[trohde78]

That's not bad at all for that many miles. It looks just like my twin turbo 335i "after" it was walnut blasted! :-)

[parbreak]

I found it really ironic as I was reading this thread that an ad for Mishimoto Catch Can popped up.

[WhiteNight]

Originally Posted by parbreak

I found it really ironic as I was reading this thread that an ad for Mishimoto Catch Can popped up.

Im surprised there isn't an essay on this thread from one specific vendor.

[parbreak]

Originally Posted by WhiteNight

Im surprised there isn't an essay on this thread from one specific vendor.

Please don't even suggest that

[L78toLT1]

I'm thinking the lack of carbon buildup is primarily a function of modern oils formulated to combat buildup. At 13k, my ports were oily to the touch but the valves looked good. We're definately ingesting a good bit of oil but based on the pics in the original post, it does not appear to cause excessive carbon buildup

[Mr. Wyndham]

Originally Posted by L78toLT1

I'm thinking the lack of carbon buildup is primarily a function of modern oils formulated to combat buildup. At 13k, my ports were oily to the touch but the valves looked good. We're definately ingesting a good bit of oil but based on the pics in the original post, it does not appear to cause excessive carbon buildup

That's a really good point, too!

I also remember the "weird" design of the valve covers on the Gen V engines GM did with the odd protrusions and cavities. It was quietly mentioned that this was a new PCV feature.

[6spdhyperblue]

according to GMs SAE article on combustion for gen v small block it is the puff of hot exhaust gases back into the intake port from the combustion chamber after the intake valve opens is what causes the majority of build up. Those hot particles hit the relatively cool material and cling to it. Over time this builds up deposits. GM focused on valve timing events and made certain tradeoffs to minimize this action.

[WhiteNight]

Originally Posted by Nicul15

according to GMs SAE article on combustion for gen v small block it is the puff of hot exhaust gases back into the intake port from the combustion chamber after the intake valve opens is what causes the majority of build up. Those hot particles hit the relatively cool material and cling to it. Over time this builds up deposits. GM focused on valve timing events and made certain tradeoffs to minimize this action.

Hmmm. If that is true then if you go with a cam with positive overlap than you are looking at major carbon build up.

[JaxChris]

Originally Posted by 62nalide

Catch can or not that's Direct Injection for you. That really isn't that bad from what we have seen with cars that only have 30K miles.

It's not bad at all. That's what BMW and VW hope to look like after a few passes of seafoam and intake additives.

[Gunmetalmissle]

Makes me feel better. I would love to know what oil he used and the change intervals.

[Spartan268]

Originally Posted by Gunmetalmissle

Makes me feel better. I would love to know what oil he used and the change intervals.

Same here. I'd imagine an aftermarket catch can will further help the engine.

[GuywithL86]

Originally Posted by Gunmetalmissle

Makes me feel better. I would love to know what oil he used and the change intervals.

Just PM'd the guy on the other forum

mobile 1, 9-12k intervals

[GuywithL86]

guy is providing me with more info, confirmed he used 0w-20

So basically what we have here is the worst possible conditions for carbon buildup.

-Long intervals between oil changes (9-12k)
-No catch can
-over 100k miles
-0w-20 oil, aka super thin, which undoubtedly allows more oil into the intake since there are numerous records of the truck motors burning it through the intake via AFM

extreme carbon buildup theory circulating all GM DI v8 forums = pretty much busted (we'll of course need more high mileage examples to make it 100%)

Thank you 00pooterSS of performancetrucks

[JaxChris]

Originally Posted by Spartan268

Same here. I'd imagine an aftermarket catch can will further help the engine.

It proves that the catch can is not needed on the GM Gen V. Your runners won't be any cleaner than that after 100k unless you vent to atmosphere.