Ch20 kohler

[John2189]

 ch20

 

replaced two new kohler coils. Ran great for about an hour. Then it started to make a tapping noise, before I got it back to the garage, it made a terrible noise and quit running. I pushed it into the garage. I thought it blew a head gasket, so I removed one of the valve covers and found a rocker arm broken in two. I ordered a rocker arm kit ,I figured if one was bad the rest would be too. When I went out to the garage the next morning, there was two big oil puddles on the floor under the front of the engine. Looked pretty clean under the front crank seal. I removed the electric clutch ond the bottom half of the seal was clean and wet. I took a rag to wipe off the grass and dirt around the top half and the seal is loose in the hole, I could pull it out with my fingers. 
So does that mean that the new seal will be loose too?

[Bill725]

On Commands, when the front seal blows out it is normally from excessive crankcase pressure, for example failed head gasket. But the fact there is a broken rocker arm raises concern and warrants further investigation as to the root cause of the failure. A possible cause could be a broken camshaft gear, of which @Brettwhas seen, which causes the valve timing to be off to the piston. This would cause the valve to be open when the piston is at TDC, hitting the valve, possibly causing the rocker arm to break.

Also FYI, in the Command Service Manual in the Reassembly under Install Closure Plate Oil Seal, it states to install the seal to a depth of 0.314". I had a special front seal driver machined, see picture.

Edited July 8, 2024 by Bill725

[John2189]

1 hour ago, Bill725 said:

On Commands, when the front seal blows out it is normally from excessive crankcase pressure, for example failed head gasket. But the fact there is a broken rocker arm raises concern and warrants further investigation as to the root cause of the failure. A possible cause could be a broken camshaft gear, of which @Brettwhas seen, which causes the valve timing to be off to the piston. This would cause the valve to be open when the piston is at TBC, hitting the valve.

Also FYI, in the Command Service Manual in the Reassembly under Install Closure Plate Oil Seal, it states to install the seal to a depth of 0.314". I had a special front seal driver machined, see picture.

Thanks Bill

 

When I pulled the electric clutch, the seal was flush with the plate. 
 

When I get the new rocker arms, I will turn it over by hand to be sure nothing is hitting. And do a compression check to check the head gaskets 
 

I did notice that when it shut down, the oil light came on. 

[Bill725]

FYI, the lifters can be pulled using a lifter removal tool without removing the cylinder head. 

[John2189]

Yes I have one of those pullers. A strong magnet will work too. 

[John2189]

Ok I pulled the plugs and turned it over by hand and it felt smooth, valves were up and down. So I am assuming nothing internal was damaged. 

[John2189]

Ok I got the new crank seal. It went in very easily. I sed the old seal as a depth gauge it was .305 thick and added a bit more 

I just pushed it in by hand. No hammer needed

[acken]

That's an all rubber seal so I usually apply something like Permatex to the OD before installing.

[John2189]

11 minutes ago, acken said:

That's an all rubber seal so I usually apply something like Permatex to the OD before installing.

I don’t like the rubber coated seals. I put silicone on the outside of it.