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First off thank for the massive amount of information everyone has contributed on these forums.
Acquired a broken 2009 MCS. Timing had slipped and bent valves. New valves, chain, guides, head gasket, etc.
Since it was put back together it idles poorly, runs smooth off-idle, but once warm loses power, backfires and is generally not okay.
Has air/vapor coming out the oil fill cold or warm, have replaced valve cover, twice. Rear PCV pipe is deleted with plugs on both ends. Smoke tested to verify no air/vacuum leaks.
Compression is 180-ish across all cylinders.
With the air/oil vapor coming out it's obvious that the PCV is actually not working or we have massive blow-by. The compression doesn't support blow-by, but everything is the same with a new valve cover.
Anyone have suggestions on what to check/test/replace next on this?
Did you replace the valve cover? If so, I would not plug the rear PCV. If everything is working as designed, that helps with crankcase pressure.
That being said, engine operation sounds to me like timing is slightly off.
Bo_9, I just had the same problem with the 2009 N12 I restored; The engine had misfires in cylinders 1 and 4 due to dropped valve seats. The mistake I made was I skipped the "check timing" in the disassembly instructions of TIS (technical information system); I didn't think I needed to "check the timing" since I was disassembling the engine and was installing a lot of new components.
Here's the catch on the check engine timing part of the manual. After installing the pin in the crankshaft and before installing the camshaft locking tool, there is a note that tells the tech to attempt to rotated the VANOS adjuster (the sprocket) center bolt. With no oil pressure, the VANOS adjuster should be locked so there is no relative motion between the sprocket portion that is driven by the timing chain and the center hub that is bolted to the camshaft. If there is movement in this step the VANOS adjuster must be replaced. The reason replacement is required is that during reassembly, if the adjuster center hub moves when you tighten the center bolt, your timing will be off.
In my case, I failed to make this check and installed the old VANOS units; the engine ran OK, but I knew something was off; I pulled up the VANOS adaptations on my diagnostic tool, and I was at 12.5 degrees. Afterward, I ordered two new VANOS adjusters from eeuroparts.com and went back to the "check timing" step. Both of my adjusters were shot. I installed the new adjusters, set the timing by the book, rotated the engine, and rechecked the timing ... good to go. Then I cleared the VANOS adaptations, eccentric shaft adaptations, and fuel adaptations. If I remember correctly, the exhaust adaptation range is 140-160. I'm running at 153. Intake range is from 40-60; I'm running at 53. The engine runs much better now, and my smooth running values are near zero for all cylinders.
Oh! Another thing that caught me off guard with this restoration project was the valve lifters; I found several that were stuck and almost all of them were not within height specs; I replaced all the lifters, and valves.
The note can be a little confusing ... I think that's due to the German to English translation. Bottom line, when you try to rotate that center hub bolt with the crankshaft locked; there should be no movement. I had several degrees of rotation with my old adjusters, and zero movement with the new ones.
Finally got back to this project. Cam was not locked when we pulled the valve cover. Rotated about ten degrees and locked with no movement. I'm assuming that it should be locked when shut down. Ordered VANOS gear, solenoid, and bolt also installed the correct hoses to put the rear PCV back to stock.
The vanos solenoid is in the back of the head on the passenger side....... when that oil port is clogged the vehicle runs like crap.....oem is the way to go......
Older design has no screen, newer ones do. Some people don't change the oil and do the long intervals. Coaking in the oil can happen and even clog the screen version. Also cheap filters can do this,, no name filters can lint and clog it. Screen version below.
VANOS solenoid had a screen on the middle section only and it was completely full of crap so changed that it.
After putting in the new VANOS gear we find that the crank locking pin drops in in two spots 180 opposite each other both with the pistons flat, all in the same position. What's the best way to tell if we are 180 out, or does it matter?
Success!
All kinds of nastiness in the VANOS solenoid and as previously mentioned the gear was never locked in place when checked it. So replaced both and it's now an amazing little engine and this thing is an air-conditioned go-kart!
Kind of an annoying thing to work on occasionally but well worth the result.
Eww
Last edited by Bo_9; Jul 9, 2023 at 09:34 AM.
Reason: Spelling
...And now after two days of joyous madness driving this insane go-kart we are getting an at-idle oil pressure warning.
I'm first going to assume that since we have not changed the oil since we began this adventure (maybe driven 200miles) that the filter is fill of the crap that comes out when you have this stuff apart and will do a change, check the spring etc in the filter housing, and then put the external gauge on and check actual pressure. If it's fine will change the Oil Pressure Sensor and run it.
While I am not experiencing this issue, I read through this thread with curiosity. I coursed through elation (vanos solenoid replacement remedied the issue) and wonderment (new issue with oil pressure) without a final conclusion.
Did changing the oil solve the low oil pressure issue?
After the fresh oil and filter we drove it for probably six hours over two days with no issues, then on day three our local temps were 90 to 100F and the low pressure warning came back at idle after about 2 hours of driving.
Found that my pressure test gauge set did not have adapters for the sensor size. Should have the correct size adapters today to see what the pressure actually is once it gets good and hot. If pressure is actually low, plan is to pull the oil pan and see if the pump screen is full of gunk again (we cleaned it when we had it apart getting the plastic bits from the timing chain guides out). From the looks of the oil filter we took out after 200 miles there is still a lot of crap in the engine.
Pull the valve cover and clean out anything their if its bad before the flush. Some people just replace the valve cover as its too much to clean it, not worth it. We have lower cost options and Metal Upgrades now.
Some N14 engine with build up that needed cleaned below.
On the oil pan / oil pickup, yea going to need to clean that also.
The oil pan can be a little of a pain if its sealed with sealant, we have aftermarket options (like 1/10th the price of Genuine MINI) now which make it easy as you can bend the flange on the pan when you remove it with sealant.
Finally got the correct adapter for my pressure gauge (mine was M16x1.5) and after letting it get good and hot pressure at idle was down around 10psi. More troubling is that the highest it got was 20psi even at 5k rpm. So our thoughts are either the pump screen is so full of crap it can't suck enough in to make pressure, or the pump is just done.
Has anyone ever seen the pressure control valve stick in such a way that causes low pressure? From what I've read it usually fails closed and causes high pressure.
Just scary low oil pressure. Once warm only about 20psi across the rev range and barely above 10psi at idle. Nothing above 30psi when cold.
Vacuum and all that have been fine since reverting the previous owners PCV modifications.
Okay, oil pump screen not full of stuff, but chain REALLY loose. Also realized that N14 doesn't have the oil pressure control valve.
So I guess we'll be ordering the pump, chain, gears. The downside it having to re-time again.
Any other (non-oil filter housing) things that could cause low oil pressure we should check while we have things this far apart?
Is it worth disassembling the pump to see if it's full of gunk or plastic from the chain guides internally?
