Olds64

So, I drove my 71 this weekend and I only made it 500 yards out of my neighborhood when it died.

I had recently replaced the mechanical fuel pump and the fuel filter. I wanted a clear plastic Wix 33003 but the auto parts store only had the metal 33033. The guy at the parts store said the 33033 had a check valve in it that would prevent the carburetor fuel bowl from draining. Fortunately, when I removed the fuel filter the car started and ran normally.

When I installed the fuel filter I made sure the directional arrow pointed the right way. I installed it before the fuel pump, the same place I had the old filter installed. I was wondering if anyone had any experience with the metal Wix 33033? Does it have a check valve in it?

I blew both ways through the filter and it seemed there was a restriction blowing the proper direction through it. Perhaps that's just the restriction from the filter? If there's a check valve in the filter I thought maybe the mechanical fuel pump didn't make enough pressure to overcome the valve in the filter? Any thoughts...

rocketraider

Where is the filter located?

Most of us who use these install them on suction side of the fuel pump, to keep crud out of the fuel pump and reduce maintenance on the carb inlet filter.

Mechanical fuel pumps can usually pull thru a clean filter.

If you have it on pressure side of the pump, get a proper metal pump-to-carb fuel line and get rid of the inline filter and rubber hose. You're asking for leaks and fire.

Since you've established the car runs ok without the filter installed, the filter is the culprit. Either the filter was assembled wrong or your new pump is weak.

*edit* never mind, I see you had it on fuel pump suction. You confused me when you said pressure, which is discharge side of a pump.

Vintage Chief

I began (~6 mos. ago) using the exact same filter prior to the mechanical fuel pump on my 1971 CS 350 cid. I haven’t had any issues. I’d suspect the filter. Like most, I’ve purchased some devices which go belly up or were assembled poorly/backwards. Those things occasionally occur.

Olds64

Well, I @$$ume the filter was a POS from the factory. Thanks for confirming my suspicions.

At least it was only a $7 filter.

Greg Rogers

I have always heard that a filter should be after the pump, except for the "sock" which is in the tank. Maybe I am wrong about this, but I heard things like problems with sucking thru filters, etc... If you guys have filters before your fuel pump maybe I am all wet??.. But as far as I know, I can't think of any OEM vehicle with a filter before the pump, mechanical or newer electric fuel injection pumps....I dunno....

Olds64

Greg, I was wondering about that. Weren't the only filters on the car from the factory the sock in the fuel sending unit and the brass cintered filter at the carburetor?

olds 307 and 403

I have that exact filter on the suction side, 0 issues.

Cosmic Charlie

NapaGold 3003 (Wix 33003) Fuel Filter

I had a new solid metal Napa fuel filter 33033 after my fuel pump and it starved my 455 until I bought a new Napa 3003 Clear one and no longer is the motor running out of gas at extended full throttle.
When new I could blow thru both filters easily but that told me nothing ... go figure ... bad manufacturing ?

GCH

+1 have always had the filter between pump and carb , both metal and plastic filters.
Not any problems with leaking rubber hoses , usually check and/or replace them.
( i do not use these hose clamps following the Wix filter )

rocketraider

I've run inline filters at the fuel pump suction for at least 35 years, both plastic and metal bodied, without issues. Started doing it on recommendation of an Olds Zone Service manager as a way to reduce wear and tear on QuadraJet fuel inlets. It has worked well for me.

The fuel tank sock may be gunked up after 50 years contributing to Olds64's problem. But my money's on just getting a bum filter especially if the one it replaced was working ok.

Olds64

I was wondering if there might have been crud in the fuel tank that found its way into the filter. I restored the tank less than 10 years ago but I always leave no more than 10 gallons in the car since I don't drive it often. I thought maybe the inside of the tank has already failed and rusted...

Phoenix8990

I have been under the impression that the inline filter should go between the fuel pump and the carb, that's not the case? That's where I've always seen them, I think. I guess I should move it? That may be why I have recently had a bog down experience occasionally when I floor it? I also increased my carb from 600 cfm to 800.

Steve

allyolds68

90% of the time when I've seen that done people use rubber fuel line with it that isn't pressure rated. Those plastic filters are junk. I'd never use one on the pressure side of the fuel pump. Their use is best saved for lawnmowers. I use an in-line metal filter between the end of the steel line for the tank and the fuel pump

Olds64

I thought the metal 33033 would be a bit more authentic than a cheapie plastic filter. I suppose the clear plastic filters didn't become common until many years after my car was built. Not that I am doing a concours restoration on my Olds.

GCH

I had a Mahle plastic filter between pump and carb in my truck for 9 years now, not having any problem. Have never heard that somebody had a problem with a plastic fuelfilter who leaking.

bccan

Seems to me that I’ve seen some Olds, circa 71-72, iirc 455, possibly W30’s with a steel fuel filter plumbed above the fuel pump. They looked like a factory or accessory item, did not seem to be “cobbled” by owners and I’ve seen more than one. I poked around trying to find a pic but have been unsuccessful. To my recollection they appeared to be plumbed between pump and carb.

Am I imagining this or can someone shed light on it?

EDIT - re rocketraiders’s post below, iirc it was the GF98 style filter, steel lines(?), one with a shepherd’s crook 180* on top w/ short hose stubs to connect(?).

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rocketraider

Installed properly an inline filter on pressure side of the pump is no problem. Pontiac, Mopar and others used inline filters plumbed with short sections of rubber hose on pressure side of the pump for years without issues. Besides, we're talking 5-6 psi tops.

Difference is those filters were mounted securely in a clamp and are connected to the steel line by very short lengths of rubber fuel hose. Using all rubber hose without a securely mounted filter, that's asking for trouble.

I recall seeing those W30 inlines too. Seems they used a GF-61 or GF-98 AC fuel filter same as a Pontiac Tri-Power.

bccan

Finally found a pic of GF98 (or similar) style filter, don’t know how correct the installation is but it looks about right to my hazy recollection. I swear I wasn’t trying to throw this thread sideways, point is, GM put this filter on pressure side of pump.




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rocketraider

That looks like it has steel line with threaded flare fittings on inlet and outlet, and rubber on the recirc line.

What say ye, W30 experts? What was purpose of this filter configuration?

Koda

They may have not included the stock Qjet filter for flow and used that beast instead?

Olds64

I'm wondering what determined the filter type in the Quadrajet? I've seen brass cintered filters and paper filters inside of Quadrajets I've disassembled. Are the paper filters replacements?

rocketraider

It probably came down to cost. The sintered brass/stone filters seemed to be more common for early side inlet QJets that used the short filter.

bccan

Just bumping this thread in hope of an explanation on that AC GF432 / GM 5651480 (that I have erroneously referred to as G98 [sic]) filter setup that has some of us curious. SOMEBODY out there knows the background or application as I’ve seen a few of them over the years on Oldsmobiles but not a lot. Help me die at peace!

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