Have a 54 Chevy 235 engine and was tole to plug the valve cover vent holes. I tried to search but not coming up with anything.
What do I need to do to plug the holes that looks good and assuming I'll need an oil cap vent? If so, what is the part number to get one. Also probably going to leave the crankcase vent on side of block.
Any explanation on why they need to be closed? Probably easier to find a later 1956-62 235 unvented valve cover and swap it out, using a vented filler cap as you mentioned. Don't get rid of the '54 valve cover. If you don't intend on keeping it, put an ad in the Truck Parts for Sale forum as I'm sure someone else will want it.
Side note - your signature line says your truck is a 1954 GMC. Guessing the original engine has been transplanted by the 235???
Last edited by Gdads51; 08/01/202412:58 PM. Reason: add side note
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
The 54 valve cover was the first four screw valve cover used for the 235. The 53 and prior covers, these were two hole center stud hold downs and used vents in the valve cover itself. The 54 is a one year only cover in that it has four small slots (as opposed to the somewhat larger vents in the 53 and earlier covers, and used a non-vented cap. Presumably the concern was that water or debris would get in the top of the valve train through these small vents. So for 55-58, the vents were eliminated and the non-vented cap was replaced with a vented cap, in the identical location as the 54 cover. 59-63 valve covers were also 4 screw hold down covers, but the vented cap was located to the center of the valve cover. I happen to agree with the above advice, hang your 54 cover on the wall, get a 55-58 cover and vented breather and you are all set.
The 54 is the orange cover, the blue cover to the right is the 55-58. The next is the 59 and up. The last one is a Canadian Pontiac 261 cover, no script but otherwise 55-58 style.
The "54 cover" is also fitted to the 55 First Series 235. Unique design with four small vents on top; two rear and two forward. Oil filler port is in the very top front of the valve cover. An uncommon item today. Makes good garage art, or use it on a 54 or early 55 235 engine.
The shape of the cowling on the 54 and early 55 trucks was the problem. A little rain past a leaky hood to cowl seal would run water onto the valve cover and down into the engine through the rear slots in the valve cover. if you want to solve the problem without doing any permanent modifications, just run a bead of RTV sealer over the rear slots near the cowling, and leave the front slots open. A solid cover and an oil filler cap with a filter in it does a better job of ventilating, and keeps dirt and dust from being drawn into the engine. Jerry
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