Thats right... although isn't an Atkinson just a Miller without forced induction? or am I totally off on this.
I only drove a Millenia once on a test drive back in late '94 IIRC when they first came out.
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Skyactiv Intake Valve carbon build up - Anyone taken a look at intake valves?
- Thread starter johnygfunk
- Start date
Thats right... although isn't an Atkinson just a Miller without forced induction? or am I totally off on this.
I only drove a Millenia once on a test drive back in late '94 IIRC when they first came out.
I'm sure there have been others too... but I believe the hybrid application has to date been the most enduring in production automobiles.
Thats right... although isn't an Atkinson just a Miller without forced induction? or am I totally off on this.
I only drove a Millenia once on a test drive back in late '94 IIRC when they first came out.
I've read Miller and Atkinson used so interchangeable to refer to an engine with very high compression ratio coupled with extreme intake valve overlap, thus reducing effective compression ratio but maintaining expansion ratio, that I'm not sure what the differentiators are. But Atkinson preceded Miller and I tend to go with the law of primacy
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Here's the proper way to clean carbon from the intake. This guy is a genius.
https://www.youtube.com/watch?v=xIijYgvxW0g
https://www.youtube.com/watch?v=xIijYgvxW0g
Two problems here:
1) CX-5's do not build up carbon in the intake (unless you've loaded an aftermarket tune that messes the breathing up).
2) The CX-5 has a plastic intake manifold. So don't try this at home.
Damn, that looks like fun...what does that say about me. (nervous)
Which brings up a good point. Diesels have had direct injection forever yet I don't know of any carbon buildup issues on the valves that is detrimental to engine performance.
umm... could be wrong, but I believe the manifold with the serious carbon buildup in that utube is off a diesel.
interesting article on egr's in diesels:
http://www.trucktrend.com/how-to/engine/1105dp-the-evil-of-egr-on-diesel-engines/
According to your article it's the EGR system that's responsible for the carbon in a diesel. The mileage and age on the intake manifold from the engine in that youtube video isn't known and like Mike said it could have been modified or not serviced correctly or had fuel delivery issues too.
The oil in the intake manifold is coming from positive crankcase vent. Our cars will eventually have oil in the intake if driven long enough to have significant blow by from the rings that will create enough flow of hot oil gas(fumes) to condense in the intake. Erg gas comes from the exhaust and will have already been burned.
I'm still not convinced that there is or will be enough carbon buildup on the intake valves and intake manifold in the Skyactiv engines (not modified) to pose a significant problem within the normal life span of an engine. There will be some carbon buildup as this is normal for any engine especially over 100,000 miles but it's not going to be enough to be an issue. Of course only time will tell but again I'm putting my confidence in Mazda engineering.
I too have a tendency to put my trust in the mfr's engineering expertise but recent events across the spectrum have clearly demonstrated that may not be wise. They are all under far too much pressure to conform to increasingly tight emissions and fuel economy metrics while still delivering an expected level of driving performance. The last time anything similar happened (the decade of the seventies) was a perfect example: in that era we had Cadillac's V8-6-4, the GM V8 diesel, highly restrictive first gen catalytic convertors, under-hood vacuum tube plumbing nightmares and imports that, while improving vastly on reliability issues of the domestics could barely keep pace with a 'double-nickel' national speed limit, among others. This era (so far) it's Ford's EccoStar, Hyundai's gas mileage claims, VW's TDI emissions claims, seizing turbos and carbon building, degrading performance GDI's across the industry.
Hardly any mystery why currently pleased owners are curious and skittish about what revelations lie next as many of the latest problems can be resolved, often by doing something the engineers just missed telling us about. Or got over-ruled by marketing who're still reaching for the 100,000 mile maintenance-free automobile nirvana. (At which point it's a throw-away, btw. So what about those who'd like to keep it longer??)
Which brings it back yet again to OP's question: has anyone seen an opened up a high mileage SA-g engine to get a feel for carbon buildup?
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- San Antonio, Texas
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- '15 CX-5 Miata AWD
Not that I have found. That is why I find it laughable when people post these things about what will make you have build up and what won't. Of course, if you have an aftermarket tune you will have buildup. Because compare the stock tune intake valves, to valves of that with an aftermarket tune, of which an example of neither has been posted, the latter showed more build up.(dunno)
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I'm not aware of any CX-5 engines that have been torn open. That generally happens when there are issues but these have proven so reliable they haven't needed opening up (at least not enough of them for pictures to find their way here). Having been available for over 4 years, you know there must be a number of high-mileage engines and if they were getting all carbon choked and blowing up, you can bet we would be hearing about it.
Care to explain how you have this information? Any extensive testing you have done or references to where you read this information?
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- San Antonio, Texas
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- '15 CX-5 Miata AWD
Yea that's a good point, but only if the owner is the type to notice and act on something that is non catastrophic. Most owners (aren't really involved in the vehicle dynamic and certainly not doing self maintenance) wouldn't act unless there was some type of noticeable to them (drivability) that prompted them to go into service and that was determined to be the problem. We don't even know if having some crud on the valve backside will make the car run noticeably different (or how much) but right now it's all conjecture until a couple of people take apart their stuff AND document it on the web.. You can drive around on old oil as long as you want until something catastrophic happens, and by then less obvious damage has probably already been done..
