Detroit Diesel injectors need "steam turbine oil"

My 6-71 suffers when out of service like all early DD.

The injectors can get stuck. This means perhaps a high throttle start with no way to shut down.

On coaches there is a flap & solenoid to close the intake to the blower , but not
usually on boats.

My WWII full Grey Marine book sez to run the engine on "steam turbine oil" before shutdown.

Any suggestions , I have been thinking of ATF , but perhaps there is a better choice?


HV8 injectors.

What is the API spec for "steam turbine oil"?

I am being a smartass for sure. But I suspect that steam turbine oil meant something in the 1940s but who knows what it is today. The base oils and especially the additives in today's motor oil are worlds apart from the 40s. ATF may be ok, because it is modern and thinner than 30W motor oil. Does thinner make it work better? Again, who knows?

David

Thinking ATF would be great. Marvel Mystery Oil would work too.

Turns out you can buy turbine oil on Amazon...

I know turbine oil does not have emulsifying agents like motor oil. But for your purposes, engine oil should be fine.

When a Detroit has been sitting, the best check is to take off the valve cover, disconnect the governor link and and work the rack by hand (engine off). It easy to see any stuck injectors. Usually with a little rack movement, back and forth, frees up any injectors. If you use a fuel conditioner with a lubricant, stuck injectors rarely happen. Haven't seen one in more than 10 years. Years ago with pre-EPA diesel, I started numerous Detroits in mothballed ships that sat 20 or more years without ever having a stuck injector. In fact, they started and ran fine on whatever old fuel was in their tanks. As usual with Detroits.

My current boat sat 6 years, below zero winter temps, without any mothballing and had no stuck injectors. Twin 671s naturals.
You can buy internal injector parts, plunger, tips, etc. online.
Pic from an old manual, but parts are the same.

My F.L. has an updraft air intake. I have considered making a coffee can type of choker in case of a run away. I do have a manual wire to the solenoid for emergency shut down if the electronics fail but a tight fitting can on the air intake might be a good idea. pete

It may be rare , but I always check and have found 2 times the injectors stuck.

We operate with diesel , , just diesel, but I guess I will be looking for a couple of gallons of fuel conditioner with lubricant.

Howes ? Stanadine? , any ideas?

Perhaps it is goodies in yesterdays oil that was removed for the modern air police requirements that kept injectors from sticking?

"But for your purposes, engine oil should be fine."

The fuel being consumed is the only lubricant in a DD injector, no engine lube oil.
When operating a massive amount passes thru , but only a bit is taken and consumed on each stroke.

A rocker arm , similar to what actuates a valve in a 4 stroke creates the injection pressure , the "rack" moves in unison the metering arms , that are what sometimes gets stuck inside the injector.

Pulling the injectors and keeping them submerged in ATF , would work, but is too much work to do for a 6 month shutdown..

Our injectors are HV 8 , the 8 stands for 80cc.

That means 80cc every 1,000 strokes.

I have many times dealt with DD injectors stuck from sitting. The fuel seems to break down into a gum that sticks the plunger to the barrel. I field strip the injectors and clean the bore and plunger with acetone, then lube with clean diesel and all is good.

I think something breaks down in the diesel when sitting. Diesel is a veritable soup of chemical compounds, not all are that stable. I think that is what is going on.

Lube oil is much more stable brew. FF, you can probably valve out your racor supply, pop the lid off, start engine and pour in maybe a gallon of lube oil as engine draws fuel out of the racor. When your jug is empty, the injectors will be filled with a mix of fuel and lube, probably mostly lube. Shut engine down and refill racor, you should be good to go.

Or take supply line to the gear pump loose and stick it in a jug of lube. That will get more lube % into the injectors as it won't be mixed in the racor.

I use Archoil AR6200 because it does several other things besides lube, biocide, and better mileage. I add it every fueling and to tanks that have sat too long. If I add it a little stronger, I get almost 10% better mileage @1800 with twin 671s. Available on Amazon and eBay or direct.

"you can probably valve out your racor supply, pop the lid off, start engine and pour in maybe a gallon of lube oil as engine draws fuel out of the racor. When your jug is empty, the injectors will be filled with a mix of fuel and lube, probably mostly lube."


Will it run on CFII 40 wt lube oil?

FF said:

"you can probably valve out your racor supply, pop the lid off, start engine and pour in maybe a gallon of lube oil as engine draws fuel out of the racor. When your jug is empty, the injectors will be filled with a mix of fuel and lube, probably mostly lube."


Will it run on CFII 40 wt lube oil?

Click to expand...

Yes, especially if it is not pure 40wt. There will be some diesel fuel mixed in doing this. After storage, the first cold start might be a little rough til the lube flushes through. Ignition temp of lube is actually lower than diesel, but it does not atomize as well.

To my Detroit customers, I don't recommend doing this unless forced to lay up for a long time (longer than winter). Here in NC we don't need to. I prefer they start them every couple of weeks to smear oil on the open liners. Run for five minutes will do it. Otherwise they rust. Side benefit is it keeps the injectors free. It is better to run under load, but if that is not practical a five minute run is better than a rusted liner or a stuck injector.

FF, your old engine should have the emergency shutdown damper on the blower...

"FF, your old engine should have the emergency shutdown damper on the blower..."

I wish , Grey Marine never stuck them on, tho the bus folks claim using the emergency shut down can suck the seals out of the blower (8V71)

Picked up the DD rebuilt injector $103 , and was surprised the core refund was only $8.00 . I guess the HV series isn't in demand that much since about 1950.

Kept my stuck unit so I can open it up and see what gives inside. $8.00 is a cheap education.

Taking one out then setting the injector height and running the rack is a PIA .

I will get some AR6200 for the tanks and tru lube oil in the Filter next year if the boat isn't sold.

Would think someone in the Bahamas would want a 50 ft Utility with 10 ton cargo capacity and the ability to live aboard.

The only time I've had stuck injectors was when I had a head gasket leak and had trace amounts of water in the oil and the rack was getting rusty, rebuilt motor and everything has been working like a champ.