trick flow valve spring problems
Aftermarket heads with stock rockers should be modified to use PM guides as stock rockers sideload the valve enough to ruin bronze guides typically fond in aftermarket heads. Some vendors offer this upgrade
Springs and other valve train components break when two solid objects attempt to occupy the same space at the same time. Simple physics, in theory. In actuality, you have to figure out why and where that is happening, and what to do about it.
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.
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.
Valvetrain is not that simple, as other posters have eluded to the particular lobes in question here are very aggressive and it is easy to buy a spring with enough lift capacity but that is NOT up to the aggressive ramps. Valves start floating and chaos ensues.
Even beyond ramp rates if say someone uses an aftermarket head with a large diameter heavy valve it will need more spring than the same lobe with a lighter valve especially if that bigger valve allows the cam to keep making power a few hundred rpm higher.
To intelligently spec a valvespring the vendor needs to know rpm, valvetrain weight, expected change interval, the exact lobes in question and they have to have the experience to figure out some of these details. You put identical heads and valvetrain on a 5.7l and a 6.0l it shifts the rpm range and the 5.7l is probably going to need to rev a little higher.
Now granted there are enough of us sharing info on the internet that we can generally copy someone else's successful setup and we don't all need to completely engineer a valvetrain from scratch. But that doesn't mean it is simple, it is pretty complex if one actually tries to understand it.
This isn't 1970 where we are choosing between stock, 3/4, or full racecam and have just three spring PN to choose from. Hotrodding has become a lot more complex.
I have seen a guy on this forum even go through like 3 sets of springs on the same cam because the square lobes used on the cam ate the first set floated so the dimwit chose a spring with more nose but the same seat pressure and that floated and then we talk him into more pressure at the seat, and then after more problems he changed the cam to reasonable lobes for the street.
