Valve Covers

[long69]

what i have on mine is- one side is pvc valve going to the vacuum source at the carb. the other side has a filler cap and then another with a check valve (i think- its not a pcv valve)and hose going to the air cleaner.

[GASoline71]

I needed a PCV on mine, and didn't wanna run it to the air cleaner. I needed full vacuum to my power brake booster, and I used the fitting in the back of my Holley 3310 for that. So I drilled and tapped a 1/4" NPT hole into my 1" aluminum carb spacer and ran a PCV hose from a fitting I screwed into the back of the 1" spacer over to a PCV on the valve cover on the passenger side.

I run a regular breather on the drivers side that pops out to fill engine with oil as well.

Gary

[piecesparts]

Originally Posted by junkyardjohn

SORRY FRANK.. I ALWAYS TYPE IN ALL CAPS. (LONG STORY) SOMETIMES WHEN I POST IT AUTOMATICALLY CHANGES TO LOWER CASE LETTERS & SOMETIMES IT DOESN'T. I WASN'T YELLING OR UPSET IN ANY WAY. LIKE I SAID IN THE PREVIOS POST..(I THOUGHT I MADE THAT PRETTY CLEAR BUT..) PLEASE DON'T TAKE ANY OFFENCE CAUSE I SURE DIDN'T MEEN IT THAT WAY. IT'S HARD TO TELL OVER A COMPUTER CAUSE YOU CAN'T SEE A PERSONS FACIAL EXPRESSIONS. I'M AN OLD FARM BOY TOO (READ THAT OLD HILLBILLY) & HAVE BUILT AT LEAST 50 OLD SMALLBLOCKS OVER THE LAST 40 OR S0 YEARS. SORRY IF I HURT YOUR FEELINGS AS THAT SURE WASN'T MY INTENT. ACTUALLY THIS WAS FOR ALL OF THE YOUNG FELLERS ON THIS SITE. THE ANSWER IS YES YOU DO HALF TO HAVE SOME FORM OF VENTILLATION ON THESE (OR ANY)OLD MOTORS. OTHERWISE THE INTERNAL PRESSURE WILL KEEP BUILDING, & EVENTIALLY FIND A WAY OUT. USSUALLY BY THE PATH OF LEAST RESISTANCE (EITHER AROUND BOLT THREADS OR THRU A GASKET. I DON'T MEAN TO SOUND LIKE A GRUFF OLD KNOW IT ALL B@STARD, I JUST FIND IT EASIER TO LEAD SOMEONE AROUND BY THE HAND UNTIL THEY COME UP WITH A SOLUTION OR ANSWER THERE OWN SELF. ONCE YOU UNDERSTAND HOW ALL THESE LITTLE PARTS WORK TOGETHER & FUNCTION.... THEY'RE SUPER SIMPLE. THATS WHY NONE OF MY VEHICALS ARE LESS THAN 25 YEARS OLD... EVEN I CAN UNDERSTAND THEM. JOHN

No offense taken---I work in Nuclear power, now, and have been turning wrenches since I was a kid on the farm. Engine rebuilds don't come as often as they did in my past, but the principals are the same. Since PCV is (Positive Crankcase Ventilation) it is best to understand that an engine will work smoother if the gasses are removed effectively from that area. The seals on the engine last longer, since the oil and vapors are not trying to push out of them and the basic performance is better. As for whether or not to have a hose to your air cleaner or just a breather on th eINLET side of the valve cover that is everyone's choice. I went with a hose to the air cleaner to keep oil residue from collecting on my valve covers. I always use a PCV valve on the other valve cover.

Many years ago Chevrolet used to have a vent setup on their intake manifold, instead of on the valve cover and the oil fill tube had a vented breather cap to let air in. That was back in the early 60s and late 50s era. Many of the Corvette engines of that time was set up that way. It did not last long, though.

Attached is the last engine that I put in my 84 and it has the hose to the air cleaner and the PCV to the carb front

[junkyardjohn]

Originally Posted by HuggerCST

Maybe I'm misunderstanding (wouldn't be the first time), but working PCV valves aren't "vented", but are hooked to manifold vacuum. The PCV valve controls the vacuum, and pulls air/vapors out of the crankcase.(through the air cleaner and tube, through the right valve cover (on a stock '67-'72 V-8), through the crankcase to the PCV valve in the left valve cover) These engines did have a non vented oil cap, but also had a vent tube between the right valve cover & air cleaner.

