8V71 - Diesel in the oil...

John D & Mammoth,
yes that makes sense. It seems POSSIBLE that the fuel pump could leak back into the underside of the blower, but seems bloody unlikely according to the interweb and the various GM experts. However, in the lack of anything else that seems obvious... Maybe?

180wanneB- that makes sense too. We left diesel "hanging" overnight up off the fuel filter, but no sign of dropping or change to the level.
I reckon we will rip the fuel pump off and pressurise it, or just replace it if we can't.

John K- might be needing your injectors yet! Ours are N65 brown ones. If you don't need em and want to sell em perhaps....

Rockwiz- that's really the first I've heard of that happening, apart from the various theories. But if the book says it, then we gotta investigate that path, by the sound of it.
We've also been advised to spend the money on a new set of injector lines, just cos the old ones are, well, 57 years old, would have been off and on a million times, and maybe we just cant see the leak with the truck running. The dye might help too, I'll look in to that..

Thank you for all your help fellas, it is very much appreciated, and we'll keep nosing around. Any other ideas let me know!
Cheers
Richard

Just cos. This was at the rebuild time...The OLD head after it dropped a valve.. 

 


 

The old girl was originally Hartridge transport, this may have been my truck many years ago, but I don't know.
Cheers

 


 

Rich

I was at Hartridge loading the Commer the day the first Kenworth arrived - was that something.

I am sure their oldest and boldest driver "Horse" was given the truck.

Wonder if it is the same one?

Lang

RichMan
gudday m8

RE: do you mean the injector TUBE of the injector? Or the injector pipes
Chek m all but the cross over between each injector

It has been known th@ some when they run out of fuel pressurise the fuel tank or the fuel filters to get er go n
the hi air pressure con blo the seals on the scavange pump

cya

Id plug off all the fuel passages in the ends of the head ,and put air pressure into the fuel gallery ,and spray detergent ,looking for foam................Ive had fuel leaks ,and always damaged jumper pipes ...generally screwed up too tight and the flare split 

It is impossible for an injector to leak fuel in bulk internally,without a cylinder misfiring.,and lots of white smoke..............the two steel fittings on the body may leak if loose or the copper washers are faulty.............same with the steel fittings on the head ...copper washers there too....................4-53s in Austin Western cranes were notorious for blowups from fuel dilution,and that was down to army mehanics overtightening the jumpers.

Greetings. If you've had oil dilution from diesel it may be wise to drop your sump and inspect No 7 main bearing ( if it's a 6-71 ) - the white metal bearings don't like diesel and you'd hate to spin a bearing and bugger the crank.. Standard practice back in the times when 2 strokes were heard daily on the roads. I very much doubt the fuel lift pump is the problem- they have a weep hole between the seals (2).Now here's my Power Point display.....

Any of the leaks indicated will be obvious with air pressure in the fuel galleries and detergent sprayed on the areas...........foam will form.

I still think dye is the go. It will take you directly to the source no matter which of 15 options without endless trial and error.