O-rings + positive stop valve stem seals replacement :
This is how I did it. Of course, it's not the only way to do it !
My method will allow you to do half of the job one day, and the other half another day.
Tools required :
1. An air compressor ( or access to compressed air ! ), 80 to 100 PSI is enough.
2. An air compressor hose attachment that screws into the spark plug hole.
3. A medium hammer and a small piece of hard wood.
4. A pair of pliers.
5. Standard sockets and classic tools.
6. A valve spring compressor.
7. Some rags to prevent oil droplets from falling on your brand new headers !
8. A white marker, a ruler and a pair of scissors.
9. Paper and pen to take notes of what you did and what you still have to do.
10. A small magnet.
11. Some special tools that can help... ( see below )
Parts required :
1. Valve stem seal kit including seals for both intake and exhaust,
assuming you have machined guides and you know machined guide and valve sizes.
( O-ring kit and positive stop seals can work together ).
Mines look like these, except I have 0,562" valve guides : http://www.jegs.com/i/Comp-Cams/249/529-16/10002/-1 http://www.jegs.com/i/Comp+Cams/249/501-16/10002/-1
2. If you didn't remove the valve covers for a long time, maybe you will have
to replace the 2 valve cover gaskets, too.
3. A set of 8 new spark plugs, depending on how old they are or how bad they look...
Estimated time :
With the appropriate tools and parts ready, I would say between 25 and 45 minutes per cylinder,
but you don't have to do all of them the same day !
The job :
First step :
If you don't already have a torsional damper with 90° marks, it's time to make one !
First, you must know the damper diameter. On my engine, it was 8", so the perimeter is 8 x 3.14 = 25.12".
This is the length for 1 turn = 360°. For 90°, divide this length by 4 : 25.12/4 = 6.28".
Take a sheet of paper and cut a small band of 6.28" long.
Stick it on the damper with adhesive tape, one end of the paper exactly on the 0° mark, and make a mark
with the white marker on the damper at the other end of the paper.
Rotate the crankshaft and do it 3 times. It doesn't have to be perfect, +/-2° is great.
Second Step :
I'll begin by removing the left valve cover ( cylinders 1-3-5-7 ) and all spark plug wires on the left side.
Slowly rotate the crankshaft until the index is at 0° ( TDC ). Look at cylinder 1 and cylinder 3 rockers.
The 2 valves of cylinder 1 should be closed, and cylinder 3 intake valve should be wide open.
If it's not the case, it means that you're on cylinder 6 firing position. Make 1 full turn on the crankshaft and check again.
This can also be confirmed by looking at the distributor rotor, if you remove the distributor cover.
Now, use some rags to cover the head oil drainback holes. This is to protect from dropping dirt/tools/anything into the engine.
Third Step :
Clean and make a white mark on the rocker arm nuts. This will allow you to check that the valves are adjusted the same way ( assuming they were correctly set ! ).
Remove cylinder #1 rocker arm nuts, rocker arms and pushrods ( necessary to use the valve spring tool easily ). Remember : All the parts you remove will have to go back in the same place and position. So don't mix them !
Separate all the parts for exhaust and intake valves. Clean and make a white mark at the top of the pushrods to prevent upside down issues.
Fourth Step :
Remove cylinder #1 spark plug. Screw in the air compressor attachment in spark plug #1 hole.
Do not tighten the attachment too much. It's useless and it's difficult to remove ! A small leak is not a problem here.
Supply air to the hose to keep the valves closed. You should hear a small "hisss" coming from the air escaping slowly by the piston rings.
Fifth Step :
With the hammer and the small piece of wood ( or aluminum bar ), break loose the valve keepers by hitting the two spring retainers.
The sound will change when the keepers break loose.
Sixth Step :
Use the valve spring compressor tool. If the last step was correctly done, the valve stem shouldn't move.
If it moves, it either means you don't supply enough air pressure to the cylinder or the keepers are still stuck
to the spring retainers --> Go back to fifth step !
Seventh Step :
With the small magnet, remove the 2 keepers. Then slowly release the valve spring compressor tool,
remove spring retainer and spring. Same thing, always remember all these parts will have to go back to the same valve !
Eighth Step :
Repeat Steps 6 and 7 with the other valve.
Ninth Step :
Remove the old o-rings at the top of valve stem, looking carefully at the small debris that could fall.
With the pliers, rotate and remove slowly the old positive stop seals ( or umbrellas ). Do not damage valve stem with the pliers !
Clean the valve guides and lubricate with clean engine oil.
Tenth step :
It's time to install the new positive seals. This is where my special tool can help a little.
Actually, it's a simple way to prevent the seal's lip from being scratched by the valve stem grooves.
As you need a lathe to make this tool, I will not give more informations about it, just pictures
that will show how it works. If you want more infos, send me a PM.
