Tonylmiller

I work on engines, but they are rocket engines (not automotive). Through the years, rocket engine development has changed quite a bit. In the early days, they performed lots and lots of tests. They would find a weakness through testing (failure), fix it, and retest. Some failures were expected, and they were part of the process.

Nowadays, we do a whole lot more by analysis and the tests are far fewer. Of course, analysis is much faster and cheaper than testing, so this is all good, as long as your analysis covers all the bases and your testing is adequate to verify all of that analysis. I think if we have a failure while engine testing nowadays, it will be a big deal. It is expected that just about all of the failures have been analyzed and designed out.

I am wondering if automotive manufacturers are doing the same thing, in order to save time and money. I'm hoping that over 99% of the LT1 engines are really ok, despite all of the Chicken Little scenarios of late. I'm wondering if the LS2 and LS3 engines were tested thoroughly, and that is why they are so reliable. And perhaps the LT1 was not tested as thoroughly, and that is why the failures are coming to light with so few miles on the engines.

Of course, it could be a manufacturing defect causing the problems, but the manufacturing process needs to be verified too, which costs a lot of money if verified through testing. Analysis methods can be used for this, too, in lieu of testing, in many cases.

What are your thoughts? I don't think we will ever get the real answer. I'm just looking for things that could contribute to these failures. The LS2/3 engines seem to be so reliable in comparison.

I really like the C7, and hope to own one someday. Not anytime soon, but a few years down the road (hopefully a Z06!). So I am not just trolling the C7 owners. I am wondering if this shift in development methodology could be a major contributing factor.

Tbong

There is absolutely no intrinsic problem with the LT1. The few that had problems had bad oil filters and just bad luck The engine is time tested and perfect. No need to waste resources on analysis. It was designed perfectly.

Seriously. LS2/3 engines have been around a long time.

IMO whenever a company redesigns a car the first task is to save money and cut corners where they feel that can be achieved without a major issue. With a Corvette the balance is more critical as they are both designing a "performance car (most people will never use the majority of) and an expensive daily driver. They have to balance the 3K a year drivers with the handful of those who will actually track their cars. I think they lean to the 3K a year scenario when designing and will just fix the others IF that cannot find a way to void the warranty. Unless it until it becomes a PR problem their practices are safe.

Many don't care because the car has a warranty...Personally I don't know many who want to deal with a car at a shop for weeks. then getting thier $65K patched up vehicle done in a shop where few have any long term experience with a specific car.
Personally I can afford to wait as I have enough vehicles. but I have not had an overnight or major warranty issue on a vehicle in over 20 years.

Harley is the king of this practice. Over the years and mostly since 2002, They used less expensive wheel, cam and main bearings, eliminated forged cranks, and save money on a variety of other areas over the years based on their study the avg rider rides 2000 miles a year. They fix the rest under warranty without question even modded bikes. They figure it's cheaper to replace an engine now and then than make ALL engines run flawless for 50K miles.

The after market Better engine parts for Harley is breathtaking. Just about every part can be replaced with either one they USED to include or a redesigned part. Many can be bought at the Harley parts counter

rcooper

Testing? Didn't like it in school....why do it now? I am the happy owner of a ls3 engine ( car also ) and have had no problems, although mine is an 09 so many were made before mine. I think that the new engine is mostly OK, have seen only a few problems out of may thousands built. And this basic platform is used in many other vehicles made by GM. I would think that there is a failure rate that is accepted by most mfg. companys being some where in the .5% range. You see problems like this in most every car line made today, except maybe Tesla. With so many suppliers of material to GM there is a chance that the problems found in these few broken engines could be from outside the engine build plants. Oil filters, fittings, hoses and other parts may be contributing factors to the failures. But, I bet that GM is doing all that they can to repair their tarnished image and trying their best to build a quality engine. As the failure rate is so low I think that they are doing pretty well at producing a quality product. Hell, half the stuff in my house falls apart within a few months of the purchase date, I just call and have it repaired under warranty. Often it is with an argument or " friendly discussion ", with the mfg. Although with an engine in a sports car there are limitations to its reliability. And there are procedures that should be followed when you are going to flog it...doesn't matter the brand, you got to use common since.

Zymurgy

From an old Chevy press release:

Zymurgy

From an 8/23/2013 post on this forum:

Tonylmiller

I just wonder how the testing compares to the C5 and C6. I'm sure I'll never know.

And how severe the engine testing was.

Slappy3243

I'm willing to bet that GM knows how to properly test an engine by now. They have been in business quite some time and are known for reliable engines if anything else. How do we know the LT1 is not just as reliable as an LS2 or LS3? The analysis personality inside of you must know it will take years of production to form a baseline here.

stevebz06

The explanation for the C&D long term loaner failure was a piece of metal sneaking past the oil filter, is that correct? Why is there metal floating around in the engine big enough to destroy an engine?

A significant number of light airplane engines, maybe most, have no oil filters. They use metal mesh screens on designs that date back to the 40's or earlier. Somehow, most of these engines survived.

I think the question that needs to be asked is, what problem or deficiency in manufacturing is allowing this metal to be inside of the engine in the first place?

z51vett

Bingo we have a winner someone finally asked the right question.
z51vett
Doug

Tonylmiller

One would think so, but I guarantee you that times are changing (or have changed). You think they are still doing engine development the way they did it 50 years ago? I bet they are not. I just wonder if they are skimping on the testing, and that is why we are seeing these failures. I have been reading these forums since the C6 came out, and I do not recall seeing failures with low mileage like this.

I'm sure they are doing some testing. But are they doing enough?

dwward

You ask a very interesting question.

I would think it's very similar to the process you described earlier re the evolution of rocket engine development. With advances in computers, more analysis is done electronically (faster and cheaper), but I don't think GM ever stops testing it's engines. As ZM pointed out, in addition to an enormous amount of computer testing, they put more than 1M miles on their test fleet by this time last year and that testing goes on. The C5/C6 engines probably had less computer testing but the miles driven in the per-production test phases was probably very similar to the LT1.

Every year these engines get better as GM's knowledge base grows and like RCooper experienced with his LS3, several years into production, the product should be relatively flawless.

The car business is more competitive than ever before in it's history and every company is under tremendous pressure to produce the highest quality product for the money spent. The car market is truly global and the public's access to information is nearly limitless. GM has more to lose in this regard than most, and it seems, at least to me, that they are responding.

The result of all this competitive pressure are the most reliable and well made cars in the history of the automobile. Something I think most people take for granted. I became aware of cars starting in the 70's and those things were real junk.

Many, if not most of the people who experience catastrophic engine failures in their corvette end up here. If they were not already a member, they join wanting advice, sympathy, etc. We only ever hear half the story -- their half of story. Some think there have been a lot of failures, but I think there have been remarkably few. We know there are 37,288 corvette LT1 on the road and how many more 6.2L Silverados, Sierras, Escalades, etc. with the same basic engine?

I think the testing is more through than ever, and if there is a problem somewhere in the production chain (where there's smoke, there's fire?), it will be identified and fixed. And hopefully, it won't happen to me.