If the engine suffered oil starvation and one of the mains is partially seized, you'll have to come up with an explanation of how it can start and idle without any additional fuel feed.

It apparently idles within the range of the governor, an impossible task if a main bearing has "spun".

I am still trying to wrap my head around any idea of friction (internal or external) causing the limited power and RPM, but it seems to be the ONLY thing that HAS NOT been ruled out. However, the oil does NOT smell burnt. It was suggested to look for particles of bearing material in the sump and oil filter, but both were changed soon after the initial problem. I did not think to look for bearing material in the oil, pan or filter when they were replaced. The only other thing I could do is have an oil analysis done. The problem with that is that there is only about 20 miles worth of engine running on the oil. Most of that is idling, as it was running while being towed to the place where it is now (needed brakes and steering to work for towing it with a chain behind another 300SD). Again, I am all out of tests to do with the fuel delivery/timing system. As far as I am concerned, I am done replacing any parts with known good ones to test with. I still need to remove all the belts to rule out any external friction. Also, the odds that the friction could come from the trans is so far out there, that it is not worth the effort to make that test until EVERYTHING else is completely ruled out. Yes I understand that all that is needed is to remove the 6 bolts holding the torque converter to the flywheel. I will wait and see if removing the belts yields any results before proceeding with any other more involved tests.

You said that it ran a little better when you advanced the timing. This seems significant to me. One other thing, I didn't see it anywhere in the thread but may have missed it. Have you T'ed in a gauge after the lift pump to see what sort of pressure its putting out?

I have not checked the fuel pressure in any way. However, I am satisfied with all the other fuel related tests/parts replacement to rule out any and all fuel starvation issues. It did seem to run a little faster with the timing advanced, but still not enough to cause it to move any better under it's own power.

It is possible that if the lift pump is putting out less than it should that it could limit fuel above idle. If we're doing this systematically I think you should rule out lift pump pressure (gauges are cheap and plentiful) before moving on to more drastic tests.

NO
 

:o I do NOT want to be correct !!! :o

I am giving him an opinion based on knowledge - experience, and hope to be wrong. :(

The figure of one mile from impact to engine shutdown is deceptive, I suspect it was :eek: zero oil supply between 90 - 180 seconds at roughly 70 MPH. :eek:


For those wanting further data on this Oil starvation topic:

http://www.kingbearings.com/files/Engine_Bearings_and_How_They_Work.pdf
However there are some factors that adversely impact the oil film, changing the lubrication regime from hydrodynamic to mixed:
* oil starvation, high loads
* low rotation speed
* low viscosity oil
* elevated temperature additionally decreasing the oil viscosity
* roughness of the bearing and shaft surfaces

Engine Failure
Oil starvation is almost always fatal to any engine, and is usually the result of a failed oil pump, a plugged oil pickup screen inside the oil pan, or a low oil level. Bearings that have been damaged as a result of insufficient lubrication will be shiny and worn where the crankshaft journal wiped away the bearing material.

Design bearings that don't seize | Machine Design
A 1-in.-diameter shaft run at 250 rpm and starved of oil may take only 20 to 30 sec to seize, for example.

http://www.peachparts.com/shopforum/diesel-discussion/335833-engine-bearing-failures-how-avoid-them.html


.

I completely reread the thread again as well.

In post #109, you (the OP) definitely got the engine to run at nearly normal rpm's by slightly advancing the timing.


This piece of data CANNOT be dismissed. It is the only condition whereby the engine would climb in rpms.


The reason the engine won't make power is the fact that the timing is late.

If the IP is timed properly (that's no certainty), then you MUST replace the timing device. I understand that you believe it to be functioning fine, but you MISSED something in there.

I am unable to comment on the event that caused the problem which may well have involved oil starvation and been the reason the machine shut down. Since then the engine has been operated for considerable time, and there is a theory that has been put forth that says internal losses from a spun or otherwise damaged bearing or set of bearings is keeping the engine from running fast enough to exceed ~2000 rpm. In another post it has been postulated that the engine output at full throttle at that rpm is 35 or so hp.