YES.. IT WAS A MISCOMUNICATION ON MY PART AS MUCH AS ANYBODYS. I WAS REFERING TO A OPEN SYSTEM & PIECES PARTS WAS REFERING TO A CLOSED SYSTEM. I WENT BACK & REREAD EVERY POST SEVERAL TIMES ALONG WITH THE ARTICAL THAT YOU POSTED UNTIL IT WAS ABOUT AS CLEAR AS MUD TO ME & THOUGHT MY EYES WOULD BLEED. I THOUGHT PIECESPARTS (OR I JUMPED TO THE CONCLUSION) WAS SAYING IT COULDN'T BE DONE, & I JUST NEW FROM MY OWN EXPERIANCES IT COULD. I'VE BUILT SEVERAL DOZEN MOTORS (I HAVE A BBC ON THE SHOP FLOOR RIGHT NOW & CAN POST PIC.S OF IT IF ANYONE WOULD LIKE) WITH NO PVC SYSTEM AT ALL. JUST TALL VENTS WITH OPEN CELL FOAM FOR FILTERS. HECK EVEN WHEN I GOT MY 1982 PICKUP ABOUT 15 YEARS AGO, (WITH A BLOWN UP 305) I PULLED THE ESC COMPUTER CONTROLLED DISTRIBUTER & ALL THE OFFENDING WIRES THAT I DIDN'T UNDERSTAND, & REPLACED THE THROTTLEBODY WITH A CARB & PUT IN AN HEI & STILL DRIVE IT DAILY. I UNDERSTAND HOW THEY WORK REAL WELL. IT WAS NEVER MY INTENSION TO HURT ANYBODYS FEELINGS & APPARENTLY I DID & FOR THAT I AM TRUELLY & SINCERELY SORRY. I'LL FREELY ADMIT THAT I DON'T KNOW SQUAT ABOUT MOTORS MADE PAST ABOUT 1985. THATS ONE OF THE MAIN REASONS ALL OF MY TRUCKS ARE OVER 25 YEARS OLD. AGAIN I'M VERY SORRY & MISUNDERSTOOD IT MY OWNSELF.(LOOKS DOWN WITH A SHAMEFUL LOOK ON MY FACE WHILE RUBBING A TOE IN THE DIRT) SORRY STILL FRIENDS?? JOHN

[piecesparts]

Shucks, fella---you all didn't have to fall onto the sword YET. We could have had some fun with this.

[HuggerCST]

No worrys John. I hope that I didn't come across like an ass, I just wanted to try and clear up the confusion for anyone who may not know the difference.

[junkyardjohn]

Heres a picture of a 396 i built.. Notice the valve covers?? The second oneis a 4.3 that i'm building with an alum. Intake-carburated fuel del. System & hei. Definatly low-tech. (i just spent the last 20 minutes trying to get this d@mn little dig. Camera my son sent me.. Used with no instructions & i'm definately technilogically challendged). No high tech. New fangled stuff here. John

[ajgriffin]

I've got to say that I have no clue which way is OK now. I think what I'm hearing is that you MUST have a PCV running to the carb, but a breather in addition to that is optional?

[cdowns]

Originally Posted by ajgriffin

I've got to say that I have no clue which way is OK now. I think what I'm hearing is that you MUST have a PCV running to the carb, but a breather in addition to that is optional?

that's why i suggest the easy way of doing things// you read the service manual once and it's in black and white with pictures and gives you the proper way that a PVC system is designed to work efficently

[piecesparts]

Originally Posted by ajgriffin

I've got to say that I have no clue which way is OK now. I think what I'm hearing is that you MUST have a PCV running to the carb, but a breather in addition to that is optional?

The important thing IS: You should have a PCV valve, but to support using that you need to have a point for fresh air to enter the crankcase. So either use a vented breather cover on the other intake or run a hose to your air cleaner. Both designs do the same thing--it is just where you get your air from. I chose the air line to the air cleaner, because I did NOT want any oil traces on my valve covers.
I have seen guys connect only a PCV valve and not vent the other side in some form, their intake becomes a muddled mess of oil and slime. If you pull on the crankcase and not provide air, then you will pull gasses past the piston rings and possibly could make your crankcase atmosphere vaporize more oil due to the negative pressure.

[junkyardjohn]

I'M KINDA CONFUSED MYSELF (NOT REALLY) BUT MY REMEMBERER IS FULL UP. IF I INPUT SOMETHING NEW IN... I HAVE TO DELETE SOMETHING... & I NEED TO KEEP EVERYTHING THATS ALREADY IN THERE. I THINK I'M SUFFERING FROM THAT DREADED C.R.S. DISEASE. I GUESS I'LL JUST HAVE TO STICK WITH WHAT HAS BEEN WORKING FOR ME ALL THESE YEARS. JOHN