Pcv

Lets also remember to keep the vented cap clean. with a PCV in use it's getting it's intake of atmosphere through the vented oil caps in these cars so road debris will be collected there over time.

Benefits of a PCV system include, but not limited to:

reduction of spent gasses collecting in the crankcase and promoting sludge build up

greating an atmosphere negative, or "depression" in the crankcase to aid in ring seal

reduction in road draft debis in underside areas of the car

aids in front and rear crankshaft seal (reduced oil leaks)

extending oil change intervals by keeping the case environment cleaner

A depression in the crankcase is always a welcome force in HP engines for all of the above reasons and more. Race fans may have noted one way valves in the header collectors of drag race cars. They are used for these reasons, especially ring seal at high operating speeds. More extreme applications actually use a vacuum pump to create case depression. PCV valves have different specs, and as I recall our sister publication (theHAMB) had quite a topic on that. Good stuff 'barners...
 
51 MERC-CT said:
Suspect that you don't have a vacuum source.
There is not a vacuum source in that area.
You could 'T' into the wiper connection.
466114
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Appreciate your assistance as you kindly point out need to tee into the vaccum source at carb.
Thanks
Phil NZ
 
So have refitted the line from PCV valve into the vaccum source for wiper and distributor.
Noted now with this set up it has dropped the vaccum gauge reading.
Suppose this would happen as now drawing from front of the gallery and oil filler tube with vent cap.
Phil NZ
 
Phil Gillespie said:
So have refitted the line from PCV valve into the vaccum source for wiper and distributor.
Noted now with this set up it has dropped the vaccum gauge reading.
Suppose this would happen as now drawing from front of the gallery and oil filler tube with vent cap.
Phil NZ
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Someone can correct me if I'm wrong but pretty sure you need to readjust your carb mixture screws now that you've added the pcv. Adjust with with your vaccum gauge hooked up to achieve highest reading at idle.
 
Will D said:
Someone can correct me if I'm wrong but pretty sure you need to readjust your carb mixture screws now that you've added the pcv. Adjust with with your vaccum gauge hooked up to achieve highest reading at idle.
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Thanks for that info will check it out as have a vaccum gauge permanently fitted. To also remove vaccum line to distributor as running a Chev unit
Phil NZ
 
Phil Gillespie said:
Thanks for that info will check it out as have a vaccum gauge permanently fitted. To also remove vaccum line to distributor as running a Chev unit
Phil NZ
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By adding the PCV to the source of your vacuum advance I would think you are screwing up the signal to it. IF I am reading you correctly. I had the same issue in my original post.
 
Gene1949 said:
By adding the PCV to the source of your vacuum advance I would think you are screwing up the signal to it. IF I am reading you correctly. I had the same issue in my original post.
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How did you overcome this then? To make a special connection just for the PCV valve below the carb ?
Phil NZ
 
Gene Just took another look at your pics and see the PCV valve is plumbed into the front area of carb inlet. Do you have the vaccum signal to distributor at rear side?
As thinking this maybe required for my set up. A single connection at front for PCV valve
with the standard connection at rear for distributor and wipers.
Am I correct with this line of thinking?
Phil NZ
 
My PCV is plumbed to the rear (secondary end) of the block. What you are seeing is the distributer source (front of carb) in the block. I wanted a steady source of PCV vacuum from both sides of motor so the rear under the secondaries was the logical choice.
I sourced the distributer advance can under the primaries. My way of thinking I wanted the advance can to react a little quicker.
 
If you look close the rear under secondaries has a blue PCV hose attached. The distributor advance line goes goes straight for the front of the aluminum block to the distributer. The vacuum for the windshield wipers come from the stock (Edmonds manifold) location on the driver's side.
Hope this helps explain it a little better. I might being a little anal about the connections (source) but it sure runs good this way (sourced from both sides of the motor with this particular manifold). With the small flow PCV valve I chose I had to adjust the idle air maybe 1 [screwdriver] blade width fatter.
 

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After reading all of this, I have become convinced that a PCV system is the way to go, so I am going to install one on my '51 coupe.

I'd put one on the "Hot Rod" engine I am just building, but I had the road draft tube chromed and it sure looks purdy.:confused:
 
Gene1949 said:
If you look close the rear under secondaries has a blue PCV hose attached. The distributor advance line goes goes straight for the front of the aluminum block to the distributer. The vacuum for the windshield wipers come from the stock (Edmonds manifold) location on the driver's side.
Hope this helps explain it a little better. I might being a little anal about the connections (source) but it sure runs good this way (sourced from both sides of the motor with this particular manifold). With the small flow PCV valve I chose I had to adjust the idle air maybe 1 [screwdriver] blade width fatter.
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Gene, Thanks for extra clarifcation that helped a lot.
Phil NZ
 
PCV 101.. The purpose of the valve in the PCV is to provide open vacuum to the crankcase, upon accelleration the valve snaps shut, thereby providing vacuum to the advance, releasing the throttle allows the system to return to open vacuum.
I had a problem with a '63 Chevy 230 CID 6 in 1963, the engine would stumble, hesitate on accelleration. Took the truck to the local Chevy dealer. When I got the truck back it would still hesitate under full throttle, took the truck back to the dealer several times. I finally got out my factory manual, which I use to buy every time I bought a new vehicle. Looked under tuneup and emissions. The purpose of the PCV and the importance of keeping it clean was clearly defined in the manual.
I went back to the Chevy dealer, showed them the section about PCV's, Amazing, they did not have a current manual in the shop.
The solution to the problem on the 230 engine was a new PCV, the original PCV was defective.

My fathers theory of not letting the directions on the can outsmart you held true again.
 
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blucar said:
PCV 101.. The purpose of the valve in the PCV is to provide open vacuum to the crankcase, upon accelleration the valve snaps shut, thereby providing vacuum to the advance, releasing the throttle allows the system to return to open vacuum.
I had a problem with a '63 Chevy 230 CID 6 in 1963, the engine would stumble, hesitate on accelleration. Took the truck to the local Chevy dealer. When I got the truck back it would still hesitate under full throttle, took the truck back to the dealer several times. I finally got out my factory manual, which I use to buy every time I bought a new vehicle. Looked under tuneup and emissions. The purpose of the PCV and the importance of keeping it clean was clearly defined in the manual.
I went back to the Chevy dealer, showed them the section about PCV's, Amazing, they did not have a current manual in the shop.
My fathers theory of not letting the direction on the can outsmart you held true again.
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Although the valve may perform some functions as you suggest, it's most important function is to prevent a crankcase explosion in the event of a carburetor backfire.
 
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