Technical 350 chev mechanical pump issues

Hey legends,

i am having issues with my mechanical pump leaking on my 350 chev.
I have gone through 2 in in the space of 2 months, first one leaked bad (took all the paint off my inner gaurd), Thought it may have been faulty so replaced it with another brand and it has started leaking aswell but with oil coming through aswell.
What could cause this to happen twice? Could it be an installation issue? Or just shit luck?

Its in my 1963 chevrolet impala motor has abit of work done, bigger cam etc.

Thanks legends!

 

Two things come to mind .
First and saddest is junk production.
Second hopefully is insufficient hardware.
If housings vary, and are not uniform thicknaess, oil leaks will occur.
Internal ( fuel ) leak is bad material and should be returned to Mfg, for compensation.
Something I have found to be true, for me, is that if I don't keep the receipt, the piece will be no good.

 

Do you have the spacer plate under the pump?

 

The mechanical pump is mounted on the side but no there is nonspacer between the block and pump. Whys that ?

 

Is it chrome?

 

No

 

This is the spacer 34Phil referred to.

 

Oil or gas leaking ?, If gas, bad diaphragm, they site on shelf for so long & rubber junk , dry rot now adays , buy Name brand $50 plus , & ethanol resistant
( for insurance)

This is what otheres are calling spacer ,
Not a spacer, its a part , plate to install & seal fuel pump rod & lube pump ,oil from lifter / cam back to oil pan block on sbc

 

I've heard that story about leaking new pumps from guys around here too.

 

The 55 to 57 T-Bird crowd says to rebuilt original factory pumps. The new ones available all last about a week if you are lucky. All offshore junk. I don't know if the originals for your car were bolted or crimped together, so this may not apply to your pump.

 

They are correct. And rebuilders will not touch an off shore pump to rebuild because as much as the look alike parts don’t interchange.

 

I wonder if a more expensive pump such as a Holley would be any better than a parts store special? I’m interested in this as I will be buying a new pump before long.

 

That's a block off plate not a spacer .

 

Block off plates “do not” have the oval hole for pump arm to pass thru.

 

maybe Gm calls it ablock off ,
But most consider pic below
Block off plates .

 

Yeah, crystal ball time...again !

You don't mention WHERE...the pump is leaking from !! OR, what it's leaking...gas OR oil !?
Four different places come to mind, right off !

Mike

 

I've not had problems with fuel pumps but most of the box stores ( AutoZone , O'Reilly's , advance ) offer 1 year warranties on most fuel pumps .

 

Is it leaking from the pump? If so, where on the pump body? Or is it leaking between the pump and the block?

 

Those are aftermarket , not stock Chevy issue , they're differently designed block off plates . The stock Chevy plate blocks off the casting on a stock SBC .

 

Share a pic , I know the pic I posted after market ,
Around 86 ish , some of block , where equipped start of Efi, I do not know if I have seen a Gm plate ,maybe boat motor , I would think a Gm would look like the plate on left steel maybe cast & more likely with Gm #

 

If you are leaking oil & fuel from 2 SBC pumps & you do not have the mounting plate I'd wager that's your issue.
The pump arm is further in than it should be, probably being depressed to far and causing your problems.
Yes modern pumps & ethanol gas don't last like they used to, but you should get a few years out of a new one at least.
They do make a "block off" plate that looks the same but has no hole for the fuel pump arm. Those are used for electric pumps. What you need is a mounting plate. Every SBC w mech pump I've ever replaced required that. Also the new pump should come w a gasket as well.
I only mention it because the last one I bought did not.

 

Like others said, use the mounting plate. The block off plates are normally used when converting to an electric pump. Use the plate and one of the pumps you took off-bet you're fixed. (gasket it)

 

Early 90's I went through 5 or 6 fuel pumps on a SBC, from 2 different retailers.
All in less than a year. Cheapie aftermarket garbage. The marks on the box were the same,
from both retailers, so I assume they were buying from the same crappy source.

One lasted 3 days. Parts guy tried to give me a hard time,
until I showed him that the arm snapped, so there was no spring return.
Parts guy couldn't believe it.
The others just stopped pumping, with no warning.

After a while, I could change them pretty fast. Imagine cold fuel on your hands,
in the middle of winter, with the wind blowing. Good times.

Was ready to spring for a big name pump, then they stopped failing.

 

OK , the plate with the hole for the pump is called a FUEL PUMP MOUNTING PLATE . The blank plates are both fuel pump block off or " fuel pump Delete" plates . There , we good now ?

 

Ok thanks mate ill check that it was fitted with a mounting plate, it seems to be leaking from the weep hole or where the pump is crimped together which i assume the leak is from a stuffed diaphragm. I had one on their for 12 months no problem

 

Looks like its leaking from either where its crimped together or out the weap hole

 

Tried 2 different brands but one was carter. Its leaking oil and gas this time, forst was was just gas. Im going to check if it has that spacer

 

Hard to tell where its leaking from but this time its oil and gas, last time was just gas but it seems to be sitting around where its crimped together as its a sealed unit either that or the weep hole

 

You are getting junk pumps, most likely. I know stuff costs more down there, but I'd try a quality, preferably rebuild able one if you can find one. BUT, only if they also stock a rebuild kit and have good reviews.
This does not have a link to the rebuild kit, is more than the chrome version (!?!) and has some bad reviews.
https://www.jegs.com/i/JEGS/555/15952/10002/-1

 

What you are calling spacer is fuel pump plat,,, If plate not installed/missing it will pump a lot of oil out , no little leak ,,
There are 2 gaskets required one between blocked and plate the other between plate and fuel pump ,
one square with point on top and one diamond shaped .