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- RDX Aspec Adv.
Or to mess with other crap.
Skyactiv Intake Valve carbon build up - Anyone taken a look at intake valves?
- Thread starter johnygfunk
- Start date
Or to mess with other crap.
Im not that much worried about carbon build up on the valves. I care about oil in the intake manifold. I just want a bone dry intake. If this also further reduces that carbon build that we dont have to worry about any more, than even better. If not, then Im extremely happy to have only stopped oil from coating around the intake manifold or head walls, throttle body, intake tube etc..
Have you ever worked on a car that has thousands of miles? When you take off the intake, throttle body or manifold you will see how much crap is in it. On my Evo the intake system (manifold, throttle body, intercooler and intake pipes) were bone dry at 48k miles, like it was new. My friends Jetta was coated full of oil and soot. The engineers didnt design the car to have oil and soot build up in the intake system. They just accept it as they are required to build it in a way to meet emissions requirements. In addition, they dont find a need to spend more money designing a catch can that most people will not want to or forget about emptying it. In their logic, the oil and soot will just take away a little of the efficiency as the car ages but wont blow up the motor or cause warranty work to be had.
I dont plan on recirculating with a catch can. I will vent to atmosphere either with catch can or without when I decide.
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- San Antonio, Texas
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- '15 CX-5 Miata AWD
There is a vent to atmospshere it gets super grimey.
I remember my brother's plymouth valiant. It was a late 50's or early 60's vehicle, before EPA or emissions controls. Whether by design or accident it vented it's crankcase fumes at the bottom of the engine compartment from a pipe that was always smoking and dripping oil. There was a persistent oil puddle right in the spot where that car parked, thick with dust that accumulated in the oil. It was my job to scrape the crud up when my dad got peeved about it.
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It wasn't an '81-'83 Chrysler Imperial or the old '80 Cadillac V8-6-4 motor was it? ;-)
I think the Imperial was some kind of analog FI
I thought I would share this in case its useful info:
What a PITA this thing is. According to the Service Manual, to get to the pcv valve you need to remove the intake manifold. However that looks to be a time consuming and a pain to remove and install back. Also I’m not sure if I would have to replace the gaskets as well if the intake manifold is removed.
I looked again from the bottom and it seems that there might be another way if we removed the starter. The PCV is above the starter and I think if I remove it I will be able to reach the PCV from the bottom of the car.
I ordered some PCV tubing. As soon as that is received I’ll attempt it from the bottom.
What a PITA this thing is. According to the Service Manual, to get to the pcv valve you need to remove the intake manifold. However that looks to be a time consuming and a pain to remove and install back. Also I’m not sure if I would have to replace the gaskets as well if the intake manifold is removed.
I looked again from the bottom and it seems that there might be another way if we removed the starter. The PCV is above the starter and I think if I remove it I will be able to reach the PCV from the bottom of the car.
I ordered some PCV tubing. As soon as that is received I’ll attempt it from the bottom.
The PCV is covered by Mazda under the Emissions Warranty for up to 8 years or 80,000 miles so I'm just going to let Mazda deal with it if there's ever a problem. But due to the highly refined nature of modern engines I don't expect the PCV to fail like they did regularly on older cars.
I was out looking at the job... it sounds a lot harder than I think it will be. Time consuming for something as simple as a PCV but straightforward enough... remove the air box and then loosen the intake. It looks to have six or eight bolts that are fairly easy to access with socket and appropriate extension (one maybe difficult and needs care). Once loosened it looks like it should roll forward to expose the PCV. It doesn't appear you'd have to remove the throttle body from the manifold, you may even be able to get away with leaving in the airbox but it will torque the flex fitting between the AB and TB pretty heavily.
I believe the 'gasket' will actually be O-rings around the ports.
I think it would be easier than pulling the starter since you're doing everything from above and access to all bolts and fittings is actually pretty good. Also, people on other forums talk about removing the intake for PCV so I kind of think that's the way.
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^^Your correct regarding the gaskets being o-ringed around the ports. Do you know if I need to replace the gaskets if I remove the manifold or can it be re-used? I’ve only driven the car just a tad over 200 miles. If I had considerably more mileage on it I would replace it without a doubt.
I'd replace them on principle: it's relatively cheap insurance for no intake leaks.
Also, I spent a little more time trying to peek behind the manifold and found something I'd forgot: the fuel rail is right behind it. That may be in the way so the manifold will probably have to come all the way out. Defo means disassembling the entire intake from the air box through to the manifold. ugg.
Also, you may not know but the PCV is held in with a clip that's pretty difficult to dislodge (a good thing considering where it is) so I don't think snaking around from the bottom is feasible either, even if you CAN get your fingers on it. In fact, all the you-tubes (older M-3's mostly) show people taking the manifold off or pulling it way back . Again, nothing extremely delicate or sensitive and most bolts are relatively accessible, but lots of dis-assembly.
Defo high on the PITA scale and not a two beer job. I've not had to change a PCV in any engine, ever. Every time I checked them they were functioning OK even with well over 100K of service. I hope this one shares that heritage and never needs changing.
Lastly: I really advise you think this through. That's a lot of dis-assembly on a motor with 5 years of warranty left on it, and then you're putting a mod in-line with a pollution control that will throw a code if not working right. If you bring this thing back with a CEL (whatever it is: it may have nothing to do with the PCV) Mazda will almost certainly say you have a mod on the motor and they can't be sure that's not the cause. You'll have to de-mod it, bringing it back to perfect stock condition, before they'll honor any warranty or even check it out.
