# Mechanical Fuel Pumps For Dummies



## Shooter (Nov 7, 2015)

All right guys. It's another garage shop day with 4 know-it-alls (and a couple of beers). 1 Pontiac and 3 GM/Chevy wizards. Talking about fuel pumps. What's the difference between sliding the arm of a mechanical fuel pump into a Pontiac 400 and a Chevy small/large block? What are they aiming for in the Chevys that we don't have in the Pontiacs? They're making a big deal about all this. These guys are using long tweezers to hold up the arm as they insert it into something?!?!?! Also having an inane discussion about using P-tex on the gasket. Yes or no?

Shooter


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## PontiacJim (Dec 29, 2012)

Shooter said:


> All right guys. It's another garage shop day with 4 know-it-alls (and a couple of beers). 1 Pontiac and 3 GM/Chevy wizards. Talking about fuel pumps. What's the difference between sliding the arm of a mechanical fuel pump into a Pontiac 400 and a Chevy small/large block? What are they aiming for in the Chevys that we don't have in the Pontiacs? They're making a big deal about all this. These guys are using long tweezers to hold up the arm as they insert it into something?!?!?! Also having an inane discussion about using P-tex on the gasket. Yes or no?
> 
> Shooter


Some engines use a steel pushrod instead of the fuel pump arm like the Pontiac. I believe Chevy uses this type and Mopar. Light Grease/Vaseline can be used to hold it in place - something that will melt and mix in with your oil once it warms up.


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## Baaad65 (Aug 29, 2019)

PontiacJim said:


> Some engines use a steel pushrod instead of the fuel pump arm like the Pontiac. I believe Chevy uses this type and Mopar. Light Grease/Vaseline can be used to hold it in place - something that will melt and mix in with your oil once it warms up.


What he said, beat me to it...I was guessing that was common knowledge idk?


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## PontiacJim (Dec 29, 2012)

Baaad65 said:


> What he said, beat me to it...I was guessing that was common knowledge idk?


Common knowledge for old F'r's like us. Not common to the young.


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## Sick467 (Oct 29, 2019)

Tell your Cheby friends to get a real car! lol. That may have been the beers talking on my behalf, it is Friday after all. At any rate, I have 2 Cheby's myself (72 and 85 trucks), so I'm not one to throw too much mud. And Yes, they have a point with respect to the common SBC...they do use a rather thick push rod above the pump and below the eccentric. Here's a tip you can give'm...

The shiny bolt in the photo can be used to snug against the pushrod to hold it in place as the pump is installed...no tweezers or goo needed. Then after it's installed, a shorter bolt can be put in with some silicone to seal up the threaded hole.

Photo borrowed from the web...


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## Baaad65 (Aug 29, 2019)

Yup I remember working on a few of my friends cars and that push rod would have to be greased up or it would piss you off sliding out 😉 Cheers


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## geeteeohguy (Feb 2, 2008)

What Sick said. Grease also works. Old guys like us have done many of them.


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## 67ventwindow (Mar 3, 2020)

I was on leave in August 89 at my parents house in FLA. Grease didn't hold so well on a very hot day. It gave me 2.47 seconds to complete the task. I believe it was me sweating profusely that caused the lack of adhesion. 

I tacked the gasket on there with RTV. After a couple misses I didnt want to find the gasket on the ground a second time.


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