JakeL

Hey all -

I tried doing a search, but didn't turn up any results

Anyway, my question is this: I've noticed with very high lift cams, folks seem to think that replacing your valvesprings every year or two becomes a necessity. I'm wondering, at what kinds of lifts/durations does that become necessary, and where can you get away with just putting in the springs and basically forgetting about them?

I guess on one end we've got the ~.550 lift LS6 cam and springs, which must be designed to go at least 100K, and on the other extreme there are the .600 lift bruiser cams.

So, somewhere in the middle must be somewhat of a crossover point. A TR220 is 220/.553/114 lift - wouldn't you be able to put that in and forget about it? Almost seems as though you'd be able to throw in LS6 factory springs if you had the lighter valves.

But, the MTI Stealth cam has 220/.581/115 - is that extreme enough that you'd have to think about replacing the springs from time-to-time?

Thanks guys,

-Jake

Phil99vette

iTrader: (11)

I would stay around or under .575. Anything higher your looking for trouble.
Phillip

equandt

iTrader: (2)

You need to consider not only the cam lift but also the lobe profile. The aftermarket cams can have a pretty agressive profile or the rate at which they open the valve. The LS6 cam has a fairly mild profile for the lift it has. A TR220 has a similar maximum lift BUT the lobe profile is much more agressive, opening the valve at a much faster rate. This wears out your springs faster.

Most of our sponsors deal with this problem daily and can suggest the correct springs for your cam. Most of the sponsors install what they sell and know what works and what doesn't. Obviously if you are purchasing a TR220 cam, you should call Thunderracing for the best advice. The same would go for the MTI cams, call MTI.

cyphur

iTrader: (10)

^ what he said

I like the TR224 myself.

Cal

iTrader: (1)

Some people have went 50,000 miles on the B1/T1 cams with 918 springs. I have a TR224 with 918's and plan to go two years or 25,000 miles. I think it may depend on how much high rpm your engine sees also. Another factor is how good you are about letting the engine get to full operating temperature before reving it to redline. Aftermarket springs are much more brittle than stock ones.

JakeL

Thanks for the replys so far guys, I really appreciate it

I realize that the best folks to talk to about a certain cam selection are the folks that make it. I'm not trying to brew my own mix here, nor am I trying to use stock springs to save money, or some other oddball reason.

However, Since everybody has the same pool of available springs to choose from, if a cam is going to wear out springs, it will wear out springs. I'm simply interested in what characteristics, or, failing that, which *cams*, are known to be easy on valvesprings.

Aside from lobe profiles and ramp angles, what parameters are easier on valvesprings? Clearly less lift. Seems LSA wouldn't have any effect - what about duration?

For my own selection, I've got, uh, aspirations (bad pun, I know) towards FI at some point (most likely turbochargers), so I'm looking to keep the LSA wide and the duration relatively low. As well, I want to keep a nice non-shaky idle. From my reading so far, that makes my lower-bound is the LPE GT2-3, and my upper bound is probably a cam like the MMS218, TR220 or the MTI Stealth.

Within those parameters, I'm looking for something that'll be easy on springs, both so I don't have to worry about it as much, and second since I've got fairly hard conditions for strong/brittle springs here in CO - over the winter it is below freezing fairly commonly, so the more resilient spring I can go with, the better.

As well, I autocross at least 20 events a year, around half a dozen open track days, and hit redline regularly on the street. So, I'm not the easiest on my valvetrain I suppose. I'm used to the 8500 from my DSM!

A cam that will make 'good enough' N/A power is fine, since eventually the turbos will provide more than I can ever put to the ground.

Any particular cam suggestions are highly welcome!

Thanks fellas - love this board. Been lurking for a few months now

-Jake

equandt

iTrader: (2)

A nice little cam is the comp cam 216/220 grind. It makes great torque w/ a nice flat torque curve and is easy, easy, easy on the springs.

This is one of the 'set it and forget it' cams. There are more powerful cams out there but this one has proven to be a reliable performer without abusing your valve springs.

Edit - I just saw you are looking at a future turbo. This may not be a good turbo cam because of the 114 lsa. I think you may want a larger lsa, like something in the 116-117 range. The Lingenfelter cam or the LS6 may be better animals for you and the turbo...a custom grind may also be in your future.