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Fuel filter

garciaj

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I am gonna change my fuel filter which was included with my holley terminator efi kit. PN is 3033 . In the install manual it says it's a 20 micron ( this one is between the tank and pump) research recommends a 100 micron filter . I'm not sure if I should put another 20 micron filter.
 

nvrstuk

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20 micron particles are smaller than 100micron and you want to keep the chunks out of your injectors...
 

ntsqd

heratic car camper
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Is that the only filter in the system?

Its location is suspect. Between the pump and the tank means that it is a flow restriction in a zone of the supply plumbing that is under a vacuum. This is because of the pump having to pull fuel out of the tank. Why this matters is because fuel behaves just like water with regard to pressure and boiling point. Lower the pressure and the boiling point lowers. In the case of fuel you can get it to boil off in ambient temperature just by putting enough of a vacuum on it. That is vapor lock because the pump can't move a gas, only a liquid. Which is why you're being told to use a 100 micron filter there, its less restrictive so less likely to result in vapor lock. 100 micron will keep out the stuff that might damage the pump, but isn't fine enough for the injectors.

If it were between the pump and the injectors then it is not fine enough of a filter. Commonly EFI filters are around 4 micron.
 
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garciaj

garciaj

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Is that the only filter in the system?

Its location is suspect. Between the pump and the tank means that it is a flow restriction in a zone of the supply plumbing that is under a vacuum. This is because of the pump having to pull fuel out of the tank. Why this matters is because fuel behaves just like water with regard to pressure and boiling point. Lower the pressure and the boiling point lowers. In the case of fuel you can get it to boil off in ambient temperature just by putting enough of a vacuum on it. That is vapor lock because the pump can't move a gas, only a liquid. Which is why you're being told to use a 100 micron filter there, its less restrictive so less likely to result in vapor lock. 100 micron will keep out the stuff that might damage the pump, but isn't fine enough for the injectors.

If it were between the pump and the injectors then it is not fine enough of a filter. Commonly EFI filters are around 4 micron.
That
is the only filter before the pump it does have another after the pump which is a 10 micron
 

Broncobowsher

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20 micron is pretty small to be sucking fuel through. As mentioned, 100 micron is a more common pre-filter. Big enough for volume, but small enough to keep the pump happy. The 10 micron is a good filter to push fuel through, and keeps injectors happy.

There is also the filter surface area to consider. Years ago Aeromotive put out some tech article regarding atual surface area in filters https://aeromotiveinc.com/pages/tech-bulletins
 

nvrstuk

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I still do not read in your original post that the filter was before the pump.
This is why I normally ask a hundred questions lol

So you do not have an intank pump?

So is this filter going in the tank, or is it going to be mounted up on the frame someplace so like TS mentioned earlier, you're gonna have to pull a vacuum through that filter?
 
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garciaj

garciaj

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fuel pump is frame mounted close to the tank , no in tank pump . I installed it years ago been running fine ( all though its not a daily driver just recreational) till the other day the pump started whining and stumbled a few times. I wanted to start with replacing the filter thinking it may be clogged . Ive read too fine of a filter can starve the pump , i was just wondering why holley would include that in the kit if that is the case.
 

nvrstuk

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Makes sense now :)

We think that Holley and some of these big corps know what they're doing and saying, but you get on a list like this and so many guys here have so much real world experience and professional daily experience that is so much better than what you get off of holley Terminator site!

I can verify that a several of their schematics for the terminator x are incorrect... ( they admit it and just say, yeah, we haven't corrected it yet"). We just assume they know what they're doing & care... right?. l o l
 

Timmy390

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Don't over complacent things....

Run a cheap universal filter beterrn tank and high pressure pump. Then a 10 micron after HP pump.

Been doing it for years with an e2000 pump. No issues

Tim
 

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ntsqd

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In the overkill dept. I've been known to use one of these marine filters as the pre EFI pump filter or as in this case the carb's only filter:
i-LZp3QrS-M.jpg

(No, the kink is no longer there!)
Those filter pads need a mod before you can also use them as a small reservoir, and the filter itself limits the effectiveness of it.
 

nvrstuk

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Makes sense now :)

We think that Holley and some of these big corps know what they're doing and saying, but you get on a list like this and so many guys here have so much real world experience and professional daily experience that is so much better than what you get off of holley Terminator site!

