Duel fuel line mod M818 855 cummins

bubba_got_you

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[FONT=&quot]Well like the title says I did a duel fuel line mod on my m818. I did some reading on a combine forum that some guys do this to there big tractors and there is a noticeable difference with it running smoother at idle and having more guts while pulling. I haven’t run it yet so I cant tell you if it makes a difference or not but for the $20 I paid for parts and since I was going to replace the fuel lines anyways I figured “why not”. I wont be able to run it until I put the fuel tanks back on it so it will be a bit before it gets tested. [/FONT]
 

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bubba_got_you

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Ya. I had to cut a hole in the cab and drill it out then tap it. But it was nice to have the hole for attaching the line, I will cover it with a plate and 4 bolts and call it an access cover lol. :whistle:
 

patracy

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I might try to tackle this on my 931 this week. It's pretty simple. Although I'm confused about the drilling and tapping though?
 

73m819

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I might try to tackle this on my 931 this week. It's pretty simple. Although I'm confused about the drilling and tapping though?
Sometimes the REAR/FRONT plugs are froze in place and are a real pain to get out, even if you can get to them.
 
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pad_cdr

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Great pictures. For those of us (or maybe just me) who are less knowlegable about diesel engines, where are the fuel lines running to and from, and what are the advantages of doing this?
 

patracy

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Great pictures. For those of us (or maybe just me) who are less knowlegable about diesel engines, where are the fuel lines running to and from, and what are the advantages of doing this?
Stock, the fuel supply line from the PT pump only runs to the front head. The heads have a passage or rail that the supplied fuel passes through. What the OP did was basically split the feed line from the PT pump into a tee and diverted half of it to the rear head that is also tapped into the same rail. Basically it allows a more even distribution of fuel to the injectors, as before #1 got first dibs at fuel and #6 would have been the last. Now with this setup, even flow/pressure is hitting #1 and #6 and meeting in the middle at #3 and #4. Helps to allow the engine to run a little more balanced and increases fuel flow to the injectors. It's been noted that this mod typically gains 20-25hp. I could certainly see it helping due to the design.
 

73m819

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A lot of 855s and simler Cummins engines had either front fuel feed, rear fuel feed and front/rear fuel feed straight from the factory, Cummins even has/had converson kits to change the feed, all the parts can be got from CUMMINS to do this mod, just need a FAT wallet and the engine SN, a lot faster and cheaper to go to the hardware store, (same parts only without the "C" stamp
 

patracy

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Starting on dual fuel feed line mod, anyone done it?

I've cut an access panel into my doghouse to get to the back of the head. So far I've only managed to sheer off a allen key bit when I try to back the plug out. I removed the sheered section and tried with a key itself and a propane torch. But the key just started bending so I didn't try any further.

If it's this difficult to get the plug out, I'm almost certain I'll end up stripping the plug if I try any harder. I haven't picked up a 3/8" drive socket though. But this key is only 5/32" So I'm worried to say the least.

I could possibly take my cutting torch to it and see if that motivates it any better than the straight propane torch did?

Next question I have is this. Are the plugs 1/8" NPT? I should be able to get a NPT to a flare fuel line and a tee if so.
 

doghead

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Do you have access enough to drill it out?
 

M813A1

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Do you have a screw Knocker ?? It might help you out . It is used with a air hammer has a 3/8 lug like a ratchet so you but your socketon the end and knock it as you turn it !! That might help you out . You can get the Knocker from Browns Tool !! We used them alot here on aircrft to get stuck screws and bolts out .
 

73m819

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From my experence over the years with the 855s, on the lower hp engines, you will not notice the difference from a single to a duel fuel feed, on the high hp motors, almost all are duel feed because of the high volume of fuel needed, and for a few other reasons.
 
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