The Stovebolt Site Forums The Shop Area Engine Shop Excessive oil out the valve cover vents

Finally got to take a long hard shake down cruise today and I still can't wipe the smile off my face
The cruise exposed some fine tuning I'll be needing to do but otherwise she ran pretty good. The speedo is inop so I don't know how fast I was running but I kept up with all the local traffic on 45 & 55 mph back roads....
The engine is a 49 216 w/a new rebuilt head but original stock valve train. Valves, springs, guides & seats are new
Most pressing issue is I'm getting excessive oil being blown out of the valve cover vents.
I have some blowby but theres enough oil blowing out to coat the sides of the engine w/oil and leave drips on the ground.
I've read some other posts that indicated that the rocker arm rod could be upside down, i.e. the oiling holes facing up rather than down, is this correct?

One additional issue is restarting when hot. If it doesn't start right off the bat it won't start without letting it cool and pouring some gas directly down the carb. I can see the gas bubbleing in the fuel filter bowl and figure I might have a fuel delivery issue.
No amount of chokeing or throttle will get it to start if it doesn't catch right off. Once it starts it runs great.
Any insight welcomed
Dave

Hard starting when hot is fairly common because the intake is in intimate contact with the exhaust manifold. An insulated spacer between the carb and intake can help. If your heat riser is stuck in the heat on (cold start) position it'll make the problem worse. As for the oil my guess would be the rocker shafts are upside down. The only way to verify or eliminate that possibility is to pull them and see. Yes the holes should be down. FWIW I have a bit of a problem with hot start as well although my '38 does start with a bit of cranking when hot. The heat vaporizes some of the gas in the float bowl which then fills the intake runners with excess vapor. You're, in effect, trying to start a hot engine with the choke on. On a hot day I plan my stops accordingly. I've considered making a simple heat shield out of some aluminum flashing to go between the carb and intake but haven't been that gung-ho yet.

I would look at the rocker arm too. My technique for hot starting is as follows. I put my left foot on the throttle and put it slowly to the mat. I hold it there for a minute or two and without moving it I work the starter with my right foot. As the engine catches I let up on the throttle. It works every time for me.

Tiny,truckernix, thanks for the input.
I did alittle troubleshooting and I found the cause and corrected it but I'm still alittle foggy on the reason why it was either designed this way or someone modified it this way. I tend to think it's a factory design but I'll post a couple pics and let those w/more knowledge comment.
The oil supply line connects to the rocker shaft right where the two half shafts connect and this is where the oil gets distributed in the shaft(s) and out through holes in the rockers to lube them.
At idle theres just enough pressure to seep out of the tops of the rockers but at higher rpm the oil will gush out. This higher pressure oil also feeds to an overflow pipe which dumps excess oil back to the sump through the pushrod gallery. My guess is once the rocker shafts get full the additional oil runs down the bypass pipe.
In this Pic the screw driver is pointing to a hole thats drilled into the overflow pipe which is directly under the middle vent on the valve cover. This Clip was clipped over the hole but I must have rotated it dureing reassembly to where it wasn't covering the hole. Instead it was allowing the oil to squirt straight up at higher rpm. This is a Pic of it properly orientated when clipped back on the tibe. In this position the excess oil defelcts out the sides and down to the head. Now why this is done is beyond my paygrade. I mean it's already a bypass pipe that dumps straight to the sump so why deflect some back into the head? It's not lubeing anything that I can tell but it looks factory so the engr's must have thought additional bypass was needed at higher rpm.
You be the judge
In any case after an hr run today after the fix the top and sides of the engine was dry .
I didn't shut it off to test the hard hot starting, we'll leave that for anither shakedown cruise
Dave

My guess is that it is a vent to prevent the oil from being siphoned out of the shafts when shut off.
I would love to ask the engineers about things like this.

Every overflow pipe I've seen has a hole in the top similar to yours. I've not seen a clip like is on yours. I don't have a good pic that shows the hole. Somewhere in my "archive" of spare parts I have an NOS piece that I'll try to find and take a picture of.

Mine has that clip on the tube also...
http://www.fiftee6.com/Fiftee3%20Picture%20Album/

I think I remember an explanation for that hole for preventing siphoning, as Dave said. I have also read that the clip is to prevent debris from getting in.

There were at least three styles of connectors/tubes.

That "clip" was on the 216s and early 235s rocker arm connectors' tube.

Another long drive today and the valve cover was still high and dry, I can mark that off my punch list

So, to summerize, the hole in the overflow pipe is to prevent syphoning of the oil out of the rocker shaft(s) after shutdown. The clip, when installed correctly, partially covers the hole which deflects the high pressure overflow oil generated at higher rpm away from the valve cover vent slots and also serves to keep debris from entering the hole.
Very good.