I can verify that a several of their schematics for the terminator x are incorrect... ( they admit it and just say, yeah, we haven't corrected it yet"). We just assume they know what they're doing & care... right?. l o l
These work great. I slap them on every boat.that doesn't have one... in fact, I'm sitting in (edit:) our boat as I just got a 15 min pull on my slalom ski... :)

Supposed to snow tomorrow night behind our place! Brrr
 
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ntsqd

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I've found that the filters can be purchased in a range of micron filtration sizes, but I don't recall 100 being one of them.
 

nvrstuk

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I've found that the filters can be purchased in a range of micron filtration sizes, but I don't recall 100 being one of them.
I haven't installed one in an EFI boat as they all come with them (least all of them I've seen). I really like carb'd boats as sitting on the shoulder of the road with dead EFI is much more comfortable then bobbing around on a windswept, tidal influenced strait so carbs are simple and easy to fix while bobbing compared to the trying to go get the new part needed for the EFI fix while bobbing. lol Obviously I work on older boats and I haven't done any repairs (knock on wood) on any boats for a while now.
 

jamesroney

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I haven't installed one in an EFI boat as they all come with them (least all of them I've seen). I really like carb'd boats as sitting on the shoulder of the road with dead EFI is much more comfortable then bobbing around on a windswept, tidal influenced strait so carbs are simple and easy to fix while bobbing compared to the trying to go get the new part needed for the EFI fix while bobbing. lol Obviously I work on older boats and I haven't done any repairs (knock on wood) on any boats for a while now.
Prefilter on my 99 Nautique with 351W GT-40 is specified by Pleasure Craft Marine at 40 microns. P/N R080024.

Superceded in 2007 to the PCM P/N R080024A which is specified at 20 microns.

It is important to remember what is going on with a pre-filter, and how the marine engineering world is slightly different than the rest of the world.

A pre-filter to a high pressure pump is designed to prevent the big stuff from clogging the pump. But the filtration size is not the only metric.

The bigger factor is water. And water means media type. MOST prefilters are fairly small surface area devices, and use stainless mesh as the media. So you want them to pass water, and trap the big stuff. Otherwise your pre-fliter has to be HUGE to avoid pressure drop and starvation.

So a 100 micron mesh stainless pre-filter works fine. Then your high pressure filter does the fine filtration and water separation.

I mention the PCM prefilter, because the filter can looks identical, but they changed the media from stainless mesh to fiber, and specify the replacement as a "water separator."

In a perfect world, the pump just gets a large area strainer that's tight enough to keep the boulders out. Then the after-filter gets the water separator and the fine particulate. The Racor guys go kinda nuts with their enormous pre-filter, water separator, and after filter. But if you pump a tank full of blue algae into your 2006 Cummins Mega Cab in Buttonwillow at 10PM, you will make Grapevine...and then you will discover the WalMart store hours in Valencia, and your family can Uber to Magic Mountain while you create a small super-fund site in the parking lot where you serivce your fuel system.

And yes, trying to service a GM TBI Throttle Position Sensor at the marina on your Mastercraft with the Indmar 350 Chevy is vastly easier on the trailer than in the "no wake zone". And I must admit that the 1970's GM 307 with the Quadrajet will troll in mild seas all day long and still motor back home. And I think I might just be remembering fondly...but I don't ever remember having to work on it. OMC stern drive with electric shift? Yeah, I got to work on that.

Cheers.
 

nvrstuk

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Laughing at the similar headaches & stories. :)

Qjets on boats were fantastic IMO.
 

ntsqd

heratic car camper
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For the FJ60 I made a ~100 micron filter for it's fuel supply system. Those vehicles do not employ a sock on the pick-up and since it was going EFI and there was the possibility of it being re-fueled by pumping dubious quality Pemex out of a 55 gallon barrel I felt that it should have something. I built the system with what was considered to be the best layout at the time. I wouldn't build it that way now, but I would still use the ~100 micron pre-filter. I say "~100 micron" because I don't know what it's actual filter size is, just that it was built using 150 micron SS mesh that a friend then in aviation filtration design gave me. It was fully over-lapped at two layers. The mesh was silver-soldered to the SS end caps of an Aeromotive paper filter element and used inside of one of their filter housings. Can see it here:
i-g4p2VxR-XL.jpg

Can see some of the rest of the fuel system forwards of the RR damper. The P4070 drew thru the modified Aeromotive filter and pushed thru the marine spin-on 40 micron filter to the GSL 392BX high pressure pump that pushed fuel thru the Wix 33481 (ubiquitous GM EFI) fuel filter. Like I said, I wouldn't build it that way now, but when it was built that was thought to be the best way to build such a system.
 
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