I am finally going to have some time to finish my cam swap, I am changing the valve springs using an air compressor plugged into the spark plug holes to hold the valves in. I have never done this before and wanted some info on doing this. Do I just let the compressor run the whole time I am changing a spring or turn it off when it reaches a certain pressure? Does it take just a little pressure to hold them in? Any tips from anyone who has done this will be greatly appreciated, I'm kinda nervous because I don't want any valves falling into the cylinders! Thanks in advance for any info.

i always just let it run, but mine and any i've used doesn't always run while they're in use. i run around 125 psi line preasure in mine, enough that it'll spin the engine moving the piston to BDC.

Thanks for the info. Is there anything I need to be extra careful with or is it pretty easy. What's the easiest spring tool to use, the one that goes over the rocker bolt or the kind that grabs it like a claw with a handle on top that you turn to compress it? Like I said I dont want to screw it up!

Im about to attempt to change 8 more springs tonite, with the head on the car. I changed 8 with the head off, as I needed to pull the head anyways. I used the one with the handle on top, and it is not very easy to use, but once I got the hang of it I was fine. The biggest problem was getting the keepers off and then getting them back on. Hitting the springs with a large socket and a hammer (socket on like the edges) before I compressed it and then after to knock the retainer out helped quite a bit.

I just did a spring swap without taking the plugs out. Just turn the crank till that particulat piston is at TDC and you can use the top of the piston as a stop. I used the claw type spring compressor, with the little handle than you screw down to compress the spring. Yes- wacking the retainer before compressing the spring got all the locks loose. My girlfriend did half of them all by herself with no problem! :rockon:

Thanks again, that is the kind of spring compressor I have also.