Bought another non-running 802a, begins to start, then falls off (Now a fix up thread)

[Digger556]

Removing the side cover was no issue, but the gasket got destroyed. Removing the pressure relief was easy. I love how servicable the engine is.

Once open, I think I understand what might have happened. Though there was no water when I changed oil, it is clear there was at least some moisture in the crankcase prior.

 

[Ray70]

Oh yea, definitely had some water in there at some point.
When searching for a cover gasket, search by DN2M and / or LPW2
DO NOT search MEP-802A or you will pay way too much.
PN is 752-10802 , it's called a crankcase door gasket.

Joint, Crankcase Door LPA/W/2 - 752-10802 941-315 Genuine FG Wilson part | eBay

Genuine original part for FG Wilson generator set. Joint, Crankcase Door LPA/W/2 - 752-10802 941-315.

www.ebay.com

 

[Digger556]

Thanks Ray, I was surfing around for the best deal on those.

 

[Guyfang]

The way we approached this when a set had this problem, or under pressure was to drain the oil, and fill the crank case up with ATF. Run it 15-30 min, and drain the ATF out and change the filter. 99% or the time this helped fix the problem, and gave the engine a real good cleaning out.

 

[loosegravel]

Thank you! Glad to help and glad to share my experiences, and yes.... been there and seen that! I've had at least 2 with the same issue, one was a pretty new, low hour machine... super clean. Ran fine in the warm weather, ( probably just barely got by with warmer oil ) but if temp was below 20F the oil was thicker and it would do the same thing, but like 80-100 PSI, not 240!
Crankcase was clean inside and relief valve looked good, but it would stick closed at times.
I have a feeling mine was stuck partially open and Digger's is completely frozen shut.

So, on this topic what's the risk of piston to valve interference when the oil pressure relief valve is stuck, thus causing bent pushrods, bent valves etc? Have you seen this on the DN2M, DN4M engines?

 

[Ray70]

The short answer is Yes Absolutely valves can touch and pushrods can bend.
I have never seen one with a bent valve because they just barely touch and they touch perfectly flat. Flat valve to flat portion of the piston.
I've seen plenty of pistons with valve imprints in the carbon layer on the piston as well as plenty of bent pushrods.
However, these were not on engines with the oil pressure issue.
The more common problem with the DN2/4M is that if you loosen the rocker arms the lifters will immediately expand fully.
When you tighten the rockers back down, the lifters do not compress immediately, the valve just opens up a little.
If you throw the valve cover back on and immediately crank the motor over, the valve will hit and the pushrod will bend.
You have to tighten the rocker arms and let the motor sit 20 minutes. I then spin it 1 revolution by hand and let it sit another 20 minutes.
It even tells you right in the engine TM not to crank it over immediately after messing with the rocker arms!.

So the long answer is that the valves definitely can and do sometimes hit the pistons, the result is almost always a bent pushrod but I have never seen it happen as a result of the oil pressure relief valve being stuck as far as I recall. It has always been due to other problems, as well as the mechanic ( me ) not reading the TM before messing with rocker arms! BUT there is really no reason it couldn't happen as a result of the oil pressure issue, I just haven't seen it personally.

 

[loosegravel]

The short answer is Yes Absolutely valves can touch and pushrods can bend.
I have never seen one with a bent valve because they just barely touch and they touch perfectly flat. Flat valve to flat portion of the piston.
I've seen plenty of pistons with valve imprints in the carbon layer on the piston as well as plenty of bent pushrods.
However, these were not on engines with the oil pressure issue.
The more common problem with the DN2/4M is that if you loosen the rocker arms the lifters will immediately expand fully.
When you tighten the rockers back down, the lifters do not compress immediately, the valve just opens up a little.
If you throw the valve cover back on and immediately crank the motor over, the valve will hit and the pushrod will bend.
You have to tighten the rocker arms and let the motor sit 20 minutes. I then spin it 1 revolution by hand and let it sit another 20 minutes.
It even tells you right in the engine TM not to crank it over immediately after messing with the rocker arms!.

