455 replacing fuel pump

This may seem like a newbie question to some of you, but are there any "tricks" involved in replacing the mechanical fuel pump on a Buick 455? I want to run a pump with a return line, as I'm having vapor lock issues. I've watched a few videos on how to replace a mechanical pump on a SBC, but I haven't found one that deals with a Buick 455. I know the "trick" for installing a pump on a SBC is to make sure the pushrod is held up as you install the fuel pump. Is there anything like that to look out for with the Buick? Thanks in advance for the help!

 

There's no pushrod like the Chevy has. The pump's arm is activated directly by an eccentric on the front of the cam. The only trick that makes it easier is when reinstalling the pump, manually rotate the crankshaft until the eccentric lobe is on the low side. This will allow the pump mounting face to line up with the timing cover with minimal fuss. If you have to push the body of the pump down hard to get it to run parallel with the timing cover face you are on the high side. Remember the mounting bolts are only going into aluminum so watch out for over tightening.

 

Thanks, guys. One more question: I installed the fuel pump, and of course didn't look at the provided instructions until after I installed it. I noticed that the instructions said to put grease inside the pump area. I didn't do that. I was planning to eventually put grease in there, but I was thinking: doesn't the engine oil splash in there to lubricate it anyways? I'm not sure I would want to put grease in there and risk thick grease getting into the engine oil. Thoughts?

I also discovered that the guy who swapped my 350 for the 455, and built the 455 just reused the fuel pump from the 350. I had added A/C to the car and swapped in a 455, but still had a fuel pump that did not have a vapor return and was having vapor lock issues. I couldn't figure out where he got a fuel pump for the 455 that didn't have a vapor return fitting until today when I realized that he reused the pump from the 350. I'm surprised it worked since the shaft that goes into the engine is shaped quite differently. I installed a Stage 1 pump and ran a vapor return line and spliced it into one of the vent lines in the tank (so I didn't need to get a new fuel sender), so hopefully my vapor lock issue is taken care of.

 

No way for the 350 fuel pump will work into the 455.He most likely used a stock big block fuel pump,it looks like the small block,but the arm is for the BB.Bruno.

 

I'd have to agree with Bruno but if it was working it was working by just the slightest amount. You mention vapor lock. I'm wondering if you weren't having fuel delivery problems in that the 350 pump arm was barely touching the eccentric and therefore barely pumping any gas. Pictures of the old pump would help to identify it.

I never heard about filling the cavity with grease.

 

The thing that made me question the pump in the first place was the fact that the arm was bent, just like this one for the 350: http://www.autozone.com/external-en...inders-j-5-7l-4bl-ohv/348787_912957_2391_6774

The fuel inlet looked just like the pump for the 350 as well. The pump I removed looks exactly like the pump for the 350, bent arm and all.

Now, here is a fuel pump for a non-stage 1 Buick 455: http://www.autozone.com/external-en...972/8-cylinders-u-7-5l-4bl-ohv/348689_0_2391/

Notice the straight arm and the fuel inlet that protrudes downward from the diaphragm a bit. As far as I know, there is also not a fuel pump made for the 455 that does not have a vapor return line. The only fuel pump available for those years without a vapor line is for a non-A/C 350, just like my car was.

 

What should the torque be according to the service manual? (going to replace my pump on 1968 430 to a stage 1 from TAp.)
Edit: According to; http://www.teambuick.com/forums/view.php?pg=400-430-455_engine_specs

Dmruschell asked about grease, is it something I should do? Some special grease or universal?

Thanks

 

I'm thinking that the possibly inadequate fuel delivery might have contributed to the issue. (I had the same problem once or twice with the 350, but only after we added A/C to the car, but it wasn't as bad.) My upholstery guy also has a 1972 GS455 (though his is a genuine GS, but it was born with a 350) with A/C, and also has a built engine. He said he's never had an issue with vapor lock, so hopefully converting to the factory-style setup for that year and engine will resolve the issue.

I don't feel so worried about the grease now. But, am I right that the engine oil will splash up into that cavity anyways? I couldn't really see into the engine while installing it, but I thought that there's always a risk of a failed fuel pump pumping gas into the oil because at cavity goes directly into the engine where the oil is/flows.

 

There is no mention of grease in the short manual for my pump.
Just a lot of examples on how to install it right or wrong.

I'm more worried about the somewhat loose wear plate on the arm.
Or that the pump has dried after been new in box at least 6 years.

 

All you need is a small amount of grease on the arm where it contacts the eccentric for lubrication before the oil has a chance to get to it. You really don't want to run it dry on initial installation. But, of course if it has already been installed & started, if it has not caused any damage, it should be OK.

 

I have a question: My new Airtex Stage 1 pump didn't have the wear plate. Is that going to be a problem? I have an AC pump on my other motor 2 years ago and I don't think it has a wear plate either.

 

As far as the wear plate goes I have a bunch of old factory AC fuel pumps and every one of the wear plates are loose so I'd say they are mean to be that way. Maybe floating that way for a reason. I have an old Stage 1 pump and it has no wear plate. Most of the aftermarket regular pumps don't have wear plates. I don't think it really makes a difference.

I got 13 ft. lbs. spec for the fuel pump to block from some old Kenne-Bell info but a '76 GM Service Manual shows 20. The list referred to above shows 20 ft. lbs. For the fuel pump I usually just did it by feel and was done with it.

If the fuel pump diaphragm does spring a leak it can leak fuel into the crankcase. I doubt the pump sitting in the box would make much difference. Imagine how much junk they are exposed to once the engine is running compared to sitting in a box.

Oil can get to the fuel pump just from running to lube the arm pivot. There must be some light duty seal inside the pump to keep oil from leaking out the fuel pump because many high mile engines I've seen have oil slowly dribbling out of the breather hole on one side.

 

I pulled nearly 22 ft. lbs. It did not feel right.
The thread closest to the block made it. The closest to the fan broke. But I was able to drill and put a screw through with a nut on the back.
And! I bought Bishko Chassis Service manual from Ebay so I can do better work.

 

Borrowed these from Jim Weise's post. Larrys engine?



Had to sneak in the garage and remove the timing chain cover, but it was worth it.


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Trying to change my mechanical fuel pump and cannot get anything on the block side bolt. I tried two different sockets one being 1/4 drive to get on it. Tried with a swivel as well. Is there a special thin wall socket or?

 

Try using a 3/8 12 point short craftsman socket they have fairly skinny sidewalls. Also bring the timing mark around to zero on the timing mark it will make your life a lot easier reinstalling the pump.

 

Thanks, I did have it at TDC. Pulled the PW pump and found out inside bolt was a 9/16 head bolt. Guessing it may have been stripped at some point?
I got it done anyway. Thanks for the help!