Forum for air cooled diesel engines and clones

[90cummins]

I M Sam
Check my posts and photos (90cummins) page 1 of this forum. Your problem may be the small end bearing on the cam failed.
All the parts are available on e-bay but I'm concerned about the quality.
I detailed the damage & rebuild with notes and photos.
Ilikeurtractor
My Chinese generator would skip/sputter at high rpm (at 40 hours) when the cam bearing failed because it changed the injection and valve timing.
The color of your exhaust suggests injection/timing issues
Check the oil filter, if you tip the gen set up on its side the filter can be removed without draining the oil.
If there are metallic particles on it the cam may be failing.
The air intake may be restrictive but that usually causes black exhaust. I did quite a lot of experimenting with injection timing, cooling air exit temperature and the air filter.
I found the air filter assembly was restrictive and with the air filter removed the engine would increase 30 or 40 rpm at full load. Cutting additional holes in the air filter box cured that problem.
Hope this helps
90cummins

 

[Ilikeurtractor]

The color of your exhaust suggests injection/timing issues

I agree the symptoms are indicative of timing and also agree lack of air *should* cause black smoke. However, the timing is right on the money (actually about 2 degrees advanced more than spec.) and the engine runs great up to around 3250 rpm. With that being said, I'm going to go out on a limb here. Please bear with me...

*IF* the intake was so restricted that a very high vacuum was developing (close to absolute zero psi) then I'm thinking there would a limited amount of air taken in for the piston to compress to build enough heat and ignite the fuel (not to mention no oxygen) - causing "white smoke". Now my intake doesn't have that kind of restriction obviously, but what happens to the air flow when the engine starts achieving those higher rpms? Thinking about how it flows in an engine, it has to continually start and stop as the engine goes through each cycle. I'm just wondering at what point it cannot accelerate enough with the given air pressure behind it and porting design to satisfy flow during the intake stroke? Certainly starting out with 14.7 psia vs. the 11.7 psia I have available will make a difference at some point, I'm just not sure if it's the point I'm experiencing or not. The intake porting might be "optimzed" (minimized) for sea-level operation, causing an inadequacy when air pressure conditions fall to less than that. I did also remove the "glow plug" that was stuck in the intake and I haven't tested it after I did that. It can only help though.

I will be changing the oil soon and will let you know how that turns out - probably in a couple of weeks.

Thanks for the tips and help.

 

[90cummins]

I'm hoping you will not be running the generator until you check the filter?
As far as the timing goes did you verify that the timing marks are correct? It’s possible the marks on the flywheel are wrong.
I would suggest removing the injector and using a dial indicator to verify the marks line up when the piston is actually at TDC. If needed make new marks.
It is also possible that the cam timing may be off 1 tooth which affects everything.
This can be checked with the indicator on the piston as follows;
Turn the engine over slowly until the exhaust valve opens then closes, now the intake valve should start to open.
This is the end of the exhaust cycle and the start of the intake cycle.
Slowly turn the crank back & forth. When the piston is at TDC both valves should be closed or only slightly open.
You are looking to see the valves starting to move as you go by TDC.
Do this forward and reverse. Both valves should start to open at say 5 degrees past TDC as you turn the crank forward & backwards. If this is the case then the cam is timed properly.
To actually check the injection timing you need to do what is called a spill test.
We can discuss that later if needed.
Hope this helps
90cummins

 

[Ilikeurtractor]

I had the air filter off and it looked ok. The motor is not on a generator, I installed it on a snowblower. I didn't verify the timing marks but I suppose it would be possible they are off some. I would think that to be unlikely though. If the cam timing was off that should show up on the flywheel timing marks (via injection timing) unless it was compensated for in the pump shims. If the flywheel timing marks are off and the cam is off one or more teeth, but it still comes out to the correct pump timing indication on the flywheel marks then I would find that to be very bizarre. All of it indeed possible I suppose, but I'm going to make the assumption the gearing is correct in the motor for now. I still need to run the engine with the glow plug out. I may temporarily run it with the filter removed to see if it makes any difference also after that. If all that checks out I'll go back to the valve procedure you describe and see what that looks like. I'll post back when I have a chance to fiddle with it more.

 

[Rubberducky]

I know that quality differs on who makes these things over in china. I have an Apache brand. With only 10hrs on it I have no complaints. I had the typical metal shavings at first oil change at 3hrs. I then changed it after 5hrs and it was very clean. I took the enclosure off and went thru it from top to bottom. I am satisfied that everything I could see is properly built, connected, tightened, and tweaked. I like the way these things look with the enclosure and think it was a great idea. I have a neighbor with a Kubota lowboy 7500. He has constant problems on anything and everything electrical. Not too mention is a lot bigger. I have found nothing in the silent diesel size that compares looks wise. Obviously time will tell how long it lasts but I am very hopeful that constant up keep will keep it going. I was also pleased to learn Apache has a main warehouse in Texas and another in NY. They are trying to establish themselves as an equipment dealer by importing these Chinese products. Supposedly they selected a somewhat reputable manufacturer in China after visiting. I know some of these units are disasters but from my brief experience I am scared to say I am happy....so I won't say it

 

[Ilikeurtractor]

I found similar shavings when I changed the oil after 5 hours - maybe about 1/2 teaspoon total. I'm satisfied with the way it runs even though I can't get above about 3200 rpm. It runs great up to that point though. I decided not to pursue it any further at this point.

 

[Rubberducky]

I ran the Apache for approx 30mins today. I started with 1500 watts of halogen lighting then added a 1500watt heater..the engine did drop some rpm upon the full load but it ran good. I have yet to run anything off the 240 side. I am still hesitant to plug this thing into my house but I guess I need to at some point. I did sink and 8ft copper rod down near where it will plug in. The unit has a grounding terminal and when I removed the control panel there were a few things run to it. When I put the house on it I will ground it but for now I just run it. I am getting about 240 degrees out of the exhaust. The block where it mates to the generator runs 140ish and further back it is about 90 degrees. The generator side is about 60 degrees but here in Rhode Island it is about 30 degrees out. Starts just fine without a pre heater or glow plug.

 

[Rubberducky]

I guess I will keep giving updates on my generator so we can see how one of these Chinese units works and how long it lasts. I ran it for another 30mins yesterday. I ran 3000 watts off the 240 side and she ran great. I finally got around to moving some breakers back and forth between my panel and sub panel. I was able to get my generator breaker under my 200 amp main so I could put my interlock plate in. I ran a reliance receptacle off the generator breaker so I guess I am legally ready to connect to the house. Wish I just went to Home Depot to get a piece of sheet metal to make my own interlock. I guess the advantage to buying it is you get the ul stamp on it. It was about 25 degrees or so and she started just fine without a pre heater. I have just under 7 hrs on it now. So my neighbor got his Kubota back from being fixed again and went to start it and noticed fuel pouring out of a dry rotted line. I made a nice 4 guage ground line to run from my grounding rod to my grounding receptacle on the gen for when I put the house on it.

 

[Kays Supply]

I have an actual L100. All was good until I put a new starter on. Now it turns over better than ever but won'
t hit a lick. The weird thing is that it is smoking out the intake more than the exhaust. I have a dribble of fuel at the injector if I loosen the nut while turning it over. I have good fuel at the output side of the petcock on the bottom of the tank. Any ideas????

 

[dex3361]

Sounds like the compression release may be stuck open. Just take fuel and compression in the right amounts to make a diesel run. Do you have a yanmar engine manual?