I've got a 6800 RPM road race LS3 with about 25 hours on it. It has TSP Brawler heads with their PAC springs.

I want to check the spring pressures. My on-head spring tester doesn't have clearance with these LS3 heads so I believe I need to remove the springs to test them. I am aware of the compressed air method to hold the valve spring up while removing it. I would want to remove all 16 springs, check them all and then decide whether to put them back or replace. But I don't think I can remove all 16 springs at the same time because won't the valves fall down into the cylinders? I forget how these are setup and whether the valve seal will hold them in place reliably.

Thoughts? Certainly this must be a solved problem!


Thanks,
Sal

 

Do one cyl at a time; when each is at TDC. Run through the firing order one cyl at a time.

Put em in a drill press with something soft (wood, brass, aluminum) padding them. DO NOT scratch or otherwise mar the springs in any way: may seem like a trivial thing, but it creates stress concentrators, and the spring is HIGHLY LIKELY to break there later on. Stack up: a scale with the appropriate range, on the drill press shelf; a soft thing, if necessary (if your scale has like a flat stainless table, you might not need this); the spring; another soft thing, for sure; the drill chuck. Set up a dial indicator to show how far the spring has compressed. Press down on the spring while watching the dial ind and the scale. Measure at whatever points are appropriate to the setup you're working with. Eeeezzzy peeeezzzzy lemon sqweeeeeeezzzzy.

 

That's what I figured. I guess worst case scenario I find a bad spring at the end of my checking and end up buying a new set.... then I'd be swapping the springs twice. Which leads me in the direction of not even bothering to buy the spring tester and just replace them outright.

Or maybe at 25 hours the spring checking is a good-to-do but unlikely to have any failures. It would also be interesting to collect some data over time to see how long they go in my application before failing

 

For sure. The problem is, you'd need multiple data points (failures) before you could gather any useful information that way.

I think the best way to approach it would be, perform the test, now; perform the test again, after however much time, however many runs, or whatever other useful measure of spring usage might apply to your situation; see how much it's changed; repeat as often as possible; make decisions from there. Needless to say that particular test won't tell you "everything" you might want to know, butt it's certainly useful. So for example if one spring stays the same for some arbitrary many tests, then suddenly tests different, time to swap em ALL. That sort of logic. Study some statistics, and learn about the methodology of "mean time between failures", and how fuzzy that can be. Which is GREATLY complicated when there are multiple discrete objects in the analysis (16 springs for example). You'll find things like, MTBF for a single spring is 1000 hours; butt that means that the probability of ONE out of 16 of them failing, reaches 50% at 300 hours, or some such. Can get kinda scary.

 

I've used zip ties in the valve keeper grooves before, just make sure you don't chew up your valve stems with the flush cutters when you cut them off, especially if they're coated titanium valves.

 

I bench test all of mine, but doesn’t LSM make a tool to test the springs on an LS head? Maybe youve got a cowl clearance issue that keeps you from using the tool? For the casual diy’er, or even a track guy that’s just missed a shift, testing springs on head is so much easier and quicker.

 

LSM Racing Products PC-100/160 On-Head Valve Spring Pressure Tester is a nice piece but I don't believe it works on the stock rocker arms. The issue will be getting the arm of the tool to grab onto the back of the rocker arm due to the fact that the back of the rocker arms are so close to the side wall of the cylinder head.


Nope, unfortunately one at a time on the bench looks to be the only way.

 

Yeah I've reached out to a couple of companies and nobody makes an on head checker for the stock rockers. I use the LSM bench checker with a dial indicator. Last set of dual springs I checked had 20k on the setup (street driven TSP 231/246 .640"/615" 111 LSA), and springs were still comparable to a spare new set. It's the titanium retainers that I'm still on the fence about. Outside of a visual inspection, not sure how to really test them for wear.

 

Valve springs last far longer nowadays than most give credit. It takes a very radical lobe to kill a valvespring quickly. Todays spring material and technology in the design makes for a vastly superior product than springs that were made 20 years ago. It’s common to see valvesprings in a performance street build get tested at 30k miles and still be within 2% of each other and within 3-5% of what they were when new. RPM is the killer, not necessarily the time on them. High RPM for an extended period heats the spring up and its heat that breaks down the spring. Since springs are oil cooled, getting oil up top with a good oil pump is important in a high performance build. Windage under the valve covers isn’t nearly an issue with the LS/LT platform as it was with the SBC. The SBC had 2 drainback holes in the heads…one in the very front and one in the very rear. Oil could puddle up there badly and windage hurt power at RPM. The LS/LT platforms have multiple very large drainback areas around the center headbolts, so puddling and windage under the valvecovers isn’t an issue.
The mention of Ti retainers is a different issue altogether. Ti is a material that gets brittle as it heat cycles. The more heat cycles, the more of a brittle material it becomes. This is why you see used TI valves selling for cheap on Ebay. Top teams know their life span and dump them to dealers for almost free. The dealers flip them for decent profit. I know builders that refuse to use Ti retainers in a street build. I know others that have no problem with them. I know guys that have had issues, but it’s rare. I’m not scared of them personally on the street, but I would change them out after 30k miles. Most hot rods we mess with don’t see crazy miles, so most are safe. If reliability is your focus, go with tool steel retainers….and don’t mod your stuff. When chasing power we tend to go to extremes, and reliability gets tossed out the window. In my eyes Ti retainers are usable on the street, but also consider them a maintenance item that should get changed out in intervals. Finding the interval is expensive and will cost you a lot of money. I’ve seen them go 30k many times, driven hard. That’s my personal cutoff. Yours will vary with usage.