My view is that 35 hp of internal losses is huge for a bearing system that may approach less than 5% of that at normal full load. There is nothing to address removing 35hp of heat from the bearings. The engine has been operated at that condition for quite a bit of time, and should be spewing bearing material. The oil should be contaminated from the runs since the pan has been replaced. And, I would expect the bearing to be unable to support any oil pressure once any measurable material has been removed. No one is reporting burnt oil smell, or a lack of oil pressure. So, there may be some bearing damage but it does not explain the 35 hp of load that would be needed to prevent the engine from continuing to accelerate, given the lack of continuing signs of damage that would be expected with 35hp of internal load. In my view the 35 hp would have caused the engine to seize by now.

On the 16 valve 190 the oil feed goes to the number one cylinder connecting rod bearing first, and when that bearing is even slightly worn, oil pressure (normally always pegged at 3, even with the engine hot and idling) drops dramatically. I am not familiar with this engine's oil schematic but by now if the connecting rod bearing was eating that 35 hp, the engine should knock loudly at all rpms. No report of unusual knocking.

This still points to fueling in my book. Don't know how, but no black smoke and the other symptoms sure sound like the fueling rate is limited by something.

Jim

Can the engine be turned over by hand with the glow plugs or injectors out? Before junking the car might be something to try.

If the bearings are going out wouldn't their be some damage to the rod bearings first and would not it be making a lot of noise?

Sorry, missed that. It's hard to keep track of chronology of events. Do you still have the oil pan and the crushed rubber piece on the bottom? Take a closer look at those parts and see if it could have caused oil starvation.

WHunter says the car was going 70 mph for a mile before it stalled. Is that true? Wouldn't running with low or no oil pressure for that long at high rpm cause more than one "spun bearing".

I don't suppose Brad looked at the oil pressure gauge after the impact? Maybe worth asking him.

Also ask him when the engine did not re-start after it stalled, whether the engine turned laboriously or did not turn at all. This may indicate the severity of the seizure at the time.

Isn't the IP's governor load sensitive? E.g., if the idle is 800 RPM in N, and you add some load to the engine by shifting the transmission into D, the governor will try to maintain 800 RPM without the need of you to add fuel by stepping on the throttle.

I have to ask how the timing device could have been damaged from bottoming out the suspension at 70 mph? Very unlikely for a simple and robust device.

At this point the poster does not want to spend a lot more time on the issue I believe.

If the original driver tried to restart the engine and it would not turn over it was most likely seized up and some damage occured. On the otherhand if the engine would roll over freely with the starter with no cool down period right after the quitting. The engine probably did not tighen up. Most people in my mind would try an almost instant restart.

There is also a chance the original owner left something out in his description of events that may have been important. It was reported the engine would not restart at the time of the event. How it would not restart seems not to have been mentioned.

What has been irritating me is I cannot decide what should or should not be coming out of the tailpipe in the current senario. Or if running the car at it's current maximum rpms for half an hour would be a good indicator of bearing friction.

The cooling system should not handle that much indicated engine loading without going too high I would expect is another test. If coolant temperature stayed normal I would have to almost assume it is not a loading issue.

Another question I asked long ago was if the throttle arm advance was linear or did the engine reach it's maximum rpm well before the end of the linkage was reached. Or just progressivly picked up rpm over its total arc.

Since there is no probability this engine is going to be rebuilt I probably would do the half hour to one hour test watching the coolant temperature gauge carefully. These cooling systems have no great reserve capacity usually. There are still perhaps a couple of variables or judgement calls required on the results though.

No heating combined with the owner statingthe engine did turn over well right away after the initial quitting I might consider jamming the mechanical timer in a well advanced position. If the engine would start that way you would want to pick up the rpms fast though as it would be far advanced at idle rpms.

Very true.

However, the range of the governor is quite limited. If you add a load to the engine beyond the range of the governor, the engine will stall. I'm quite sure a partially seized crankshaft bearing would apply more than sufficient torque to require the driver to add fuel with the pedal. The governor couldn't keep up.

Agreed.

But, what else do you have?

The engine ran almost "normal" when he advanced the timing with the IP.