replacing valve seals on a 318 procedure?

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D

DQ81

'73 Dart
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replacing valve seals on a 318 does this involve taking the heads of?

I've never done it before, as it seems straightforward I'm just curious if by using the piston to push the valve against when removing and replacing the valve spring I might bend the valve stem or damage the valve itself or the seating...

What's the 'procedure' for replacing the valve seals, tried and true?
 
There is a fitting used to load the cylinder with compressed air so you dont drop the valves.
 
DQ, you do not have to remove the heads, but if you do not have an air compresor with the spark plug adapter to pressureize the cylinder to keep the valves up in the head whle depressing the springs to remove the locks, etc.....

A head removal will be needed. At the bottom of page 1 and somewhere on page 2 of the below thread, theres some info on what is needed to be done. A spring compresor tool of ethier the one shown or the bigger "Around the head" like unit will be needed to compress the spring.

The way it is done in the thread, the valve will drop and hit the table. A soft rag or rubber/plastic base will avoid any issues. If you use a rag to cusion the valve and hold it up on reinstalation, check under the valve for traped rag ends.
http://www.forabodiesonly.com/mopar/showthread.php?t=10508&page=1&pp=20
 
You can use compressed air with an adapter screwed into the spark plug hole to hold the valves in place. Then, you'll need the correct "head on block" valve spring removal tool. A small magnet is also helpful to get the retainer locks out.

If you have the "umbrella" style seals be careful to not cut them on the sharp edges of valve stem top. Most seal kits come with a small plastic tube that you fit over the valve stem top when installing the seal to prevent seal damage.

Hope this helps.
 
I just did the same thing on a 225. I used a nylon rope and just feed it into the cylinder and then turned it by hand until it wouldn't move. I put about 3 feet in before it would lock up the engine. When done with one just back it off pull out the rope and move on to the next one,
 
no don,t push on the piston. run it up to the top incase you drop the valve and use compressed air in the cylinder to hold them up.It is a pain in the *** because the air wants to push the piston down but it can be done. Try low pressure and a breaker bar on the damper pully to hold it. good luck.
 
Like dartcuda said I have dune this before, Starting with cylinder number 1, put the engine a little before, or after Top Dead Center. This is easier to find without the distributor cap (rotor installed). Start feeding the rope into the cylinder through the spark plug opening (much easier said than done, you guys with air compressor don't have to deal with this, But it can be dun,
I used a 1/2 inch drive breaker bar and socket on the damper to turn the motor by hand, I removed all the spark plugs first to do this, It does work.
I hope all goes smooth, It seems like the You'll probably have to tap on, or force the spring all the way down (they like the spring keepers, and grow quite attached to them).
 
Mike's right. Use a socket and hammer to give the retainer a medium strength "tap" to free the retainer from the locks. You'll feel it when they free up.
 
Personally,I say save your back. Pull the heads and do it on the bench with a big c clamp style spring compressor. You could have all the seals done this way in under 10 minutes and no compressed air or sore back!
 
I did this last year with only a nylon rope and screw/clamp type valve spring compressor. Like the other posters said turn the engine so that the piston for the cylinder you want to work on is near the bottom, then feed in rope through the spark plug hole as much as you can before it starts bunching up. Then rotate the engine again until it locks up on the rope. Next compress the valves, hitting the retainers if you need to to free up the locks, and remove the springs with the old seals (which will probably be crunchy and break apart, watch out). Put the new seals on, repeat everything backwards, then start on the next cylinder.
 
MOPEkidD-3:
You funkee Homosapien!

needsaresto:

Good thinking on the back pain, hadn't though about that. As I'm supposed to be operated on my back for a herniated disc (L4-L5) in the coming months these are things I have to take into consideration.

I was also thinking, while the heads are pulled I'll have a machine shop plane them and I can flow them as well. The more I think about it the more I want to go this route.

Any recommendations on how much to take off the head (Rumblefish?), say a happy medium between raised compression and no compromise of head integrity? I'll be replacing the cam with a 340 spec cam and the timing chain with a double if that's of any relavence...
 
Don't forget how heavy the heads are to get out from under your hood and not counting all the bolts and then putting everything back in and don't forget the exhaust removing and intake :angry7: I would do a couple at a time and take a brake from it, That's how I would have to do it if I was on my own. leave it in. my 2 cents8)
 
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