Mechanical Fuel Pump Install / Can't Line Up Bolts

[Spline64]

Hey all,

My last post trying to fix a missing issue has now caused me more pain. Having an issue with the installation of the mechanical fuel pump.
I can get the pump under the push rod ok but the bolt holes don't line up. I can back the pump out to line it up almost to where I can start the bolt but then the pump lever slips off the push rod.

The pumps are identical with one exception which is the spring design. I think this is my issue? The old pump had some give in the pump lever I could move with a finger but the new pump (airtex...yeah) takes both arms pressing together to compress the spring. Hell maybe that's normal for all I know.

Tried a half second crank of the engine to see if I was on the lobe but same results. It's just so damn close, thinking that little bit of give on the old pump allows it to line up. Or maybe that pump was shot?

[geezer#99]

Push the rod up and put a bolt in one of the holes just in front of the fuel pump. I can't remember which one!
The bolt will lock the rod in place. Install the pump, release the rod.

[chengny]

A new fuel pump (or a used one in good shape) has no free play in the arm. It should normally take some effort (and both hands) to overcome the spring pressure and fully stroke the pump.

Try re-positioning the cam again. The lobe for the fuel pump isn't like a lifter lobe- it's duration is like half of the total rotation. So it's 50/50 whether you are off it or not:




If you find that it is just excessive spring pressure causing the issue, use sightly longer bolts. If they allow the gasket to make up properly (i.e. they don't bottom out) - leave them in. If they do bottom out before the gasket makes up, pull one out at a time and re-install your originals.

[Spline64]

Thanks Geez, but unfortunately I don't have that configuration. I wish I did.....using a hack saw blade here (works pretty good actually).

Did some more research and I should be at TDC to make sure the push rod is in the the block as much as possible to allow more room for installation. Guess I blew my estimate that it would take a half second to move off the high point of the lobe?

Tomorrow will manually rotate engine until I can move the push rod to the deepest position in the block to give the most room available. Heck, might already be there but have to rule it out.

Thanks,
Spline64

[chengny]

The bolt hole referred to above is only helpful for keeping the pushrod from slipping down while attempting to inserting the actuating arm under the rod tip. It won't drive the rod any further in.

The way I read it: the OP has the pump arm inserted into cavity and properly positioned the under the rod. But, he can't get the arm to depress enough to the point where the bolts can be started. But I have been wrong before.

[Spline64]

Thanks chengny for the confirmation on the lobe possibility and pump spring strength.
Thinking (hopefully) that it's my issue. Will check tomorrow night after work and post back.

[Spline64]

[/QUOTE]
The way I read it: the OP has the pump arm inserted into cavity and properly positioned the under the rod. But, he can't get the arm to depress enough to the point where the bolts can be started. But I have been wrong before.

This IS the problem I am having.

and apparently have no idea how to use quotes....

[enaberif]

On the engine near the fuel pump will be two bolt holes. The upper bolt hole is a pass through hole and the lower is not.

Take a long 3/8x16 bolt and feed into this hole. While you are threading the bolt take the push rod for the fuel pump and push it into the cavity and when it hits bottom tight the bolt down just finger tight so the fuel pump rod doesn't slide down.

Then install your fuel pump as usual and remove the bolt to allow the push rod to move. Then re-install a short 3/8x16 bolt into the hole with some rtv on it to prevent any leakage.

[cadillac_al]

Originally Posted by Spline64

Did some more research and I should be at TDC to make sure the push rod is in the the block as much as possible to allow more room for installation. Guess I blew my estimate that it would take a half second to move off the high point of the lobe?

Tomorrow will manually rotate engine until I can move the push rod to the deepest position in the block to give the most room available. Heck, might already be there but have to rule it out.

Thanks,
Spline64

It's as simple as that. Turn the engine by hand to get the rod up inside the engine and the fuel pump will drop right in. I also use the longer bolt trick in the front of the block to hold the rod up. Just don't forget to remove it, and put the short bolt back in.

[Slammed84]

Ive always put a dab of wheel bearing grease on the pushrod before I shove it in the hole. It doesn't hold the pushrod forever but long enough to get the pump positioned and bolts started.

[enaberif]

Originally Posted by Slammed84

Ive always put a dab of wheel bearing grease on the pushrod before I shove it in the hole. It doesn't hold the pushrod forever but long enough to get the pump positioned and bolts started.

Yup had to do this myself today. Mechanical fuel pumps are an absolute beyotch to install. If I ever have to replace mine I'm going to electric fuel pump.

[Spline64]

Finally got back to this,
I made sure I had the pin up in the block the highest it would go. Then ended up getting a Carter fuel pump which has this neat feature of being able to depress the lever a little bit with very little force required. With that bit of assistance, I was able to line up the bolt holes. It's installed and working great.

I really don't see how the heck I could have installed the Airtex pump that I was trying to install. No way I could have compressed that pump with one hand against the block. Live and learn....

Thanks everyone!
Spline64

[Slammed84]

Good to hear it! I had to do one at night on the side of the road one time. I think thats the most profanity I've ever used within a one hour period.

[enaberif]

Originally Posted by Slammed84

Good to hear it! I had to do one at night on the side of the road one time. I think thats the most profanity I've ever used within a one hour period.

If my mechanical pump ever fails I will switching to a electrical fuel. That is some serious horsecrap that Chevy made us have to deal with.

[patrickth]

I am having this issue myself. My brother in law has suggested an easy fix. Going to try it today. Get a 3/8 inch all thread. Cut it long enough to screw into block, protruding enough to install fuel pump to get a nut on. Tighten it down and install second factory bolt. Tighten that down and remove all thread. Install original bolt and tighten.

I had a stroke, so my left arm doesn't work right anymore. Have to try new ways to do things that used to be somewhat easy.