Valve stems on C123 engine

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PaulW_NJ

Member
Do the valve stems on the C123 engine (240 tractor) have two grooves?

After having the head redone on my 240 Utility, and ending up with oil spraying everywhere through the exhaust, I took the head back to the rebuilder to find out why the valve seals in the gasket kit were left off. The main reason is that there is a second groove in the stem of the new valves that were installed right in the place where the seal is supposed to ride. Hence there isn"t a good surface to seal against. Did they install the wrong valves during the rebuild? I know the factory head didn"t use valve seals, but is it possible to put them on?

When I pulled the rebuilt head there"s a puddle of unburned oil on top of all 4 pistons. I know the bottom end may still be the problem, but due to the quantity of oil getting by, the fact that there"s no blow-by into the crankcase or rocker case, and good compression data, the head is most suspect.
 
Umbrella type ride on the stems and do not care whether there is a groove or not. The PC type are vary close to the top of the guide and might miss this extra groove (I would use them either way) JimN
 
Are you talking about the groove where the " hair pin " goes? I was told that was to keep the valve from dropping on top of the piston if the keepers failed. I think it had to do with a slight oil control. Anybody have any hard evidence on this? On those pistons, are they oily only on the edges or all the way across?
 
Paul
I just ground the valves in my "53 sc w/123 eng. It had spring pins in the second groove.IH parts book lists them as retainer valve stem 42098d. Hope this helps. I have groud quite a few valves and this is the first time them.Maybe if a valve spring breaks the valve won"t drop on the piston,just a guess. Ron
 
The tops of my pistons have a depression in them, and all four had a pool of oil in them, maybe a thimblefull, when I removed the head. It"s hard to see it, but this photo showed it before the head rebuild. I"ve got oil droplets blowing out the exhaust. It never even smoked before I had the head rebuilt. The tolerance between the guide and new valves is OK, but no seals had been installed. I know the first suspicion is the rings, but the compression all runs 120-140.
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