Onan Knocking

So, I've got an old Onan in my 64 Bobcat. It started knocking, and from what I was hearing, it was a deep knock, but wasn't real bad. I assumed it was a rod, so I pulled the engine and checked things over. There were no signs of any damage at all, and for an over 50 year old engine, the rod bearings looked great. While it was out, I found I had almost zero compression on one cylinder, and the valves were very burned. Luckily enough, I've got the tools to grind valves and seats, so I got that all fixed up, and assumed the knock was related to the valvetrain. Anyhow, the engine is back in and running better, but I still have that knock.

Reading around on the net, I've see some people refer to a camshaft bushing that can work itself out of place. Can anyone provide more info on this issue, and can it be ignored for a little while, or is there damage being done?

On the plus side, while searching around for parts, I see there is a place in WI that is offering NEW ONAN short blocks for $399+tax with free shipping. I already have purchased one, and put it on the shelf for safe keeping!
I found them on ebay, and there were multiple shaft sizes and such. Couldn't pass it up.

Onan has been making engines since 1925. Which one do you have.

Not 100% sure, but I believe it is a CCKB.
Numbers on the tag are:
Model - CCK-MSV/1242C
Serial - 35C819297

That is March 1965.Sprec C. The CCK was one of Onans best units. I would do the valves. Clean the carbon out of
the heads.If any.Smokstak is a good place to get parts and help.I anm also over there.
The CCK was used on many units. Very hard engine to kill.I will look up the manuals you need. You can down load
them from the stak all free.

Valve seat Angel 45
Valve seat Face 44

That should be Smokstak. Take a look at this manual I think it will help you.

927-0754

I had one do that. Turned out carbon had filled up the cut out in the head at the bottom and finally broke the piston. Re did the
valves new pistons ran better than a new one. Found that the manual said heads were supposed to come off and be cleaned on
schedule.

It isn't carbon. I had both heads off and removed carbon from the heads and pistons while I did the valve grind.

I'm thinking it is something in the camshaft, but didn't inspect that area. My biggest concern is if I'm doing much damage running it. Either way, I've got a new short block on the shelf ready to go if needed.