803 Bogs Down and dies at 85% Load

[rhurey]

I have to rethink my calculations. Getting senile in my old age. V=IR

Yeah, was about to mention that...

P=(I^2)(R)
V=IR

You're 20K in elements are still 20K in power consumption in parallel. They'd drop in series because the voltage drop across each in series would be reduced depending on how many are in series.

Since you are using a pure resistance load, the % meter will be off. It's calibrated for a load of PF=0.8, pure resistance is PF=1.0, s, when you see 80% on the meter, you should be @ 100% load in reality.

I'd use a (good) clamp on meter instead of the mil load meter to start with, and adjust the % meter to match the clamp on.

Honestly, it sounds like you're not sure how much power you're pulling, and trying to troubleshoot what may not be a problem.

 

[USAMilRet]

OK her it is in a nutshell. The shutdown happens instateneous as soon as you reach aroud 40 amps per leg or at about 81% or 82% load. Black smoke, engine bogs down, fuel flow is still up at 6.5PSI engine RPM decreases rapidly, power output drops to 140VAC HZ is down below the scale end, engine oil pressure gets down to who knows, and this causes a oil pressure fault usually resulting in the engine dying. I determined this by adding more and more load on the genset until it bogged down. Sometimes I was able to back off the load and save the generator from dying but by then the oil pressure fault causes the DC system to shut down causing fuel flow to stop and the engine dies until reset of the crank switch.

Now I have no idea why this happens and it is repeatable time after time after time. Crank up the load bank to about 40 amps and the genset dies. It happens so fast that I can not even get a video of it right now.

I have some work to do on my load bank that will help so I am off to that right now and will be listening for questions.....

 

[USAMilRet]

low oil pressure shutdown? could the L.O.P shutdown switch be bad? might try single weight oil 30w or 40w and see if the engine will run long enough to get the rated load up to 100%. things are improving though. does this engine have an engine oil cooler???

It has 10W30 break in oil

 

[USAMilRet]

Yeah, was about to mention that...

P=(I^2)(R)
V=IR

You're 20K in elements are still 20K in power consumption in parallel. They'd drop in series because the voltage drop across each in series would be reduced depending on how many are in series.

Since you are using a pure resistance load, the % meter will be off. It's calibrated for a load of PF=0.8, pure resistance is PF=1.0, s, when you see 80% on the meter, you should be @ 100% load in reality.

I'd use a (good) clamp on meter instead of the mil load meter to start with, and adjust the % meter to match the clamp on.

Honestly, it sounds like you're not sure how much power you're pulling, and trying to troubleshoot what may not be a problem.

Yeah....senility....

Check the videos. I am using a good clamp meter to measure amperage....

 

[USAMilRet]

It has 10W30 break in oil

Oil pressure is fine until engine bogs down so far that the oil pressure drops enough to trigger the fault.

 

[justacitizen]

https://www.google.com/url?sa=t&rct...le/fid/15604&usg=AOvVaw3ZjyA77WJqnJxKG-tFrkE9

i hope this works. look at page 15

 

[Zed254]

ok if the fuel delivery is in spec .......

I'm still not convinced it is.......so, one more shot at fuel pump specs. Original primary fuel pumps were Facet 40193 as shown in TM 9-6115-642-24P on p67/153.

68 PAOZZ PAOZZ PAOZZ 72850 40193 ..PUMP,FUEL,ELECTRICA 1 1 MAIN

It appears Facet no longer makes the pump but I was able to find printed specs at 2 vendors that sell Facet pumps: https://www.cps-parts.com/catalog/eppages/facetpumps.php and https://www.finditparts.com/products/3685305/facet-fuel-pumps-40193n. The first vendor has a specification sheet that I've attached. 3rd row from bottom shows the 40193 specs as having a max pressure of 30psi and a flow rate of 10 GPH.

....or it could be a plugged G-17 inline filter.

 

[justacitizen]

on page 15 10w30 engine oil is for intermittent operation only. 30w oil is recommended for a narrow temp range. 40wt oil is not recommended. 15w40 fits the temp band and operation requirements. 20w40 is also recommended for hotter temp range. also is noted that break in oil is 10w30 for first 100 hours.

 

[justacitizen]

if oil was in spec 15w40 the engine would run cooler and carry higher OP and not shut down when more load is applied. might need to adjust governor for more fuel delivery?but black smoke indicates fuel might be OK. what would happen if the LOP safety didn't shut down the engine? in the LPW manual it indicates use of 10W30 oil could cause excessive oil consumption. what does this do to power???

 

[USAMilRet]

I do not think that the oil specs has anything to do with this. Using a 30W vs 40W is not that big of an issue. I am using 15W-30 break in oil because that is what you are supposed to use the first 1`00 hours then change to a 15W-40 depending on climate.

This is almost as if the generator sees a demand for 200 Amps at 83% load and wants to fulfill the demand and bogs down because it can't meet the 200 amp demand. At 40 or so amps it is fine. At 41 amps, the genset acts like it is overloaded. And this is exactly how I remember the gensets from when I was in the military acting, if you tried to put a too heavy load on them.

