Attention Valve Spring Failures/Concerns
Race Director
Joined: Aug 2019
Posts: 12,351
Likes: 14,185
From: Central Illinois
Same spring goes in LS/LT cars and trucks from 2014-2021 models. Just a bad batch, it's happened before and it will happen again. Kinda like the flu, once we all get over one, there will be another that comes along.
Safety Car
Joined: Oct 2015
Posts: 4,128
Likes: 616
From: St Louis Area IL
Race Director
Joined: Dec 2012
Posts: 11,127
Likes: 3,221
From: Sunny Florida
C8 Corvette Valve Springs Problem Acknowledged By GM, Other V8 Models Affected
24 Sep 2020, 19:31 UTC ·by Mircea Panait
Home > News > Recalls
As with every first year of production, the 2020 Corvette isn’t perfect. Quality control is questionable at best, the mid-engine sports car had to be recalled over the “flying frunk” issue, and a technical service bulletin issued by General Motors only recently reveals that many LT2 engines need replacement valve springs.
https://www.autoevolution.com/news/c...3I4-OolYhVgwak
Pro
Joined: Sep 2005
Posts: 595
Likes: 38
From: San Jose CA.
Race Director
Joined: Aug 2019
Posts: 12,351
Likes: 14,185
From: Central Illinois
C8 Corvette Valve Springs Problem Acknowledged By GM, Other V8 Models Affected
24 Sep 2020, 19:31 UTC ·by Mircea Panait
Home > News > Recalls
As with every first year of production, the 2020 Corvette isn’t perfect. Quality control is questionable at best, the mid-engine sports car had to be recalled over the “flying frunk” issue, and a technical service bulletin issued by General Motors only recently reveals that many LT2 engines need replacement valve springs.
https://www.autoevolution.com/news/c...3I4-OolYhVgwak
It's a bad batch that went everywhere in a ton of engines, when they fail they will rear their ugly head. If they don't fail they don't have a problem.
Team Owner
Joined: May 2005
Posts: 37,583
Likes: 5
You're probably right, but the same dynamics would apply to the manufacture of the drawn wire, and the process of winding and cooling for case hardening could go haywire as well if the equipment is not functioning to spec.
The drawn wire is heated before winding, and then must be cooled at a predetermined rate for proper hardening.
The drawn wire is heated before winding, and then must be cooled at a predetermined rate for proper hardening.
So these early spring failures are indicative of a highly incompetent supplier.
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Safety Car
Joined: Dec 1999
Posts: 4,721
Likes: 1,461
From: Virginia Beach, VA & Port Charlotte, FL
This could be a multi-tier problem. There could of been a bad batch of steel going to the wire MFR...or... the wire MFR could have problems how the wire was drawn, leaving potential fracture imperfections in the drawn wire. The spring MFR. could have slipped up in the spring tempering process. I'm not saying these were the cause, simply stating there could be a multitude of reason's for the failure. Just saying...
I remember when GM got a bad batch of C6 Z06 rocker arms that liked to spit needle bearings throughout the engines. It was one bad batch, from January 2007 through July 2007.
I remember when GM got a bad batch of C6 Z06 rocker arms that liked to spit needle bearings throughout the engines. It was one bad batch, from January 2007 through July 2007.
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
It does not seem like weak springs, as that would cause valve float. It would appear to be brittle springs, or maybe surface imprecations that allow cracks.
Safety Car
Joined: Oct 2015
Posts: 4,128
Likes: 616
From: St Louis Area IL
This could be a multi-tier problem. There could of been a bad batch of steel going to the wire MFR...or... the wire MFR could have problems how the wire was drawn, leaving potential fracture imperfections in the drawn wire. The spring MFR. could have slipped up in the spring tempering process. I'm not saying these were the cause, simply stating there could be a multitude of reason's for the failure. Just saying...
I remember when GM got a bad batch of C6 Z06 rocker arms that liked to spit needle bearings throughout the engines. It was one bad batch, from January 2007 through July 2007.
I remember when GM got a bad batch of C6 Z06 rocker arms that liked to spit needle bearings throughout the engines. It was one bad batch, from January 2007 through July 2007.
Pro
Joined: Sep 2020
Posts: 568
Likes: 271
From: Arizona
This could be a multi-tier problem. There could of been a bad batch of steel going to the wire MFR...or... the wire MFR could have problems how the wire was drawn, leaving potential fracture imperfections in the drawn wire. The spring MFR. could have slipped up in the spring tempering process. I'm not saying these were the cause, simply stating there could be a multitude of reason's for the failure. Just saying...
I remember when GM got a bad batch of C6 Z06 rocker arms that liked to spit needle bearings throughout the engines. It was one bad batch, from January 2007 through July 2007.
I remember when GM got a bad batch of C6 Z06 rocker arms that liked to spit needle bearings throughout the engines. It was one bad batch, from January 2007 through July 2007.
Last edited by Alea_Iacta_Est; Sep 25, 2020 at 09:30 AM.
Drifting
Joined: Oct 2006
Posts: 1,372
Likes: 311
From: Bristol, VT
It wouldn't surprise me one bit if GM is using the same valve spring on those 7 different motors to save cash. I know GM uses the same lifter and has for years on many different motors that are radically different for each other. One part designed to work OK in many different applications vs. one part specifically engineered to work perfectly in one application.
