One for the books

[SEVEN]

I have a friend with 8V71 NA. He had smoke at start up for about 30 seconds. He also had fuel residue on the water coming out of the exhaust. He had a friend who says he knows a lot about DD and would adjust and run the rack plus other adjustments to stop that. Long story short he didn't do a good job and all the adjustments had to be re-done. However, the guy put 2 gallons of Marvels Mystery oil into one tank that had about 200 gallons of fuel. Now that the adjustments are correct and the motor starts and runs smooth, it blows out gray smoke which it never did in the past. The motor ran for 1/2 hour and the amount of gray snake never lessened. What is everyone's thoughts? To much oil in the fuel? Stuck Ring?

[Glory]

The mystery oil likely has nothing to do with the smoke.

Your friend needs to find more talented help!

[SEVEN]

I've known him for 35 years and he does everything frugally. I just told him today that if he would have used my guy first it would have been cheaper. The second guy who re-adjusted the motor said two gallons of the oil would be enough to treat 1200 gallons of fuel and that's why it's smoking. Maybe now he will use my guy.

[racclarkson@gmail.com]

Sounded about right to be honest (the 30 secs and a little residue).

[davidwigler]

Check the oil level and see if it is making oil.

[finatic]

I met a guy who was on the original design team for the 8V92's. He recommended a gallon of marvel for every 100 gal. of diesel. He says he does his with every diesel he owns. I do it and do not have any smoke.

[piripucha]

Grey smoke is unburnt fuel, I do not think that the mystery oil is to blame. The concentration is to small to make any effect on the combustion. I once filtered my old oil from am oil change and dumped into the fuel tank at 5% concentration and apart from turning my diesel dark it did not smoke at all nor it gave better performance. The only advantage was the ease of disposal of the old oil.

[MikeP]

It's important...REALLY IMPORTANT...to understand that MMO is an excellent detergent and will seriously clean deposits in the oil and fuel system. That's good...sort of. The downside is that using it in a system that is not clean to start with will put a lot of previously deposited gunk into the oil/fuel system, to the point where it can totally clog filters and cause all sorts of smoke due to burning of these deposits.

Unlike most of the various snake oils sold for engine use, MMO really does do what it is advertised to do. In fact, for many years, it had a mil spec number and was commonly used in the military for maintenance of heavy equipment engines. SO...the good thing is that it works, and will loosen deposits. The bad thing is that it works and will loosen deposits. BUT those deposits have to go somewhere...

[bobk]

It's important...REALLY IMPORTANT...to understand that MMO is an excellent detergent and will seriously clean deposits in the oil and fuel system. That's good...sort of. The downside is that using it in a system that is not clean to start with will put a lot of previously deposited gunk into the oil/fuel system, to the point where it can totally clog filters and cause all sorts of smoke due to burning of these deposits.

Unlike most of the various snake oils sold for engine use, MMO really does do what it is advertised to do. In fact, for many years, it had a mil spec number and was commonly used in the military for maintenance of heavy equipment engines. SO...the good thing is that it works, and will loosen deposits. The bad thing is that it works and will loosen deposits. BUT those deposits have to go somewhere...

Adding to Mike's post, I sat in on an engine discussion in an MTOA rendezvous that was led by the late Bob Smith (developer of the venerable Ford Lehman marine diesel). The subject of MMO came up as it often did. Bob answered a question about it's efficacy by asking for a show of hands if members saw any difference in smoke etc. when they added MMO as Bob always recommended. The result was a lot of hands raised. It seems to be snake oil that works. I bought my trawler new and used MMO from the git go so could not comment on it. The engine was just about broken in at 3300 hours when I sold it for the 48MY.

Bobk

[Top Hatt Craig]

Interesting topic, I have no experience with MMO but see it wouldn't be difficult to make your own. https://en.m.wikipedia.org/wiki/Marvel_Mystery_Oil