Valve Springs Removal

[1BIGJIM]

Ok question 2 for the day. I have always removed valve springs when the heads are off the engine. I know they make a tool that I can use when the heads are still on? I know I need to bring the pistion up to TDC but do you still need to inject AIR? WIll the valve sit on top of the pistion. Its been years since I have done this. The guy I bought the heads from said they tested 300 pounds. Should have double checked myself before installing them..

[victorfb]

the air injection is a good idea. especially when re-installing the springs. though the seals should hold the valve in place. its just a bitch to get the keepers on if you keep hitting the stem and knocking the valve down a bit.

[DetroitJim]

I all you want to do is check spring pressure there is a tool to check them on the motor. Jeg's or Summit has them.
If you really need to pull them off, I never use air. Just feed a nylon cord into the spark plug hole and bring the piston up with a breaker bar until it stops turning. Stuff rags in the oil return openings so you don't lose a keeper into the motor. Keep a magnetic pickup tool handy to catch the keepers. Get a lever type compressor that mounts on the rocker stud, give the retainers a tap with a mallet to crack them loose, and fire away.
DJ

[DOHARA]

Another trick is to stuff teflon cord in the spark plug hole, then rotate the engine over by hand until that cylinder comes up on the compression stroke. the teflon cord will fill the space between the valve and piston keeping the valve from dropping. One bad thing about using air is that if the valve job isn't good the air could leak throu enough that the valve may drop. also make sure to remove teflon cord before starting I know someone that forgot and cracked the cylinder bore Just my .02
Good luck
Dano
OOps looks like someone posted just before I did

[shaun]

I've heard about people filling the chamber with small rope/string. i've never tryed it.

[396_Z]

I just use the compressed air method, it's easier to me.

[Infomaniac]

Use air if you are changing them right away. Otherwise the rope trick is good.
What are the cam specs. ? Roller? Solid?

[Fiat48]

I know you don't want to hear this, but sounds like time to pull the heads off of that thing and let us try to determine what you have.
300 lbs spring pressure. Is that open pressure or seat pressure. Is this a roller cam or a flat tappet?
Do we really have 9 to 1 compression? Did you change the pistons to get there from the 8 to 1 you had before or was the head a smaller chamber?
Trying to determine cranking compression gauge readings verses static compression ratio is guess work at best. The bigger the cam, the less cranking compression. And hard to find compression gauges that even match on readings as the little shrader valve that comes in them are different.
Did the cam get degreed on the install? Advanced? Retarded? All makes a difference.
There is a hand tool made for changing springs that is available at most Napa stores. K-D used to make them. Moroso makes a spring tester where you can spring test on the motor also. Not totally accurate unless you calibrate it, but good for ballpark. As for changing springs, most guys use a leak tester and air in the cylinder at TDC.

[HammerDown]

Originally posted by Shaun
I've heard about people filling the chamber with small rope/string. i've never tryed it.
This is how I do it...but the piston is at TDC. Even if the valve drops, it's not very far if at all. And you can just start over.
I use nylon clothes line. The thick stuff.

[1BIGJIM]

I am here with an open mind. If it comes down to taking the heads off I will Never to old to learn. Hey I'm 42 and don't have all the answers. Thats why I post things and could never thank you guys enough for any reply Honest alot of this is going over my head. I must have been lucky building my engines before. Static, Dnyanic compression... Never delt into it this deep. I admit it and find it interesting..
Thanks again guys. I can't sleep, keep thinking about all this.. Wish I paid this much attention in college :frown:
Oh yes, I did change the pistons to what I thought was 9:2.
Simple, no roller cam this time. Nothing big like you guys put together. Basically put together specs by Dennis Moores BBC book..