im working on converting my truck to veg oil. i have a couple questions about the IP and filter.

Im trying to identify the supply and return lines on the IP. and everything else thats connected to it.From what i gather,
#1 is the supply line (5/16"?) coming from the filter on the block (#5)
#2 not sure?


#3 i think, is the IP return line. It tee's in with the injector overflow line, then heads to the tank.
#4 not sure?


#5 filter output (going to IP [#1])
#6 filter input (coming from lift pump)


#7 This is the hose from the tank to the racor filter befor the lift pump. (trying to figure out the size or type of this hose because i need to splice into it with a brass T



Im also trying to figure out if the bolts for #5 and #6 are removable or what i can do with them as i would like to attach rubber hose to those ports instead. I need to instal a valve between #5 and #1

And lastly, i know on other diesel engines, the injector overflow line loops back to the filter. does the filter on the block only have two ports or am i missing something.

Sorry for the huge question but i thought id throw it all out there at once. please correct me if im wrong on any of them.
thanx very much in advance for any help!

 

1- feed line from filter head
2- KSB feed line. Do not mess with this one
3- Injection Pump (IP) return line. Do not mess with this one either
4- AFC boost reference line. Not a fuel line at all. Directs manifold pressure to the AFC housing for fuel control. Leave this alone.
5- Banjo bolt from filter head to IP with bleeder screw. This screw is loosened to bleed air after a filter change.
6- Banjo bolt from lift pump to filter head
7- Feed line from tank. It's basically just plastic, 1/4"id or close to it. You can cut it with any kind of shear or blade. It's a quick disconnect fitting. Push in both tabs on the end fitting and it will pull off. Push on to connect.

The injector overflow line on the early cummins (1st gen) loops back to the IP and helps maintain IP case pressure and therefore injector timing. Do not mess with this one or you'll throw off your dynamic timing. The filter head only has an 'in' and an 'out' on the first gen. The 2nd gen filter head is different and the injector overflow directs back into it.

"Bolts" 5 and 6 are removable. They have sealing washers behind them. They are metric thread so you'll have to source metric fittings from a vendor as regular SAE barb fittings won't work. Vulcan Performance is one source.

 

hey thanx very much for the good info.

you mentioned that the injector overflow loops back to the IP to maintain case pressure?. Where would this line be? from what i can see the inj. overflow "T's" into the IP return line and they both head back to the tank. i could be missing something though.

what i need to do to the fuel line is put a valve before and after the LP and also a "T" right befor the IP. So what i was thinking was instead of cutting any of the metal lines. removing their fittings and replacing with barbed fittings. A simpler method would be to cut the lines and clamp hose onto the open ends where needed. but i think id have to remove the line to have access to cut it.

Also i will be putting another valve on the return line but can do that after it switches back to the plastic line.

 

If you follow the injector return line it does in fact T into another steel line that runs to the IP. The other end of that T runs to the tank. I'd tie into it after the T and maybe even run a check valve in there so you don't backfeed WVO into the system when you're trying to flush the lines with diesel at shut down. You are right in that the easiest thing would be to cut the steel lines and clamp rubber onto them. Most of the conversion kits have you do this.

 

So i guess the simple way to ask this would be, what direction is fuel flowing on #3? if its back to the tank, that should be fine because ill have a valve after that T allowing the choice of what tank to send to. so it will return to the VO tank until the lines have been purged.

If its flowing into the IP then im kinda confused cause that would mean the IP is pulling it in, and therefore wouldnt it also be pulling from the tank?

Also, as much as id like to keep it simple and cut metal line and clamp hoses onto them, im not sure how to do that for the line from the "filter out" to the IP. i think i would have to take that line out to cut it. any advice on doing that? do i hold the big nut and undo the small one or vice versa?

Do you happen to know what size the metric threads are for 5 and 6? and i assume i would have to use the existing washers on there still.

And the plastic lines for feed (#7) and return (after that T) will the work with a normal 1/4" brass hose barb? they seem like a hard plastic.

thanx again

 

Fuel is flowing out of the pump there.

The small "nut" is the bleed screw. You just unscrew the whole banjo bolt. For your purposes it would probably be simplest to replace the injector pump feed line with hose. The fittings on the filter head and injection pump are all M12 X 1.5.

Don't know on the last one.

 

sorry for my ignorance but for the IP and filter fittin thread size M12 x 1.5

which of the numbers refers to the thread? is it 12mm threading?

 

12mm thread, 1.5mm pitch.

 

Here is how I did my fuel system. I had, at one point, a secondary fuel system plumbed in as well for my WVO system. Note the fittings used to replace all of the banjo bolts and whatnot from the filter to the pump.

http://www.cumminsforum.com/forum/89...e-finally.html

 

nice work on your truck. do you still have WVO runnin?

so the IP and filter fittings are all 12mm x 1.5 pitch. is that the same for the LP as well. thought i saw in your post that it was 14mm x1.5?
does the pitch refer to the internal threading of the banjo bolt?

and since youve replaced the banjo bolt with metric/jic fittings. do you loose the ability to prime the system with the lever on the pump? or do you just loosen the new fitting a bit while pumping then tighten back up when fuels comin out?

 

Yeah, all you have to do is loosen a fitting.

Pitch is the number of threads per mm of bolt length. An M12 X 1.5 bolt is considered coarse thread.

 

is there a specific length of fittin that is required? just wondering about the appropriate depth for the new fitting to be threaded in.

 

is there a trick to taking the fuel supply fitting off the IP?
no matter how much force i use it wont budge and i dont wanna strip the nut.

 

Nope. Just standard reverse thread.

 

thats the trick i was lookin for. i thought it was normal thread. i was goin counter-clockwise to loosen.
Thanx!