trick flow valve spring problems
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Lift is 649 I believe and I don't know where they was purchased a guy I had install them bought everything together heads are tfs 235 s on a stock 6.0 with tfs hardened 7.4 pushrods keeps breaking springs and bending pushrods
Those are from the new spring vendor that TFS started using in 2011.
You could use the original springs that were used in those heads from 2006-2010 which are our Max Pressure springs since they'll work with your retainers. http://www.briantooleyracing.com/650...l-springs.html
Or you could switch to a PAC 1207X spring kit that we offer so you have more room to play with. http://www.briantooleyracing.com/700...retainers.html
You could use the original springs that were used in those heads from 2006-2010 which are our Max Pressure springs since they'll work with your retainers. http://www.briantooleyracing.com/650...l-springs.html
Or you could switch to a PAC 1207X spring kit that we offer so you have more room to play with. http://www.briantooleyracing.com/700...retainers.html
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You can also purchase through one of our dealers.
The fact you think lift capacity is THE spec to look at says you should get ahold of a professional and just trust them because you don't understand valvetrain. Lift capacity is just one critical spring criteria, how much open and close pressure the lobe needs for a given rpm with the valvetrain mass is HUGELY important and completely ignored if you just look at peak lift capacity.
7.4 are too short. You typically need 7.5" but you should measure to be sure. If you're breaking valve springs you're valvetrain is most likely setup wrong. What rockers, lifters, and do you know installed height on the spring?
Btw those are either PAC 1904s or 1905s. The 1904s are wrong for the LSK lobes, but the 1905 would work.
Btw those are either PAC 1904s or 1905s. The 1904s are wrong for the LSK lobes, but the 1905 would work.
Also, the valve train is really rather simple. It's simple geometry. Remember the game of Mouse Trap? it's like that. One action leads to another, which leads to another, and so on.
If the push rods are too long, they will hold the valves open when they should be closed. That results in poor performance, and backfiring through both intake and exhaust. If the valves are held open too much, they'll contact a piston and bend the valve. Or worse.
Bent push rods are caused by a variety of reasons. Usually it's something obstructing the full movement of anything between the lifter and valve face. The push rod is often the weakest link, and that bends first.
If you're breaking valve springs, that's usually caused by coil bind. That's when the springs are stacked up so tight they can't be compressed any more - the spring coils are attempting to occupy the same space at the same time.
Installation of aftermarket springs with an aftermarket cam MUST be done with a micrometer. MUST be. There's no way around that, unless you're willing to WAG it. Which it sounds like your "professional" did.
It's a simple math problem. Coil bind height+0.050"+valve lift = minimum installed height.
Last edited by .boB; Apr 23, 2014 at 08:19 AM.
Get rid of the cam, put the Max Pressure springs on it like Brian said, and you will be good too go. What rockers and valve guides do you have? Any "pro" that would choose a MS4 cam with that setup is not a "pro" in my book