I know this bridge has been crossed so many times that the bridge is now probably broken but I don't see an answer to my question. Maybe I missed it but I'm gonna ask anyways. The man that built my 455 blocked off the PCV passage in my B4B manifold with an expansion plug and had me running my valve covers with a breather in each side as well as an oil fill on the driver's side. My question is 1, is this a safe setup to run on the street and 2, if it is more recommended to run a PCV then can I just install one in the correct spot with the valve covers still vented on both sides? It's not a race car and is not heavily driven, occasional and weekend cruiser. Thanks all!
You will pull better crankcase vacuum if you only run one breather. I ran 3 breathers no PCV for years street and strip. 3rd was where PCV would go. No issues other than having to change oil more often. Also never ran in cold weather where you need PCV to pull moisture out from condensation.
Yes, you can add the PCV valve. You can also simply plug the extra breather hole, no big deal. Any street driven car should have a PCV system.
Larry you are saying it would work to leave the breathers in (both of them) and also run the PCV? If it would work better with one breather then any ideas what to plug a breather hole with?
Bruce said it would work better. I'm not sure about that. How big is the hole you need to block, diameter?
I'm not in a place where I can measure the diameter on the breather hole but I'm going to say it's at least an inch in diameter.
You need to measure it. I just cut 2 holes in my new Poston valve covers, 1.25" in diameter. I put a breather in the rear, and Spectre oil fill plug in the front. It pushes right in. https://www.ebay.com/itm/Spectre-17...912002&hash=item2ae3228436:g:KUgAAOSwqkxeYX6T
Thanks Larry, I will look into that, otherwise I will probably just try the PCV with both breathers in place.
The downside to running a PCV is that you will get intake valve deposits if you have any amount of blowby. I have taken motors apart with and without PCV and it is quite noticeable. One way around it is to run a separator in the PCV hose.
I like MOROSO but it's pricey. I have that on one car but the Stage 2 I just used an air compressor separator. (less $$$ for sure). Hey looks like I need to drain/clean it.....
r Very cool. Just checked Moroso, looks like they can even be mounted to the firewall or intake manifold. Appreciate the idea!
There's eleventy-two billion cars out there with a PCV valve on the engine. They work just fine. If you think you need an aftermarket "separator", you need better baffles, or you need engine work.
In a perfect world, yes....but ...Most older engines that we are dealing with have some blowby. And...most race motors are looser than production motors. Plus when you let off the throttle at 6500 going thru the traps and vacuum is high there will be some oil mist getting sucked in. I ran 2 motors one with reg PCV and one with separator and the one with separator had spotless intake valves the other pretty gunked up. You drain off the oil out of the separator so it's not imagined..... I did have one race motor that I took the separator off since I was getting no oil to drain but then it blew up. Interestingly it had gapless rings......zero blowby. Or just use SeaFoam every now and then to clean them up.
