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If it's a NON-W30 442 (1970)then you'll use the....
> "raised" grommet in the D side valve cover (for your PCV valve), and
>the flatter grommet on the P side valve cover (for the valve cover/crankcase breather parts.....these run to the air cleaner metal base)
>AND - the air cleaner metal base will have one unused round hole in it over on the D side - this gets plugged with a round factory rubber plug (available repro from ILT)
On a 1970 W30 the PCV hose ran from the base of the carb forward to the PCV valve and then into the front of the aluminum intake (via a metal tube fitting pressed into the alum intake).....so the factory used the "flatter grommets" and breather setups on BOTH valve covers.
Last edited by 70Post; December 14th, 2016 at 08:02 PM.
Non W-30 😕, but a factory W25 car. So, no W30 intake or carb. I am actually going to run a performer intake and aftermarket carb. My plan is to buy a repop air cleaner assembly, drop the base to fit and use the OAI flapper assembly.
Now that I have completely muddied the water.
1) Would a Non W30, but factory W25 car come with the OAI assembly?
2) If it did would the grommets be the same as the W30 structure, or just replicate a typical 455?
My thought is get it close to what it would have had from the factory and make it fit.
1970 OAI-optioned AUTOMATIC TRANS 442 (non W30) (and some others) would have the setup I described above (breather/flat grommet on P side valve cover, raised grommet w/PCV valve on D side valve cover, flat rubber blockoff plug in extra hole on D side of metal air cleaner base).
Why do I specify "automatic trans"? ....because I believe a 4 speed manual trans equipped OAI-optioned 1970 442 (non W30) would have had the same PCV and valve cover breather arrangement as the W30. Sure, the 442 would have the cast iron intake BUT I believe the factory went ahead and drilled the iron intake for the PCV setup like the alum intake-equipped W30's had.
I'll verify it in the Assembly Manual (Product Information Manual).
Last edited by 70Post; December 14th, 2016 at 09:26 PM.
......or, if you really wanted the symmetry of a breather on both valve covers (it does look sort of cool) you could do what I've already started on as a custom project for and Edelbrock alum intake equipped 70 motor.....
Make your own version of a factory PCV-in-the-alum-intake setup.
I've already made the aluminum "boss" that I will have welded onto an Edelbrock 04B alum intake and the "riser tube" that will get pressed into the alum boss after it's welded on and drilled out. Since the intake ports are taller VS. the factory intake I figured the taller metal press-in tube would be needed and from there I'll attach a repro/stock rubber elbow, the PCV valve and the rubber hose to the carb base.
Pic attached showing the taller "riser tube" I fabricated, the weld-on aluminum boss, an original Olds metal "riser tube" and the rubber 90 degree elbow that slips over the top of either tube.
Sorry to veer off the path of your thread but figured I'd throw that idea out here if you decided you really like the look/setup of the dual valve cover breathers.
It's "easy" for me to do.....I'm using an old used Edelbrock O4B intake for this idea and I can have the boss welded on and THEN clean up the intake and make it look new. If you're working with a new intake then the surfaces are already nice and new looking so any welding work would likely require some cleanup work/time/$ that wouldn't be needed BUT FOR the addition of the alum boss.
AND>>>>WARNING>>>>> If you use a setup like a factory W30 intake or my idea...both being PCV-in-the-intake setups....you will need to run a full stock metal "turkey tray" type intake gasket (or at least utilize the turkey tray portion spanning the intake/lifter valley TO BLOCK OIL SPRAY to the PCV valve..and, NO, the smaller narrow "baffle" that gets bolted into place just above the lifter valley openings to the cam isn't enough IMO).
What happens if you don't???? Possibly MASSIVE OIL CONSUMPTION. Leaving the PCV valve "open" to an uncovered lifter valley will allow the PCV to suck up MUCH MORE OIL. Saw this happen on a buddies Buick 350 motor (they have the PCV in the intake as well....behind the carb with a rubber PCV valve grommet right in the cast iron intake) and the "engine builder" used composite intake gaskets and left the lifter valley "open" (no shield, no turkey tray, etc). On one hour highway trips he'd use something like 1 quart or more of oil....PCV was sucking up oil/vapors in a major way and no, the rings, etc were all just fine (fresh motor at that).
