327 positive crankcase ventilation

[brumbach]

I've got a 65 vette with nom engine. The person I bought the car from built the engine using a 68 block. One day I hope to build a correct engine but until then, I'd at least like to dress up this engine to mimick the correct engine. I want to replace the polished valve covers with the cast aluminum ones. The engine is currently vented thru the valve covers. The cast aluminum covers are solid and won't allow this. The car has the original oil fill tube, and I can make the connection to the carb as it's suppose to be but the rear of the block seems to be missing the opening to make the connection to the air filter to complete the ventilation loop. Was this opening eliminated in 68? If so, is there another way I can pipe in filtered fresh air for PCV?

 

[vette-dude]

In most cast valve covers there is a bung hole that you knock out to put in either a oil filler breather cap or a PCV valve or both (opposite sides). You have to buy a couple of valve cover rubber grommets (Moroso make them) to fill in the hole and then the breather and PCV can be inserted into the grommet. I used Moroso valve covers but most others probably have the knock outs too.

Randy

 

[jerrybramlett]

Yes, the small block V-8 rear vent hole (behind the distributor) was eliminated in mid-1968 engines. You will have to use valve covers with breather holes in them to have a true PCV system.

 

[studiog]

If you are like me you probably don't want to punch any holes in the aluminium valve covers. If I'm not mistaken the factory covers with pcv ports in them also have baffles in them to reduce the amount of splashed oil that gets sucked out. I have heard discussion of drilling a PCV hole through some manifolds (without hitting any intake runners) to the lifter valley but that sounds like allot of work and experimentation and you would still need some sort of baffle again. Maybe someone else here has some experience with your situation.

 

[vette-dude]

If you buy a good quality of valve covers they normally come with a kit that contains the baffle plate and drive screws to install them under the PCV valve. The bung holes have a extened area to install the baffles and mine even came with a template to mark the holes. I do recommend a drill press with a depth stop however, and don't ask me how I know that!!!!


Randy

 

[brumbach]

Thanks, I thought as much but was hoping I was wrong. Well for the time being, I can at least purchase some better quality valve covers and vent that way. Bill

 

[00fxd]

I am looking for an original look as well. Useing steel covers w/o provisions for pcv presented a problem. My covers are not mint so I had no problem holesawing a hole at the vertical extreme at the firewall for a pcv gromet. I then welded a small baffle on the inside. The system will breath in thru a breather cap on the oil fill tube on the manifold. I suggest this to you because there are aftermarket aluminum Corvette covers out there that it would not be too blasphemous to chop up.

 

[brumbach]

Thanks.

 

[vettefinderjim]

70-72 Z-28, and LT-1 covers

The Camaro and Lt-1 valve covers of the lates 60's early 70's look great, and will allow you to route PCV correctly. Once you get the original motor back in, you will have very tradeable covers for the correct 283 units. You will find these Lt-1 units are more expensive so watch e-Bay for a good deal.