Too much filtering?

I finally took the time to install a complete used Racor fuel filter/water separator. I got it from a junkyard IDI turbo truck a couple years ago where it was mounted in place of the original WS. It's a whopping 2 microns, think that'll be ok pre-pump? It has a pretty large R26S filter so it shouldn't clog too fast. Presumably it didn't cause problems on the truck it came from.

My RV's stock WS is missing, so I removed the cage and put the Racor there.

I was debating even running the old used filter but since the stock engine filter is after it, it should be ok. Money is a little bit tight, with needing to do an oil change in the next week. Plus changing the cheap 80w90 diff oil I put in 1200 miles ago to help clean out the nasty old oil it had. Putting in Valvoline 75w140 now

Havent run one before the lift pump, but have run a 2 micron in the stock location for a lot of years. You WILL have problems with wax plugging it if temps get below zero.

Black dawg said:

Havent run one before the lift pump, but have run a 2 micron in the stock location for a lot of years. You WILL have problems with wax plugging it if temps get below zero.

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Thankfully I'm never anywhere that cold. Typically mid to upper teens is the worst I see, and only one or two days a year.

When I have the extra money in a month or two, I have my eye on this 14 micron one, which I think is compatible:
https://www.napaonline.com/en/p/FIL3211

Hmm, something is odd about it. Maybe an o-ring on it is bad causing a seeping leak, or maybe it's due to how low it's mounted? When I start it up, the engine acts like it's pushing out just a bit of air, but it's never enough that it feels like it's going to stall. It just feels a little shaky. After a few seconds, it smooths out and it's fine. I drove almost 40 miles on the highway today (max about 63mph) and it was fine then too, no stuttering or lack of power. I don't see any obvious dripping leaks when I bend down and look under. Maybe the manual pump up on top isn't quite tightened all the way or something. I guess I'll crawl under in a couple days with a flashlight and give it a good looking over, after the rain/storms pass by.

Well, I see no leaks at all. Everything is bone dry where I recently touched the fuel lines. Maybe it's a fuel supply issue, where it's draining back to the tank a little in the line because of the low W/S bowl. Maybe a check valve between the tank and the W/S would help. I guess I'll get one later and see. I also double checked that I didn't somehow put it backwards on the return lines, and I didn't.

Change the hoses to after pump & see if it runs better. Probably having a hard time pulling thru the 2 micron filter.

riphip said:

Change the hoses to after pump & see if it runs better. Probably having a hard time pulling thru the 2 micron filter.

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If that's the case, why is it fine after the first few seconds? The pump pulls from the factory filter first, which makes me think it's somehow draining back a little. Or maybe it just takes a bit to get the fuel flowing through the filter fully. 2 micron is excessive, I'll get the mid range one (~16 micron) when I replace it.

I can't change just hoses. It's mounted under the driver's seat. That's where the W/S got put on vans, so I put it in the same spot as the missing original. I would have to run hoses across to the pump, and then back.

In addition, this is what it says in the installation instructions:

These units should be used on the suction (vacuum) side of the fuel transfer pump (and are permitted for use up to 7 PSI of head pressure).

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Source: https://www.parker.com/static_content/parkerimages/Racor/7238 Rev D (200 Series).pdf

Cubey said:

I finally took the time to install a complete used Racor fuel filter/water separator. I got it from a junkyard IDI turbo truck a couple years ago where it was mounted in place of the original WS. It's a whopping 2 microns, think that'll be ok pre-pump? It has a pretty large R26S filter so it shouldn't clog too fast. Presumably it didn't cause problems on the truck it came from.

Click to expand...

Thats a very fine filter to have on the suction side of simple diaphragm pump. Fine filters are meant to be 'pushed' through. You could be helping an air-inlet leak briefly until fuel starts moving.

Its better to have say a 20-30 micron there, and save the 2 micron for the pressure side.

u2slow said:

Thats a very fine filter to have on the suction side of simple diaphragm pump. Fine filters are meant to be 'pushed' through. You could be helping an air-inlet leak briefly until fuel starts moving.

Its better to have say a 20-30 micron there, and save the 2 micron for the pressure side.

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Nope.... the 2 micron filter says right on it that it's for the vacuum/suction side. Maybe it has to do with being a water separator, maybe pushing would push the water out?

But I agree, it should have a lesser micron. I'll get one when I can.

