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Catch can on a 5.3L LT - how much does it actually catch?

pronstar

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Since I’ve installed this catch can, I would periodically dump it out, but I never looked at how much over time.

So this time I thought I’d better to get some meaningful data to share.

I emptied it when I last changed my oil.
This is how much crud it collected over 5k miles.

IMG_4697.JPG


A lot more than I thought.

Time to put a catch can on Mrs Pronstar’s Suburban, because I don’t want this much crap going back into the intake on a DI motor.



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t&y

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Huh? Splain to me please cuz I don't know W.I.T.F. you are talking about :cool:
 

rivermobster

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Huh? Splain to me please cuz I don't know W.I.T.F. you are talking about :cool:
The Chevy guys, especially the LS fans, don't wanna explain it, cause it's fucking embarassing!

But it's like LOF said, the PCV system can't keep up with the massive amount of blow by those engines have.

There are TSB's galore on this issue. Different valve covers, different this and that to try and fix it.

The aftermarket world stepped up with these catch can deals to try and help with the problem, since GM can't seems to solve it.

 

LargeOrangeFont

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The Chevy guys, especially the LS fans, don't wanna explain it, cause it's fucking embarassing!

But it's like LOF said, the PCV system can't keep up with the massive amount of blow by those engines have.

There are TSB's galore on this issue. Different valve covers, different this and that to try and fix it.

The aftermarket world stepped up with these catch can deals to try and help with the problem, since GM can't seems to solve it.

Honestly nearly all modern engines have this same issue, forced induction engines especially. If you put a can in line on the dirty side of any modern engine, you'll get some amount of oil in it through the life of an oil change. In the LS and LT engines this is not caused by blow by. It is not blow by on any modern engine. The the LS/LT engines It is caused by returning oil falling down from the heads onto the spinning crank, and lack of bay to bay air movement inside the bottom end of the engine. The crank whips some of that falling hot oil into a very light mist that then gets sucked through the PCV system under vacuum into the intake manifold. The catch can gives the mist an area to collect, cool and form back into oil so you don't just run it through the engine.

On a street engine you can address this pretty easily with a catch can and/or a couple small changes to the PCV system. In a car that consistently runs higher RPM, a couple 3/8 lines are not simply not enough to control the ventilation of the crankcase sufficiently.

My track car with an LS used to consume almost a half a quart of oil per track day when I had the PCV system intact and functioning with 2 large catch cans, one for each side of the system.

I went to an open system with a -10 line from each valve cover and a -6 line from the valley cover into a vented can and the can collects about 2oz of oil per day, and the car consumes no noticeable oil now.
 
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rivermobster

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Honestly nearly all modern engine have this same issue, forced induction engines especially. If you put a can in line on the dirty side of any modern engine, you'll get some amount of oil in it through the life of an oil change. In the LS and LT engines this is not caused by blow by. It is caused by returning oil falling down from the heads onto the spinning crank. The crank whips some of that oil into a very light mist that then gets sucked through the PCV system under vacuum into the intake manifold. The catch can gives the mist an area to collect and form back into oil so you don't just run it through the engine.
Yep. Very true also. Sorta.

But it is manly a blow by issue. I know this cause this is what I do for a living and I've watched this issue progress over many decades. It has a more to do with today's modern ultra low tension piston rings than just about anything else. Ford dealt with this back in 86 when the first 302HO came out. Super thin rings, that let that engine use mass quantities of engine oil between oil changes. That was embarrassing too, but it was quite a few years ago now.

Toyota had the issue as well for a few years too when I was shop foreman at Longo. They also long since figured it out.

BMW probably has the best handle on this issue of anyone. Probably because they were the first with gas direct injection? But, even before they had DI, they had a Cyclone Separator system that keeps the engine crankcase under full vacumm at all times. They have a good handle on it now.

And we also need to note, that every other manufacturer out there has solved this issue, regardless of the multiple causes, in house. Typical GM nonsense. We can't figure out how to fix it, so we will just ship that shit anyway. :rolleyes:
 

LargeOrangeFont

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Yep. Very true also. Sorta.

But it is manly a blow by issue. I know this cause this is what I do for a living and I've watched this issue progress over many decades. It has a more to do with today's modern ultra low tension piston rings than just about anything else. Ford dealt with this back in 86 when the first 302HO came out. Super thin rings, that let that engine use mass quantities of engine oil between oil changes. That was embarrassing too, but it was quite a few years ago now.

Toyota had the issue as well for a few years too when I was shop foreman at Longo. They also long since figured it out.

BMW probably has the best handle on this issue of anyone. Probably because they were the first with gas direct injection? But, even before they had DI, they had a Cyclone Separator system that keeps the engine crankcase under full vacumm at all times. They have a good handle on it now.

