Mechanical Fuel Pump For Nailheads - P/N Please

[XframeFX]

4 hours ago, gungeey said:

Welcome to nailhead country

The Fuel Pump is "IN" and with the proper 3/8" Inlet.

Sorry, once the 1/4" gap at the flange closed-up, I did gain clearance although just 3/8" to the bracket and block.

What an effort! Like I changed the Timing Chain but didn't. I was able to peek inside and as I suspected, my nailhead still has the nylon cam gear and appears all there. Ticking time bomb?

[EmTee]

6 hours ago, XframeFX said:

I was able to peek inside and as I suspected, my nailhead still has the nylon cam gear and appears all there.

Really - did Buick use those in '63?  I had the same concern for my '64 GP, but when I removed the fuel pump and peered into the timing cover I saw a steel cam gear.  I do not think mine has ever been replaced...

[RivNut]

Oh yeah. When I took the cover off the engine in my 64, I found my chain was really loose. Turns out all the nylon was all in the bottom of the pan.   I’ve been told you can tell if the nylon on the gears is gone by putting a bar on the crank and moving it back and forth while you watch the rotor in the distributor.  If the crank moves and the rotor doesn’t, you’re probably missing the nylon on the gear.  It’s also hard to get your timing set “by the numbers” if the nylon is missing.

[gungeey]

1 hour ago, RivNut said:

Oh yeah. When I took the cover off the engine in my 64, I found my chain was really loose. Turns out all the nylon was all in the bottom of the pan.   I’ve been told you can tell if the nylon on the gears is gone by putting a bar on the crank and moving it back and forth while you watch the rotor in the distributor.  If the crank moves and the rotor doesn’t, you’re probably missing the nylon on the gear.  It’s also hard to get your timing set “by the numbers” if the nylon is missing.

The test is correct.

 

But if you stick your open end wrench on the power steering pulley nut and apply a little thumb pressure on the belt the engine will turn.

 

Suddenly the hardest part is taking the dist cap off. 🕳️

[kegart]

6 hours ago, EmTee said:

Really - did Buick use those in '63?  I had the same concern for my '64 GP, but when I removed the fuel pump and peered into the timing cover I saw a steel cam gear.  I do not think mine has ever been replaced...

I had a 1970 Pontiac that had the nylon timing gear. When it failed it was like the key was turned off. Someone must have changed yours. 

 

Kevin 

[EmTee]

20 minutes ago, kegart said:

I had a 1970 Pontiac that had the nylon timing gear.

Yes, our family had a '70 Catalina and had the cam gear changed at 50 Kmi.  I don't know when GM started using the nylon clad sprockets; I thought it was '65 or later, but it sounds like Buick definitely had them in '63.  I know my '67 Riviera has one; it's on my to-do list...

[XframeFX]

6 hours ago, EmTee said:

Really - did Buick use those in '63?

My thinking exactly, 1963 being very early and wondering which GM division started embracing the nylon cam gear first. Buick for1963?

I have been troubleshooting my Nailhead on & off over the 2 years since it's maiden voyage Nov. 6, 2020 out of hibernation. So the timing chain was on my list to check and wasn't going to do it until I had a replacement fuel pump on-hand which proved daunting.

 

If the fuel pump rebuild kit stated compatibility with ethanol fuel, I would've used it. With no such claim and appearing inferior to components in the 70s era rebuild, The kit is now my spare. Being familiar with the internals, If I ever had to use the kit, I'd do it in-place! It was quite the effort to install that $OB pump!

 

4 hours ago, RivNut said:

When I took the cover off the engine in my 64, I found my chain was really loose.

I am not the expert on Timing Chains. But, I thought I heard that nylon timing chain sets purposely had a certain amount of slack for the nylon cam gear to survive. A steel/iron gear set would have the steel crankshaft gear wear faster than the iron cam gear since it turned twice as fast. Or, maybe not being of different materials. Anywho, the cam gear has a greater contact area (more teeth) to the chain than the little gear on the crank. So, nylon would wear similar to cast iron? However, the nylon coated aluminum gear (2 materials) is 60 years old and seen temperature extremes where, cast iron doesn't care.

I also heard years back before I got back into my project the Timing Chain slack of less than 8 degrees for an OE GM Nylon Timing Gear and <2 degrees for a steel Timing Gear is acceptable. This raises the question, distributor rotor or crankshaft degrees?

 

Inserting my pinky into the fuel pump opening, I could pull on a chain link and yes, slack. How much? How bad? Not sure

 

I plan to purchase a new timing chain set as part of my emergency spares. Timing Chain cover bolts have been soaked with Aero Kroil occasionally and bolts tapped with a hammer and flat punch. However, no plans to tear into the engine just for the timing chain. I have no seal leaks anywhere even with syn. oil.

 

3 hours ago, gungeey said:

if you stick your open end wrench on the power steering pulley nut and apply a little thumb pressure on the belt the engine will turn.

For rotating the engine, a 1" socket w/short extension and ratchet on the balancer worked fine to test the fuel pump before connecting hoses. I could hear the fuel pump "sqawk" and no binding inside.

 

I see Gungeey's image where the AC fuel pump has a 5/16" inlet hose on the angle 1/8" NPT fitting. This has been my issue all along, I wanted to stay with a 3/8" hose, only that replacement fuel pumps no longer have 1/8" NPT ports to pick-and-choose the appropriate fitting for the application.

 

5 hours ago, RivNut said:

Turns out all the nylon was all in the bottom of the pan.

So, rotating the engine over twice in increments and snapping numerous pictures through the Fuel Pump opening, I see the nylon all there. Nailhead has about 70K miles.

 

Thanks All!

[telriv]

Even though it's not showing signs of wear I would think about replacing it anyway.

IF you wait then you will also have to pull the pan to get the broken pieces out.

 

Tom T.

[RivNut]

26 minutes ago, telriv said:

Even though it's not showing signs of wear I would think about replacing it anyway.

IF you wait then you will also have to pull the pan to get the broken pieces out.

 

Tom T.

Tom is telling you that pulling the pan on a nailhead in a Riviera is no mean* feat.  Undo the motor mounts, jack up the engine.  Not something you want to do lying on your back.

 

*mean by definition means average.

[arnulfo de l.a.]

What bracket caused the problem? I had absolutely no clearance issues when i i stalled mine. Maybe different because mine is 65? photo taken from under car