I was looking at a few photos in the workshop manual and one in particular shows that the OHV six after 1961 was supposed to have a crankcase breather coming from what looks to be the old oil filler which was blocked off for the change of blocks.
Does any one have any more information as to the photo and why the production engines do not have this?
Wiz.
Here is how I remember the crankcase breather on OHV sixes:
1961 Road draft tube, off of the side tappet cover, much like the flat head. 1962 Road draft tube - goose neck shape, off a 'new' hole in the block, ahead of the distributor, below the generator. 1963 & 64 PCV had a tube fitting off of the rear tappet cover, a rubber hose and a PCV valve screwed into an elbow at the intake manifold, just above the heat riser area.All had a vented breather cap, on the valve cover.
California cars, which were adapted later, had their own unique setups.
I have been playing with all three setups on the Flathead and used the later style which I plumbed into a fabricated carb spacer. I did this as the PCV system can not, with any degree of ease, be installed into the original manifold close to the carb. The hose from the oil filler comes from the air filter but this might not matter but I did not want to create any type of seal. The mesh in the Flathead filler cap is to trap dirt from entering the crankcase so it must, at times, be under vacuum. On an OHV engine running the oil filler/breather cap to the air filter allows the vacuum from the PCV system to draw air from the top of the engine down to the crankcase and up into the carb with no chance of any extra pressure blowing out through the caps and into the atmosphere. With the positive flow from the top to the bottom of the engine this also helps oil drain back.
Wiz.
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