The largest micron I can get from retail seems to be in the form of the 14 micron Wix/Napa 33211. Only Parker/Racor makes a 30 micron one. I'd have to order it and have it shipped to an address, since Amazon itself doesn't sell it, nor does Walmart.

Well, I can either:

A) Leave it be and let it act funky when it gets started and replace the filter with a Racor 30 micron in about a month

B) Get a Wix 14 micron within the next week

C) Remove it from the fuel system and have no water separator again for the next ~800 miles

Heck knows how long it's been running without one. I have been for about 3k miles so far myself. Not too good for it. Probably worse on the engine than the shaky starts with the current 2 micron. Unless it starts causing bad enough air intrusion that it stalls, I guess I'll leave it alone until I can get a genuine Racor 30 micron element.

Cubey said:

Nope.... the 2 micron filter says right on it that it's for the vacuum/suction side.

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Sure, it's designed for it. The stock diaphragm fuel pumps aren't very strong though.

Would be interesting to have a vacuum gauge on it, or a chunk of clear fuel line to check for air.

u2slow said:

Sure, it's designed for it. The stock diaphragm fuel pumps aren't very strong though.

Would be interesting to have a vacuum gauge on it, or a chunk of clear fuel line to check for air.

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Think a 14 micron would be okay? That's quite a lot bigger than 2, but still half as small as 30.

It would only be a matter of changing a couple of hose connections to remove whole thing from the fuel system if 14 is still too much. I didn't cut the hose that was linking two steel lines where the W/S was, I just moved it to the filter head's inlet from the tank side and added a piece from the outlet to the pump side.

I bit the bullet and will try 14 micron Wix. I ordered one to a Napa about 30 miles away where I'm heading tomorrow. The 20% off when you order stuff online for store pickup is pretty good. $32+ tax. Amazon would have been about $30 with tax, and I would have had to wait longer to get it.

If, for some reason, they don't get it in time, no big deal, you pay when you pick up. The estimated pickup is Tue, new years eve. Maybe they'll be open that day. If not, I will still be in town until the 2nd, so I can get it then.

The old used 2 micron filter could be clogged up some too, but since it does fine driving and idling after it gets up to normal idle speed and fuel pressure, it's not too big of a deal for another bit of driving tomorrow. It's too messy to bother bypassing it again for such a couple stops tomorrow before I get to my destination. Then I can walk the half a mile to pick up the filter from Napa in the next town on Tuesday.

It's just that initial startup where it has to (presumably) build up the fuel pressure though the filter that it acts funky. Driving and idling is perfectly fine after those first few seconds.

Its got to help. If the 2micron is a used filter, who knows what's growing in it.

u2slow said:

Its got to help. If the 2micron is a used filter, who knows what's growing in it.

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It sat for over 2 years after I got it with no fuel in it, before I put it on here, so at least it wasn't sitting there mushy and growing with constant moisture for all that time. The inner core is the input side so I could see it pretty well by removing the bottom bowl. It didn't look too bad, honestly. The output side of the filter that's hiding inside? Who knows.

Since the main 6.9 fuel filter is supposedly 6 micron, from what people have said on OB and other forums, I figure 14 before the pump should be fine. I'm running a Motorcraft FD-811 main filter that I put on around February 2019. No stores are listing the micron for it, but Wix/Napa and MicroGuard (O'Reilly brand) say 6, so it's that's probably correct.

Cubey said:

I finally took the time to install a complete used Racor fuel filter/water separator. I got it from a junkyard IDI turbo truck a couple years ago where it was mounted in place of the original WS. It's a whopping 2 microns, think that'll be ok pre-pump? It has a pretty large R26S filter so it shouldn't clog too fast. Presumably it didn't cause problems on the truck it came from.

Click to expand...

I have been running two micron Racor on my IDI and 2001 PSD for at least a decade. I got rid of the stock filters on both.

This is the supply pump on my IDI.

https://photos.app.goo.gl/sSqqted6VE5vzL2d9

A couple times I have it turned off, and drove 50 MPH, and the engine didn't seem to notice. The IP pulled fuel thru the filter and the supply pump.

The PSD uses the stock 60# pump.

If you look thru these pics you will see how the filters are mounted.

https://goo.gl/photos/LJNV4esgmYmSzKdL8

https://goo.gl/photos/hQSWmXVQ6HsMVWzh6

And if you look about half way down this album you will see a Ford branded, two micron Racor behind the wheel on my 65 Mustang.

https://goo.gl/photos/PPcZpByXAgfp8kTk6