*delete

[mainstreamer00]

Hmm, a couple things stand out to me from that report.

First, was the leak down test repeated after the cylinders were cleaned? The oil that was in there might have made the leak down numbers look better if it was helping seal along the piston rings.

Second, I would measure the pressure at the port on both airboxes before blaming anything. It feels like too many variables were changed at the same time to immediately place blame on the Karb box. Pressure numbers are indisputable and will tell you if the airbox is truly sucking in oil or not.

These are good point - I’ll follow up with them to confirm.

I appreciate everyone’s time and input here btw. Thanks!

[Slideways]

The airbox is currently with the car at the shop.
They mentioned that there seemed to be a slight different in the underside of the breather connection between airboxes - OEM/evolve has a scallop or indentation, Karb appears to be flat.
I can get photos or more substantiation here, but this will likely need to be vetted physically by Karb.
More curious about any QC issues or similar experiences especially given their new design at that time. Not questioning their quality/service either. I’ve had amazing service and products from them between their roof and airbox.

Yeah, their previous versions don't have those two teeth on the port which keep that vent hose from rotating. The main issue I saw with that port underneath was that the diameter was too large on one example and on another, the length was too short causing the line to be loose or fall out with the slightest bit of force. I mentioned this to them a few times, but all they said was that no one has reported an issue.

I'm not sure how that oil line being loose would cause this issue though. Maybe someone has a better understanding of how the venting system works in regards to that vent hose.

[Obioban]

I very much doubt the airbox is at fault here.

[digger]

normally the simplest answer is the correct one in that oil control is a problem with the valve stem seal, oil rings and/or honing, incorrect windage control etc. it would be very odd for the Karb box to create a low pressure region around the port on the OP's but not others. not impossible i would say (under certain conditions i.e. load or rpm combinations) but in the meantime i would block the vent to the airbox and just vent to atmosphere and monitor presence of oil in the chamber (as opposed to monitor in the airbox)

[R1pilot]

I agree that this sounds more a problem with the engine and not the intake, but why would the same thing have happened to the original engine?

[Arith2]

The airbox is NOT your failure. Many of us are actual subject matter experts and have been formally trained. We are not making uneducated points based on thin air. The airbox will not cause detonation or excessive blowby. This thread should've shifted away from the airbox at fault to figuring out what screwed up internally. This is classic case of bad piston rings or cylinders not getting a proper hash marking. It could be something else but this isn't an intake problem. There is literally no way the airbox caused this.

We want you to find the problem, not chase ghosts. If the engine was rebuilt again and doesn't have the issue, then it was probably a bad build or bad parts.

[jet_dogg]

Would love to find out what the cause of this is to see who's guess was correct.

Sorry to hear about this happening to op though sucks.

[sapote]

Taken from the recent report:

22. 17/03/21 Checked airbox found oil in bottom of the box. Checked catch can for oil residue. Found 1” of volume on the dip stick.

Any oil collected in the air box should already be drained down to the oil pan via the hose from dipstick to the airbox bottom, whenever engine turned off. Regardless how the oil got in there, there should be no oil after engine turned off.

[Cubieman]

Does anyone actually have a hose that attaches from the bottom of the box and goes to the dipstick?

My drain line simply goes straight down to the oil pan and every S54 dipstick I have seen listed online does NOT have the connection for the drain line. Doesn't mean much, just an observation.

[dl.m3]

Does anyone actually have a hose that attaches from the bottom of the box and goes to the dipstick?

My drain line simply goes straight down to the oil pan and every S54 dipstick I have seen listed online does NOT have the connection for the drain line. Doesn't mean much, just an observation.

My 2002 6mt is like what you described, tube directly into oil pan. But realOEM seems to indicate otherwise, and seems to show what looks like a check valve possibly? Into the dipstick tube

Sent from my HD1905 using Tapatalk

[jet_dogg]

Cubieman brings up a valid point, etk is often wrong in its depictions for whatever reason. Same reason why cdv doesn't show up in there intentionally.

Looking at both m3 and csl dipstick tubes there is no other aperture for a line to fit in to.

[heinzboehmer]

Does anyone actually have a hose that attaches from the bottom of the box and goes to the dipstick?

My drain line simply goes straight down to the oil pan and every S54 dipstick I have seen listed online does NOT have the connection for the drain line. Doesn't mean much, just an observation.

Yeah mine goes straight into the pan too

[Slideways]

Yeah mine goes straight into the pan too

His posts are sometimes confusing. They all have the drain straight to the oil pan, not the dipstick.

[Cubieman]

His posts are sometimes confusing. They all have the drain straight to the oil pan, not the dipstick.

Simply a reference to a link (in this thread) from realoem with a clear image showing the drain line attaching to the dipstick vs. what I've seen in person and online.

[sapote]

I was misled by RealOEM part diagram