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Variable Compression Ratio

Variable Compression Ratio

RE: Variable Compression Ratio

It will be interesting to see how it works out, have they gone into production? It has a lot of extra wear parts and some interesting leverage ratios happening. I have a feeling they will need a nice CGI block and not aluminum for that one. I think the integral exhaust manifold idea is bad news, something not needed in an aluminum head is more heat, unless the plan is adiabatic like Cummins tried many years ago, but then aluminum would not be a good choice of material.

I did enjoy one of the comments below the video about how the poster feels those engines will never be overhauled. And how the person has seen so many late model cars scrapped for no apparent reason, since they had no visible damage. It does seem power train components as well as whole cars are becoming a throw away item with in very few years of ownership nowadays. Now why is that?

RE: Variable Compression Ratio

Govt mandates for emissions durability started it.
Most components are now good for 100k miles.
Service costs have risen.
If many components fail at say 120k miles then the second failure makes the car unsalable.

Mike Halloran
Pembroke Pines, FL, USA

RE: Variable Compression Ratio

I don't understand the "second failure" comment.
If the owner chooses to have the car fixed, then it is still a car...

Jay Maechtlen
http://www.laserpubs.com/techcomm

RE: Variable Compression Ratio

Ah. Yeah, you'd expect that any number of things would be hitting end of life at same time.
I've had pretty good luck with my last few cars, but not everyone does.
I got an '12 Impala with the 3.6 and six speed automatic, with 150k miles on it- will be interesting to see how it does.

Jay Maechtlen
http://www.laserpubs.com/techcomm

RE: Variable Compression Ratio

Yes, the Holden (GM) Alloytec motors are a good example of this. The timing chain set fails regularly at around 200,000 km or very roughly 100k miles. Cost to repair is around $2-3k. This makes the cars very difficult to resell at only 10 years old or less, unless the work has already been done.

RE: Variable Compression Ratio

Infiniti's mechanism basically adds a few more con-rod joints. I suspect they have done their homework.

Bottom-end failures (that aren't because someone ran it low on oil) are pretty rare.

RE: Variable Compression Ratio

My last car was an Acura TL with the Honda 3.5L V6. It had 240,000 miles when I gave it to her and had never suffered a failure; it was still pulling strong. I was ready to buy another, but Acura dropped the TL and didn't offer the V6 in the nearest model, so I bought a 2017 Honda Accord Touring edition. It turned out to be good timing as they dropped the V6 option in 2018!

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