checking valve springs in place

[Alan L]

Is there any cunning way to check whether the valve springs are both intact, without having to remove/strip the engine?
My track machine feels a bit down on power - I may be imagining things. But I am going thru the process of trying to source any possible problems - leakdown tests etc.
I wonder if I may have a broken valve spring and went to check them. But forgot how deeply buried they are in the cam housing. Is there anyway to peer in the cavity to inspect them?
Thanks
Alan

[HawgRyder]

Perhaps a fork shaped spring compressor tool?
One that acts as a lever to compress the spring.
And the force needed to compress would be measurable with a torque wrench, so any "light" ones would be suspect.
Bob

[Eagledriver]

Bob has the right idea. You can just push on the valves with a wooden dowel or any other object that won't slip/damage the rocker arm. You'll find that you can't open any of them except the one with the broken spring. We found one at the track that way on an SC. It was pretty easy to push it in (maybe 30 lbs or so).

-Andy

[john walker's workshop]

just use your thumb on the rocker. if you can move it without hurting yourself, it's busted.

[Alan L]

OK, that will do me. Thought the one spring may have still been a bit tough - but the idea sounds excellent.
Thanks
Alan

[Tippy]

They are really light springs compared to pushrods motors.

[Alan L]

OK, thanks guys. Seems to work quite well.
What I did was make up a tool for the inlet side that worked well. flat steel about 1/2" wide, 1/8" thick. long enough to tuck down in the lip inside bottom of cam case below valve. Just after it passed the valve stem I bent it up about 30 deg and had about 2" extending beyond bend. This gave me something to lever on. Worked really well in all confined spaces. Did not work on the exhaust valves - different case configuration and studs in the way. So I put a 13mm socket on the valve adjuster and a long extension bar on the socket and pushed on that - about as hard as I could to deflect the valve. Still got one lower side to do, but seems all is OK so far.
Thanks again. Always learning something new on this board.
Alan

[Walt Fricke]

For applying a bit more force, this simple tool design (and photos) is courtesy of Wil Ferch. I've had broken inners and broken outers (happily never at the same time) on my race motors, and something like this pinpoints them quickly, as you can easily notice the difference in force needed for any depression.

My experience with one of the two valve springs breaking is that it acts kind of like a rev limiter - the valves start floating (and the engine stops reving higher) at low enough revs that I've not damaged anything. But in each instance it wasn't just one broken spring, it was four or more.

John Walker must have fingers of steel.

[Alan L]

Hi walt. That tool looks a bit like mine - except it looks like it probably works a bit better, and on the exhaust side too. One thing I did with mine was to braze another piece of the steel under the lever just where the valve adjuster hits. This doubled the distance I could compress the valve before the tool hits the case.
Thinking back on my previous track engine with a broken valve spring, yes it is the top end that noticeably suffers. I guess with half the closing force it gets to a point where the valve cant follow the cam adequately - varying with the spring strength and cam lift. In the region of 5-6000rpm I can recall a flattening of power.
I think my current issue derives from rings now.
Thanks for the pics - I am going to make one up like that next time I have the valve covers off.
Yes, I'd like to see Johns fingers too. I could barely depress my exhaust valves with a socket and extension bar - and I dont think I have high rate race springs.
regards
Alan