Engine at all oil and over revved like mad!!

[atoll]

Originally Posted by Dockhead

How could all the oil in the sump rise up through the block and head and end up going through the breather? I'm not questioning your theory, I'm just really curious -- I can't at all imagine it.

These engines don't have air filters -- they have a rough circular screen. The breather attaches to the flange of the screen by a rubber hose from the valve cover.

high crankcase pressure,caused by blowby will force oil out,plus crank turning at 6000 rpm turns oil into droplets.

most engines have large galleries between the sump and the head/tappet cover for lube oil to drain back to the sump by gravity where the connecting rods are located

over filling or diesel mixing with the oil,just starts the overrun,then it feeds on it self till no oil left,or no air,or engine explodes!

[atoll]

another possable scenario is a burnt/worn valve causing lack of compression and diesel entering the crank past the rings

[stevensuf]

So a duff piston ring, or bad valve will both let oil through, im wondering if we threw a ring as when it started it made a rattly noise before going runaway, if so then im probably looking at a scored bore/piston as a bare minimum. the engine at least is not siezed and turns over by hand/starter with no bad noises as yet.

[glenn.225]

A piece of 1/2 plywood with 1/8 sheet rubber contact cemented to it and a handle on other side, sized appropriately for intake makes a great "Chicken Board". Remove filters, etc so you can cover air intake fully. Shuts down a diesel instantly and cheaply. Always have one at hand when doing anything with fuel governor systems. I always had one except once, and I never want to hear a 6V53 scream like that again guys were dropping tools and running.

[model 10]

Originally Posted by stevensuf

So a duff piston ring, or bad valve will both let oil through, im wondering if we threw a ring as when it started it made a rattly noise before going runaway, if so then im probably looking at a scored bore/piston as a bare minimum. the engine at least is not siezed and turns over by hand/starter with no bad noises as yet.

I like the "duff piston ring" terminology but you don't "throw" a piston ring. You throw valves, rods and maybe a piston. I think you just break a ring. Hope you didn't. I've seen broken rings and I don't think they make any noise. If it were a broken valve your cylinder would probably be junk because it it's pretty hard on a piston. If it were a bent valve you would probably be able to tell by the way the engine cranks over. You would have no compression in one cylinder. Does not sound like you have that

[rtbates]

Originally Posted by stevensuf

the oil was less than 150 hours old, there was a funny rattling noise when we first started the engine, which was strange.I wish it was something easy.

Sounds like ti could very well be a broken piston ring, or even a broken piston. That would certainly allow the oil to blow by the piston into the combustion chamber and go away out the exhaust. Is the exhaust un-usually oily?

good luck with the fix.

[Cheechako]

Whatever you do, be careful how you shut it down blocking the intake... you need something heavy or solid.... not your hand! and not something that will be sucked right in there....
I've heard of this before but never heard anyone who actually had it occur, sounds scary.
To determine if you are getting fuel into you crankcase, how about this plan: Remove injectors so the engine wont start, and crank the engine for quite a bit of time (in no more than 20 seconds per crank) drain the pan and see if fuel comes out...? I dont know if that's very feasible or not.....

[LeaseOnLife]

I wouldn't try to start it, but rather remove injectors and do compression tests.

[sww914]

Nobody has addressed the fact that in warmer waters your engine may run a bit warmer and need thicker oil. They don't even sell 30w around here, it's all 40 and 50 and even some 60 for single grades. Multi grades go up to 25/60 here.
I think 30w may be too thin for summer in Florida.

[stevensuf]

the oil was 15-40 mineral, no luck with a co2 extinguisher yet... may try with new oil and block of wood to stop air?

[sailcruiser]

I'd check the governor.

SC

[stevensuf]

the governer wont cause the engine to consume 5 litres of oil in 3 minutes

[Charlie]

I had a problem with my engine a 4JH4E. It had a faulty injection pump with a transient problem. When it was bad it would pour diesel into the crankcase and then if the crankcase got too full the mix of oil and diesel would travel up the breather tube and cause the engine to smoke and run away. I always was able to catch it right away so it never consumed a large quantity of oil from the crankcase.

If it were me I would check the lift pump for holes -- a common problem with these engines. Then I would change the oil. Run it for a half hour and then change the oil again. From there monitor the oil level and make sure that you aren't making oil. If you are the next step is to have the injection pump tested. I would advise that you have it tested before the pump is disassembled disassembled. Cost me $1600 to have the pump rebuilt. When they tested it they couldn't find a problem. Held pressure fine. Took it off discussed it and then ran the pressure test again and it was blowing bubbles bad. Good luck with this.

Not saying the other guys are wrong. Just my experience with this particular engine.

[stevensuf]

Charlie, we have found diesel in the sump, you are spot on,it has something to do with either the lift or injector pump!

[atoll]

Originally Posted by stevensuf

the governer wont cause the engine to consume 5 litres of oil in 3 minutes

you need to seperate cause and effect when trying to work out what happened.

ie EFFECT with an over run it is quite possable that the engine running out of control forced the oil up the breather and was consumed by the engine via air intake.
once an over run has started cutting off the fuel supply will not nessacarily work to stop the engine,as it is vaporising and ingesting the oil from the crankcase,and using this as fuel

CAUSE
1 valve not seating properly causing a cylinder not to fire and leak diesel into sump.
2 govenor weight or spring dropped off causing injector pump to supply max fuel
3 fuel entering crank via faulty injector pump
4 fuel entering crank via lift pump
5 fuel entering crank via broken ring
6 oil level too high
7fuel control on injector pump /faulty/broken spring
8 petrol fumes or other combustable vapours in engine roon,ingested by engine
9 poor quality oil that has become too thin

im sure others can think of a few more causes