ls3 valve springs
 

I'm going to change my valve springs, and I want to pressurize the cylinder with compressed air. to hold the valves up. How much air can I pressurize the cylinder with, without hurting the rings? after this I can do the Whipple install.

Last time I did this - I just used 120lbs of air....

I think I used 90 psi last time I did valve springs. What tool do you have?

Nothing your air compressor could put out would ever hurt those rings.

Yes whatever you can put out, yet.....4:10 gears are pretty steep hopefully your nice to the things as I have heard over the years the higher you go the more prone to breakage and the only cases I heard of were 4:10- 4:11 as the teeth get so small and if your draggin that's a shock even with all the suspension mods I baby my axles until someday I can get some 1000 hp drag axles and or a zl1 rear... Good Luck I know its hard getting help in Hawaii...And a whipple...More likely to make too much boost for stock hypereutectic ....2300-2900? Your going to have to keep it turned down, and I don't see on your list of mods a cam..... so worrying about the springs? I would too with boost and want duals....

You'll find the sweet spot. Too little and the valve will open when compressing the spring. Too much and the motor will spin.

Once pressurized, tapping the retainer with a socket and heavy rubber hammer helps to free up the locks. They can tend to bond themselves to the retainer/valve. If the valve just keeps going down when using the spring removal tool. Tap on the retainer again with the socket and hammer. Some can be stubborn if on there a while. I have a BBC drag motor that after a season of racing, takes a small sledge/socket whack with about 140lbs in the cyl to break them free. If you tap the retainer top with a socket and hammer, and air pressure pops out...the locks are stuck. As soon as they free up, the hit will just bounce the spring without the air pop. Then crank down the spring remover.

Yah, I didn’t mention, I did get a blower cam. I bought everything from Jannetty racing. I just finished the cam install doing valve spring, seats and seals. Did cam, timing chain, gear, milling oil pump, pined crank, crank seal, and I have to do the trunnion upgrade. When I’m done I’ll start the supercharger
My son has been helping me cause I have back problems, he into turbo Subaru’s, since he’s been helping me he seems interested on doing most of the work, he says it’s easier then working on his car. I told him “you weren’t here when I had to center the oil pump, then the timing cover” it wasn’t that bad, just takes time. I told him it’s just a lot of little details when putting thing back together.

I've done a few by just rotating the engine, so each piston is at TDC when you're working on it, that way there's 0 chance of the valves falling in.
No air needed, much easier and faster. Just stick a long straw in the spark plug hole until you feel the piston at the highest positions.

How I did mine

I did mine this way too. No problem, valves not going anywhere with the piston at tdc. Did the first couple with compressed air and then decided I didn't want to waste any more time getting the cylinder pressurized; what a pain that was.

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Agreed, safest was to insure no dropped valves...

-Don

This is the meathod I use too...works great!