Trunion "Upgrade" Failure
12-06-2019, 11:57 AM
#81
Not saying its enough to cause it to wear out fast enough to notice.. But with anything, you have to apply more pressure to more an object fast vs moving it slow. More pressure is more stress/heat/wear.... And you cant tell me that 10,000 rpm slinging a piston and rod around isnt putting more wear on bearings vs 5,000rpm, and the same goes for opening and closing a valve. How much more??? I dont know lol
Cams spin at half rpm so at most the cam sees 3250 rpm. The valve is really only loaded a partial amount of that also due to the base circle and change in direction as well.
Valves are made of specific steel alloy usually 23-5 or 23-8 or better to make sure they last. Some of the stock gm valves have hardened pressed in tips as well to help made of a different material.
Miles and hours do take their toll, but the larger issue there would be vibration and instability as well as oil quality and/or lack of oiling.
Since valves are usually mass manufactured in batches, we have seen bad batches from a few aft5 companies. Most notably recently is ferrea. Their stems were wearing even on bronze guides which is saying quite a bit. And quite a few cyl head companies had to get those taken care of. Most of that was last year and prior year, but can bleed over due to heads changing hands, or actually being used for the first time after purchase.
Another option there of course.
Valve weight can also be an issue.
So many forks off the main trail to go down, its easy to get lost quickly.
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DualQuadDave (02-02-2024)
12-06-2019, 12:04 PM
#82
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.
Ls7s have .590s
But none over .600 yet.
Ive seen alot of 243 heads off ls2s have some higher than normal guide wear. Thats likely due to oiling not lift there though.
I keep track of alot of things.
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DualQuadDave (02-02-2024), G Atsma (12-06-2019)
12-06-2019, 12:33 PM
#84
Most of the broken stock springs ive seen are on trucks. They dont rpm much at all and have smaller cams.
Quite a few stock trunions ive seen are on early fbodies and trucks. Not ls6 vettes or ls3 or ls2 stuff. So not something more rpm happy so to speak.
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G Atsma (12-06-2019)
12-06-2019, 05:07 PM
#85
Keep in mind it all always rides on a film of oil. That's why you don't see wear as long as there is lube. And why can in some cases see mint condition bearings come out of a 300k mile motor.
That's why it don't matter if you spin it to 5k or 10k, the metal pieces don't touch. If they did engines wouldn't make it 100 miles. Or 10
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Ls7colorado (12-09-2019)
12-06-2019, 05:08 PM
#86
The tsp rockers are way better than any aluminum. Also they are "investment cast" just like stock. Not stamped steel. Not your fault for not knowing that.
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.
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.
If I would have used my brain for even half a second I wouldn't have said they are stamped lol. They don't even look stamped they look cast. But I do appreciate the info as always.
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G Atsma (12-09-2019)
12-09-2019, 02:41 AM
#87
did a little more digging on other sites, like yellowbullet, and it seems that the straub and smith bro failures aren't too uncommon. same symptoms--high wear and a groove worn into the bushings, around 5k miles. i think there was one instance that the lift was lower than .630, i think i read .612... i am not sure how the tiny bit of extra lift is going to matter.
i did have some thoughts.
first was making sure to use the correct assembly lube with the bushings. i did read something about a failure of a set that was installed by straub themselves, so i am not sure this can always be to blame.
second, was rocker and valvetrain oiling. at idle or very low rpm, i have read, they get much less oil than at rpm. it makes me wonder how much low rpm and idle time the bushings see, and how much that will actually affect the wear on the bushings vs higher rpm use.
i did have some thoughts.
first was making sure to use the correct assembly lube with the bushings. i did read something about a failure of a set that was installed by straub themselves, so i am not sure this can always be to blame.
second, was rocker and valvetrain oiling. at idle or very low rpm, i have read, they get much less oil than at rpm. it makes me wonder how much low rpm and idle time the bushings see, and how much that will actually affect the wear on the bushings vs higher rpm use.
