Diesel fuel? - PeachParts Mercedes-Benz Forum

kip Foss · #1 09-02-2008, 08:22 PM

I had the injection pump from my Ford tractor overhauled last month. It only had 1,000 hrs on it and I thought this was a bit soon for a major o/h. The tech told me that when Diesel sits for a while-weeks or months- that it will varnish up like gasoline. I know for sure that gas, esp. this new stuff will gum up but I had never heard this about Diesel. Has anyone else heard this or had the experience of an early o/h?

#2 09-02-2008, 08:28 PM

Nope. Diesel can sit for months and still be good. Water contamination is the primary concern for any Diesel that has been sitting for long periods.

I keep an emergency 2gallon tank in my trunk and rotate it (dump into the tank and refill with fresh) every year without a problem.

bbail2x2 · #3 09-02-2008, 08:53 PM

sounds like the tech was more of a salesman than an honest tech. thats the good part about this forum, most guys are here to help, not sell you something. when you search and find a good honest tech, thats where you continue to do business.

Diesel911 · #4 09-02-2008, 11:12 PM

You did not say what make of Fuel Injection Pump was on your tractor. In the past (back in the 1970s) Ford tractors used Simms (an inline IP) and CAV (a rotary IP) Fuel Injections pumps.
I am guessing it is a CAV pump. In the CAV pump there are 2 small pistons (free floating pistons) that create the high pressure for fuel injection. The pressure that pushes these 2 pistons out at the most under full load is around 30-35 psi. At engine cranking speeds it can be as low as 3-7 psi. This means that if the pistons become sticky there is not much force available to push them out.
Also since your pump had not been used much the clearances are still tight to begin with. The best thing to do is to get out and run the tractor up to operating temp and enough to also get the IP hot. This will move out any build up and help keep moisture from building up in the IP.
Last problem is that the older CAV IPs have a manual bleed screw you must use to bleed the air out of the head of the pump; air bleeding is not automatic. If your fuel hoses loose there prime from sitting along time it is a good idea to open the Air Bleed screw and crank until fuel is spruting out of the Air Bleed screw before closing it
The Simms pumps also have a manual Air Bleed Screw but have a hand primer on the Diaphragm Fuel Supply Pump.
As mentioned moisture is a problem. CAV pumps have their advance pistons at the bottom of the IP. Any water that condenses in the pump will end up in the bottom of the pump. In some models the Advance Piston is made of steel in others some sort of non-metallic stuff. In both the bore the Advance Piston rides in is steel and rust can build up there. If the pump sits unused rust can freeze up the advance piston.
Here is a site selling Ford IPs; the 2 at the top are CAV pumps and the 3rd from the top is a Simms inline pump.
http://www.brokentractor.com/ford%20fuel%20parts.htm

NC Benz · #5 09-03-2008, 01:26 PM

Quote:

Originally Posted by kip Foss

I had the injection pump from my Ford tractor overhauled last month. It only had 1,000 hrs on it and I thought this was a bit soon for a major o/h. The tech told me that when Diesel sits for a while-weeks or months- that it will varnish up like gasoline. I know for sure that gas, esp. this new stuff will gum up but I had never heard this about Diesel. Has anyone else heard this or had the experience of an early o/h?

I used to maintain a 350kW Cummins Diesel generator that had a 2000 gallon tank (amongst other gen sets). I never had an issues, but just in case I would add an anti-bacterial to keep the slugies away, and make sure the tank was tight to prevent moisture/condensation. I have never heard of a gumming up unless there are other items in the fuel.

kip Foss · #6 09-03-2008, 02:42 PM

I am going to contact a Diesel fuel distributor/manufacturer and ask about this. I have always heard that Diesel will last for ever. I realize that hospitals, etc. with huge stand by gen sets run them every month or so but still they have thousands of gallons of fuel mostly just sitting there year after year. How do they keep it from gumming up?

Diesel911 · #7 09-03-2008, 03:04 PM

I would still like to know if your Ford has a CAV IP on it.
I also missed one area that can cause trouble on these pumps. The Fuel Supply Pump that is built into the IP has a small spring and piston that regulates the fuel supply pressure in the pump. The piston can also stick/rust in it’s bore.
Unfortunately Diesel Fuel attracts water. Especially in above the ground Fuel Storage Tanks which allow the Day and Night temperature fluctuation to have an effect on it. During the heat of the day some of the Fuel evaporates off while mixing with the air. At night moisture from the air can condense in the tank and gets into the Diesel fuel where it can cause steel tanks to rust and of course the dreaded Algae to grow.

3 years ago I drained the Diesel Fuel out of my Pop Tester. 3 years later when I wanted to use it I found that the plunger was froze up due to dried diesel fuel. I had to take it apart clean it before it would function.

Diesel911 · #8 09-03-2008, 03:11 PM

Article on Diesel Fuel "Diesel Sludge".
http://www.dieselcraft.com/fuel%20facts.html

kip Foss · #9 09-03-2008, 03:34 PM

I have a 3 cyl. 4400 industrial Ford tractor with a CAV pump. I keep my fuel in my garage in a plastic 55 gal. drum so I don't think I get any moisture in it. I have a large cartridge type filter between the tractor tank and IP. I have never torn into my IP simply because there is nothing I can do in there. In the end the pump will have to go to the IP people.

I got some additive recommended by the IP people but, like so many additives, I think there claims are mostly BS.

The Dieselcraft site is interesting, but neither of their referral sites are available. Also, what are they selling? They are selling products to cure a problem that they are defining. From my own experience, esp. on offshore supply boats in the Arabian Gulf, I know that fuel pollution is a problem. We had DeLaval fuel separators and clarifiers but no additives. Where can one get a straight answer?

Diesel911 · #10 09-04-2008, 12:08 AM

I did not realize that you had not had the pump rebuilt yet. Is the IP still on the tractor?

I have some ideas if the pump is off of the tractor.
When CAV pumps are timed they use a set up that hooks to (filtered) compressed air. The compress air is piped into the #1 cylinder fuel outlet, to the #1 injector and the pump is rotated in the direction of rotation until you feel it contact the Cam Lobe On the Cam Ring.
If it is the 2 Pistons that are sticking in IP head rotor 125psi if air may free the pistons up as the air pressure pushes the pistons outward against a part called the Cam Ring.

Also there is a cover on the side of the pump held with 2 small bolts. you can open that cover (if you have the ford manual this is the cover you would view the IP timng marks through). If the pump was laying on a bench you could open the cover and fill the pump with Penatrating oil (not an oil with graphite though) and let it soak several days to disolve any deposits.
Last though is as I remember the 3 cylinder engines for some reason are harder to bleed the air out of the IP. If the pump is still on the tractor you might try opening the air bleed screw on the Head of the pump to bleed the air and try to start it again. This will also tell you if the IP is gettin fuel from the Fuel Supply Pump.

Diesel911 · #11 09-04-2008, 01:02 AM

I added some text to this pic.