Bio Diesel & ULSD question.

[Lonnie]

Hi all,
I'm new to this forum & I'm sure this question has been covered but I couldn't seem to come up with the answer in searching.

To start, I bought a 1982 720 SD22 yesterday. I'm not new to diesels as I've owned a 96 Dodge cummins for 9 years, just new to Datsun...

My plan is to start making Bio diesel & I understand I will need to replace the fuel lines, but my question is will the Bio or the low sulfer diesel hurt the pump? I just remember what the low sulfer fuel did to my 84 Ford's pump. It wasn't pretty...

Thanks in advance for any help!

Lonnie

[asavage]

Welcome aboard!

I bought a 1982 720 SD22 yesterday.

My plan is to start making Bio diesel & I understand I will need to replace the fuel lines . . .

See my post on viton lines on '82 720 SD22.

. . . but my question is will the Bio or the low sulfer diesel hurt the pump?

Biodiesel (ASTM D-6751 that is) has much higher lubricity than petrodiesel. No, it won't harm the IP, on the contrary. That is, if you wash your fuel and remove the residual glycerine/soap.

I just remember what the low sulfer fuel did to my 84 Ford's pump. It wasn't pretty...

If you mean, back in '91 when we went to LSD (<500 ppm), the issues were the reduced lubricity of the fuel caused by the process that reduced the sulfur, not the missing sulfur itself. The way PD is refined these days does not have as drastic lubricity reduction as did the process used fifteen years ago. And the Stanadyne DB2 IP that your (and my) '84 6.9l use is not what I'd call a real robust IP. Rarely do they go 200k miles without a complete overhaul, even with the best fuels and additives.

The Kiki Diesel (Bosch design under license) IP is extremely robust by comparison. Some people are getting away with SVO with this IP -- which is something I don't advocate.

Biodiesel and the SD has been discussed extensively here; do a little more searching.

[Lonnie]

Thanks Al!

I did read your post on changing the fuel lines & I've book marked it for when I get ready to make the change.

Our local college teaches a class on how to make bio so I plan on taking it this spring. I'm not generally the type to cut corners & I like to do things right the first time.

When I drove this thing home last night I noticed a vibration. So when I got home I checked the u joints & sure enough the rear one was in bad shape. Bad enough to ruin the rear tranny seal! So that's what I'm working on first...

Thanks again for the help.

Lonnie

[Zoltan]

Biodiesel is an excellent detergent as well. Be prepared that years of dirt that settled out of petrodiesel in the fuel tank will be liberated once you start using biodiesel. It will travel down the path and will show up in the small pre-filter (small plastic cylinder with wire mash in it) and might clog your main fuel filter as well. Make sure you have a pair of spare filters on hand when the time comes to switching to biodiesel.

[glenlloyd]

snip.. I'm not generally the type to cut corners & I like to do things right the first time.

Welcome Lonnie

I am a big advocate for doing it right the first time. I always try to live by the motto, "If you don't have time to do it right, when will you find the time to do it again!"

steve a

[scottyk]

Hi Lonnie,
I have the same truck as you and just bought it last Monday. I am going to run it on Biodiesel, but would prefer to buy it from a retail or distributor before making it myself. I already have two primary fuel filters on order from Nissan, might pick up a secondary filter as well from Napa. Good luck.

[philip]

SNIP- I already have two primary fuel filters on order from Nissan, might pick up a secondary filter as well from Napa. Good luck.

The primary filter is a SCREEN ... not a paper filter. Common mistake is to substitute the same little filter having a paper element from the gasoline 720 truck. The screen is easy to backflush clean.