Lets play a game - What is causing my oil consumption?

[TurboTapin]

Freshly built stroked RB25/28. Motor runs great but consumes a lot more oil then It should. This summer with the heat I was consuming roughly a quart per 1800-2000kms. Now with the cold weather coming in, I'm consuming a quart per 1000kms which is no bueno. I had originally chalked this out to break in taking a little longer then it should, but I'm now around 4000km's on this engine. I think it's fair to say something isn't quite right.

Here's the kicker, can't find what's causing it. I've also spoken to my engine builder and Precision Turbo and can't figure it out. Here's my train of thought on possible causes and what I've done. 

Precision Turbo - I originally started thinking my oil pressure might be a tad too high for my 6466 Gen2. I took the center cartridge out, and while yes there's signs of oil on the turbine heatshield, it's very moderate. There's also very minor in/out play that concerns me. I sent pictures and videos to precision and they said the residue and in/out play is minimal and they doubt this is the issue. For piece of mind, I went ahead and installed a Turbosmart OPR V2 to bring oil pressure down. Made no difference. Precision is willing to take it in on RMA for an inspection and I'll probably take them up on that offer for peace of mind. BTW. Is it just me or does the turbines inducer's look clipped and not even between each other? I just noticed this now while posting and looking at the picture zoomed in. Might just be the picture... 

Rings - Hot compression test and leak down test look good. Compression is 160 +-2psi across the board. I leak down at 16% on cyl 1,2,3,5,6 and 18% on cyl4. Keep in mind I have a snap on leak down tester and they read high (I.E, 15% on my wifes 2018 Sentra with 70000kms). Sparkplugs show minimal oil (Only #4 seems to have a tad). At a quart per 1000km's though, I would be expecting them to be wet. Here's the kicker, I run WMI. I'm thinking what if my compression rings are great, but I have an oil control ring issue on cyl4 and my WMI is steam cleaning the pistons and sparkplugs? I can still see the "Spool" logo on top of my CP pistons. The only time I see smoke out of the exhaust is in the high rpm/load range. So far, this is my main culprit. I'll probably turn off my WMI and go out with the car at spring pressure tomorrow and repull the plugs. Other thing that's strange though is that I have never seen any oil in my catch can. Thing is still dry after 4000kms.

Cyl1 - Left, Cyl6 - Right.

Valve seals - They're new and I would expect oil consumption on idle, first cold start or during decel. None of which is happening. 

Crankcase pressure - I have 2x 10an valve cover lines to a vented catch can. Head drain and opened up internal oil drain paths. I also don't run E85. I've never seen any oil in my catch can. Doubtful this is causing any issues. 

Rear main seal - I have no visible leaks, but figured maybe it was my rear main seal. After now having added 2-3 quarts, I would expect oil to leak out the bottom drain channel and/or my clutch to be slipping. 

Let me know your thoughts. With winter coming and taking the car off the road until spring, I'm fine with pulling the motor apart but I would hate to take it all apart and the turbo was the issue in the end. 

 

Edited October 6, 2024 by TurboTapin

[Dose Pipe Sutututu]

Had to google what a quart is lol.. so rough as guts a litre.

That's a bit excessive, also what oil weight are you running?

The whole steam cleaning idea isn't too far fetched either.

Maybe as you suggested, turn off the WMI (assuming your Kebabtech pulls timing, boost, etc.) and run it for a bit and see if there are any noticeable changes in spark plug colouring.

[TurboTapin]

9 hours ago, Dose Pipe Sutututu said:

Had to google what a quart is lol.. so rough as guts a litre.

That's a bit excessive, also what oil weight are you running?

The whole steam cleaning idea isn't too far fetched either.

Maybe as you suggested, turn off the WMI (assuming your Kebabtech pulls timing, boost, etc.) and run it for a bit and see if there are any noticeable changes in spark plug colouring.

Haha yea sorry, metrification happened in Canada around the same time as Australia but I'm still stuck somewhere in the middle. I run my WMI ON/No fault condition as 4D for my ignition/fuel maps and boost levels. No dangers running without, I tuned both like you would with E85. I'm running conventional Driven HR1 15W50. I always wondered where the Kebabtech reference comes from for Haltech? 

So I ran without WMI for roughly 30kms today, plugs look the same. Hmm. I would expect them to be wet with that much oil consumption. The mystery continues... 

 

Edited October 6, 2024 by TurboTapin

[GTSBoy]

Haltech -> Halaltech -> Kebabtech, particularly given Haltech's physical and usage location coinciding with the Lebanese population concentration in Western Sydney.