So the long answer is that the valves definitely can and do sometimes hit the pistons, the result is almost always a bent pushrod but I have never seen it happen as a result of the oil pressure relief valve being stuck as far as I recall. It has always been due to other problems, as well as the mechanic ( me ) not reading the TM before messing with rocker arms! BUT there is really no reason it couldn't happen as a result of the oil pressure issue, I just haven't seen it personally.

I too learned from reading the TM last year when I torn into that DN4M with the bad pistons/rings. It clearly describes how to bolt down the rocker arms like you just wrote about. Without reading that information in the TM, I could have easily done some damage to an engine that I just finished putting back together by turning the engine over with the starter.

 

[Digger556]

A step forward, a step back. My new gasket showed up, so I got back to work today. First thing was tearing apart the pressure relief. It was definitely stuck. After removing the retainer and spring, the plunger would not come out. I flipped it over and had to tap it out with a hammer and punch. Very nasty inside. No rust, which is what I expected, but full of sludge, like river bottom mud. It was plugging the relief port holes in the plunger.



I soaked the parts in diesel and gave them a good scrub, then reassembled everything. I added 1 qt of ATF after reading Guyfang's suggestion and topped off the crankcase with 15w-40.

The engine fired right up, holding 55-60 psi. Then after 2-3 seconds, it died, and I cannot get it to restart. I opened the injector lines, the number 1 injector was still primed, but number 2 needed repriming. Still could not get it to start.

Some observations:

1. It is trying. I manually flip the fuel stop lever back and forth during cranking and there is a noticeable difference in rpm and starter effort.

2. The exhaust was cleaner this time and there was no white/grey smoke when it died, so I still believe there is compression.

It could be a weak fuel pump now, but its late, so I will try again tomorrow.

 

[loosegravel]

A step forward, a step back. My new gasket showed up, so I got back to work today. First thing was tearing apart the pressure relief. It was definitely stuck. After removing the retainer and spring, the plunger would not come out. I flipped it over and had to tap it out with a hammer and punch. Very nasty inside. No rust, which is what I expected, but full of sludge, like river bottom mud. It was plugging the relief port holes in the plunger.

View attachment 889198

I soaked the parts in diesel and gave them a good scrub, then reassembled everything. I added 1 qt of ATF after reading Guyfang's suggestion and topped off the crankcase with 15w-40.

The engine fired right up, holding 55-60 psi. Then after 2-3 seconds, it died, and I cannot get it to restart. I opened the injector lines, the number 1 injector was still primed, but number 2 needed repriming. Still could not get it to start.

Some observations:

1. It is trying. I manually flip the fuel stop lever back and forth during cranking and there is a noticeable difference in rpm and starter effort.

2. The exhaust was cleaner this time and there was no white/grey smoke when it died, so I still believe there is compression.

It could be a weak fuel pump now, but its late, so I will try again tomorrow.

It sure sounds like you’ve got the oil pressure issue resolved. Have you replaced both of the fuel filters yet? You could very well have a restriction there. With the S1 in the run position you should have a steady stream of fuel returning to the tank.

 

[Digger556]

It sure sounds like you’ve got the oil pressure issue resolved. Have you replaced both of the fuel filters yet? You could very well have a restriction there. With the S1 in the run position you should have a steady stream of fuel returning to the tank.

Yes, I did that first before attempting to start the engine. There was good flow at the injectors and purge vents on the canister filter. The old filters still looked really good. Based on hrs and date written on the filters, this engine has sat a long time without being run.

 

[loosegravel]

Yes, I did that first before attempting to start the engine. There was good flow at the injectors and purge vents on the canister filter. The old filters still looked really good. Based on hrs and date written on the filters, this engine has sat a long time without being run.

Do you believe that the fuel rail is moving freely? Does the engine sound like it has compression when it’s cranking over? It’s apparent that you’ve had several of these units before.

