Fuel Filters for Detroit GM

[nedskelly]

Changing out my filters and have a ? regarding fuel filters. The filters I am replacing are the the same dimensions, the new replacements, Fleetguard are different, The bigger filter Fleetguard FF5207 is the primary filter and I am assuming that it is for the inlet line and the smaller filter is for the return line. Is my assumption correct.
Gary

[T1 Terry]

Makes sense but I've never seen that sort of arrangement, generally 2 filters in series so the bypass in the first filter if it blocks does not dump garbage into the fuel system. As GM engines demand a constant high fuel flow to act as a coolant for the injectors a fuel filter that restricted flow would cause major damage. I've seen poorly maintained set ups spraying fuel out of a rust hole in the primary filter due to water being separated and trapped but then left sitting because the filter has bypassed. Funny to see when you know the cause but what a mess because the filters sat high mounted behind the prime mover resulting in the fuel spraying all over the trailer.

T1 Terry

[BruceS]

Yep, pretty sure it'd be both inline.
Primary & secondary.
As for size .... I guess as long the sealing rubber etc is the same size it should be OK.
There is a site for finding other makers compatible part numbers. I'll see if I can find it.

[BruceS]

Some measurements etc here....
http://www.ebay.com.au/itm/BF5800-BF581 ... xyQyJRkLfl

[Busman]

The usual setup is for the fuel to be sucked through the primary (biggest one) by the fuel pump, which then pushes it through the secondary at between 10 and about 70 psi, depending on engine speed. The bypass does not need to go through a filter, it has already been filtered before it got to the injectors.
That's why many people fit an electric lift pump, if out of fuel sometimes they struggle to pick it up again.
Easier just to not let it run out of fuel !

[T1 Terry]

The usual setup is for the fuel to be sucked through the primary (biggest one) by the fuel pump, which then pushes it through the secondary at between 10 and about 70 psi, depending on engine speed. The bypass does not need to go through a filter, it has already been filtered before it got to the injectors.
That's why many people fit an electric lift pump, if out of fuel sometimes they struggle to pick it up again.
Easier just to not let it run out of fuel !

There are a lot of plus to the electric pump idea, filter replacement self bleeding being the biggest, self bleeding after running out of fuel is a secondary but certainly not something to do in a GM, remember the fuel is a coolant in these engines so reduced fuel doesn't allow enough volume in the tank to give an acceptable cooling period before it goes through the loop again. Hot diesel forms serious coatings to build up through the system requiring a lot of cleaner to remove and the end result is that junk passing through the injector nozzle.... not good. Water in a GM injector nozzle is an instant injector fail, the water boils to super heated steam with no where to go but blow the nozzle tip off, end of the injector and the start of an engine failure.

T1 Terry

[native pepper]

Got a 671gm in my motor sailer, have 4 fuel filters on it, the 2 standard ones a huge water trap and filter and an in line throw away. It also has a 24v fuel pump so we don't have problems bleeding it, but never had to in more than 20 years of use. These engines are designed to run on just about anything that will compress and fire, many years ago we refueled at Bridport in Nth Tas, but they never had a water trap or checked the tank for water ingestion and we got a load of it.

We were off Waterhouse island when the engine started to hunt and slow down, then noticed a huge cloud of smoke coming out the stack. As we were in a decent sea with a good northerly blowing, we couldn't stop the engine until we were sheltered and the oil pressure hadn't dropped. So it took us about 15 minutes to get behind the island and into shelter, hoping the engine wouldn't blow up before and put us on the rocks. The problem was the filters were full of water and still the engine ran, so we switched to a tank we knew had no water in it and bled the water out of the lines and filters, with the engine still going and puffing out huge clouds of steam and smoke.

That's when decided to put a big water trap filter and throw away on her, re-piped the system so we could bypass any tank or filter if something like that happened again.

Checked with a mate down here who is a gm fanatic, to see what damage the water had done and he told me, it would have cleaned out the engine as these motors were designed to run on just about anything, including water in the system as they were built for tanks and landing craft for ww2 and the fuel always had some water in it. Haven't touched the engine since and she screams like a banshee.

[Toolman]

Yes FF5207 is a 50 micron primary filter.

[nedskelly]

Thanks for the help, filters are in and engine fired with no hiccups.
Gary

[bagmaker]

Thanks for the help, filters are in and engine fired with no hiccups.
Gary

That doesn't sound right for a GM, perhaps try it again until you gets some hiccups?