Hey guys so I'm gonna be looking at doing some valve springs for a guy and we are playing with the idea of using compressed air to hold the valves up.

I'll be the first to admit I've never done it this way before but is it just as easy as hooking up some air, taking the old springs off and installing the new ones?? How does a guy replace the seals and seats of air is holding things?? If the seals get pulled would that allow too much to pass and drop the valves??

Is there a better way to accomplish this besides obviously pulling the heads?

Let me know what's worked for y'all cause I feel like one little hiccup will make things interesting real fast

 

In theory, yes.

In practice, often not.

In theory, theory and practice are the same; in practice, they may not be.

Rope is better. Stuff the cyl full of about 5/16" or 3/8" nylon rope with the piston near TDC; bring the piston all the way up; do the springs on that cyl; pull the rope out. Works about 6000 times better than compressed air. Maybe even 7000.

Butt more to the point of "practice" is the issue of getting a spring compressor on all the cyls with the motor in the car. Can't comment on whether that's easy, or impossible; only, that it's an aspect of the job that MUST be considered.

 

Rope huh?? Okay I've never heard that one before. So how much rope are we talking about here?? 18 inches or so?? And then I guess just watch the rope sticking out of the cylinder to see the "squish" ??

 

Rope is used frequently, though I've never used it. Probably because I'm usually at the end of mine!! Anyway, I've had good luck with compressed air. It works well, as long as you dont try using one of those little tire inflator type comsqeezers. Use a decent 3hp or better compressor, something with some decent volume, and you'll be good.
NOTE!! If the engine has ever floated the valves, then it can be a real bitch to separate the retainer from the stem. Just sayin'. Best of luck.....

 

Gotcha no dinky tire air comps. Hopefully the valves haven't been floated. Lol haven't even started and it's getting interesting

 

Another nice thing about air is there is probably less chance of dragging foreign material, like dirt, into the cylinder. Whenever I'm going to open an engine, even just opening the spark plug holes to change plugs, I try to clean and blow air across the engine BEFORE I do whatever it may be. If there's no dirt anywhere ( you'll never get rid of ALL of it), it can't get into the engine if it's not there. I carefully use the power washer at a car wash. If you do this, DO NOT aim wand at the wiring plugs/weatherpak connectors. DO NOT let the pressure wand dwell too long at any one point. I can also say that if you put too much air pressure into the cylinder you can actually force the piston downward. I mentioned floating the valves because when the valve slams shut it is much like a hammer. That retainer really pile drives itself into the keepers. If youve floated the valves, like if you missed a gear, then maybe rope would work better. I floated the valves in my LS7 once, and I had a Helluva time removing the retainers. I had to compress the spring first, place an appropriately sized socket on the retainer, then actually use a small ball pein hammer to break them loose. The shock while under tension is what did the trick. BE CAREFUL!! If your aim with that hammer isn't good, you can quickly do some serious, expensive damage.....

 

Just remember when some jackass down the road wrecks into a power pole the air compressor will go out. Rope won't do that. Rope also makes no noise and doesn't care if somebody needs the shop air while you have springs loose.

 

Copy that! So how much rope are we talking about?? If I say stuffed 18" in there and left 6" hanging out the plug hole and watched for the rope to "squish" I should be okay ish??

 

I’ve seen a hurt headgasket from someone using too much air pressure AND piston was at BDC. Basically lifted the head. Don’t try it without watching a pressure gauge. We always used rope while doing this at the track and in a hurry. Rope won’t hurt anything and won’t let you down. Pull all the plugs, and bring each piston to the top..ish. Push a couple feet of paracord or similiar in the hole. As Grinder mentioned, just make sure everything is clean so you don’t push dirt in the hole.

 

I used rope as well and it worked great. I also put some assembly lube on the locks so they would stick to the valve and stay in place while I uncompressed the new spring and that worked pretty good.

 

Fantastic guys! It's sounding like the rope method is the way to go. I'm thinking that the direction we're gonna steer. Thanks everyone

 

Good call Dusty. I forgot to mention…should be obvious, buuuut…..you have to place clean rags or shop towels around the area of the head. If a lock goes down an oil return hole, you’re pulling a head, and if you’re lucky, you’re not pulling the pan AND the windage tray to retrieve it. Grease on the locks will help them stick to whatever they fall on.

 

Oh boy yes that's a really good idea. It would defeat the purpose of doing this if a lock dropped into the motor! I'll be sure to stuff rags in anywhere something can drop into

 

So the rope method for the win! That's what I use. New clothe line rope. 18" about. Take all the plugs out so its easy to rotate the engine. Rotate the engine so the piston is at TDC. Use a small screw driver to find TDC and then back down the piston. Feed in the rope and then bring the piston up slowly to compress the rope against the valves.
I bought a tool that compresses two valves at time. Worked great.

 

Yes sir I've got a comp cams tool that compresses both valves at a time

 

+1 for rope

 

The best thing about the rope method is if the locks are stuck and you need to tap the retainers to get the loose, you have something tangible (the rope) for the valve to bottom out on and provide some resistance.

Also be aware that the locks and retainers can get a little stuck and pop loose as the tool compresses things down and the locks can go flying. Be sure to cover the locks with a rag or something while trying to get them loose if they don't easily come loose as the springs compresses.

 

I always keep a pen magnet on the locks when I compress. It keeps the locks from flying.

 

Oh yea that's a really good idea. If those things go flying who knows where TF they'll end up

 

i do the exact same thing every since had one go flying i never found on a ls2 years ago. ( yes i still use air but i just never tried the rope method, sounds like a good idea)