We had 3kw gensets that went to out shelter but needed a 5kw genset for use of the on board heater. Boy those fires for warmth in the shelters were life savers. Any ways, while trying to start the 5kw heater with a 3kw genset causes the genset to the try to meet the demand even though it can't so it bogs down and dies.

This is the type of shutdown that is happening at 85+/- displayed load.

 

[Guyfang]

I have just read this whole story, all 13 pages, twice. So let me recap it here. At this point, you can run the gen set, up to 79%, ( more or less) and it will run forever? Then if you increase it over 80-81%, ( more or less) the engine rpm falls off, you get some black smoke, and at some point in time, due to the engine low rpm, the engine oil pressure falls below the trip point, and the low oil pressure Safty switch triggers the fault indicator circuit "low oil pressure" and the engine shuts down? That about get it right?

You are missing the fuel cut off solinoid.

Are you running the set in emergencey by pass mode?

I assume you are holding the fuel cut off lever in the full rpm position with a wire or something like that. You are adjusting the rpm with the hertz adjust knob.

This can not be an electrical problem.

We need fuel, air and compression to make a Diesel engine run. One of those things is failings at ALLWAYS the same point in time.

If if you are sure that the air flow is clear, (and if you have taken the filter out, looked into the filter housing and hose, that should do it) then it can only be the other two. I have seen numerous air restriction problems in my life. This dosnt sound like one. Not if the engine can run forever at 79% forever. Have you ran it for long time periods at 79% load?

Fuel. If the fuel pressure stays the same, from start up to PAST the failure, can't be the fuel pump. If the fuel lines are clean, and proved clean, and in a serviable condition, then that's not it. If the injector pump inlets are clean, and proven clean, then the fuel system is good to that point. If the pop off pressure on the pumps has been checked, and is in within limits, that leaves the injectors. Testing them and the injector pumps is critical. But if they are in spec, then that leaves compression.

You our have told us that there is no sign of pressure on the crank case. So compression, (rings) should be good. The valves, well, that just dosn't sound like a valve problem. Not loosing power always at the same point, anyway.

Have I missed something? Any other clue you can add?

 

[Guyfang]

I do not think that the oil specs has anything to do with this. Using a 30W vs 40W is not that big of an issue. I am using 15W-30 break in oil because that is what you are supposed to use the first 1`00 hours then change to a 15W-40 depending on climate.

This is almost as if the generator sees a demand for 200 Amps at 83% load and wants to fulfill the demand and bogs down because it can't meet the 200 amp demand. At 40 or so amps it is fine. At 41 amps, the genset acts like it is overloaded. And this is exactly how I remember the gensets from when I was in the military acting, if you tried to put a too heavy load on them.

We had 3kw gensets that went to out shelter but needed a 5kw genset for use of the on board heater. Boy those fires for warmth in the shelters were life savers. Any ways, while trying to start the 5kw heater with a 3kw genset causes the genset to the try to meet the demand even though it can't so it bogs down and dies.

This is the type of shutdown that is happening at 85+/- displayed load.

If the gen set saw a 200 AMP load, it would shut down for an overload failure, not low oil. No gen set adjusts engine speed in referance to to load unless it a precise power gen set. Your 3 kW and this 10 kW are utility sets.

 

[justacitizen]

https://www.steelsoldiers.com/showthread.php?140596-Acquired-a-Military-surplus-load-bank/page2

informative with good vids of an 803A under 133% load.

 

[justacitizen]

I have just read this whole story, all 13 pages, twice. So let me recap it here. At this point, you can run the gen set, up to 79%, ( more or less) and it will run forever? Then if you increase it over 80-81%, ( more or less) the engine rpm falls off, you get some black smoke, and at some point in time, due to the engine low rpm, the engine oil pressure falls below the trip point, and the low oil pressure Safty switch triggers the fault indicator circuit "low oil pressure" and the engine shuts down? That about get it right?

You are missing the fuel cut off solinoid.

Are you running the set in emergencey by pass mode?

I assume you are holding the fuel cut off lever in the full rpm position with a wire or something like that. You are adjusting the rpm with the hertz adjust knob.

This can not be an electrical problem.

We need fuel, air and compression to make a Diesel engine run. One of those things is failings at ALLWAYS the same point in time.

If if you are sure that the air flow is clear, (and if you have taken the filter out, looked into the filter housing and hose, that should do it) then it can only be the other two. I have seen numerous air restriction problems in my life. This dosnt sound like one. Not if the engine can run forever at 79% forever. Have you ran it for long time periods at 79% load?

Fuel. If the fuel pressure stays the same, from start up to PAST the failure, can't be the fuel pump. If the fuel lines are clean, and proved clean, and in a serviable condition, then that's not it. If the injector pump inlets are clean, and proven clean, then the fuel system is good to that point. If the pop off pressure on the pumps has been checked, and is in within limits, that leaves the injectors. Testing them and the injector pumps is critical. But if they are in spec, then that leaves compression.