 

[loosegravel]

Yes, I did that first before attempting to start the engine. There was good flow at the injectors and purge vents on the canister filter. The old filters still looked really good. Based on hrs and date written on the filters, this engine has sat a long time without being run.

I’m sure you’ll get it figured out. Tomorrow’s a new day. A cup of coffee in the morning and it’ll be running in no time!

 

[Digger556]

Success! I didn't nail down exactly the root of the problem, but I pulled apart the rear injector and verified no junk internally and plunger moved freely. I reset the injector positions and verified rack function, fuel return flow, and re-bled the injector lines. Hit the starter and it took off!

With the engine running, there are some new problems to solve. The FU1 fuse was blown when I first received the generator. It was replaced, but now with the engine running, it has blown again.

The frequency meter and oil pressure gauges are dead, so need to dig into that.

The best news is that it does make power at the convience outlet and the output lugs, so there is hope for this unit to ride again.

Thanks everyone for your help and suggestions, especially Ray for nailing the oil pressure issue. I'm no expert on these units, but this is the second one I've purchased and brought back to life with this group's help.

 

[loosegravel]

Success! I didn't nail down exactly the root of the problem, but I pulled apart the rear injector and verified no junk internally and plunger moved freely. I reset the injector positions and verified rack function, fuel return flow, and re-bled the injector lines. Hit the starter and it took off!

With the engine running, there are some new problems to solve. The FU1 fuse was blown when I first received the generator. It was replaced, but now with the engine running, it has blown again.

The frequency meter and oil pressure gauges are dead, so need to dig into that.

The best news is that it does make power at the convience outlet and the output lugs, so there is hope for this unit to ride again.

Thanks everyone for your help and suggestions, especially Ray for nailing the oil pressure issue. I'm no expert on these units, but this is the second one I've purchased and brought back to life with this group's help.

Good work!

 

[kloppk]

Did you check the output frequency with an external meter to verify the RPM is set correctly?

 

[Ray70]

What size fuse did you put in there, was it 30A?
I've seen them blow if the batteries have an issue, but if batteries are good and you had a 30A fuse in there and it keeps popping you will need to do a little digging.

 

[Digger556]

What size fuse did you put in there, was it 30A?
I've seen them blow if the batteries have an issue, but if batteries are good and you had a 30A fuse in there and it keeps popping you will need to do a little digging.

No, it had a 20 amp in there and I stupidly put another 20A in without thinking. 30A is already on order.

So I'm reading the TM to diagnose the frequency meter issue, and step g. says "Multimeter indication should be 0.096 to 0.104 DC milliamps." Is that really ~0.100 milliamps or should that read 96 - 104 milliamps?

 

[kloppk]

...
So I'm reading the TM to diagnose the frequency meter issue, and step g. says "Multimeter indication should be 0.096 to 0.104 DC milliamps." Is that really ~0.100 milliamps or should that read 96 - 104 milliamps?

The reading in the TM is in milliamps. So ~ 0.100 milliamps is the expected measurement at that step.
The Freq Meter is a 200 microamp full scale deflection meter. It takes 200 microamps to make it read 65 Hz. It takes 100 microamps to make it read 60 Hz.

0.100 milliamps equals 100 microamps.

 

[Digger556]

The reading in the TM is in milliamps. So ~ 0.100 milliamps is the expected measurement at that step.
The Freq Meter is a 200 microamp full scale deflection meter. It takes 200 microamps to make it read 65 Hz. It takes 100 microamps to make it read 60 Hz.

0.100 milliamps equals 100 microamps.

Thanks for clarifying

 

[Digger556]

This month I dug back into this unit. Many of the gauges were non-functional and even since it ran last, the AC voltmeter quit working. I have swapped nearly every gauge off my parts donor unit to make this one functional. The oil pressure gauge off the donor was dead too, so I bought a new one.



This unit was missing its fuel solenoid and the air cleaner was damage, along with some of the nearby sheet metal, not sure what happened there. So I swapped that too and replaced the missing intake filter hose.