And we also need to note, that every other manufacturer out there has solved this issue, regardless of the multiple causes, in house. Typical GM nonsense. We can't figure out how to fix it, so we will just ship that shit anyway. :rolleyes:
Yea the low tension rings play a role for sure, but every modern car I've ever looked at had oily residue in the intake. It is a universal problem, but some OEMs certainly mitigate it better than others.

All of these cars would generally perform fine under a leakdown or compression test so excessive blow by isn't the primary cause.
 
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rivermobster

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Yea the low tension rings play a role for sure, but every modern car I've ever looked at had oily residue in the intake. It is a universal problem, but some OEMs certainly mitigate it better than others.

All of these cars would generally perform fine under a leakdown or compression test so excessive blow by isn't the primary cause.
I would say GM is the primary cause! 😂
 

pronstar

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Yep. Very true also. Sorta.

But it is manly a blow by issue. I know this cause this is what I do for a living and I've watched this issue progress over many decades. It has a more to do with today's modern ultra low tension piston rings than just about anything else. Ford dealt with this back in 86 when the first 302HO came out. Super thin rings, that let that engine use mass quantities of engine oil between oil changes. That was embarrassing too, but it was quite a few years ago now.

Toyota had the issue as well for a few years too when I was shop foreman at Longo. They also long since figured it out.

BMW probably has the best handle on this issue of anyone. Probably because they were the first with gas direct injection? But, even before they had DI, they had a Cyclone Separator system that keeps the engine crankcase under full vacumm at all times. They have a good handle on it now.

And we also need to note, that every other manufacturer out there has solved this issue, regardless of the multiple causes, in house. Typical GM nonsense. We can't figure out how to fix it, so we will just ship that shit anyway. :rolleyes:
Toyota/Lexus had this issue with their now-discontinued 2.5L DI V6.

Every other DI engine in their lineups had D4S which included both port and fuel injectors.

So the amount of crud is unchanged, it just gets cleaned-off the back of the intake valves with the port injector.


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rivermobster

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Toyota/Lexus had this issue with their now-discontinued 2.5L DI V6.

Every other DI engine in their lineups had D4S which included both port and fuel injectors.

So the amount of crud is unchanged, it just gets cleaned-off the back of the intake valves with the port injector.


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Toyota had that issue WAY before DI came out. Everyone had this issue. Like I said, it's a by product of low (thin) tension rings. I was working for Ford when they first dealt with it, back in 86. DI just made it a more "prominent" issue that needed to be dealt with and fixed.

When I worked at Longo, people would come in complaining about oil consumption issues. To verify, we had to do a fresh oil change and then paint seal the engine completely. After X amount of miles, we would unseal it, and check the oil level...

If there was no more than 1 quart in a 1k miles being used, that was considered normal usage. There were Plenty of fights on the service drive about that! lol

Wanna blame somebody? Blame the CARB and the EPA for the stringent requirements they put on ALL of the vehicle manufactures. They were (and still are) doing everything they can to reduce internal engine friction.

0-20W synthetic engine oil is as thin as water and as slick as pure silicone. Don't think for a second that shit doesn't just slip right on by the rings. And yet, the engine still has to pass a smog test! Round and round we go. It's a NEVER ending battle that is constantly being fought.
 

pronstar

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Toyota had that issue WAY before DI came out. Everyone had this issue. Like I said, it's a by product of low (thin) tension rings. I was working for Ford when they first dealt with it, back in 86. DI just made it a more "prominent" issue that needed to be dealt with and fixed.

When I worked at Longo, people would come in complaining about oil consumption issues. To verify, we had to do a fresh oil change and then paint seal the engine completely. After X amount of miles, we would unseal it, and check the oil level...

If there was no more than 1 quart in a 1k miles being used, that was considered normal usage. There were Plenty of fights on the service drive about that! lol

Wanna blame somebody? Blame the CARB and the EPA for the stringent requirements they put on ALL of the vehicle manufactures. They were (and still are) doing everything they can to reduce internal engine friction.

0-20W synthetic engine oil is as thin as water and as slick as pure silicone. Don't think for a second that shit doesn't just slip right on by the rings. And yet, the engine still has to pass a smog test! Round and round we go. It's a NEVER ending battle that is constantly being fought.
Sorry I was just referring to the gunk on the backside of the intake valves.

I’m not too hip on oil consumption issues


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rivermobster

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Sorry I was just referring to the gunk on the backside of the intake valves.

I’m not too hip on oil consumption issues


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Where do you think that gunk comes from bro? It's not fuel deposits, it's oil deposits. It comes through the valve guides, the rings and from the PCV introducing it back into the intake system. The more blow by there is (less ring sealing) the more pressure there is pushing oil into the combustion chamber from Every possible direction.

Oh and then add a turbo charger into the mix!

