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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Stewart G Griffin on January 18, 2009, 08:39:27 pm

Title: FUEL PUMPS 101:
Post by: Stewart G Griffin on January 18, 2009, 08:39:27 pm

i need to know everything and anything there is to know about mechanical fuel pumps.  Specifically the ones found on small block/big block/ inline 6 chevy and other GM's

In addition, if there are any links that provide abundant information and, if possible, cross sectional views of the pumps that would be great.

Thanks a million!

Title: Re: FUEL PUMPS 101:
Post by: joesgarage71 on January 18, 2009, 09:02:48 pm

 Heres alittle info
http://news.carjunky.com/how_stuff_works/mechanical-fuel-pumps-vs-electric-fuel-pump-cde613.shtml

http://www.aa1car.com/library/fuel_pump_mechanical.htm

Title: Re: FUEL PUMPS 101:
Post by: VileZambonie on January 18, 2009, 10:58:18 pm

All you need to know?

They bolt to the engine block.

The camshaft actuates the lever.

Some use a push rod.

The diaphragm creates a low pressure void which draws fuel from the tank.

It pressurizes the fuel and pushes it into the carburetor to fill the fuel bowl.

On some models it has a return system that allows excess pressure to bleed the fuel back to the tank.

Most OEM ones were grey.

Most aftermarket ones are chrome.

If the diaphragm bursts it will allow fuel into the crankcase.

Title: Re: FUEL PUMPS 101:
Post by: Stewart G Griffin on January 18, 2009, 11:22:25 pm

i mainly need to know about the internals----how do they work---exactly.   

Cross-sectional views, better yet videos would be helpful.

Title: Re: FUEL PUMPS 101:
Post by: ccz145a on January 19, 2009, 08:38:50 am

Got Google?

(http://www.geocities.com/jeep_resources/upload/fuel_pump_exploded.jpg)

Title: Re: FUEL PUMPS 101:
Post by: DnStClr on January 19, 2009, 11:34:48 am

Just curious-Whatcha gonna do with it Stewart?

Title: Re: FUEL PUMPS 101:
Post by: Stewart G Griffin on January 19, 2009, 07:59:44 pm

Well, at this point it's no longer an emergency;  i originally wanted to know exactly how they worked, but since my pump is putting out the right pressure, the game plan has changed (see other post).

When my problem is taken care of and over, i will probably take a used pump apart to see exactly how they work.

Title: Re: FUEL PUMPS 101:
Post by: ccz145a on January 20, 2009, 07:53:55 am

Mechanical fuel pumps are the simplest of pumps. A diaphram moves actuated by a lobe on the camshaft and fuel enters the chamber through a check valve. A spring keeps the arm of the pump riding the camshaft, so as the lobe goes around the fuel is expelled through another check valve.

There are 4 moving parts, the actuator arm, diaphram, and the 2 check valves.