VEHICLE: 1971 Chevrolet C-10 Pickup
Certification Expires: June 30th, 2016
ASE Certification ID: ASE-1785-9774
Until the early 1970s, consumers had no way to distinguish between incompetent and competent mechanics. In response to this need, the independent, non-profit National Institute for Automotive Service Excellence (ASE) was established in 1972.
PHOTO ONE — TOOLS NEEDED
The first step should be a dry / wet compression check followed up by a cylinder leak down test. If the result of these two diagnostics reveal the rings and valves are in the minimal acceptance range, then the valve seals are responsible for the blue smoke.Valve seals are an easy enough "on car" repair if one has an air compressor in their garage capable of maintaining at least 120 PSI, any less pressure than that, then there is a good chance the valve will drop down into the cylinder bore.
PHOTO TWO — ROCKER ARM HOLDING TOOL
Before re-installing these items a quick bath in solvent is in order.
Additionally, this would be a good time to measure and record push rod diameter and length for future reference, in this particular case the push rod diameter is 5/16 " and 7.8125 " in length.
PHOTO THREE — AIR HOLD DEVICE
CAUTION : Make sure there are no obstructions in and around the fan belts / fan because as soon as you connect the air hose to the air hold device the pressure will force the piston down and rotate the engine approximately a quarter turn.
With the spring compressed, remove the valve keepers ( having a small telescoping pocket magnet will assist greatly in this ) and you should be able to see the valve seal at this point.
Sometimes the seal is so deteriorated that very little of it, if any, remains on the valve stem.If you do see the seal, use a dentists pick and remove it. The seal will most likely be very brittle and will break off in tiny pieces.
Pull the spring compressor tool straight up to expose the valve stem. At this point you can clean the valve spring ( still compressed in the tool ) and the valve stem in the head with a little bit of solvent.
PHOTO FOUR — VALVE SEAL GROOVE LOCATION
NOTE: It would make life a heck of a lot easier if the valve seal could be left on the valve ( as illustrated in PHOTO FOUR ) and the spring installed on top of it, but it can not.
The compressed valve spring must be installed FIRST, then the valve seal installed, then the valve keepers. Once these items are installed, then you can turn the valve spring compressor counter-clockwise to extend the valve spring.
If the valve seal is installed first, when you place the valve spring assembly over the valve stem, the spring retainer will rip / cut the valve seal and all your work will amount to nothing but blue billowing smoke out of the exhaust.
Rest assured this is a very tedious operation, however, if you have the correct compression on the valve spring with the tool, you should be able to just barely see the valve seal groove from the top of the valve spring.
With a little petroleum jelly over the valve stem and a pointed dentist pick, you should be able to work the valve seal down into its groove.Make sure the valve seal does not turn itself inside out during the installation.
PHOTO FIVE — VALVE SEALS INSTALLED
PHOTO SIX — REINSTALL ROCKER ARMS and PUSH RODS
Install a compression tester to #1 cylinder and bring the engine up to TDC.
Install a compression tester to #6 cylinder and bring the engine up to TDC.
PHOTO SEVEN — OIL STOPPERS / DEFLECTORS INSTALLED ON ROCKER ARMS
Reinstall the spark plugs, distributor cap / wires and plug any vacuum ports that may have been opened by removal of the air filter, valve covers, brake booster hose and whatever other items you had to remove for access.Now start the engine and let it warm to operating temperature.
NOTE: If you want to avoid steam cleaning the engine bay after this procedure, then I would suggest placing heavy duty aluminum foil over the exhaust manifolds and engine bay area as oil splash protection.
With the engine warm and running, back off the rocker arm adjusting nut until you begin hearing a distinct " clacking " sound, then turn the adjusting nut in until the " clacking " sound stops, then turn the adjusting nut in another ¾ turn.
Repeat this process for the other 15 valves.Shut the engine off, clean up the tin foil and check the engine oil level.
PHOTO EIGHT — INSIDE of VALVE COVER COATED with GLYPTAL
PHOTO NINE — VALVE SEAL REPLACEMENT COMPLETED: JANUARY 2012
Should you be interested in the theory behind valve stem seals, click here, to read my technical article.
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