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Titanium Will Bend

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Old 12-16-2007, 02:13 AM
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Originally Posted by slt200mph
Well since we are playing "you show me yours and I'll show you mine" carnage photos..here are a couple more bloody photos.... a little LS2 rod bolt failure..GM didn't want this one back..the customer who did it had a history of blowing up motors in his Corvettes..he paid the bill for the new crate engine.





i aint even going to ask what happen-
Old 12-16-2007, 12:09 PM
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Originally Posted by OKcruising
I'm also quite curious if the problem has been located to a batch number and if so, I'm going to remove those craptastic springs, get some nice ones, and put the originals in a box or something for the collector or whatever.
Batch numbers are discussed in this thread, DeepblueZ started a list:

https://ls1tech.com/forums/generation-iii-internal-engine/728254-comp-cams-918-spring-broke.html

Why 918s suddenly started to show failures (Comp went with a different supplier) made obvious by Chris Osborn's post here:

http://web.camaross.com/forums/showthread.php?t=526319
Old 12-17-2007, 01:49 PM
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Originally Posted by Fraser@SpeedInc
Theirs different grades of titanium, its still a steel alloy. You can have a steel with 10% titanium and call it titanium.
GM did the titanium for "ooh, ahh" factor for people who don't know any better, and nothing else. They should have done double springs instead, if they did that engine would be just fine today.

Titanium parts in a street car.........
Old 12-17-2007, 02:10 PM
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Um, they did titanium valves and rods so they can spin the motor to 7K rpms. The titanium intake valves vs steel ones saves you over 30 grams per ONE valve, so if you add that up over the 8 valves, and the lighter beehive springs vs the dual, you have MUCH better valvetrain dynamics, faster revving etc... And the engine wouldn't particularly be "fine" with double springs because that one little spring can't control a heavy *** steel valve of that size and length so you'd most likely smack a piston into the valve and possibly snap the valve off the stem and boom, you need a new motor.

I think I'll stick with the Titanium in my street car.....
Old 12-17-2007, 02:14 PM
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Originally Posted by lilmachine
GM did the titanium for "ooh, ahh" factor for people who don't know any better, and nothing else. They should have done double springs instead, if they did that engine would be just fine today.

Titanium parts in a street car.........
The springs are not titanium..they are spring steel ..the valves are titanium ..they are very large compared to LS1/2/6 valves... if that had been a steel valve the damage to the engine would have been significantly more extensive..the head of the valeve would have broken off .. the 7,000 RMP red line and the large moving parts is the reason for the titanium connecting rods valves...not the ooooo aaaaah factor you mentioned .. I have seen a number of stock C5 Corvettes come in with broken vavle springs too..usually a $3500-$4000 repaire bill ...
Old 12-17-2007, 02:23 PM
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Originally Posted by Beaflag VonRathburg
^ I think that's what happened to mine except it was on startup so not as extreme. The damage looks really similar though. I haven't torn it down yet.

Crappy 98 rod bolts.


That guy must have tried something stupid to have a rod bolt fail on a less than two year old engine.
Yes he mechanicly over reved it..thought he was going from 6th to 5th gear and went to 3rd instead..rod bolt broke and tried to saw the engine in half..the guy has a long history of stupid situations with Corvettes .. that is the reason he had to buy the new engine..the photo is about two years old.. it happened a while back..
Old 12-17-2007, 05:31 PM
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Originally Posted by slt200mph
Yes he mechanicly over reved it..thought he was going from 6th to 5th gear and went to 3rd instead..rod bolt broke and tried to saw the engine in half..the guy has a long history of stupid situations with Corvettes .. that is the reason he had to buy the new engine..the photo is about two years old.. it happened a while back..
gee's
Old 12-19-2007, 01:01 PM
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Every story has a happy ending .. Nothing like a new LS7 crate motor to cheer you up..





Old 12-20-2007, 10:24 AM
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Originally Posted by slt200mph
The springs are not titanium..they are spring steel ..the valves are titanium
I know that. Are you saying a double spring would NOT have saved this mess from happening?

I had 8 broken springs, my valves are steel, and my engine is perfect because I had double springs. Rev limiter is at 7,300 rpm. 427ci LS6. Drove around with them broken for months and didn't know it. Because 8 springs don't break all at the same time.

Therefore.....Double springs have one purpose and ONE purpose ONLY, to save an engine when a spring breaks. So, if GM had spent a little more money, very little, and used double springs, that engine would not have had ANY damage, except to the broken springs.

I bet that Vette owner would have paid another $200 for his Vette to have better protection, which means a BETTER engine overall.












Old 12-20-2007, 12:44 PM
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That's not something you see very often with an LS7.

BTW, the factory rev limiter is set at 7,200, not 7,000. It may not sound like much, but I sure to love those extra two hundred RPM's.

Last edited by Outlaw1; 12-20-2007 at 01:08 PM.
Old 12-20-2007, 12:49 PM
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Originally Posted by lilmachine
I know that. Are you saying a double spring would NOT have saved this mess from happening?

I had 8 broken springs, my valves are steel, and my engine is perfect because I had double springs. Rev limiter is at 7,300 rpm. 427ci LS6. Drove around with them broken for months and didn't know it. Because 8 springs don't break all at the same time.

Therefore.....Double springs have one purpose and ONE purpose ONLY, to save an engine when a spring breaks. So, if GM had spent a little more money, very little, and used double springs, that engine would not have had ANY damage, except to the broken springs.

I bet that Vette owner would have paid another $200 for his Vette to have better protection, which means a BETTER engine overall.












Controling the dynamics of the valve train is the main reason for the dual valve spring configuration..but the second spring does add a certain safety value to the dual spring set up .. I have broken both dual springs and dropped a valve before(SBC C/Gas @ 8600 rpms) ...nothing is guarantied bullit proof at high RPMs..I am sure that if you give GM a call they would welcome your engineering advice...I find it hard to beleive that you drove around for months with all those broken springs..
Old 12-20-2007, 05:07 PM
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Originally Posted by slt200mph
I find it hard to beleive that you drove around for months with all those broken springs..
I heard noises every now and then, throttle got flat going through some of the rpm's like the gas was getting shut off and I found a couple tiny pieces of metal at a couple oil changes. The peices were parts of the retainers coming apart under the springs.

It had to be at least 8 months with one or all of the broken springs. When I took the valve covers off there were 4 broken springs on each head.

And as I said once, and I'll say it again.....you would have to believe that all 8 broke at the SAME exaxct time to think I wasn't driving around like that for a long time. This is a 100% street car and has never seen a track. 490 RWHP street stroker.

Even after 40 years in the biz you still see new, crazy ****, eh!!!



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