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Lousy Mechanical Fuel Pumps Now Days

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Mar 9, 2009
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I had a new Pierce mechanical fuel pump fail from the moment I installed it and I have been reading other people have been battling mechanical fuel pump failures. I cut my year-old pump apart and found the check valves were hanging open and not even sealing so it's no wonder it failed. Even major brand names like Holley and Carter are failing which makes me suspect the internal check valves are being made in China.

Rather than risking another failure I went ahead and installed a 100 gph Carter electric fuel pump because the electric fuel pumps of today are so reliable. Carter makes two versions; a 72 gph and a 100 gph and the 100 gph requires a larger 5/16" return line because without the larger return line it'll produce 9-10 psi of pressure. There are several other quality brands to pick from and all will do a great job.

If your C3 is a daily driver and you experience fuel pump output problems you would be better off changing over to an electric fuel pump that doesn't use check valves. Yes, it would take some work and $$$ but in the end it'll be trouble free. The electric pumps only draw 2-3 amps and produce very little noise; just a slight "hum" at idle.
 
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Should've stuck with AC Delco


The lousy quality also affects AC Delco because all AC Delco parts are made abroad now days. I bought a new $85 AC Delco washer pump a few years ago that was made in Mexico and it only pumped two times. Upon taking it apart I discovered the plastic parts were so soft they wouldn't hold their shape when assembled and the rubber parts were too stiff to seal. I ended up leaving the pump on and teed a '78 thru '82 electric pump into the feed line so now it'll pump as long as I depress the washer button. And the electric pump only cost a measly $10.
 

kpic

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If your C3 is a daily driver and you experience fuel pump output problems you would be better off changing over to an electric fuel pump that doesn't use check valves. Yes, it would take some work and $$$ but in the end it'll be trouble free. The electric pumps only draw 2-3 amps and produce very little noise; just a slight "hum" at idle.

So you want drain back?
The Edelbrock 8873 etc are fuel filters with a check valve to prevent fuel draining back. A lot of people use a Moeller 033801-10 about $12 + S&H.
 

Antz81

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The lousy quality also affects AC Delco because all AC Delco parts are made abroad now days. I bought a new $85 AC Delco washer pump a few years ago that was made in Mexico and it only pumped two times. Upon taking it apart I discovered the plastic parts were so soft they wouldn't hold their shape when assembled and the rubber parts were too stiff to seal. I ended up leaving the pump on and teed a '78 thru '82 electric pump into the feed line so now it'll pump as long as I depress the washer button. And the electric pump only cost a measly $10.

The fuel pump i got a few months back was made in the usa.
 
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The fuel pump i got a few months back was made in the usa.


It might have been assembled in America but I'll bet the check valves came from China. Back in 2010 I burned up 3 sets of 3/4 clutch packs in my TH700R4 because the filters (three different American brands) had Chinese-made seals. The seals would shrink about .020" and fail to seal; causing the pump to suck in air.
 
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Seals or O-rings?


I'm referring to the orange 3-lip seal that is on the filter neck. Back in 2010 all of the filter seals were shrinking so much the filter would literally fall out of the pump when the pan was dropped. I solved the problem by removing that orange seal and installing three 7/8" X 11/16" X 3/32" Viton o-rings (450 degree temperature rating). Now days the problem is probably over but during 2010 it was a BIG problem.
 

kpic

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1997 boosted silver coupe
I'm referring to the orange 3-lip seal that is on the filter neck. Back in 2010 all of the filter seals were shrinking so much the filter would literally fall out of the pump when the pan was dropped. I solved the problem by removing that orange seal and installing three 7/8" X 11/16" X 3/32" Viton o-rings (450 degree temperature rating). Now days the problem is probably over but during 2010 it was a BIG problem.

Basically, I am clueless as to what size O-Ring would work as I prefer rowing or shifting.

In Viton I'm having a bit of trouble finding the size you listed.

ID Inside Diameter OD Outside Diameter CS Cross Section .070" .103" .139" .210" .275"
O-Ring Standard (AS568B)
The above are per AS56B for inch sizes. As an engineer you do know you listed the values of the O-ring in the wrong order.

You can find the size you mentioned here:
http://www.parker.com/literature/Praedifa/Catalogs/Catalog_O-Ring-Guide_ODE5712-EN.pdf
However, Parker doesn't offer a Viton O-ring...

However, care to discuss O-rings and lip seals? Or did you find it on the web?

I'll open with according to Parker, 0-Rings are rated at 1500 PSI which gives a lot of room as most passenger car applications are considerably less than 1500 PSI.
In short, if you read all 96 pages of the Parker manual; stacking O-Rings has no value added.

For O-Rings to work as intended the correct durometer must be selected and also the correct compression.

Just to help you along: Viton, o rings, o-ring, o-rings, kit, metric - Seal and Design

BTW, how are your under inflated tires wearing or was that another lie this time by tire manufacturers?







 

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