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1954 CORVETTE PCV CONVERSION
In California a car that is 52 years old is exempt from smog
equipment or testing for annual registration. The only
regulation is that it must not be emitting billows of white or
black smoke. My ’54 was in complete compliance with all state
laws.
In June 2003 I joined the Corvette 50th Anniversary Caravan to
Bowling Green, KY. As the “senior” car in the contingent from
CA, it drew some attention. I am not sure but believe it was the
only 6 cylinder Corvette in the Caravan. Some of my Red Line
Corvette Club members insisted I be placed in with their
predominant line up of C-5’s. This was fine with me! After the
first 100 miles or so of desert driving I noticed my companions
opting to pass me. It was rewarding since I felt they were
impressed how well the old “stove-bolt” 6 ran and were confident
I was doing fine by myself. Wrong! After much prodding, I
finally got several to confess that “I stunk”! There was no
smoke or oil on their windshields but there was quite a pungent
odor similar to following an old diesel bus. I also noted that
after driving freeway speeds there was white smoke coming from
the crankcase vent tube when I stopped for a traffic light.
Later on I did want to continue driving in SACC caravans and did
not want to offend my “followers” and obviously wanted to do my
share to help the environment. So, I decided to see if the car
could be adapted to a PCV system.
The car is mostly all stock with matching numbers except for a
12 volt conversion which was necessary for the trip to Bowling
Green. Something about starting a 6 volt Corvette in hot
weather? I did not want to drill any holes or destroy any
original parts.
The best place to catch the crankcase emissions was at the
crankcase vent in front of the distributor. Then install a PCV
vacuum check valve in the tube and then run a hose to the intake
manifold. There are 4 slots in the valve cover which would act
is the intake for the vacuum? I sketched this out and was
wondering if it would be effective and if the slots were too big
in the valve cover. I mentioned the concept to Larry Pearson (SO
CAL SACC Secretary) at a board meeting and he said he thought he
remembered seeing a Chevrolet Service Bulletin for doing a
similar mod on Chevy trucks used in heavy (dusty) farm work.
Larry was right and a week later he sent me the information from
1956. The truck and passenger Chevy cars all have one
carburetor, different valve covers and intake manifolds. They
required some drilling in the valve cover and air filter. See
attached R.P.O. #417. The basic principle is the same for
recycling the crankcase so I felt my concept should work. I did
not want to do any drilling! I was not planning on taking the
’54 on any dusty farm roads.
First remove the crankcase vent assembly which requires some
tapping with a rubber hammer from side to side while pulling to
loosen the press fit into the block. Once removed, install a
steel pipe 1-1/4 “o.d. and 10” long into the hole for the vent
tube. Again it will be a press fit.
Next, select a PCV valve from any parts store that will fit a
grommet that will snugly fit into the 1-1/4 “ tube. You might
take the pipe to the store to assure a proper fit. My selection
was for a Toyota. While there pick up 3’ of 3/8” hose for the
run from the PCV valve to the manifold fitting.
The vacuum line from the fuel pump which taps in the front of
the manifold is removed. A ¼” “T” with 3 internal ports will
serve as the connection for the new PCV vacuum line and the
reinstalled fuel pump vacuum line. You will also need two ¼”
unions to connect the “T” to the manifold and vacuum line. These
parts, along with a tube fitting for the PVC hose, are available
at any hardware or auto parts store. Thus, no permanent changes
are made.
The attached photos depict the final configuration. I have taken
the ’54 on numerous caravans and no one has complained about the
“odor” and the white vent smoke is obviously eliminated. The car
runs fine and with no adverse effects and the environment is
cleaner. I can put it back to NCRS status in less than 30
minutes, but I don’t want to!
Bruce Fuhrman |
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