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Maybe I missed it. I did read this entire thread but have not seen one shred of evidence that what you plan to do will improve the engine one bit.
Why would you remove the intake manifold on a brand new, factory sealed engine?
Pure idiocy. Don't you have something valuable and worthwhile to do with your spare time??
Its jut to keep oil out of the intake manifold and head ports. The car will not gain any HP or free any HP or go faster in any way. Unless it was clogged and venting it clears the bottleneck, which its not.
I havent fully made up my mind yet to remove the starter and go from underneath or remove the intake manifold and go from the top. It’s a small possibility I might just give up since its not really a sport car and I dont want to do all this work on a new car. But every time I think of how much oil over time is recirculating back and coating inside walls of the intake manifold/head kind of pisses me off.
Simply put, No oil residue in the intake/head is always better than oil in the intake manifold/head ports.
It's not clear to me why you are upset.
There is no evidence that the engine is impacted negatively in any way by the breather system. None. Nada. Zip.
Why does this piss you off?
Well, I simply dont want to have oil/grime build in the intake manifold and head over time as it can effect engine performances negatively. It may not be a drastic difference on our Skyactiv-g motors as other turbo cars that have intercoolers etc.. But its still something and that something I simply dont want.
The oil, grime, soot accumulation on all engine motors can effect the intake air flow, oil traps heat (intake manifolds, intercoolers etc..) and depending on how much oil is with the blow-by its mixed with the combustion chamber. Yes I know a little oil gets burned from leaking through the piston cylinder wall but this just adds on to that.
I’m not a mechanic but I have personally worked on cars with PCV left as OEM and those that ran working baffled catch cans or vented. There is a huge difference between the two manifolds and heads. I didnt take apart the head, just looking inside of the intake ports to the valves on how much oil, grime and soot has built up. I just rather have my intake side looking as if it was new even when I’m at 50k 100k 200k miles than to have that build up inside.
Think of this as a personal preference like those guys that bought Star Wars toys in the old days and kept them in the packages un opened vs those that took them out. Over time the unopened well stored looked as new and most of the opened ones dont. Its not a great comparison but hope you understand what I’m trying to say.
yes they do.
4G63T is hoping that the smelly blow-by-gases he plans to release into the air will mask his trail.
Btw.. to add some fuel to the fire, this thread over on the mazda3 revoultion forum has some pictures of the oil covered intake and what looks to me like clean, shiny, intake valves. (the poster has a different opinion on the cleanliness of the valves)
http://mazda3revolution.com/forums/...ctiv-owners-beware-intake-valve-deposits.html
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Making the claim that "it is still something and that something I simply don't want" is not evidence that the breather system will ever have a negative impact on the engine. And there is still not a shred of evidence that you are concerned about anything that is grounded in reality.
The fallacy you present here is that all cars are basically the same, ie, if one cars breather system causes soot build-up on the valves, then all cars breather systems will do the same thing. There is no evidence the CX-5's breather system will harm the engine. None.
You are assuming two things here:
1) That by modifying your CX-5's breather system the valves will still look new after 50-200,000 miles.
2) That a new looking valve with 50-200,000 miles will be better than a valve that does not look new.
But what actually matters to the performance and reliability of the engine is the functional condition of the valve, not it's appearance. And I have no reason to believe that a valve operated in an environment without crankcase vapors present will help the valve last longer or stay in better shape. Any oil vapor that may be present, could actually protect the valve and valve guides from wear.
I think I'm getting what you're saying. If you don't open something it will stay in it's original condition better. And that is the advice I would give to you regarding your intake manifold - don't needlessly break the factory seal between the intake manifold and the head.
I’m not saying dirty intake will be terribly bad just not 100% same efficiency as a considerably cleaner one. Lets say 2% worse for the sake of the argument. And I care about that 2%. In addition, as I have mentioned in this thread it will not give any power increase. But a cleaner intake over time is better than dirty grimy oil covered intake. If the CX-5’s valves stay clean because its engineered to run hotter and burn it off then I’m not arguing with that. However my argument is the intake manifold and the ports to the valves.
You keep talking about how there is no harm for the engine. I agree with you there is no “harm” to the engine. But a cleaner intake manifold is just simply always better than a dirty one.
My assumption is not the valve itself, I’m just talking about the ports in the heads that lead to the valves. If me wording it as "Ports to the valves” is interpreted as valves as well, then I apologize for the confusion.
All engines PCV system is pretty much the same. Only difference is some have it on the block, most have it only on the head/valve cover. Best place in my opinion is what the CX-5 engineers did and put it on the short block so its relieved straight from the larger source (the crank case area).
Maybe I’ve been kind of over exaggerating about the intake looking brand spanking new. It’s not going to be off the shelf new but very clean compared to the oil and soot covered ones. Its just the difference between the two is so far apart you would mention one was new in a conversation. Also depends on the EGR if it recirculated or the actual location it recirculates back, then it will accumulate soot over time. But the ports that are before the EGR recirculating back in are cleaner. I just didnt want to add that part in the conversation as it goes off topic from the PCV. So if the EGR recirculates in the manifold runners then half would be clean and that half can accumulate soot. If in the head ports, then intake manifold will be “clean” but head ports can accumulate soot. This is just off topic though. So I’m not going into it or including it in this thread.
I agree that I dont want to take apart the seal between the intake manifold and head. But gaskets can be replaced or I might just go from the bottom to avoid that or a big maybe just give up and leave it alone.
That's the most sensible idea I've heard all day!
