The Stovebolt Site Forums The Shop Area Engine Shop 235 valve cover altered?

I recently aquired a 52 2 ton Chevy in great original shape (44,000 actual miles) but have found something odd on the valve cover. It appears that someone had closed off the vent holes on the top with brass brazing and a tube and connector was fitted to the top rear of the valve cover. A hose is connected to this and goes into the top of the oil bath air cleaner in the same fashion. Now I have been reading the forums on positive pressure of the crankcase, PCV's, and oil cap ventilators and checked this system out. There is no valve in the hose from the cover to the cleaner and no lines and valve assembly coming off the oil filler and ventilator cap. The ventilator/oil filler is exactly like my 216, in that it goes down the side of the cranckcase and points down. This one is not plugged and appears to work when the engine is hot. Is what I have tried to describe something I should return back to original. What was somenody thinking when they did this??

In very dusty area's or high dirt(maybe a farm) it was a not uncommon to do that.The thinking was that the air going into the motor(or coming out) would be filtered instead of dirt(water) going straight into the valve cover.

I have a 1960 (March 28 from Flint) 235 and It came with a valve cover with the breather cap in the center (spanwise) and no additional slots or holes. This engine supposedly came out of a truck. Would it be a cab over? I am curious although I have succumbed and purchased a Wayne valve cover to replace it. Cheers

Terry, I have a 59 235 engine out of a pick up with a valve cover like yours.235's didn't have the breathing slots.Used a vented oil fill cap instead.

In 54-55 they had slots ,i have 3 of them here off original trucks.Dont remember if my 56 235 motor does though.

If that 52 235 is the original motor it is a babbit pounder & has the same valve cover as the 216 & did have the vent holes. Sounds like someone at one time tried to remidy the crankcase fumes from entering the cab by welding the vent holes up. I guess they then installed the vent tube to the air cleaner to make up for it.

Mothertrucker, I suspect you are right. But what I am concerned about is that when examining the rocker arm and valve springs, they appear much dirtier than the ones on my 216 babbit knocker with original vented valve cover (86,000 miles). There is even rust showing on these parts. It does not seem that the air cleaner intake is creating much of a vacuum when I run the 235. Could moisture be building up in this valve cover due to the covered up vent holes? This setup looks almost factory done as I am sure the air bath oil cleaner is, looks just like Sec. 0 sheet 4.00 of the factory assembly manual with the exception of nothing coming off the oil filler and vent cap (road draft tube). Oh and my filler cap on the valve cover is not vented. Thanks for the reply.

I built an actual pcv system for my 62 235. I took off the road draft tube and replaced it with a chunk of chrome pipe from the hardware store, got some copper fittings and soldered them up to the end to take it down to about 1/2", and connected some hose to that, and then I got a pcv valve off some mid 60's carb that would screw into the hole under the carb on the intake manifold and hooked the other end to it. you will need to use a vented cap on the valve cover to let fresh air in.
This setup works pretty good, helps gas mileage a little bit, can stop the nasty oil drips from the draft tube, and should help to keep the nasty vapors out of your engine.

Rob