16-92 broken valve question

Were these Reliabilt parts or DD parts? Head etc? Is it still under the 90 day DD warranty? Several things could cause a valve to break, water in the fuel. A defective valve, valve guide, or seat, a rocker arm that wasn't properly installed/adjusted or just plain sitting for a long time without being run.

How will water in the fuel cause a valve to break if it hadn't already rooted the injector?

Please re read my post, there was no mention of an injector damage in the post I referred to which is why I asked.

Use your imagination but it probably makes sense immediately if you have an Android phone from what I can see online.

You can't compress water, so provided it gets past the injector without splitting the tip, a little water in the combustion chamber can break a valve. Rare, but can happen.

I looked at a 16v92 boat that hadn't been started in a year. They started the engines before a survey seatrial and the stbd engine must've had the o-rings fail in the heads and water in 2 cylinders and bent 2 rods. Anyways, when they took the valve covers off, all of the rocker arms were very very rusty, I had never seen anything like it.

Yes, could've been any engine. The o-ring failure though is mostly a 92 thing as not many engines use o-rings to seal the heads and from sitting and old coolant. But just went to mention how a marine engine sitting in a saltwater environment can degrade VERY quickly. You could never run a diesel farm tractor and let it sit in a barn for 10 years and most of the time they'll start right up with fresh fuel and fluids and run fine.

Many old diesels on land will start after years with the same fuel and oil in them that was in them when they last ran. I am not saying that is the best way to go but that it is quite possible.

I wish I would have only had a bad valve last year on my 12v92. Unfortunately I did "drop a valve" and it was much more than swapping a head and a turbo. When the piston pushed the valve back up the stem went right thru the head. Exhaust, coolant and oil all mixed rapidly and then the remainder of the valve proceeded to beat the heck out of the piston. So you were very lucky and as you said, did not drop a valve like I did.

Capt J, your comments hit close to home for me, and explained some things I've been wondering about for a while.

I work in the factory (Continental AG, formerly Motorola), where we used to make the DDEC (Detroit Diesel Engine Controller). Back in the 90's and early 2000's, we made the DDEC III, DDEC IV, and for while the DDEC V units.

I was the Customer Returns Analyzer for these units. I got to perform the electronic "post mortem" analysis on these DDEC units that came back from the field with various forms of damage. It was a fascinating product, and I loved that job.

Long story short-- suddenly around 2005 we lost the DDEC contract, and were told DD had found a lower cost supplier. I was rather surprised to hear this, as Detroit Diesel had supposedly been very pleased with our performance as a supplier.

Now hearing you say that DDEC had been bought out by MTU, it all makes sense.

I thought Sturdy was the manufacturer of the engine controls (not the engine computer)? I just had all that stuff shipped back and forth to Sturdy to have it checked/fixed and sent back. This was a DDEC 2.5 boat. Sturdy manufactures the engine controls for CAT and did for MTU up until recently. (Throttle/gear shifters etc.)

Hi Capt J,

Yes, Sturdy may well be the manufacturer of the user-level engine control system. Motorola (at the time) built the ECUs. If ya ever had the chance to pry one open, you'd see the 'Circle-M' for Moto on the main micro. Made right here in the middle of Central TX, no less.

The main processor in the DDEC III and DDEC IV was an industrial grade Power PC micro, in 16/32 bit quad flat-pack form. There was a custom ASIC made for us by AMD (if memory serves) that was in charge of the injectors.

The reason for the dedicated ASIC was because of the "golden rule" in DDEC controller land was 'Thou Shalt Not Miss An Injector Event'. That is, it simply wouldn't do for the main micro to be preoccupied handling something like a CAN bus communication task when a cylinder comes up for injection. So the ASIC was focused on real-time injector management, while the main micro oversaw general ECU events.

The operating software (Strategy) was flashed into a couple of EPROMs, and the main memory was kept 'alive' by an internal 3.2V Lithium battery. We warrantied the DDEC unit for 5 years, which happened to be the life expectancy of that little battery .

DDEC V was the last DD ECU model I worked on. It had the newer BGA version of the main micro which ran on 3V (although it still used that old 5V ASIC from AMD because they had made like a bagillion of 'em and they were dirt cheap by that time).

It's funny-- I've never laid hands on an actual Detroit Engine, but I've had many hundreds of the ECUs come across my workbench. They'd come back from the field with a variety of damages, the description of which would fill up a whole 'nother post.

I was sad to see DDEC go away from our factory. In general, our 'industrial' customers such as DDEC, Allison, and Cummins, understood that a quality product will cost what is necessary, and they didn't price-pick too much. This is in contrast to our automotive customers such as BMW, Ford, GM, etc... who tend to nit-pick about every little cost point.

(By way of disclaimer, I should say here that I'm not in management or a spokesman in any way for my company... just an old grunt level technician who enjoys talking about the art.)

Peace and take care.

Thank you for the information. I enjoyed reading about the history. You might do well starting a little business fixing the cpu's.