12-09-2019, 11:00 AM
#88
TECH Senior Member
did a little more digging on other sites, like yellowbullet, and it seems that the straub and smith bro failures aren't too uncommon. same symptoms--high wear and a groove worn into the bushings, around 5k miles. i think there was one instance that the lift was lower than .630, i think i read .612... i am not sure how the tiny bit of extra lift is going to matter.
i did have some thoughts.
first was making sure to use the correct assembly lube with the bushings. i did read something about a failure of a set that was installed by straub themselves, so i am not sure this can always be to blame.
second, was rocker and valvetrain oiling. at idle or very low rpm, i have read, they get much less oil than at rpm. it makes me wonder how much low rpm and idle time the bushings see, and how much that will actually affect the wear on the bushings vs higher rpm use.
i did have some thoughts.
first was making sure to use the correct assembly lube with the bushings. i did read something about a failure of a set that was installed by straub themselves, so i am not sure this can always be to blame.
second, was rocker and valvetrain oiling. at idle or very low rpm, i have read, they get much less oil than at rpm. it makes me wonder how much low rpm and idle time the bushings see, and how much that will actually affect the wear on the bushings vs higher rpm use.
12-09-2019, 11:12 AM
#90
Where's @Cstraub in all of this? Not that long ago everyone crapped on stock rockers and the Comp stuff and the Strain/CHE is the be all end all. Would be nice to see some info from them unless I missed it.
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DualQuadDave (02-02-2024)
12-09-2019, 11:16 AM
#91
I think the main advantage of the CHE over the Straub and others is the increased surface area, but they'll probably still wear close to the same. The wear will be harder to see, though, because the shaft doesn't have that stupid groove like the Straubs do. I'm not a fan of the groove because it cuts down on surface area. I never liked it from the beginning.
12-09-2019, 11:19 AM
#92
12-09-2019, 11:23 AM
#93
TECH Senior Member
It's getting plain to see that the stock rockers aren't so bad after all. When you consider the bazillions of them out there, and that they are NOT exactly front page failure rate items, the picture changes a bit. Now with very high lifts and high revs, something different needs to be used. But for the mainstream, stock works!
12-09-2019, 11:25 AM
#94
It's getting plain to see that the stock rockers aren't so bad after all. When you consider the bazillions of them out there, and that they are NOT exactly front page failure rate items, the picture changes a bit. Now with very high lifts and high revs, something different needs to be used. But for the mainstream, stock works!
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G Atsma (12-09-2019)
12-09-2019, 11:31 AM
#95
TECH Senior Member
Right! Just astounding how good stock LS hardware is. OEM lower ends good for 600+HP, stock heads good for almost as much; to get that much from ANY Gen I small block required a full compliment of race-quality hardware. Now, just get an LS3 and put a cam in it.
12-09-2019, 11:32 AM
#96
12-09-2019, 11:42 AM
#98
TECH Senior Member
I think the deal here is they are put down because they are STOCK. Gotta use something better. Same for LS7 lifters. Limitations? Oh yeah. Work for over 90% of engines being built? Yup.
12-09-2019, 11:43 AM
#99
I've said this about ls7 lifters too. Compare how many stock lifters and rockers are ran compared to aftermarket....orders of magnitude more. That's why there are so many more failures leading to bad publicity.
12-09-2019, 01:28 PM
#100
I think the main advantage of the CHE over the Straub and others is the increased surface area, but they'll probably still wear close to the same. The wear will be harder to see, though, because the shaft doesn't have that stupid groove like the Straubs do. I'm not a fan of the groove because it cuts down on surface area. I never liked it from the beginning.
I think it is much more than just an across the board issue.
Mr Urban has put these through their paces much more than anyone else really could but his attention to detail and not just using xx vanilla brand whatever.
I think valve weight and stability make alot of difference, based off of the records i have been keeping on nearly any reported failure.