[TurboTapin]

Continuing with my search, I started wondering why my catch can never has a drop of oil in it... I've never had a motor, especially a looser built engine have zero oil in a catch can. I find it even more odd as there's clearly oil vapour coming out of the catch can ventilation filter when the engine is idling, let alone running hard (My car smells like an old oily rag). 

I run an ATP catch can that fits nicely into the ABS spot. I decided to take the inlet filters off to see the inside baffling. Nothing, nada, completely open. Ok ok, so that's not entirely true... I shine light into the AN ports and i cannot see it coming through where I removed the filter. I'm thinking they welded in a plate in front of the AN ports to act as a baffle between the ports and the rest of the catch can. 

The catch can filter itself was saturated with oil and yet none in the catch can... makes me think that small baffle plate isn't doing much. Maybe my oil consumption is actually blow by and it's just venting out the catch can into the engine bay as a fine mist. Like I mentioned above, there's visible fumes coming out of the can/filter at idle so the engine is in fact breathing but catch can is well.. not catching. I always filled my other cans with stainless steel wool to trap the oil, so I'll go pick some up tomorrow and do the same. If I see the catch can does start to fill after this, I'll look into upgrading my valve cover baffles. It's a stretch, but I'll try anything at this point. 

Edited October 7, 2024 by TurboTapin

[TurboTapin]

2 hours ago, GTSBoy said:

Haltech -> Halaltech -> Kebabtech, particularly given Haltech's physical and usage location coinciding with the Lebanese population concentration in Western Sydney.

Aww, thanks for the explanation! I'll sleep smarter tonight. 

[Dose Pipe Sutututu]

7 hours ago, TurboTapin said:

plugs look the same

Very even markings on the spark plugs, looks quite healthy to me.

I may have missed it, however is your sump and catch connected? If so, perhaps block off the sump to catch can vent/drain and see if you get less oil consumption.

(Assuming the oil vapours have a bit more time to catch along the oil galleries/passage inside the motor and not continue as vapour out of the cam covers).

Worth a shot, I have a ball valve on mine so when I'm not beating it at the track the sump/catch can drain/vent is blocked off.

[TurboTapin]

11 hours ago, Dose Pipe Sutututu said:

Very even markings on the spark plugs, looks quite healthy to me.

I may have missed it, however is your sump and catch connected? If so, perhaps block off the sump to catch can vent/drain and see if you get less oil consumption.

(Assuming the oil vapours have a bit more time to catch along the oil galleries/passage inside the motor and not continue as vapour out of the cam covers).

Worth a shot, I have a ball valve on mine so when I'm not beating it at the track the sump/catch can drain/vent is blocked off.

Thanks. I agree, looking at those plugs in conjunction with good compression/leak down tests I'm not too certain its ring related anymore. 

I have a Swagelok ball valve on the drain and tubed it lower down to the left side of car to easily dump it into a container. I do not drain back into the sump. I've never had to drain it though as there's never been any oil in it. 

[Duncan]

Mostly likely it is blowby....past the rings, through the crank, straight through the catch can and out the breather so there is no evidence it ever happened.

I know the compression test was good but that is really the only way to loose oil without any (much) evidence, assuming nothing is plumbed back into the intake of course.  It would be interesting to see if the cold compression test is much different as that could be when it is getting through the rings

Still....just fill it up and keep going if it makes good power, a lot of higher power RBs are built with loose piston clearances and use a bit of oil as a result

[TurboTapin]

6 minutes ago, Duncan said:

Mostly likely it is blowby....past the rings, through the crank, straight through the catch can and out the breather so there is no evidence it ever happened.

I know the compression test was good but that is really the only way to loose oil without any (much) evidence, assuming nothing is plumbed back into the intake of course.  It would be interesting to see if the cold compression test is much different as that could be when it is getting through the rings

Still....just fill it up and keep going if it makes good power, a lot of higher power RBs are built with loose piston clearances and use a bit of oil as a result

Compression test is good. Leak down is same across the board but could be lower. It's a loose engine, I specifically asked my builder to build it on the loose side as I was planning on running 35+psi. I'm also growing more convinced it's blowby. My engine builder wanted me to do the good old oil in cylinder then compression test to see if it goes up so I'll go ahead and do a cold, hot and hot with oil compression test to see. 

I also went ahead and filled my catch can with stainless steel wool to see if it accumulates anything now. I'll report back in 200-300km's. 

