ls3 intake rocker failure has anyone seen anything like this before??
09-16-2018, 04:19 PM
#1
ls3 intake rocker failure has anyone seen anything like this before?? 
I’m kinda at a loss here guys ls3 crate long block, btr stage 4 cam, stock heads milled .030, stock head gaskets, ls3 rockers with trunion upgrade by Michigan motor sports, c5r timing chain, Johnson 2116 lifters, mahnton pushrods measured to correct length with added preload, stock intake. Made 506 wheel hp and ran like a beast for about 500 miles and now this rocker snapped and all the intake rockers have an indentation on the tips. Pistons were flycut and had 0.085” of ptvc and I don’t spin the engine over 66-6700.
Help
Last edited by j88l98irocz; 09-16-2018 at 04:32 PM.
09-16-2018, 04:46 PM
#3
Did you send them your GM rockers to upgrade or did you just get the trunions and swap them yourself? Or buy assembled rockers from them?
1st thought is rockers weren't hardened correctly.
Hopefully you can flush all the debris out, put new rockers on, and hit the streets.
1st thought is rockers weren't hardened correctly.
Hopefully you can flush all the debris out, put new rockers on, and hit the streets.
09-16-2018, 05:15 PM
#4
Did you send them your GM rockers to upgrade or did you just get the trunions and swap them yourself? Or buy assembled rockers from them?
1st thought is rockers weren't hardened correctly.
Hopefully you can flush all the debris out, put new rockers on, and hit the streets.
1st thought is rockers weren't hardened correctly.
Hopefully you can flush all the debris out, put new rockers on, and hit the streets.
09-16-2018, 05:41 PM
#8
Did you send them your GM rockers to upgrade or did you just get the trunions and swap them yourself? Or buy assembled rockers from them?
1st thought is rockers weren't hardened correctly.
Hopefully you can flush all the debris out, put new rockers on, and hit the streets.
1st thought is rockers weren't hardened correctly.
Hopefully you can flush all the debris out, put new rockers on, and hit the streets.
09-16-2018, 09:43 PM
#11
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OE suppliers have much more rigorous QC also. Typically.
09-16-2018, 10:15 PM
#12
TECH Senior Member
It seems with so many things LS related, OE is best, especially when it comes to sensors and highly stressed small parts LIKE rocker arms. You don't want the short end of the stick with that kind of stuff. The LS is state of the art when it comes to pushrod OHV engines. The surrounding parts MUST live up to that...
09-17-2018, 12:10 AM
#13
TECH Addict
Just some more info,, I worked a consulting gig with a couple companies in CA,, while there I got to know a guy who was staying at the same hotel and worked for an engine parts, manufacturer. They had to move most of the manufacturing of their products overseas due to US regulations choking them to death.. Ane he learned a few hard lessons along the way.
In the process one of the main issues they came up with was the Asian companies that could do castings, would not police their metal supply. So one of the costs of having their billets cast and forged over there was they had to hire a bird dog to follow the metal, from the scrap processing through shipping back to the US for final machining.. They kept finding un-melted scrap like hardened bolts embedded in the billets when they tried to machine them, kept tearing up some expensive tooling.
I would bet that's part of the problem on the cast rockers.. Not enough material QC to insure consistent results of the final products.
In the process one of the main issues they came up with was the Asian companies that could do castings, would not police their metal supply. So one of the costs of having their billets cast and forged over there was they had to hire a bird dog to follow the metal, from the scrap processing through shipping back to the US for final machining.. They kept finding un-melted scrap like hardened bolts embedded in the billets when they tried to machine them, kept tearing up some expensive tooling.
I would bet that's part of the problem on the cast rockers.. Not enough material QC to insure consistent results of the final products.
09-17-2018, 12:58 PM
#14
I'd say you got EXTREMELY LUCKY that all the valves are still in the head. By the looks of the broken rocker pressing on the retainer only, the locks should have come right out and dropped a valve into the cylinder.
Yes, you get what you pay for with off-shore components. Not that ALL are bad, but there is risk with ANY component like that.
Do yourself a favor and get a set of new OEM intake and exhaust rockers, a CHE trunion kit and install them yourself. All it takes is simple hand tools and a bench vise.
Here's some more info on the CHE kit.
https://ls1tech.com/forums/generatio...nion-kits.html
Yes, you get what you pay for with off-shore components. Not that ALL are bad, but there is risk with ANY component like that.
Do yourself a favor and get a set of new OEM intake and exhaust rockers, a CHE trunion kit and install them yourself. All it takes is simple hand tools and a bench vise.
Here's some more info on the CHE kit.
https://ls1tech.com/forums/generatio...nion-kits.html
09-18-2018, 06:53 AM
#18
FWIW, I happened to have an OEM LS3 style intake rocker to compare. This came off a stock GM engine that I installed the aftermarket trunnion kit on.
09-18-2018, 07:49 AM
#20
I'd say you got EXTREMELY LUCKY that all the valves are still in the head. By the looks of the broken rocker pressing on the retainer only, the locks should have come right out and dropped a valve into the cylinder.
Yes, you get what you pay for with off-shore components. Not that ALL are bad, but there is risk with ANY component like that.
Do yourself a favor and get a set of new OEM intake and exhaust rockers, a CHE trunion kit and install them yourself. All it takes is simple hand tools and a bench vise.
Here's some more info on the CHE kit.
https://ls1tech.com/forums/generatio...nion-kits.html
Yes, you get what you pay for with off-shore components. Not that ALL are bad, but there is risk with ANY component like that.
Do yourself a favor and get a set of new OEM intake and exhaust rockers, a CHE trunion kit and install them yourself. All it takes is simple hand tools and a bench vise.
Here's some more info on the CHE kit.
https://ls1tech.com/forums/generatio...nion-kits.html