Again, sorry to "veer off thread" but you opened the door and I figured the thought of using both breathers on the valve covers might have crossed your mind but the non-PCV-enabled aftermarket intake may have thrown up a roadblock.
Last edited by 70Post; December 14th, 2016 at 09:35 PM.
I will be working on my OAI set up this winter and following along with this thread. I kinda set everything on the carb the other night and realized it's going to take some work so I'll get to after some other more pressing items.
It may be a "generic" part - in other words...same exact intake used on the auto and 4 speed cars (same casting number, etc) with the only difference being the factory drilled out the cast-in boss and pressed in a metal tube for the PCV elbow for use on these 4 spd cars.
The PART NUMBERS for the two cast iron intakes may be different BUT.....I'm talking about the CASTING NUMBER that actually appears on the intake which may be the same whether it's for an auto or 4 speed.
Any idea of the CASTING NUMBER on the intake you saw?
Long story short is you may be able to use ANY '70 455 cast iron intake (except for Toro intakes which ARE shaped differently) and have the correct part for the car.
Sorry, it's been so long since I've had my hands on a cast iron intake for one of these motors that I'm not 100% sure on this. I believe the "auto trans" intake casting number for '70 is 405621...may be the same on a "4 spd OAI" intake.
Last edited by 70Post; December 17th, 2016 at 10:18 AM.
Also, this is the cast iron intake that came with my 442, but I do not know if it is original. Mine being a factory W25 Freemont built automatic. It does seem to have the casting for it.
Troy - As I thought.....Olds used the same casting/casting number for AUTO and 4 SPD W/OAI. As you see, the pad/boss is there for the press-in PCV steel tube (once drilled out).
Not really a rare intake in that it came on all the '70 455 non-W cars (except the Toros which had the flatter intakes). I had one a few years back (auto version from a 88 or 98) that was on a spare motor I acquired. A guy from a nearby town came up and bought it....I think I sold it for something like $50 and felt lucky to be able to actually sell that heavy chunk of iron.
Shipping would not be cheap but the cost would be all weight as a package would not be considered UPS or Fedex "oversized" (dimensions).
Was the idea to get suction from both heads into the crankcase, up through the intake, and to the carb for burning as opposed to pulling it through the driver's side head? Better, more uniform, flow?
What does the plugged OAI cleaner hole get used for in the w-30 setup?
Was the idea to get suction from both heads into the crankcase, up through the intake, and to the carb for burning as opposed to pulling it through the driver's side head? Better, more uniform, flow?
What does the plugged OAI cleaner hole get used for in the w-30 setup?
Who really knows??.....my thinking is they thought additional crankcase venting was needed for some reason on the W-30 motors (and the 4 speed OAI 442s) so the PCV-in-intake setup was the "default move" to allow two breathers. Just my opinion but it sure would be cool to ask whoever came up with the idea at Olds exactly what lead to that decision.
....OR...maybe to aid oil drainback under BOTH valve covers since we've seen the "argument" presented that Olds's pumped oil up into the valve cover areas excessively and/or the drainback holes weren't extremely effective. This "position" is sometimes used when discussing main bearing saddle, etc oil restrictors.
As far as the plugged OAI hole in the air cleaner base.....on a W-30 the hole was used to accommodate the valve cover breather setup that was installed on the D side valve cover (same parts as used on the P side breather setup but with a slightly different length rubber elbow used in the air cleaner base hole on the D side VS. the P side...the holes in the base apparently weren't EXACTLY symmetric in their relation to the holes in the center of each valve cover).
Last edited by 70Post; December 17th, 2016 at 10:55 PM.
Keep in mind that the table in the FAQ was generated by Chris Witt back in the 1990s based on his personal observations of cars he saw. It is not data from Oldsmobile factory documentation.
December 14th, 2016, 07:48 PM