Everything we know about this issue at this time points to a manufacturing or processing defect in a specific lot batch of springs, not a design issue, so even bringing up that this spring is used in multiple applications and suggesting that makes it worse, makes no sense.
Race Director
Joined: Oct 2008
Posts: 16,673
Likes: 7,739
From: NJ
All the Gen V engines use the same head and valvetrain design. The engines are very similar with slight differences to camshaft timing, intake, exhaust and accessories to package in different vehicles and to get truck vs. performance car power characteristics. The valve spring requirements overlap, it would be silly to have a bespoke part number and drive unneeded cost. Every engineering company tries to re-use as many existing components as possible. That's just sound engineering. if anything the truck engines are getting a better valve spring designed for the performance car envelope.
Everything we know about this issue at this time points to a manufacturing or processing defect in a specific lot batch of springs, not a design issue, so even bringing up that this spring is used in multiple applications and suggesting that makes it worse, makes no sense.
Everything we know about this issue at this time points to a manufacturing or processing defect in a specific lot batch of springs, not a design issue, so even bringing up that this spring is used in multiple applications and suggesting that makes it worse, makes no sense.
Pro
Joined: Sep 2020
Posts: 568
Likes: 271
From: Arizona
All the Gen V engines use the same head and valvetrain design. The engines are very similar with slight differences to camshaft timing, intake, exhaust and accessories to package in different vehicles and to get truck vs. performance car power characteristics. The valve spring requirements overlap, it would be silly to have a bespoke part number and drive unneeded cost. Every engineering company tries to re-use as many existing components as possible. That's just sound engineering. if anything the truck engines are getting a better valve spring designed for the performance car envelope.
Everything we know about this issue at this time points to a manufacturing or processing defect in a specific lot batch of springs, not a design issue, so even bringing up that this spring is used in multiple applications and suggesting that makes it worse, makes no sense.
Everything we know about this issue at this time points to a manufacturing or processing defect in a specific lot batch of springs, not a design issue, so even bringing up that this spring is used in multiple applications and suggesting that makes it worse, makes no sense.
VAG (VW/Audi group) is only one example, VAG uses VW parts in its entire lineup. You can find the same part such as a HL switch in VWs, Audis, Bentleys, Porsches, even Lamborghinis. It truly is just smart engineering. Now, how VAG distributes those parts is another issue. The same HL switch with a VW P/N will not be the same price for the exact same part with a Bentley P/N.
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
Agree completely with your points.
VAG (VW/Audi group) is only one example, VAG uses VW parts in its entire lineup. You can find the same part such as a HL switch in VWs, Audis, Bentleys, Porsches, even Lamborghinis. It truly is just smart engineering. Now, how VAG distributes those parts is another issue. The same HL switch with a VW P/N will not be the same price for the exact same part with a Bentley P/N.
VAG (VW/Audi group) is only one example, VAG uses VW parts in its entire lineup. You can find the same part such as a HL switch in VWs, Audis, Bentleys, Porsches, even Lamborghinis. It truly is just smart engineering. Now, how VAG distributes those parts is another issue. The same HL switch with a VW P/N will not be the same price for the exact same part with a Bentley P/N.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 35,024
Likes: 12,406
From: NE South Carolina
One I like is an Admiral in WWII who's in charge of shelling the beaches in Normandy and asked her to be sure there are no shells that fall short causing "friendly causalities."
Mary asked how many shells he plans to fire. He says 1 million. She notes their normal statistical sample is based on testing one shell in 5000 for length (or some such number) and they fall in a bell shaped distribution curve to there is still a chance that out of a million, 100 will probably fall short of the minimum distance he specified. She goes on to tell him if she increases the sampling to X the number reduces to Y. He insists he wants none to fall less than what he specifies.
She then says IF we test every shell in a huge batch BUT one, there is still a chance (albeit very small) that last one will fall shorter than you request!
So what percent of valve springs are acceptable to have fail?
SIDEBAR:
Interesting text. I still have my hard bound copy, which Amazon says is available at ~$900! Paper back $33. It has 23 Charters covering from basic Probability and Statistics, Factorial Experiments (which I used extensively) to Expression of the Uncertainties of Final Results!
Last edited by JerryU; Sep 25, 2020 at 10:47 AM.
Safety Car
Joined: Oct 2015
Posts: 4,128
Likes: 616
From: St Louis Area IL
All the Gen V engines use the same head and valvetrain design. The engines are very similar with slight differences to camshaft timing, intake, exhaust and accessories to package in different vehicles and to get truck vs. performance car power characteristics. The valve spring requirements overlap, it would be silly to have a bespoke part number and drive unneeded cost. Every engineering company tries to re-use as many existing components as possible. That's just sound engineering. if anything the truck engines are getting a better valve spring designed for the performance car envelope.
Everything we know about this issue at this time points to a manufacturing or processing defect in a specific lot batch of springs, not a design issue, so even bringing up that this spring is used in multiple applications and suggesting that makes it worse, makes no sense.
Everything we know about this issue at this time points to a manufacturing or processing defect in a specific lot batch of springs, not a design issue, so even bringing up that this spring is used in multiple applications and suggesting that makes it worse, makes no sense.