[Aaron65]

I've done a search about valve sealing here, but I want to make sure my head's right on this one. Ha ha!

My '74 350 seems like it's never been disassembled, has 88,000 miles, and doesn't use an appreciable amount of oil in the 1,500 or so miles I drive it a year. I do smell some oil in the exhaust on a cold start up. Therefore, I plan to replace the valve seals (o-rings?) over the winter.

Unlike many car guys, I have almost no interest in how fast the car is, so I won't be needing to do any upgrades right now, and I don't plan to pull the heads at this time. With that being said, are their any tricks or pitfalls I should be looking for on this job? It's my only Pontiac, so I'm basically looking for the Pontiac-specific stuff. It has the positive stop rocker arm studs and the shields (46 heads).

I have an air compressor adapter and the "wheel" style valve spring compressor. Any guidance will be appreciated, as always! Thanks!

[54nomore]

It's fairly straight forward, you just have to do it in a specific order. Compress, remove keepers, remove old o-ring, install new o-ring, install keepers, release spring. Voila! The only problem you will probably encounter is brittle original O-rings breaking into small, hard to retrieve pieces. The tip of a small pocket knife may help to split the o-ring for easier removal. Good luck!

[Aaron65]

Sounds good, thanks!

[GRX]

'54nomore' pretty much covered it. Order is key. Spring assembly has to be compressed down far enough to replace the o-ring. Then release so the ring fits into the retainer cap so it works in conjunction with outer shield to act a big umbrella.

[edit] - for easier disassembly, one thing I would suggest is smack one side of the retainer at an angle with soft hammer (plastic, rubber, etc ..) to help break the wedge effect.

[Squidward]

Wrap plastic or an old sheet around the entire area to keep stuff from falling down the drain back holes. Use a magnet tool to pull out the keepers. Put the piston at the bottom of the cylinder when you pump it full of air. And I like the lever style compressor because the wheel type never worked well for me.

[Schurkey]

Originally Posted by Squidward

Put the piston at the bottom of the cylinder when you pump it full of air.

If the piston is at the bottom of the cylinder, and you happen to knock a valve or the air compressor hose ruptures so as to lose pressure in that cylinder, the valve falls through the guide into the cylinder...and then the head comes off to retrieve it.

"I" assure that the piston is UP in the cylinder. The valve could possibly fall, but not so far that you couldn't grab the stem and pull it back up. This also means that the cylinder pressure could push the piston down unless you're precise about getting the piston to TDC. If the piston goes down it will rotate the crank in the process. I try to make sure that my necktie is not wrapped around the fan blades so I don't get choked to death.

[Will]

Originally Posted by Schurkey

... I try to make sure that my necktie is not wrapped around the fan blades so I don't get choked to death.

Try a bow tie. They don't get tangled in things so easily.

[Squidward]

Originally Posted by Schurkey

If the piston is at the bottom of the cylinder, and you happen to knock a valve or the air compressor hose ruptures so as to lose pressure in that cylinder, the valve falls through the guide into the cylinder...and then the head comes off to retrieve it.

"I" assure that the piston is UP in the cylinder. The valve could possibly fall, but not so far that you couldn't grab the stem and pull it back up. This also means that the cylinder pressure could push the piston down unless you're precise about getting the piston to TDC. If the piston goes down it will rotate the crank in the process. I try to make sure that my necktie is not wrapped around the fan blades so I don't get choked to death.

True. Putting it at the bottom offers more risk with the valves, but makes the job simpler.

Because of the rotation risk you mentioned above I stopped doing valve spring changes naked.

[glhs#116]

Whatever happened to the old "rope trick"? This is what I did when I replaced my valve springs, seals, keepers. Feed in some rope through the spark plug hole and then turn the crank until the piston is smushing the rope up against the valves (keeping them closed). Simple and pretty fool-proof.

[steve25]

On other thing to check as you go thru valve by valve is the rocker arm nut, flip it over so the flat side is facing you and make sure there are no radial cracks showing going from the center hole out to the edge.

[NeighborsComplaint]

Make sure your kit comes with a plastic sleeve to slip over the valve stem before installing the new O rings. It covers up the "lands" for the valve lock (keepers) which have very sharp edges. If you roll the O ring on the valve stem without it you run the risk of damaging the O ring if it catches on the sharp edge..

[steve25]

Those stem condoms are only needed for installing seals, not O rings!

[racegto65]

Originally Posted by 54nomore

It's fairly straight forward, you just have to do it in a specific order. Compress, remove keepers, remove old o-ring, install new o-ring, install keepers, release spring. Voila! The only problem you will probably encounter is brittle original O-rings breaking into small, hard to retrieve pieces. The tip of a small pocket knife may help to split the o-ring for easier removal. Good luck!

You also might try replacing the o-rings with a simple umbrella seal(Pioneer OS-450).
I've done that on many sets of heads originally equipped with just o-rings
(better oil control but doesn't need any machining).

[Aaron65]

Originally Posted by steve25

On other thing to check as you go thru valve by valve is the rocker arm nut, flip it over so the flat side is facing you and make sure there are no radial cracks showing going from the center hole out to the edge.

Will do....thanks for the tip.

I've heard about the rope trip, as mentioned above, but I have an air chuck and air compressor, so I'll probably just use that.

[ponyakr]

This might be a good place for another one of my dummy questions.

Most recommend the one piece stainless valves for high performance builds. These don't have the o-ring grooves.

So. for the low budget guys, are there any one piece stock type replacement valves, which do have the o-ring groove ?

Or, are all the cheap replacement valves two piece ?

OK low budget guys, are you listening ?

I just called SI valves. They sell one piece valves, with the o-ring groove, for about $6 a piece. The exhausts are stainless. The intakes are not. I assume these would not come apart like factory 2-piece valves.

Don't know anything about the quality of SI valves. The guy @ CVMS is the only guy I've heard of that used & recommended SI Valves.

http://sivalves.com/flipbook/2016-SI-Catalog.html#p=5

[phil400]

I've also seen where the springs and keepers are "stuck" together, use a socket that's the same diameter as the spring shield and tap with a hammer to free it up, when tapping with a hammer it'll change sounds when it frees up.

[steve25]

Use those SI valves like you would a factory valve, as even though they will not loose there heads , the Exh valves are still not up to dealing with the Exh temps seen in 500+ hp motors or in Turbo or super charged usage!

[racegto65]

Originally Posted by ponyakr

This might be a good place for another one of my dummy questions.

Most recommend the one piece stainless valves for high performance builds. These don't have the o-ring grooves.

So. for the low budget guys, are there any one piece stock type replacement valves, which do have the o-ring groove ?

Or, are all the cheap replacement valves two piece ?

OK low budget guys, are you listening ?

I just called SI valves. They sell one piece valves, with the o-ring groove, for about $6 a piece. The exhausts are stainless. The intakes are not. I assume these would not come apart like factory 2-piece valves.

Don't know anything about the quality of SI valves. The guy @ CVMS is the only guy I've heard of that used & recommended SI Valves.

http://sivalves.com/flipbook/2016-SI-Catalog.html#p=5

I have been using SI valves for years in all my builds(stock to race including my own race car!) never had a failure and their customer service is excellent.