348 Fuel pump R&R and some supply chain woes

First, I'm not throwing anyone under the bus.

Second, your results may vary.

I figure, that at 30 years of age, just rebuilding the fuel pumps and ordering the ethanol safe fuel rubbers and switching to the 53mm pumps (ala, @Ferrarium thread). I order all the parts, they arrive, I take everything apart, the plastic fitting crack, the pump rubbers look actually pretty good, but are starting to deteriorate.

Historic note: my car sat from 2001-2008 basically, and during its prep for sale, the fuel tank was gone through. I suspect pumps and rubbers were done then, just given the current state of deterioration.

See! Not so bad.

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Given that the plastic fitting were likely going to deteriorate, clamping new tank safe hose on seemed like the best bet. New 53mm pumps went in, new 53mm rubber went in, new hoses went on, new clamps went on. Everything is great, right?

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Here's where I made a mistake. I used a remnant of the black plastic shoved into the new fuel hose, and figured i'd be clever and just shove the tube into the hole in the bottom of the swirl cup. WRONG! The fuel actually needs to shoot across the gap, and that hole is the ONLY way into the cup when the fuel is low and below the height of the cup. After everything was back together and fueled and not leaking, I had to drain it once more to put the drain plug o-rings on, so I figured "It's just a few bolts, i'll pop it out, make the change and shove it back in. What could possibly go wrong if everything is made from ethanol/fuel safe rubber? (a week had passed by this point).

Then...

What the hell? Why is the pump look like it's squishing out? Why is the pump rubber squishing out of the cup?

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WTF is this??

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I go and grab one of the old 60mm ones from the trash....(it's on the right)

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Houston, we have a problem...

Contact all sorts of people trying to sort this out. Somewhere in the supply chain, whoever molds these used the 100% wrong material for them to swell like that in a week. Instead of viton or nitrile they're likely just a natural rubber.

Here's some options:

1. Wait for a new set to be molded. It's a 120 day lead. Hope those are better. What happens if they're not?
2. Get a set of 53mm rubbers from another parts source. The catch here is that they likely ALL come from the same source, and there's no guarantee the new ones will be better. They'd have to live in a jar of gas for a week before I put them in place.
3. Design my own new system, using safe, tested materials.

Now, it's just pure chance that I had to go back into my fuel system and found what I did. There are other cars out there with rubber from this batch. I don't know the batch, I just know that they were part of an order from last November. So if you've done 53mm pumps since November, you might have bad rubber.

(The not throwing anyone under the bus part)

I order my parts (and will continue to) and have been talking with Daniel at Ricambi. He's been great to deal with, and I'm sure he wants the best for all his clients. This isn't any parts supplier's fault. His "bad" batch arrived in early November. There's no guarantee that the supply chain hasn't been making them wrong since before then. No one has likely had any complaints because (looking at this logically), who goes back into the fuel tank a SECOND time in a week's span? If the rubber continues to degrade, there could be more serious issues down the road.

There's no guarantee that other suppliers (rutlands, dealers, superformance, etc) who are likely getting the same parts, aren't going to be faced with the same issue.

I have some ideas on a design, I have some prototype parts coming my way, I'm building a model that I'll check for fit and if I'm happy with it, I'm likely building a set for myself as a test. I'll keep this thread update with progress.

I'll also be dropping a chunk of the bad 53mm ones into a jar of gas to see how bad they degrade.

sjd

 

I have 2x 53mm pump gaskets, 2x base and sets of caps for my early dual fuel pump F355. I still haven’t installed them. I’ll submerge them in fresh Shell gasoline for a week starting tomorrow and report back.
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No need to do the caps. they're great.

The rubber under the pump cup is slightly suspect, but looked fine when I pulled it all back apart a third time a couple days ago to get measurements on some things.

When was your order?

EDIT...and just do one of the rubbers!!! so you can put them side by side and compare!

Part number 153188, BTW

sjd

 

Part number is also 153188. Ordered July/28/2020.

I will do just that. Put 1x of each in the fuel and compare a week later with the new ones. Thanks

 

Did mine this fall as a result of chasing a fuel leak.

They pumps did have to come out a second time, as the leak ended up being from a crack in the tank; not where I thought it was from.