[Kinkstaah]

My gut feeling was also blowby, it is absolutely crazy when you see how much engines actually breathe when they run a lot of boost or are heavily modified. If you can ever see a motor on a dyno it's pretty crazy, full on steam train action.

I thought I was going crazy when filling a 500ml catch can in one 20 minute track session, or maybe two. It's been awhile. But then I saw how much _worse_ it is with harder running engines and I was pretty shocked. In any case I would definitely use more than 1L in 1000miles with that kind of load going through it :p

It going nowhere.... is... unusual

[blind_elk]

Can I suggest a 15W50 oil is too heavy. Its a brand new engine - you should be able to run something like a 10W30.

Shove some steel wool into your catch can  - more technically "oil/air separator" - so that the oil vapour has something to condense on.

[Dose Pipe Sutututu]

2 hours ago, blind_elk said:

Can I suggest a 15W50 oil is too heavy. Its a brand new engine - you should be able to run something like a 10W30.

I am going to chime in here and say that is very bad advice for a built motor, making decent power of 400kW+

Especially if the rings have been gapped on the looser side. The more power you make the heavier you need your oil to be to be able to maintain that suspension between the moving parts, if not you'll have journals and bearings making love and grenade a motor.

Remember that all moving parts inside the motor aren't ball bearing and are journal bearings and require oil to separate the surfaces from contacting.

[TurboTapin]

6 hours ago, blind_elk said:

Can I suggest a 15W50 oil is too heavy. Its a brand new engine - you should be able to run something like a 10W30.

Shove some steel wool into your catch can  - more technically "oil/air separator" - so that the oil vapour has something to condense on.

Like @Dose Pipe Sutututu mentioned, 10W30 on a built motor would not be a great idea. As for the steel wool, we think alike as I went ahead and put SS wool into my catch can as per my above posts. 

[tsuokun]

Any updates on this?

Although not a stroker, nor built especially loose, my car has the exact same symptoms. Although I feel they were not there to begin with. Since rebuild with forged parts I have done about 40k kms and it feels like during the last 15k or so, the oil consumption has gotten progressively worse. 

Compression test showed - what I thought at least - similar 10-10.5bars in each hole without oil. I have not yet done blowby test though, due to limited garage access. #2 plug is the looks the most foul and that was the one with 10bars.

Nothing in the breather tank. I only recently disabled PCV and left only the hoses running from the valve cover via smallish tank to turbo intake pipe there and did some mildish 2nd gear pulls so the car was definitely on boost (1.4bar or so). Removed a hose from the tank and it was basically dry - meaning, the wipe I used had basically no oil on it. Last time I checked, the turbo and IC piping seemed dry as well (will have to see about that again after those pulls).

For the past year and a half though, the car has been driven like a granny would for 99.99% of the time, since it mainly serves the purpose of carrying the family around nowadays. A lot of slow, stop and go city driving and most of the trips it barely sees any boost, but gets up to temp properly every time. Although there can be weeks it is not started at all.

The car does not smoke, or at least not that I can see. (CAT is in place though). There is slight visible sweating at the Ex cam cover seal and I recently tightened the oil cooler lines as there was some mist on them too. It runs and idles extremely nicely and feels all around healthy.

Like TurboTapin, I too am suspicious of my turbo. I have had IC pipes pop out from 1.6-2bars of boost a half a dozen times during the years. The turbo is a HX35/40 hybrid.

So, a very similar mystery. Around 1500kms and a litre of oil surely cannot disappear to thin air. Apologies for the wall of text, not sure if any of the above is useful for best guesses/things to check next.

 

[tsuokun]

Put an endoscope down the hole and saw this. Not quite all around the bore but a good 60% at least.

Chin to the chest and towards further disappointments I guess.

[GTSBoy]

Oh, that's grim. Something bad has been happening there.

[Dose Pipe Sutututu]

The last few photos nearly look like rust from the motor sitting around for ages, however I'm semi colour blind so that doesn't help lol.

[joshuaho96]

13 hours ago, tsuokun said:

Put an endoscope down the hole and saw this. Not quite all around the bore but a good 60% at least.

Chin to the chest and towards further disappointments I guess.

To me that looks like a rust ring in the bore. An engine that has sat for too long in humid conditions without fogging oil in the bores?

[GTSBoy]

Yeah, I wasn't giving two f**ks for the ring running around the bore. I was looking at the vertical scratches running up and down across the hatch marks.