You our have told us that there is no sign of pressure on the crank case. So compression, (rings) should be good. The valves, well, that just dosn't sound like a valve problem. Not loosing power always at the same point, anyway.

Have I missed something? Any other clue you can add?

yes this is an engine problem. i am beginning to think maybe the cam timing might be off. what you think? the smoke at 70% aprox load says unburnt fuel. low oil pressure indicates"to me" wrong viscosity or to much heat. the engine it being killed by the safety for LOP so can't really establish how much grunt it has. one thing for sure though "it isn't running correctly" need to confirm that the injectors and the pumps are correct for this engine and application too.
y

 

[USAMilRet]

I have just read this whole story, all 13 pages, twice. So let me recap it here. At this point, you can run the gen set, up to 79%, ( more or less) and it will run forever? Then if you increase it over 80-81%, ( more or less) the engine rpm falls off, you get some black smoke, and at some point in time, due to the engine low rpm, the engine oil pressure falls below the trip point, and the low oil pressure Safty switch triggers the fault indicator circuit "low oil pressure" and the engine shuts down? That about get it right?

You are missing the fuel cut off solinoid.

Are you running the set in emergencey by pass mode?

I assume you are holding the fuel cut off lever in the full rpm position with a wire or something like that. You are adjusting the rpm with the hertz adjust knob.

This can not be an electrical problem.

We need fuel, air and compression to make a Diesel engine run. One of those things is failings at ALLWAYS the same point in time.

If if you are sure that the air flow is clear, (and if you have taken the filter out, looked into the filter housing and hose, that should do it) then it can only be the other two. I have seen numerous air restriction problems in my life. This dosnt sound like one. Not if the engine can run forever at 79% forever. Have you ran it for long time periods at 79% load?

Fuel. If the fuel pressure stays the same, from start up to PAST the failure, can't be the fuel pump. If the fuel lines are clean, and proved clean, and in a serviable condition, then that's not it. If the injector pump inlets are clean, and proven clean, then the fuel system is good to that point. If the pop off pressure on the pumps has been checked, and is in within limits, that leaves the injectors. Testing them and the injector pumps is critical. But if they are in spec, then that leaves compression.

You our have told us that there is no sign of pressure on the crank case. So compression, (rings) should be good. The valves, well, that just dosn't sound like a valve problem. Not loosing power always at the same point, anyway.

Have I missed something? Any other clue you can add?

Yes that is a good recap. The RPM drop off seems to be connected to any increase in load beyond that.

I am aware that I am missing the fuel cutoff/run solenoid. It is not necessary to run the engine and has no bearing on the amount of fuel metered as that is supposedly handled by the governor. The cutoff solenoid is on order and I am expecting it soon.

No, the genset is only running in normal mode.

Yes on the fuel lever and adjustment.

There appear to be no air restrictions. I have removed and inspected the entire air system and even looked into the intake manifold as far as I could with my little snake monitor.

The fuel is clean. Fuel flows with no issues. All 4 injectors are new and were replaced with the rebuild. All fuel metering was checked and one metering pump was replaced because it was borderline in spec.

No, you have missed nothing. This is what had the rebuilder/seller so confused about. For the life of him he could not figure out was was causing the 85% more or less stoppage.

All I can say is the shutdown happens exactly the way I remember the overloaded generator. It is like a switch that triggers on at 85% plus or minus load saying give me 200 amps now and the genset engine dies trying to up the output to match the demand placed on the generator.

 

[USAMilRet]

If the gen set saw a 200 AMP load, it would shut down for an overload failure, not low oil. No gen set adjusts engine speed in referance to to load unless it a precise power gen set. Your 3 kW and this 10 kW are utility sets.

I was being a smart a$$. But the end result is the same. A demand is suddenly placed on the generator (happens when you connect anything to it) and the genset ups the output to match the new load. But if you place a 5 kw load on a 3 kw genset, it will try to fill the demand before the protection cuts in. This means that the generator tries to provide the 5 kw but can not and puts such a drag on the engine that the engine dies from being overloaded.

 

[DieselAddict]

Have you checked for any problems on the exhaust side like a restriction in the muffler?

 

[USAMilRet]

yes this is an engine problem. i am beginning to think maybe the cam timing might be off. what you think? the smoke at 70% aprox load says unburnt fuel. low oil pressure indicates"to me" wrong viscosity or to much heat. the engine it being killed by the safety for LOP so can't really establish how much grunt it has. one thing for sure though "it isn't running correctly" need to confirm that the injectors and the pumps are correct for this engine and application too.
y

The LOP safety only kicks in after the deman can not be met by the engine trying to fill the demand placed on it by the generator.

The builder took the engine apart after the rebuild because they though the cam timing was off. If you go to the other thread of me picking up my genset, there are pictures in there showing the placement of the timing marks.

 

[USAMilRet]

Have you checked for any problems on the exhaust side like a restriction in the muffler?

I can find no restrictions in the exhaust system.

 

[justacitizen]

Have you checked for any problems on the exhaust side like a restriction in the muffler?

is there a spark arrestor built into the exhaust? could the engine have been assembled with the wrong pistons? or cam?