[cellsafemode]

I liken this debate to the one about exhausts.

A. Is oil on intake valves not ideal? Yes

B. Are restrictions to exhaust systems not ideal? Yes

A. Would reducing oil in the intake lead to less oil and residue getting baked on valves? Yes

B. Would using larger diameter pipes or pipes with smoother and less curves improve the flow rate of the exhaust system? Yes


The question that the topic of this thread and most everyone else is asking though is :

A. Does it matter? ??

B. Does it matter? No

We have been shown categorically in fairly scientific back to back dyno tests that you can put significant restrictions to exhausts and if they occur where the exhaust gas is hot and thus, less dense, it has no effect at all to engine performance.

We have little hope of a similar test for valve buildup on our specific engines. However, what would be nice at least, is some anecdotal proof that the buildup is more than superficial.

We have had and still have nothing more than evidence involving other engines, and even among that evidence, little to no evidence that the buildup pictured led to any measurable decrease in power or efficiency.

[18Hotwheels-SS]

WOW, W hat a post. I have an idea. If you want one buy one and if not don't. I have seen the issues on DI when it was first introduced into the market place. VW / BMW. The problem went away with engineering. Drive your car, enjoy it and do what makes you sleep better at night. Its your car.
PS: I sleep fine with out one.

[mdhopt36]

Post #221, I don't see anything that would be catastrophic in affecting engine performance. Sure, there's some smut there, but nothing that is a severe detriment.
Would like to know the miles when pics were taken (?) Any idea?

[SSDan]

Originally Posted by mdhopt36

Post #221, I don't see anything that would be catastrophic in affecting engine performance. Sure, there's some smut there, but nothing that is a severe detriment.
Would like to know the miles when pics were taken (?) Any idea?

According to the post on page 14 those photos are from a 2014 Corvette LT1 with 5500 miles.

I am on the fence with this one. I added a catch can on my gen 5 when I did a cam with bolt-on build. I would catch 1-2 oz of stuff every 1000 miles. But when I had a cam failure after 17K miles (that's a story for another day) and had to pull the heads for a re-build - the piston tops and valves did not look all that clean. In fact some people asked me if I ran cheap or crappy gas and the answer was no. I only use top tier 93 octane. So, I can not with any confidence say a catch can made any difference. I am leaving my LT1 alone. If I keep it long enough that it may need a valve cleaning - then so be it. I'll deal with it then.

[mdhopt36]

Yes, I feel the same way. If it looks cruddy later with more miles, will look into a clean-out.
(17K should be on the tack end of next year)

Not so many car motors I've been in, but lots of small stuff, 2+4 stroke.
Anyone ever see what happens with carbon build-up on head/piston of a 2-stroke?

(think of compression increase)

[IH8WNTR]

It just seems like it is one more thing to have to worry about on this car. I have enough already. I love it, barely get to drive it, and I’m averaging about 2500miles a year. By the time it could be an issue... I’ll be upgrading any way.

[craigss50]

Originally Posted by 00 Trans Ram

Well, how about we ask a former GM engineer about the matter?

https://www.corvetteforum.com/forums...post1590915548





https://youtu.be/7Pz0zTQ1bz0

Pic of LT1 at 12k miles (no can)



Another few pics of an LT1 with 20k miles:








Source - https://www.corvetteforum.com/forums...-owners-3.html

As stated earlier base LT1 Corvettes do not have an oil separator system like the Camaro does. Is this a base?

[777]

Over 200 posts and I think there's only been 1 person post pictures based on the questions asked? Here's my 2017 Camaro SS 1LE. Car has 16,xxx miles on it and is my daily driver. Pulled the manifold this morning took maybe 20 minutes. No mods, no catch can.

[kodiakk]

A while back, there was one of the engineers from Chevrolet who works and designs engines for the Corvettes and he said that the catch cans were totally unnecessary and most of the paranoia is from 1 guy trying to get another to buy the same needless product he bought. He went into detail about the DI and how it was built to deal with it

[Whocares05050]

Originally Posted by kodiakk

A while back, there was one of the engineers from Chevrolet who works and designs engines for the Corvettes and he said that the catch cans were totally unnecessary and most of the paranoia is from 1 guy trying to get another to buy the same needless product he bought. He went into detail about the DI and how it was built to deal with it

Please... tell us all how the engine magically deals with carbon buildup all by it self on the backs of valves....

[Whocares05050]

Originally Posted by 777

Over 200 posts and I think there's only been 1 person post pictures based on the questions asked? Here's my 2017 Camaro SS 1LE. Car has 16,xxx miles on it and is my daily driver. Pulled the manifold this morning took maybe 20 minutes. No mods, no catch can.

THANK YOU. That looks pretty much as expected. I hope those with 80k miles can take pics as well...

[Nsxmatt]

Originally Posted by Whocares05050

Please... tell us all how the engine magically deals with carbon buildup all by it self on the backs of valves....

How does fuel magically turn to carbon?

