When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm pretty sure that the PCV valve on my 63 Dynamic 88 is toast. I ordered one from rock auto, but they sent the modern style. Is there a way to convert from the big vacuum pcv to the more modern style? I can source an NOS one, but it would much easier to just run a modern PCV valve.
You'll need the valve cover grommet and a vacuum connection on the carb or intake. I can't say 100% but I think a PCV valve grommet from 65-later Olds engine will fit in the D-shaped valve cover opening where the original goes.
Some carbs of that era have an appropriately sized threaded plug on back of the throttle body, which is where the factory made the PCV connection on California-bound cars.
You can set up the fresh air breather two ways. Either use the original breather cap on the oil fill tube which will work fine, or find a Mopar style push-on breather cap with a nipple and then connect that nipple to the nipple on the air cleaner snout with rubber hose like your original setup. That will give you a semi-closed PCV system with sufficient fresh air for the crankcase vent system to work.
Last edited by rocketraider; July 18th, 2021 at 08:21 AM.
Before condemning the old flapper PCV valve, wash it out good with kerosene or parts washer solvent. The flapper can get stuck in years of blowby goo and not function. Soak it till the solvent runs clean and you can hear the flapper rattle when you shake it. Then blow out the small vacuum port, clean the intake vacuum port for that and replace its vacuum hose.
Before condemning the old flapper PCV valve, wash it out good with kerosene or parts washer solvent. The flapper can get stuck in years of blowby goo and not function. Soak it till the solvent runs clean and you can hear the flapper rattle when you shake it. Then blow out the small vacuum port, clean the intake vacuum port for that and replace its vacuum hose.
I totally agree, unless the spring is broken there is not much to go wrong in a PCV valve. Cleaning it thoroughly resolves the problem most of the time.
These don't have a spring. There's a flat disc in it. A combination of venturi-induced air flow thru the air cleaner snout and manifold vacuum thru that tiny elbow lifts that disc off its seat and allows blowby gas to re-enter the engine for reburn thru the snout.
I've always called this design semi-positive crankcase ventilation but it made the feds happy for a couple years.
These don't have a spring. There's a flat disc in it. A combination of venturi-induced air flow thru the air cleaner snout and manifold vacuum thru that tiny elbow lifts that disc off its seat and allows blowby gas to re-enter the engine for reburn thru the snout.
Does it have anything in it that might be damaged by gumout? If not, then maybe it is also cleanable. Seems to me that a 30 year old unit, if saveable, would be better made than some of the cheap asian current replacement parts.
Does it have anything in it that might be damaged by gumout? If not, then maybe it is also cleanable. Seems to me that a 30 year old unit, if saveable, would be better made than some of the cheap asian current replacement parts.
The particular valves in question are not being re-produced .
There is , however , a pretty good supply of NOS ones on E-Bay .
Gumout or carb cleaner won't hurt it at all. Just might take a whole lotta cans to do it! A gallon of kerosene is what, 4 bux? And can be strained and reused. Good solvent.
I am kinda new to the 'vintage' Oldsmobile world, but then again, not really. I have a '49 88 Club sedan, the car shown in my avatar that i restored-modernized over a period of five years that has a Mondello built Olds 403 with a 2004R trans..
In early September I stumbled onto a very nice 53 Olds Super 88 that I just had to have. The 53 is dead original, 77,k miles on it. I intend to keep the car stock, with some improvements.
One of the improvements I intend to make is the addition of a Positive Crankcase Valve.
The system that Chevy came out with on the '63 283 V8's and Ford used on the 292 V8's '63-64 is a very simple application that lends its self to many engines with very little fuss. I have used the Chevy and/or Ford PCV on many engines with great success.
The application is very simple, block off the road draft tube, use a breather cap on the crankcase fill tube and access vacuum below the throttle plates on the carb. On many engines the addition of a spacer plate between the carb/manifold with a 3/8" pipe fitting solves the vacuum issue.
Some intake manifolds have a threaded vacuum port somewhere in the manifold for vacuum assisted power brakes.
It is a fact that many people do not know, the introduction of the PCV in 1963 reduced emissions by 95%, everything else that has been done to clean up emissions was/is done to clean up the remaining 5%.. Wm
Just wondering if I added offenhauser breathers to the sides of the valve covers. Would it breath better? and left the blow by tube attached. Mines a 62 with no pvc. Would look alot better.
If the road draft tube isn't gooped up from 59 yrs of blowby, the added breathers won't hurt anything. If the engine has a lot of blowby you'll probably see oil film on them.
Before going to all that trouble make sure your oil fill/breather cap is open and allowing fresh air to the crankcase. Some 394 had a washable metal mesh in the cap, most had a replaceable foam ring under the cap that could be washed in solvent and re-oiled several times much like a lawnmower air filter.
During the course of doing more TLC on the engine in my 53 Supper 88 I noted that the mesh in the oil fill tube breather cap was totally plugged with what appeared to be a total lack of PM during over 60 years of use. I soaked the cap in solvent for several days, no effect. I then soaked the cap in a pan filled with engine cleaner, not much effect. As a last result I soaked the cap in oven cleaner, that did the trick, the metal mesh came sparkly clean, reveling the original brass color..
I had recently purchased a GM Oldsmobile factory manual. Reading through the engine ventilation section I noted that the '53 engines actual have a pretty slick ventilation system.
The oil fill tube is place in a position on the front of the engine with a cap that contains a metal mesh, The cap must be washed in solvent on a regular basis. The placement of the fan and fill cap allows air to be forced into the fill pipe and thereby providing ventilation to the engine without relying on the vehicle being in motion.
I noted that with the engine running at an idle there was a small amount of blow-bye with the cap off of the fill tube. When I placed the clean cap on the fill tube the blow-bye went away.
During the course of the engine cleanup and general maintenance I noted that the crankcase breather tube comes out of the rear of the block above the bell housing then extends down the right side to the bottom of the pan. It appears to me that this arrangement would make it very simple to use a variation of an early SBC smog PCV. Wm.,
July 18th, 2021, 06:17 AM
