Trying to put a bow on my 455 build and I want to ensure I do the crank case venting correctly.

Engine is a 455, Sniper EFI, OAI air cleaner setup.

I assume I need to do the following:

Driver side - use crank case vent filter (See image) - put PCV valve in that, and then run vacuum line to manifold vacuum
Pass side - use crank case vent filter (see image) and run hose to air cleaner base and use filter (see image)
OR
Pass Side - just use a valve cover vent filter (K&N, Morroso, Etc.)

Engine is new, only run about 20 min so far and have the expected initial blow by/ring seating smoke from the breather on both valve covers so it triggered me to remember to get this setup correctly

 

Norm - its a 72, no longer using the charcoal cannister. Yes using the Tans vacuum( I have a TH400).

** I do see I can use what my 350 had, a rubber grommet and a vent "pipe" to the OAI air cleaner. I just wasn't sure since the car didn't have a 455 when I got it.

My goals is not not stink like the car or my wife will shoot me and never want her or the kids in it LOL

 

Ah.. no I’m running full electronic controlled ignition through the sniper.

reason I’m confused ...see attached from my assembly manual it doesn’t even show a PCV valve on either side just just shows pipes coming out of the valve covers and going into both sides of the air cleaner with no filter on it..

 

Look again. The "dual ventilation system" with two breathers was for W-30s and MT cars that have the PCV nipple on the intake. Note the star and the note:




AT cars used Plug P/N 405727 in the driver side hole in the air cleaner housing and the PCV valve goes in the driver side valve cover on those cars.

 

AH ! - mystery solved. I didn't know that this was also a PCV function and filter

 

It is not "also PCV function and filter". Again, don't confuse W-30 cars with others.

 

Thank you Joe and Norm - as always a wealth of info and knowledge.
So I plug the driver side on the air cleaner base and run the breather/PCV to Manifold vacuum - Pass side as shown in the image...pretty easy, also to be clear no extra "filter" in the air cleaner, just the rubber connection and the air cleaner filter takes care of it from there ?

 

Correct

 

Joe, i have always wondered the the 4 speed 442's got the dual vent system with the PCV in the intake. Do you have any insight on that?

Thanks!

Pat

 

Pat, I'm not sure exactly what you're asking. The cast iron intake used on the 70-72 cars had a boss right behind the water crossover. On AT cars this was left blank. On MT W25 cars, it was drilled and a nipple pressed in just like on the W-30 manifolds.

Here's the 404521 iron intake with the nipple in place.






Here's the same 404521 casting with the boss undrilled.

 

Sorry if I was not clear. My question is why did Oldsmobile chose to use that design with the PCV valve in the intake on the 442 4 speed cars? Was there some technical advantage to it for venting the engine better? Personally I think it looks better.

Pat

 

Can't say that I have a good answer. The MT engines had a more radical cam than the AT engines. Maybe there was an issue with not enough vacuum for the PCV system to work reliably - except that the AT W30 used the same cam as the non-W 442s.

 

Okay, thanks. One would think they must have had some good reason for it, but maybe nothing significant. Maybe something to do with downshifting?

Pat