[hotlap]

Originally Posted by kodiakk

A while back, there was one of the engineers from Chevrolet who works and designs engines for the Corvettes and he said that the catch cans were totally unnecessary and most of the paranoia is from 1 guy trying to get another to buy the same needless product he bought. He went into detail about the DI and how it was built to deal with it

This?

Originally Posted by Glen e

just to add a diff perspective, this was written over at the corvette forum in 2014 when the c7 was introduced. This guy is like Becky here (and there) Becky knows him:

He writes:

I was the one that contacted someone from the Stingray Consultant team from GM...Here comes is what he wrote back on this matter.

"The Stingray was evaluated with over one million development miles on 200 captured test fleet cars. There are tens of thousands of direct injection vehicles on the road from General Motors alone. During the evaluation hundreds of engines were literally torn down in to part piles and evaluated. There are hundreds of thousands of LSx family of motors (where part of this catch can hype started) on the roads and the many of these motors are running well past 250,000 miles without a catch can.

The cars have a 100,000 mile powertrain warranty and that includes mechanical failure of the engine. Trust me when I tell you that there are not reams of data (not even pages of data) on cars coming up lame because of oil at the MAF. It just isn't the problem that the "internet" makes it out to be. When you ask a GM Powertrain engineer about a catch can the reply is that the only thing you get is added weight.

In looking at the extra effort and added cost that went in to the Stingray, do you really believe for one second that if a $20.00 part attached to the engine would improve reliability, limit warranty claims and replacement costs, that GM wouldn't have put it on if it was necessary as part of their evaluation?

Every single GM engineer that I have spoken with told me in one form or another that a catch can is predominately a "gimmick" device created by tuners looking to make a few extra bucks on their engine modifications.

As a by-product of the PCV system, excess oil vapor is recycled to prevent it from leaching out in to the environment. It will condense back in to liquid if the temperature and environmental conditions are right. A catch can is an oil separator device. It allows the heavier oil in liquid to condense in the bottom of the can and only pass the air (gases) back. This is basically the same thing that is happening at the front of the MAF where most of the oil can be found.

The theory is that this oil in the intake system will collect on the valves and in the cylinders and cause excess carbon deposits. The catch can will reduce (not eliminate) oil pooling in the MAF.

Where the plan breaks down is that there aren't thousands of cars detonating because of the oil. As I told you on the phone, This isn't new. The engines are designed to deal with a quantity of oil mist presented via the intake.

You asked what I should tell the customer, my answer is I'm not sure because I don't know what his question is. If the question is is this normal? The answer is yes. If the question is should I put a catch can on? The answer is what ever makes you feel better. If the question is do I need a catch can? The answer is a resounding no. If the reply is that they saw it on the internet, apologize politely and tell them virtually every thread about it has started with a vendor selling a product or a consumer that was fooled by the hype and trying to make themselves feel better about their purchase by getting others to agree with them.

If he has concerns about his condition he should take the car to his dealer for evaluation.

Here is my standard response to the dozens of emails I get each year with a link to a thread like you posted (and often, that very same thread).

Simply stated, absolutely not on the catch can. It simply isn’t warranted for any street driven car. We can talk in more detail about it tomorrow and Dan will appreciate it as I’ve all ready had this conversation with him as well. Since the advent of the PCV system, cars have released some oil in places where it wouldn’t normally have gone in a fully sealed system. It ends up in vapor which condenses back in to liquid form in the intake path. As a result of that, the system is designed to ingest and subsequently digest some extra oil. Higher revving produces more oil and repeated higher revving (drag racer, track duty car, etc.) would be in the realm of uses that I might consider adding the can. Daily driving, occasional back road romp or stop light to stop light burst, not so much.

With all of that said, they won’t hurt anything. For those that don’t want to take my word for it, can feel comfortable adding it but it won’t make an appreciable difference in the life of the motor or the efficiency of the system.
If you dig deep enough in to forum information about catch cans, all roads generally lead back to a performance tuner, aftermarket part supplier or fabricator who has a vested interest in selling catch cans." Stingray Consultant


Mike Furman ~
"Be kinder than necessary, for everyone you meet is fighting some kind of battle"

[18Hotwheels-SS]

Years ago there was a old school tech that I had working for me that took a water mister, that they use in the summer to keep cool, and set it up by the intake of a running Kubota engine we had at the shop that did a lot of idling. The engine was getting tore down for a valve job. He let the mist get pulled into the intake for an hour or so as the engine sat there idling. It cleaned the carbon and soot out of the intake like had never seen before. The engine would actually start knocking as carbon came off and was affecting the piston to head clearance. ( shouldn't happen on a gas engine ) It makes sense due to the fact that steam cleans off carbon. Have you ever took a head off a engine after it blew a head gasket or cracked a head at a coolant passage. The piston and complete head for the affected cylinder would be steam cleaned. I may try this and let you guys know how it worked. They use to make water injection kits to increase power. Time to start the google search. Maybe the answer to the problem was figured out years ago. I only have 4k on my HW's so I may have to try another engine.