Help!!!!!!! Detroit 12v71 oil pressure problems

[Truck Shop]

While most on here won't or refuse to believe this, I knew and worked on Detroit's that a guy owned THAT never Removed the DRAIN plug till major work was done, Filters only.
He only added-Most all ran a minimum of 500,000 He two 8V92 silvers that ran close to 800,000 before needing cams. Fact.

 

[Nige]

While most on here won't or refuse to believe this, I knew and worked on Detroit's that a guy owned THAT never Removed the DRAIN plug till major work was done, Filters only.
He only added-Most all ran a minimum of 500,000 He two 8V92 silvers that ran close to 800,000 before needing cams. Fact.

I'd believe that. Speculating that it was probably because the amount of oil that the engines leaked/burned led to him effectively changing the oil every X miles/hours by having to add fresh oil regularly to keep the level up to the mark.

 

[Birken Vogt]

I'll bet that oil was a pleasure to wash off if it got on your hand.

 

[Vetech63]

Ahhhh....the memories. I feel like I'm 25 and working for Terex again! Thanks guys

 

[Truck Shop]

India Ink! Now you know why I hate V series detroits.

 

[John C.]

The other issue that no one has addressed is fuel dilution. A V12 has a whole lot of jumper lines that could develop some seepage or a leak.

 

[kshansen]

The other issue that no one has addressed is fuel dilution. A V12 has a whole lot of jumper lines that could develop some seepage or a leak.

That's true with four connections for each cylinder you have 48 possible leaks. Plus if someone did not know what they were doing when installing a fuel pump and put a pipe plug in the threaded holes between the oil and fuel seals that could be another source of dilution!

 

[DMiller]

We would eliminate the Oil Side Murphy switches on Driptroit powered Trucks, would bump low oil pres and Die at inopportune moments, Idle would or could be as low as 2-3psi

 

[Truck Shop]

The guy changed a filter noticed low psi, apparently had no issue before-now we are into making oil?

 

[DMiller]

If swapped a bypass for a full flow could do it as to low pressure, marine used to be all upgraded spin ons.

 

[terex herder]

Another post and run.

 

[Bluox]

The guy changed a filter noticed low psi, apparently had no issue before-now we are into making oil?

I'm gonna bet he prefilled his filter with 15-40 oil and you know what that will do .
Bob

 

[Bluox]

I know nothing about Detroit’s,but during the 90’s I bought some scrapers for a quick job,then sold them.I recall an important thing or 2 about them……they ran on straight 40w oil and would all work fine until they needed servicing.They would run about 40 bar then after a month would suddenly drop to 10 bar.They would immediately get oil filters and new oil and work another 200 hours or so before doing it again.This was the case with all the scrapers.My fitter was never concerned.
The correct oil,oil filters and frequent changes was vital to these engines.Air filters were also important to keep clean.
They were good engines,but took no abuse unlike the Cat engines

I find it real hard to believe you had DD motors running 560 PSI oil pressure.
Bob

 

[chidog]

I find it real hard to believe you had DD motors running 560 PSI oil pressure.
Bob

I agree, maybe he's not sure about the conversion of BAR to PSI. I'm guessing he meant 40 PSI and then it would have dropped to 10 PSI, no engines I know of could use 40 BAR of oil pressure, that would over whelm the oil control ring from the massive spraying and windage in the crankcase, and likely erode the bearings.

 

[nicky 68a]

I agree, maybe he's not sure about the conversion of BAR to PSI. I'm guessing he meant 40 PSI and then it would have dropped to 10 PSI, no engines I know of could use 40 BAR of oil pressure, that would over whelm the oil control ring from the massive spraying and windage in the crankcase, and likely erode the bearings.

Yes,I meant PSI .
Sorry about that.It was a long time ago and, as I mentioned,I’m no fitter.I’m just the chap that owns them and moves muck with them.
I employ better men than I to advise me how to spend my money on my machines.This has worked very well for me over the last 30 years allthough mistakes have occurred
My ownership of Terex scrapers was deliberately brief and I ran some for just one particular job.They we’re impressive little scrapers and considerably lighter than the equivalent 627’s I’ve worked with over the years and would work in soft material far easier than the 627’s.

 

[nicky 68a]

I find it real hard to believe you had DD motors running 560 PSI oil pressure.
Bob

Obviously an error on my part.40psi sounds more like it.
Again,my apologies sir.

 

[dimitri69]

Guys. Sorry for the late update. I don’t always get a chance to visit the boat. After some searching, there was this tip about diesel seeping in to the oil through the injectors. When I had a chance, I took the dipstick out and would you believe it, it smelled 100% like diesel!!!! So this is what is going on. It’s totally unrelated to changing the oil filter. That’s what we were thinking because it was fine before we did that job, but like another poster mentioned, some other stuff could happen and misguide you. I am hoping that it’s the injectors only. Not sure yet how to easily analyze this, and I’m hoping it’s just on one side of the engine because is unbelievable how hard the access is in a boat. Any tips would be appreciated to er this job going. I don’t have a workshop manhal on this engine. Thanks guys!!

 

[dimitri69]

The other issue that no one has addressed is fuel dilution. A V12 has a whole lot of jumper lines that could develop some seepage or a leak.

John, this is EXACTLY the problem. I smelled diesel on the oil dip stick! Any tips would be appreciated on how to go about fixing this! Thank you!

 

[Truck Shop]

Pull the rocker covers, if the fuel was that diluted it probably has washed the cylinder heads fairly clean of black oil. Dump engine oil add new oil.
Start and idle watch all fuel crossover/jumper lines for leaks right at there base fittings go through and physically grab each one and see if any are
loose or have more movement than others.

Good catch-John C.

 

[dimitri69]

Thank you very much! I will try that as soon as I can