Valve Stem Seals

[ccflorida]

I have heard pros and cons about doing this.. How hard a job is it and long will it take doing it for the first time...One repair shop told me two days..All advice would greatly be appreciated...
Thank You

 

[smurfvet]

First, go to a aprts store and buy a screw type valve spring compressor and a spark plug air fitting. You'll need these.

After pulling the valve covers, pull all the spark plugs. Put a big wrench on the bolt holding the harmonic balancer. You'll need to spin the engine by hand to figure out where the valve lifters are. Start with cyl. 1- spin the engine until the crank mark is at TDC. Then, use the air chuck to pressurize the cylinder you are working on.

Count the turns you have to loosen the rocker arm to where the pushrod is loose. Loose means just a little "jiggling" space, or where the tension is gone from the lifter and the pushrod can be moved. Write this down.

Compress the valve spring assembly. After the spring cap comes loose, use a magnet to pick up the two "keeper" halfs. Take off the spring, spring cap and valve locks . You might have to tap (NOT WHACK) the spring cap to loosen them. Be careful- dropping one of these locks into the engine means much more work.

After you take the spring assy. off, the seal is visible on the end of the valve guide. Again, CAREFULLY pull it off. It will probably be very brittle, so be careful. Clean the end of the valve guide and valve stem. There will probably be some form of black residue, especially on the exhaust stems.

Put the new seal on, then reverse disassembly. If you do one at a time, you can get the lifters lashed down to close to the original point, making final adjustments easier.

This method does not require removal of the head. The problem is you can't measure the wear in the valve guides, stems and seats. Normally, the exhaust guide is worse than the intake- higher temp. Pulling the heads allows you to check the guides, replace them if needed, check the valves and seats, etc.

Check to see what they are doing in the two days. If the engine has 100K miles or more, it's better to do the full "pull the heads" route. You might find more normal wear that needs attention.

 

[fastglass95]

Good Advice!

Thanks smurfvet!

That pretty much sums it up.

Ever heard of using nylon rope , inserting into cylinder thru spark plug hole, then turning motor over to compress nylon up against piston top and valve to keep the valve shut during seal replacement procedure? Instead of the "air-chuck" method.

I have not tried this yet. Sounds like it could work?

Anybody done it this way?

Thanks,

 

[Ken]

I've heard or read about that someplace Tom, I just can't remember where.

How ya been anyhow? Too bad you didn't want to make the drive to Farmington when I was there. Dave treated me good.

_ken

 

[billd]

nylon rope method works

I have several friends with small block chevys that habe done this with a rope and it worked well. It just takes alot longer than doing it with a compressor.

As far as the tool goes I tried the screw in style spring compressor that smurfvet was talking about and found that the lever style (dirt cheap) from autozone actually worked alot better for me.

 

[billd]

one other thing

Make sure that the rubber washers that you replace go on after the valve is compressed but before you put the keepers in or else the whole thing is for nothing.

I actually wrote up a procedure for doing this a couple of months ago I'll see if I can find it.

 

[billd]

I found it

Here is the procedure I used on my 84 it might be different for yours but I hope this helps

Basically to replace the vavle seals is a pretty straightforward thing if you dont learn it the hard way like I did. Pretty much with a car that age the seals are probably shot.

To replace them
Basically you

pull the valve covers
remove the plug on the cuylinder your fiddling with
insert a tool to pressurize the cylinder (AutoZone $10.00)
apply compressed air to tool (just squirts air into the cylinder- through the spark plug hole)
remove rocker arm
install valve compressor ($8.00 Autozone) (use the rocker arm- nut to do this) (I had to bend to tool more than it already- was to fit it in but it worked well after that)
This is the tricky part

Make sure the air is going into the cylinder
pull on tool to compress valve spring (you may have to tap it with- a wrench just as to start to compress it to dislodge- keepers)
take out the keepers
put them somplace safe (you might want to purchase some- spares in case you lose them i did and i needed them)
pull the spring off
remove the cup seal at the head and the oring on the valve
install the new cup seal
THIS ORDER IS IMPORTANT
reinstall the spring
Compress the spring
install the oring in the SECOND groove on the valve
install the keepers and remove the tool

DO NOT release the valve compressor once the oring is installed and before the keeper is installed

install the rocker arm and set the lash by twisting the pushrod while tightening the nut. The pushrod should just turn with your fingers and no axial slop should exist.

After this is done done if the engine ticks just remove the vavle cover and set the valve lash with the engine running (kinda messy but really easy to do, use a feeler guage to find the culpit, since this is a no lash system the guage shouldn't go through )
just tighten the nut till the noise goes away.

Hope this helps

 

[ccflorida]

Thank You

Thank You,Thank You for all of your great advice. Being that I never have done this before any estimates in time to complete the job...

Roy