talked to say no. Appreciate any help you can give. Rex

 

I went to the Rockauto website just now and looked up a fuel pump for a 1968 Delta 88 with a 455, the first year the 455 was available. They show availability of a pump with just a single inlet and the outlet for the carb. $13.







They also show this one. Costs nearly three times a much, and they say only one remaining.

 

Always noticed these things come with two gaskets. Any thoughts as to why?

 

One for you and one for your wife.

 

Of the photos of pumps at the Rockauto site that show gaskets at all, some show two gaskets and others one. In googling around, I've seen some comments where they say that some pumps need a spacer between the pump body and the engine block. So a gasket is needed for each side of the spacer. I've never seen a fuel pump with a spacer.

 

The "chrome" pump is likely the TSP pump. It's more of a generic fit than the ones shown above. You can change orientation of the head and, yes, you can block the return without affecting pump performance - at least on this TSP pump. I know because I've done it. I ran one for about 5 years with no problems.

 

Here you go sweettart I got you somethin' real nice.......don't say I don't do nuthin' for ya!

 

If you cap the return line, the fuel pressure will be excessive. The pumps are designed with a small internal leak to circulate fuel, if you eliminate the circulation, the pressure will be too high.

Either get a pump with no return fitting, or install a return fuel line. Obviously the correct pump is far easier.

 

I hear that, but I've capped a lot of fuel return lines on Oldsmobiles in the last 50 years and never had a flooding problem as a result.

 

I have never had a flooding issue, but hot restarts are definitely a problem. Put a fuel pressure gauge on, then pinch off the return line. The pressure goes up quite a bit.

 

Thank you all I’ve been very busy sorry for the delay in replying. I found a chrome pump at speedway that is probably the generic one someone mentioned and am going to try that. Hope it works and is reliable but time will tell. I appreciate all the replies to this what should be a simple question but what’s simple these days. Thanks again

 

If you end up blocking the return, at least do yourself a favor and plumb in a fuel pressure gauge. At least that way you'll know what you're pushing to the carb. In my case, the TSP chrome pump ran at about 7psi with the return blocked. I checked it with the return plumbed back to the tank and pressure stayed in the same range. Definitely didn't make any difference to the carb I was running at the time. I don't know how much variation is reasonable to expect from pump to pump. These days who knows?

 

The pump I wound up with doesn’t have a return line so no problem there and my engine has a fuel rail with gauge on a edelbrock carb so as long as I have around 6 psi I’ll be good 👍

 

UPDATE just installed a TSP mechanical chrome pump and upon starting the engine observed a very loud clacking noise from engine. Removed pump and temporarily installed an electric pump just to run it and noise went away. Called to get a replacement but started wondering if these pumps are known to have problems. It’s a generic pump and probably made in china. Should I trust using another one or just go with a more traditional pump. The noise this thing made was scary as all hell!!!!

 

I had one, never installed and actually don't know what did with it. The one review I found, showed it worked fine. Honestly nearly all fuel pumps are made in China. The Carter fuel pumps, some put out too much pressure. You may have got a bad one. Maybe the arm is bent wrong and hitting the timing chain?

 

Sorry to hear that. Never had any problems with the one I ran. Used it for about 5 years. Never noticed any abnormal sounds. Do you know what pressure you have at the carb? If you're flooding the engine with fuel you may hear some unwanted noise.

 

Hi, this one sounded like a lifter clacking but much louder. Have a replacement coming. has anyone heard of a spacer for these olds pumps? this car did not have a mechanical pump when i bought it so don't know what was there originally. I did a new timing chain and sprockets along with the pump so freaked out when i heard the noise. I checked the clearance between the pump arm and chain, and it was fine not even close. Well have a replacement coming and will see.

 

I recall reading somewhere that the Holley pumps sometimes hit a double roller chain. The fix is to use a rat tail file and slightly elongate
the mounting holes to move the pump forward just a little bit.

Look over the pump lever arm, can you see marks where it hit anything?

 

Yep, I had read about that as well.

Also, the Holley pumps were prone to cracking through the pump arm pivot pin hole. The one I had eventually cracked. I wonder if the TSP chrome pump is prone to the same cracking issue?

 

The one I ran for about 5 years did not crack. It was on a 400G which had ~9.5:1 compression and a double roller chain. No bad noises. This was the 'chrome' TSP pump.

 

When you replaced the timing chain did you put that little offset pulley like thing (concentric) back on? That's what the arm of the fuel pump rests on and works the lever up and down. Or the pump may have been installed wrong but I wouldn't thing the car would run....(pic borrowed from a post a few years back by you, Kenneth, hope you don't mind)

 

Not at all, since it's not actually mine - I found it during an internet search for a picture showing the timing cover removed.

 

UPDATE TO UPDATE, Just installed the second TPS chrome mechanical fuel pump and thought I was good to go. Started the engine and did my checks had 6psi then it went to over 7psi then it seemed to level out at 6.5psi and no noise. took the car out for a ride about 5 miles and on the return leg engine started bogging down and would barely do 40mph. and had a dead pedal like running out of fuel. eventually cleared up and made it home and open the hood and had less than 1psi !!!!! i have given up on TSP pumps and i guess i have to just put an electric pump in every 200 miles or so and get a good towing company on speed dial. It would seem having a classic car these days with everything made in china is just a losing proposition. Surely i can't be the only person having so much trouble with these after market parts but your mileage may vary. i'm done and thanks for all the help. Rex

 

The Carter M6108 is a 2-line mechanical pump, which may fit your application. If you buy from a local auto parts store you can bring it back if it doesn't work as expected.

 

I too have restricted the fuel return on my mechanical pump. Without the restriction, pump would NOT maintain 5-6 psi at higher rpm. Usually runs 6-7psi and has been that way for years.