Long time ago they had us grease monkeys use walnut shells to blast off the crap on the back side of the valves, without having to disassemble the engine. What's REALLY funny about that is, we did it at Ford in the 80's. Imagine my surprise when BMW had us do the same thing with the 335 first came out. I was so shocked!!! :rolleyes: 🤣:p
 

pronstar

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Where do you think that gunk comes from bro? It's not fuel deposits, it's oil deposits. It comes through the valve guides, the rings and from the PCV introducing it back into the intake system. The more blow by there is (less ring sealing) the more pressure there is pushing oil into the combustion chamber from Every possible direction.

Oh and then add a turbo charger into the mix!

Long time ago they had us grease monkeys use walnut shells to blast off the crap on the back side of the valves, without having to disassemble the engine. What's REALLY funny about that is, we did it at Ford in the 80's. Imagine my surprise when BMW had us do the same thing with the 335 first came out. I was so shocked!!! :rolleyes: :p
Oh I know where it comes from...I’m just focusing on the specific issue of gunked -up intake valves, and you just don’t see that anywhere near as bad with port injection.


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rivermobster

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Oh I know where it comes from...I’m just focusing on the specific issue of gunked -up intake valves, and you just don’t see that anywhere near as bad with port injection.


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Well since you're not old enough to remember how a carb engine works, I'll let you stand on that! lol

But truthfully EVERY engine out there does it. Carbed, EFI, port, throttle, sequential, DI, they all Eventually gunk up the valves. It's the nature of the beast my brother. Even as clean an fuel efficient as these new engines are, they still have to have oil in em.

Keep in mind one of the current issues is, the computers are So sensitive detecting Everything that goes on in the engine, they will set codes for this kinna shit! Back in the old days, the computers could barely control the timing, even with the help of a knock sensor. Now they detect Everything.

There was a day when you only had 20 fault codes to deal with, and today there are literately hundreds. This is why working at the dealership is for the birds anymore. Those guys are just part changers. There just isn't much diagnosis going on any more.

Well...

For real cars like you and I have been used to dealing with anyway. American cars are still ages behind, and GM is at the back of the pack. (as you can see by your catch can experiment)

:(
 

Bigbore500r

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Yep. Very true also. Sorta.

But it is manly a blow by issue. I know this cause this is what I do for a living and I've watched this issue progress over many decades. It has a more to do with today's modern ultra low tension piston rings than just about anything else. Ford dealt with this back in 86 when the first 302HO came out. Super thin rings, that let that engine use mass quantities of engine oil between oil changes. That was embarrassing too, but it was quite a few years ago now.

Toyota had the issue as well for a few years too when I was shop foreman at Longo. They also long since figured it out.

BMW probably has the best handle on this issue of anyone. Probably because they were the first with gas direct injection? But, even before they had DI, they had a Cyclone Separator system that keeps the engine crankcase under full vacumm at all times. They have a good handle on it now.

And we also need to note, that every other manufacturer out there has solved this issue, regardless of the multiple causes, in house. Typical GM nonsense. We can't figure out how to fix it, so we will just ship that shit anyway. :rolleyes:

The only uncontrolled hot air I can see is your anti-GM biased post :cool:

1592929202669.png
 

LargeOrangeFont

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Toyota had that issue WAY before DI came out. Everyone had this issue. Like I said, it's a by product of low (thin) tension rings. I was working for Ford when they first dealt with it, back in 86. DI just made it a more "prominent" issue that needed to be dealt with and fixed.

When I worked at Longo, people would come in complaining about oil consumption issues. To verify, we had to do a fresh oil change and then paint seal the engine completely. After X amount of miles, we would unseal it, and check the oil level...

If there was no more than 1 quart in a 1k miles being used, that was considered normal usage. There were Plenty of fights on the service drive about that! lol

Wanna blame somebody? Blame the CARB and the EPA for the stringent requirements they put on ALL of the vehicle manufactures. They were (and still are) doing everything they can to reduce internal engine friction.

0-20W synthetic engine oil is as thin as water and as slick as pure silicone. Don't think for a second that shit doesn't just slip right on by the rings. And yet, the engine still has to pass a smog test! Round and round we go. It's a NEVER ending battle that is constantly being fought.
To be fair we aren't not talking about oil consumption issues here. This is a couple of ounces of oil in the PCV system. It did not get in the catch can because the oil got past the rings.

I can put that same device on any car and it will collect some oil.
 

rivermobster

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Anybody who designs a car with a liquid cooled alternator and requires you to program the car to change the battery can go blow themselves!
That would be tough since the company is owned by a woman! LoL
 

Cole Trickle

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Hard to tell how much is there but a couple ounces between oil changes with a di engine seem normal.

I have one on my g8 and the mustang and they both work.

Tried to order one for my 6.2 2020 silverado and nobody will ship one to me due to the ca no compliance carb bs...lol
 

pronstar

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The dudes running $500 catch-cans make me laugh.
Chevy truck forums are full of these idiots.


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