Another "while I'm in there" story. I'm going to add PCV to the '51s 216. Parts are finally all on the work bench and the new tubing bender shows up today so I can bend the 3/8 hard line from the new valve to the intake's vacuum port. Today I pulled the draft tube, cleaned it up and popped the top cap, amazingly it wasn't caked up with gunk.
All set to go, but wait. I've had a lot of clutch chatter for a while. Can burn the oil off and it's better for a while. My suspicion is the rear main rope seal I installed a few years ago is leaking since there's always oil on the clutch dust cover. Then I recall something Jon G posted sometime back about the side-cover (pushrod cover) leaking on the rear lower corner and most folks mistakenly thinking it's the rear main.
Nope, not messing with the side cover. Need to get the truck out of the shop. My chief consultant Mrs. Kathy said, you've got to do the side cover if it keeps you from fussing about the leaks and clutch chatter.
So, that's where things are. Gasket ordered (Fel-Pro PS5004D Push Rod Cover Gasket Set). $10 bucks cheaper than I can buy at the local chain store. The side cover is off and ready for paint.
Next week I'll know if the side-cover fixes the clutch issue, and if the PCV valve by creating negative pressure in the engine helps with other leaks. With the gravel roads in my part of the world, the now sealed slits in the valve cover (JB Weld) will reduce the dirt pulled into the engine due to the draft tube. It'll take a few years to tell how much benefit no dust is, but it's gotta be a good thing.
Are you adapting the PCV to the hole in the vent pipe where the draft tube used to attach? If so, it's very possible you're going to create an oil burner from droplets of oil being pulled into the valve as it pulls the crankcase vapors in. The factory PCV setup puts the valve up around the level of the valve cover. Jerry
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Jerry, no. The draft tube is intact (just in case I want to revert back) and it's plugged. I removed the cap on top of the assembly, drilled a .75" hole for the grommet and PVC valve and reinstalled it with sealant. I did consider going with a standpipe to get to the top of the head but thought I'd give this a try first. Sitting in the recliner at 5am and without measuring, the valve is a foot or so above the hole in the block where many install it.
Also being a bit lazy of late, another reason for the experiment is lack of a suitable piece of tubing on the rack needed for more elevation. If the valve pulls oil or a oil mist, I'll cut the swedged portion off the standpipe and weld it to a suitable piece of tubing, raise it up to the valve cover.
Little Bro's motto, "If a things worth doing, it's worth doing twice". I seem to have adopted his motto over the past few years.
This thread really needs to be in the Engine Shop.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
I’ve got a prototype PCV setup on my 235. Unvented oil fill cap that has the PCV and grommet. Getting its vacuum from manifold wiper port. FILTERED makeup air via a motorcycle breather clamped on the bottom of road draft tube.
I still need to find some time to test how much vac the crankcase is under. (Was going to test at the dipstick tube). But early results are good. No stinky vapors up front. No excessive smoke out back.
I did mine ('52 GMC 228) by blocking the hole in the oil fill tube where I had cut the road draft tube off. I replaced the cap on the road draft tube with a Mr. Gasket push-in valve cover breather/oil filler plug that I added about 4" of rubber hose to its bottom. The hose is a nice push fit into the original oil fill tube. This is my air supply. I already had a valve cover with with a plumbing fixture, so I hooked a rubber hose to it and ran it through a clear plastic oil separator (from an air compressor outlet) and thru another short rubber hose into a tube I welded to the air cleaner. Seems to do the job. I clean out the oil separator once every 3 or 4 tanks of gas. Never more than 2 CCs or so.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
If your valve cover, side cover or oil pan cover is not completely sealed from air coming in, for example, the whole PVC system is worthless.
The original early design (car RPO 417) takes crankcase air from the crankcase via the oil mist collection tube, through a PCV valve, through a metal pipe and is connected to a connector on the intake manifold for vacuum. If there is a leak, think of a vacuum reservoir with a hole in the tank. No or low negative pressure (vacuum).
Also, when you add a PCV system, flow is important to determine the PCV valve needed. If you install a small diameter hose, that restricts the flow, the valve may not function properly. All the parts need to be sized and designed properly to make the system work.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Putting the period on the sentence here. A few details to work out but the new side cover gasket is installed, no leaks (yet). Valves adjusted, new points installed, PCV system complete, oil changed and a can of Rustoleum Charcoal Gray enamel put to good use.
Used a V-237 PCV Valve, bought a stick of 3/8th tubing for the vacuum line and used excess inventory heater hose for the makeup air line from the clean side of the air filter to the oil fill cap in the valve cover. Copied Jon G's approach on the oil fill cap and used a grommet with a 1/2 copper 90 deg. elbow to connect the hose. The air filter fitting is a repurposed nylon 90 degree ell that's normally part of the heater hose to water pump system on a GM 3.8 engine. Used a large blob of JB Weld to secure the nylon elbow to the air cleaner (very substantial at the moment).
I almost hate to mention this. If you have a radiator hose to bust or a radiator to leak, where does the coolant go in the engine compartment? Murphy's Law says exactly where you don't want it to go. GM put the PCV air cleaner connection on top for a reason.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Good point Gord. RonR, are you planning to modify this air cleaner to use a modern dry filter?
It's a dry element filter, converted it a few years ago. I can't call a specific manufacturer but I recall some '60/'70s cars having the pcv fresh air connected to the bottom of the filter housing. Of course I've had false memories before.
