Diesel Engine Fiasco Confessional

[SkiprJohn]

Please don't do these mistakes. Diesel engine fiasco. I bought my boat in ’90 with the full intention of finishing her and sailing to the Big Island from Oahu but got waylaid in construction due to retirement, a move, building a house and many other things. At the time all this happened I was working on a replacement engine for the boat. The original engine was a Mercedes OM636 and had been trashed before I purchased the boat. So, my original thought was to buy a replacement engine just like it so it would be an easy refit. I decided to get a newly rebuilt from ThermoKing then transfer all the marine gear to it since it was the same block they used for their refrigeration units. That was big mistake #1. I started the project. There was no crankshaft pulley bolt hole in the ThermoKing version. Out comes the crankshaft. Hole gets drilled. Crankshaft gets put back. Original trashed engine oil pan gets put on the new engine after modification to fit large oil pump. The old flywheel with new starter ring gear gets fitted. Somewhere in there the fuel injection timing gets thrown off a few degress. That was big mistake #2. Then stuff happened, I moved the engine to the Big Island and stored it on its side thinking I’d get right back to it. That was big mistake #3. Many years later. I weld up some engine mounts, move the engine upright and want to fire it up. I soak the cylinders with oil for a time, then turn the engine over by hand, remove the oil from the cylinders. Check the glow plugs. Have the starter from the trashed engine rebuilt. Make certain there is oil in the engine. Bleed the fuel lines. Turn the engine over many times. No firing!! Big mistake #4 was not filling the fuel injection pump to the proper oil level before turning the engine over many times. I didn’t know that right away. So, I spray a mixture of motor oil and kerosene in the intake to see if this will bleed the system enough to get it going. That was big mistake #5. Since the injection timing was not set properly the engine did a lot of pre-ignition because I tried about 10 times hearing it run until the sprayed fuel ran out thinking it would run on its own the very next time. I should not have done that at all.
At this point I knew something was very definitely wrong. I decided to pull the head, found two glow plugs were burned and they weren’t before. When I looked at the head, two prechambers were burned and out of round. Since I had the head off and I wasn’t going to start the engine soon I took the fuel injection pump in, had it and the injectors redone. I got a different head from an engine I found in Oregon on eBay. Put it all back together. Still no firing!! I then decided to check the engine fuel injection timing and line up all the marks. After I lined up all the marks, replaced the fuel injection pump, adjusted it for fuel feed and bled the fuel system there was a different sound coming from the injectors. They were making a faint popping noise when they had no air in the injector lines. I hooked up all the wiring, cooling water lines, ran a garden hose to the engine, routed the exhaust away from the house. I heated the glow plugs for 45 seconds and fired and ran after the second rotation of the engine. Runs perfectly now. Still have to install it but it runs great. Many years, many mistakes made, about $2000 in additional costs but the engine will be great and I learned a lot about diesel engines..
Lessons learned: Don’t buy an engine for a boat rebuild until you are just about ready to go in the water.

Not marine related, but a good story just the same, Back in my trucking days, the company mechanic decided to build one of the old 8V92's we had laying around. He went all out. 120 injectors, big turbo etc. He fired it up in the shop, but forgot one minor detail. ALWAYS have a fuel cut off when starting a new diesel. Especially a Detroit. I am pretty sure it hit 6000 rpm before someone was crazy enough to get close to the thing and put cardboard over the intake. Amazing it didn't grenade.

[SkiprJohn]

Aloha Kai,
Good thing to always have something solid around to put over the intake in case of a runaway. Funny that it didn't just suck the cardboard in the intake and keep on running.
JohnL

That point came up. The agreed reaction was to RUN!

[markpj23]

The Navy 6-71s I worked around also had a tedency to suck the crankcase oil into the blower and keep running on that after the fuel cutoff was tripped.

[SkiprJohn]

Aloha Mark,

My neighbor, Navy vet too, watched a runaway 6-71 as it was ready to go ballistic. He said the engineer took his white hat, dipped it in the bay and threw the salt water hat and all in the intake. Stopped the the thing cold. Not recommended!!

Regards, --JohnL--

[SkiprJohn]

An additional comment to my original post. I now have a brand new everything in a very heavy marinized engine designed in the 50s for Mercedes 170 and 180d cars. Could have had a good used Yanmar for the cost and would have saved many many hours and aggravation.
Anyone constructing or renovating please consider what I've had to say.
Regards, --JohnL--

[Talbot]

One of the good selling points for the Beta series of engines in UK is that they are designed to make replacement of other makes a simple affair, in that the engine mounts can be set up to mimic others. The engines are based on well proven kubota blocks so spares are easy, the engine is reliable. surprise surprise, a lot of boats are being retrofitted with these!.

I'll tell ya, a big diesel running away is an erie sound. I have also heard of them sucking oil up into the turbo, and continuing to run, but I took it as a wives tale. Never seen it happen.
John, Advice well taken. It is amazing the logic that drives one to stick with a project like that. How many of us have spent $3 in gas to find a gas station that save us $2 in a tank. I guess it is the "This thing isn't going to win!" attitude It wins over common sense every time.
Talbot, do you have stock in Kabota?

[Lloyd Price]

Whilst helping sail a 50' mono from Dunk Island to Melbourne (Australia East Coast) we had the 6 cylinder Ford engine run-away. Very scary, so much so my family of three girls were packing their bags ready to jump overboard. Never could work out how they were going to get the bags ashore?

Motor stopped on its own accord by siezing ... what a noise! Cause of run-away ... a split in fuel pump diaphram which filled the sump with dieseline ... the crankshaft did a great job of frothing the fuel/oil mixture and the fumes were sucked into the combustion chambers fueling an uncontrolled motor.

I was very impressed with this old motor, as, with the fuel pump repaired, it started first go and took the craft all the way to Melbourne.

[Alan Wheeler]

They are noisy alright. You think each piston is going to come out of the top of the head;-)
The engien would most likely have been running on pure Oil/Desiel mix, not the fumes. As the oil level builds, it eventually gets to the sump breather and is sucked raw through the air intake manifold. It takes a great gulp of the mixture and "runs away" with itself sounding like 6 large hammers belting away at the top of the head. I imagine you would have created a smoke screen a WW2 battle cruiser would have been proud of:-)
The siezing part obviousely wasn't a sieze due to the fact it started again, but it most likely was enough predetonation that it stopped the engine solid by firing well before TDC. Kind like a hydraulic affect, but not as detromental to the engine. If enough fule oil was sucked through, a haydraulic is actually possible and theat would have been death to the engine at that speed. I have seen a Block cracked due to a major hydraulic. Although this one was Water not run away though.