I can’t recall which size mine are; I’ll check tomorrow. But they were fine when they came out the second time and had been in fuel for about a month.

I’ll also check were I got the rubbers from; I tend to mix and match between dipiers depending on price.

 

I hope it's just an isolated thing....or maybe my sunoco 90 octane ethanol free is really sneaking gnarly stuff in there. I can't remember if the 3 gallons I'm messing with came from the shell up the street or from them.

sjd

 

Sorry just double checke a few things....

1) you would appear to have the wrong part number. The part number you quote is for a 456 fuel pump rubber; is this intentional as part of the conversion? 53mm rubber for a 348 is part number 144232. Is this intentional?
2) you have incorrect fuel lines fitted.
3) I cant see the vent pipe fitted, perhaps it is hidden by the camear angle and the pump itself?
4) where the rubber is coming out of the plastic and there is a cut out, isnt this where the vent pip is suppose to go?

 

1. 144232 is unavailable at several suppliers. (I just clarified with Daniel, it's a discontinued number, 153188 is used now)

Here's the notation for 153188.

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2. I've replaced/modified with intank hose because the nylon style line are NLA. They'll work fine. It won't be original, but who's looking. There was no swelling or oxidation on the hoses.
3. The vent pipe is there, and as a note, it needs to go ALL THE WAY into the chamber, there was some speculation it was just a dowel, and the 153188 is a closed hole where the vent goes.
4. i had already removed the pipe by the time the picture was taken.

that final picture was taken after the parts had swollen, they went in normally, and there was no cause for concern, I even measured the 53mm because on my first order I was sent 36mm ones by mistake.

 

And for the record, the car started and ran great, any "issues" were ones in my head. Rather than they become issues (probably a manifest of "running out of fuel" but not being empty, then starting and driving fine a few minutes later...), I took action. Failure modes and engineering analysis.

sjd

 

I would have made a barb fitting on the back side of the return inlet on the hose so it stays there.
As far as the return line and plastic nipple, why not sleeve together 3 inches of the old plastic return line and nipple to the new flexible hose and snap in the old plastic barb? I could machine a thin barbed sleeve with 2 different OD's and a constant ID and a smooth fillet on the inlet edge.

 

Without the o-rings, there's pretty good grab, the "tug test" says it's not going anywhere, and there's no pressure (at least not fuel rail levels).

I did use the old plastic line, and I have the squirter ends, PTFE line would work well too.

sjd

 

My pumps are the other size, and the rubber parts came from superformance, so I can’t give you a direct comparison unfortunately.

Get what you have done on the fuel lines. They are showing as available in the uk; just shows how much is around and about on different stores systems; but so difficult to trace down unless you know exactly which site to go to.

Be interested to see what you find out.

 

Got my fuel from the same station i normally use for my F355(Shell). The parts are submerged just before noon. I’ll check back in a week.
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I just did this last month. Single pump 355 parts were Ricambi America

I saw nothing specifically saying it was ethonal proof in the description.

 

Given the 20-25% increase in size, mine were molded with the wrong material. For them to swell to larger than a 60mm pump rubber clearly is an error in manufacturing.

IIRC, the replacements were billed as ethanol safe...but that wording seems to have gone away in favor of "reproduction"

sjd

 

Following with interest. I have purchased the full kit from Ricambi last year but had not yet got around to fitting it.

 

I pulled them out today just to see a daily progression of these parts. These have been submerged now for about 26 hours. Here is what I’ve found...
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Cracks have developed on the pump gasket in many areas...
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WOWWWWWWW!!!!!! HOLY MOLEY.

sjd

 

Is there an ethanol content in your fuel down under? I don't necessarily think it's ethanol doing this now. it'd be a great data point to have.

steve.

 

So not a single part is fuel safe?
I am dreading taking it all back out.

 

Ofcourse. I can get that. I took the fuel sample from the bottom of the bucket. Looks like I have about 8% ethanol.
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How long has yours been in place?

sjd

 

Ok. You are in the bay area like your header says. MAD828 is in Australia.

I think my fuel was remnant from an ethanol free fill up, but I can't remember.

Worldwide data!

sjd

 

I've got a sample of nitrile rubber in a vial of fuel, and while I'm seeing some swelling after 4 days, I'm not seeing the degradation.

sjd