Author Topic: question on fuel injection piping 8V-71  (Read 2186 times)

Offline bevans6

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question on fuel injection piping 8V-71
« on: October 19, 2012, 01:27:07 PM »
My first trip with my new engine ended with more oil in it than when I started - obvious fuel contamination confirmed by a sample analysis.  I am going to redo the fuel injection piping but have a few questions.  First thing - the two inch or so tall "stand pipes" that screw into the head that the fuel pipes to the actual injectors attach to - is there supposed to be a copper sealing washer between the stand pipe and the head?  Mine had thin steel washers and that's what I put back in, but it seems to me that would be a useful place for a copper sealing washer.  Second - the fuel pipes are the ones with o-ring fittings, not the taper type, and I re-used a number of the old o-rings.  That's what I really suspect is leaking.  Does any one know the correct size specification for those o-rings?  Or can I order them from Detroit, do you think?  Anyway, my plan is to take all the fuel pipes off, and replace all the o-rings so I need a bunch of them, 32 I figure, so I'd like to order the correct size.

Any other advice?  Obviously checking each pipe for cracking, but is there a good way to tell where the leak is, visually?

Thanks, Brian
1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Allison MT-647
Tatamagouche, Nova Scotia

Offline luvrbus

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Re: question on fuel injection piping 8V-71
« Reply #1 on: October 19, 2012, 02:46:26 PM »
The washers are steel just check for clean spots  there will be no oil standing in the area where the leak is I would check other places for the o-rings DD will give you a heart attack for those suckers 

Check your gasket set if you bought a complete set the o-rings will be in the set

good luck  
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Offline Just Dallas

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Re: question on fuel injection piping 8V-71
« Reply #2 on: October 19, 2012, 04:14:07 PM »
Brian, I'm not sure I still have any but I did have a couple of Head overhaul sets that came with the O-rings.

I'll check tomorrow or Sunday, unless shipping to Ca from TX is more than you can buy them for in Canada.

Check the Felpro Website, the nice people that build those sets for DD.
I'm just an old chunk of coal... but I'm gonna be a diamond someday.

Offline bevans6

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Re: question on fuel injection piping 8V-71
« Reply #3 on: October 20, 2012, 03:58:29 AM »
Good advice, thank you.  should have thought about it dispersing the oil myself!  Glad the steel washers are correct.  I have the rest of my full DD gasket set still in my shop so when I get back there I will dive in and look for those o-rings!  Man, that engine ran so well that I was happy to see it wasn't using oil like my old one, but then when it was obviously gaining on it I knew I was going back in to fix it...  Should be easy at least.

Brian
1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Allison MT-647
Tatamagouche, Nova Scotia

 

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