Push the new seals until they are firmly set on the valve guides.
Eleventh Step :
Replace the first valve spring, its retainer, and use the spring compressor tool again.
It's now time to put back a new o-ring seal in its place. The most important thing is to keep
the retainer centered with the valve stem. This allows you to slip the o-ring easily in its groove. Caution :
The o-ring valve stem seal goes on the SECOND grooved notch of the stem.
The first one from the top is for the keepers.
Then put back the two keepers. A small droplet of engine assembly grease can help to keep them in place.
Release slowly the valve spring compressor tool, paying attention that the keepers will not move.
Some small hits on the retainer with the piece of wood and the hammer will help the keepers find their place.
Do the same thing with the other valve.
Twelfth Step :
Put the pushrods, rocker arms and nuts back, and adjust the valves lash for this cylinder. ( Refer to a manual ).
If you made a mark on each nut, it should be easy to set them as they were.
But preferably, only use the mark as a final verification.
Thirteenth Step :
Remove the air compressor attachment in spark plug #1 hole. Screw in and torque the spark plug.
This cylinder is done !
Fourteenth Step :
Rotate the crankshaft clockwise until the next cylinder corresponding timing mark aligns with the index.
Beginning from cylinder #1, I chose to do #3, #5 and #7 respectively. Then the other side, #2,4,6,8.
This is how much degrees you will have to turn the crankshaft ( with firing order 1-8-4-3-6-5-7-2 ). Caution : Some camshafts have a different firing order !
Each angle is measured from the previous cylinder, and always clockwise.
#1 = 0°,
#3 = +270°,
#5 = +180°,
#7 = +90°
#2 = +90°,
#4 = +270°,
#6 = +180°, ( Here, you should be aligned with the 0° timing mark )
#8 = 1 full turn + 90°.
Alternative possible order for passenger side head :
#2 = +90°,
#8 = +180°,
#4 = +90°,
#6 = +180°. ( Here, you should be aligned with the 0° timing mark )
Use the paper and always write which cylinder you're working on, and which cylinders are done.
Immidiately after a crankshaft rotation, note it ! It'll allow you to drink a beer from time to time and not make any mistake.
Important Note :
Don't forget to remove rags from the head oil drainback holes ( could be disastrous ! ) before you put back the rocker arm covers.
And now a few pictures to make things clear... Note : Pictures show the procedure for cylinder #4.
The compressor :
The air compressor hose attachement ( old spark plug drilled, air hose and fitting ) :
The valve spring compressor tool ( Summitracing ) :
Special tools :
Set crankshaft at cylinder #4 TDC :
Removed left rocker arm cover and four spark plug wires :
Air compressor attachment is screwed in spark plug #4 hole :
Removed 2 rocker arm nuts, 2 rocker arms and 2 pushrods :
After keepers break loose, first spring is compressed ( while compressed air is in cylinder 4 ).
Use the magnet, don't let the keepers fall in ! These are small and slippery parts :
Intake valve keepers, retainer and spring are removed, exhaust spring valve is now compressed :
Old o-rings and positive stop seals can now be removed :
New positive stop seals installation, after some cleaning and lubrication :
The new o-ring seal has to be installed now ( after spring & retainer ), as long as spring is still compressed.
Remember : Second groove from the top. Picture shows the black o-ring installed on the valve stem :
Keepers are back on the valve stem and will stay in place easily with a little assembly grease :
Spring released and valve spring compressor tool removed :
Second valve is done the same way :
Pushrods, rocker arms and nuts are back, respectively :
Valves lash is adjusted, as long as piston #4 is still at TDC ( Firing ). I used 1/2 turn past zero lash.
As a verification, it's nice to see that the marks on the nuts are still in the same orientation :
And now, it's your go !!!
Last edited by 73StreetRace; 09-29-2009 at 02:16 AM.
Reason: Comments added to the pictures...
Very nice write up, well done. Another method, if an air compressor is not available, is to feed small nyon rope into the cylinder through the spark plug hole, then roll that piston up. The rope will hold the valves up while the seals or springs are changed.
I tested the car for 30 minutes this afternoon...
No oil leak, I removed a few spark plugs, they look really clean.
No blue smoke, no abnormal hydraulic lifter noise, everything works the way it should... ( I keep my fingers crossed )
I'm back on the road...
And you know what... I'm happy !
Last edited by 73StreetRace; 10-27-2009 at 02:14 AM.
Real nice job on the write-up. Thanks for sharing.
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great write up and step by step pics..if i may...i dont like using an air fitting when changing seals .....it does not allow me to push the valves off their seats to check for guide wear...using air in the cylinder lets you replace the seal and new seals will work on worn guides for awhile..... but if the guides are worn out it is just a matter of time before the new seals will wear out also......good luck to you and again, a nice tutorial.....