Trunion "Upgrade" Failure
Thread Starter
10 Second Club
Joined: May 2018
Posts: 168
Likes: 21
Thread Starter
10 Second Club
Joined: May 2018
Posts: 168
Likes: 21
the problem with the stock rocker is that it goes over center with too much lift and locks up. This is the main cause of stem wear. Too much spring pressure is also an issue.
Doesn't really work that way
If it did high hp motors that rev faster would wear out bearings faster since they rev faster
Everything rides on a film of oil that separates the metal from touching. You're not gonna see wear whether the rocker is pushed open slowly or quickly
Also, the higher the rpm the quicker the rocker is actuated. If lifting it "faster" caused wear people that revved higher would be wiping out rockers and valves and we don't see that.
If it did high hp motors that rev faster would wear out bearings faster since they rev faster
Everything rides on a film of oil that separates the metal from touching. You're not gonna see wear whether the rocker is pushed open slowly or quickly
Also, the higher the rpm the quicker the rocker is actuated. If lifting it "faster" caused wear people that revved higher would be wiping out rockers and valves and we don't see that.
I was under the impression that with aggressive ramps and high rpm that the roller lifter can bounce off the lobe which I think would in turn increase wear at the rocker tip.
Thread Starter
10 Second Club
Joined: May 2018
Posts: 168
Likes: 21
TECH Enthusiast
Joined: Feb 2018
Posts: 640
Likes: 297
From: Michigan
Interesting thread, the design of the Smith Brothers kit had me worried about this exact thing, so I went with the CHE kit when I did my cam about 8000 miles ago. I plan on doing heads this spring so I'll have to check them out. Hopefully they look ok.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
TECH Fanatic
Joined: Jan 2017
Posts: 1,758
Likes: 442
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
I seriously doubt here is ANY mass production engine with .600 or more lift. Not due to engineering issues, just that it is not needed. Camaros and Mustangs have over 450HP available, a historic high. All achievable with lifts far under .600. The LS3 has lifts of .550/.525. No more is needed. And they live forever that way.
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Right. So then you buy/make the necessary pieces that will live with high lifts.
The factory has no need for such high lifts, so don't depend on them for that kind of capability.
They only needed pieces that would see lifts UP TO .600, so that's what we get.
Anything above that, roll your own or use the aftermarket.
The factory has no need for such high lifts, so don't depend on them for that kind of capability.
They only needed pieces that would see lifts UP TO .600, so that's what we get.
Anything above that, roll your own or use the aftermarket.
I just watched a 3 week old video on YT showing the bronze wearing.
https://youtu.be/9ngAqJeul5w
I got talked into the bronze trunnions and already knew that bronze was too soft.
https://youtu.be/9ngAqJeul5w
I got talked into the bronze trunnions and already knew that bronze was too soft.
I wonder what lift he was running?
Guess it's time to throw these out and go for a different design when the time comes.
Last edited by dreadpirateroberts; Dec 5, 2019 at 09:30 AM.
I seriously doubt here is ANY mass production engine with .600 or more lift. Not due to engineering issues, just that it is not needed. Camaros and Mustangs have over 450HP available, a historic high. All achievable with lifts far under .600. The LS3 has lifts of .550/.525. No more is needed. And they live forever that way.
But we were are talking about the valve tip and rocker tip on the post you quoted.
Where are all these threads where people have worn out valves stem tips and rocker tips?
And really, most people are not wiping out valve train components. Thousands of stock engines have wiped out lifters, springs, and rocker trunions too so that kinda disputes your theory that higher power and higher rpm is the cause. Where are all the guys wiping out bottom end bearings from higher horsepower and higher rpm (there's increased load and rpm on the bottom end too)? And I'm not talking about when someone over revs and stretches the rod bolts and causes a bearing to spin. I'm talking when setup right and running for years without issues.
Last edited by 00pooterSS; Dec 5, 2019 at 11:26 AM.
That is a concern when running high ramp rates, higher rpm, having springs that aren't strong enough to control it.. But it's an issue with the valve spring controlling the valve train and the reason why we upgrade/run the correct valve springs for the combo. You can have that same scenario with a stock cam if you turn up the rev limiter and the springs can't handle it. I broke 8 of 16 valve springs doing that on my SS lol. It didn't like going to 7000 every day on 140k mile valve springs. Put in LS6 springs and that fixed the issues.
If you haven't look up some videos on valve float and you'll see things bouncing and vibrating and what causes all the destruction. There's some pretty cool high speed film videos of it happening on youtube
I've seen a hand full of threads about the stock rockers coming apart online. But you can find anything online.
And I've had thousands of LS powered vehicles in the shop over the years and never seen a rocker failure. I'm a tech that has always worked at shops that also do oil changes so we have multiple LS trucks and cars in and out of the shop every single day. I started in shops in 98 so I've been around since LS motors came out, and haven't seen a single rocker spit bearings. Not saying it doesn't happen.
I think the failure rate is blown out of proportion.
After keeping an eye on the rocker arm situation for years, I would go with the WS6store rockers or the Texas Speed rockers if I wasn't going to go to aluminum rollers. TSP has the stamped steel rollers and I dig that plan too.
And I've had thousands of LS powered vehicles in the shop over the years and never seen a rocker failure. I'm a tech that has always worked at shops that also do oil changes so we have multiple LS trucks and cars in and out of the shop every single day. I started in shops in 98 so I've been around since LS motors came out, and haven't seen a single rocker spit bearings. Not saying it doesn't happen.
I think the failure rate is blown out of proportion.
After keeping an eye on the rocker arm situation for years, I would go with the WS6store rockers or the Texas Speed rockers if I wasn't going to go to aluminum rollers. TSP has the stamped steel rollers and I dig that plan too.
They have an infinite fatigue life vs limited in comparison to aluminum and are much lighter over the valve PLUS you can use a shorter pushrod for less flex and they can use a CHE bronze bushing also.
Investment casting is where a wax positive is made of an object. Then casting put around it. Then the liquid metal is poured into the mold melting out the wax. That is how the structure can be so strong yet intricate with its trussing. Super strong and durable and lower price to manufacture so it translates over to the customer.
As far as the shops.
One was an engine machine shop. The other is a straight automotive repair that work on any type/brand of vehicle but do see ALOT of chevy trucks from 99-16. They also see quite a few stock spring failures and burned valves. Which I have referenced before.
Been sick so catching up. Any other questions i missed? Or references?
Our interlocking bearing design will hold up better than stock. You have to LITERALLY destroy the race to get the rollers out and they are not needles like stock either.