Finally bought a MEP-831a

[AfghanVeteran2010]

I adjusted valve lashing to .13mm inspected push rods all were good. I checked the timing it was spot on 17 degrees. Fired it up seemed to act way better than before no smoke at all, I applied a 2600 watts of load it happily went along for about 6 mins then bogged out. I reduced load to 2400 and ran it for an hour, I dropped the load and was going to let it cool down fro 5 mins. I heard a click noise and the set started to pour out white smoke, I recorded event and shut down set.
It might be sucking oil from rocker cover gasket, threw oil hole. Oil is at proper fill level.

https://youtu.be/OwXmuGeA-Bk

https://youtu.be/GQNV5I38h2Y

 

[AfghanVeteran2010]

Found oil in intake near valve, the source is either the (oil start hole) or (valve steam oil seal).

Ill reattempt breaking in tomorrow Ill replace valve cover gasket I have a replacement on hand, if this does not address issue its probably the stem seal.

 

[AfghanVeteran2010]

I could not get it to start up this morning, valve lash is in spec. Fuel is being delivered to injector pump. When I pull start cord I can feel compression for a few seconds I can also hear a leak somewhere.

The first time I attempted it popped threw exhaust and shoot some soot out, scared me pretty good.

Here is second attempt
https://youtu.be/KmSlm580Hgw

Should I keep trying to start it?

 

[DieselAddict]

Nope. Don't keep trying to start it. Can you pop out the injector and use your air injection thingie to see where the leak is?

 

[AfghanVeteran2010]

Nope. Don't keep trying to start it. Can you pop out the injector and use your air injection thingie to see where the leak is?

Sure can try.

I've been hunting where compression loss is. Ensuring the rockers are not interfering with it. During the compression stroke stopping at TDC the valve lashing is good, but when I rotote the fly wheel once back to TDC the valve lashing is very tight. Demonstrated in video.

https://youtu.be/3TgIvDKlFxA

And I also removed rocker in this clip to see if they were holding valves open, I don't think they were interfering

https://youtu.be/24iTFnCTLTI

 

[AfghanVeteran2010]

LOL it leaks more than what it used to.

Sent from my SM-G935P using Tapatalk

 

[DieselAddict]

Ouch. Can you determine the source? Valves or piston??

 

[AfghanVeteran2010]

The valves are leaking the exhaust is leaking pretty good and the intake is minor. When I plugged up the port and turned flywheel there is really good compression.

https://youtu.be/fkt7g8G15jc

 

[DieselAddict]

That is pretty unusual. This may sound odd but... Try tapping the valve stem with a hammer. You want to give them a nice pop against the seat. See if that seals them back up.

Edit - You can do it with the air pressure on the cylinder. It will make some noise when it pops open then closed.

 

[AfghanVeteran2010]

Hammer didn't do any good. I did it while pressured up.

thanks

 

[DieselAddict]

That is about the end of what I can suggest. The next step for me would be to pull the head and look at the valves and seats.

 

[AfghanVeteran2010]

exhaust valve and seat looks cruddy the intake looks a bit better.

https://drive.google.com/drive/folders/0B45AWBFXIAUtWE92eHpPS1IyNWM?usp=sharing

 

[DieselAddict]

That looks like you were burning a good bit of oil. Was your oil level dropping?

I'm going to have to take a better look at the photos after work.

 

[AfghanVeteran2010]

I just looked at oil level really close there was some oil burned off, not much maybe two threads worth.

Thanks for your help.

 

[boatman69]

That "smoke" isn't blue enough to be oil. I will go with unburt fuel.

 

[AfghanVeteran2010]

That "smoke" isn't blue enough to be oil. I will go with unburt fuel.

When it was failing to start yes that was unburned fuel. As for oil loss that was probably from it running for a hour during it first hour of operation since tearing into it.

 

[DieselAddict]

Man, that exhaust valve didn't take long to coke up. Have you tried to clean them up? It doesn't look like there is any damage there. If they clean up ok and seal let's hope on the next run the rings wear in and seal up a bit better. I wonder if the crankcase pressure was a bit high and that was holding the oil up top.

 

[rustystud]

Are you sure the "pressure relief" (decompression lever) is closing ? If it is not allowing the valves to seat properly then you would have this same problem.
Also did you "reset" the "low oil pressure" fault ?

 

[AfghanVeteran2010]

I cleaned up the valves


Before I tore it down yesterday, during the compression stroke to TDC the valve lashing was spot on .13mm. When I rotated it once again on the exhaust stroke the valve lashing was very tight. This doesn't seem right , I think something maybe be off. Don't exactly have another engine to compare it to.

As for the pressure relief lever was not down, so it shouldn't of released any pressure. When i was trying to start it the actuator was full open "low oil" shutdown wasnt the cause.

I'm thinking that the valve never completely sealed up like they should of, maybe some fine lapping compound will cure this. 400 to 600 grit. I starting to think when the machine shop tested them they may of put oil on sealing surfaces.

 

[Light in the Dark]

I cant believe how many 831s are being dumped right now on the auction sites.