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Flip or Flop...Well, it is a flip ---> N18 Edition
I went another rout on this. I'm usually hunting for N14s but this one was the first for this kind of work. So I picked this nice 2011 MCS from the auction as Inoperable (no start no run).
I got the car delivered and started hooking it up to read errors. two codes appeared for intake and exhaust cams sensors. So, I swapped them and the codes came back. The car cranks but does not start. So, I figured, let's move to the next step and take the valve cover off
well, this speaks volume....lol...I'm surprised that N18's can potentially have a timing chain failure! The next couple of days well be checking compression and installing a new kit.
Just an FYI, a super easy way to check hall sensors without running the engine is to apply power as usual to the sensor, put a piece of steel (stainless might or might not work, not sure) near the sensor's face, and see if the signal changes. Depending on the sensor, it will be 0v with or without metal and 5v the other way.
More of the broken chain...Also took the front main seal. Today I put the new kit and main seal. Took the oil pan down and cleaned the pump from broken pieces. Sealed it and put it back to dry. Tomorrow should be interesting :-)
Yep, it can happen on the n18 but not as frequent as the n14. The upper T guide part can wear and break off that causes the chain to have some issues. Thats my guess. Lets hope it did not bend anything.
Yep, it can happen on the n18 but not as frequent as the n14. The upper T guide part can wear and break off that causes the chain to have some issues. Thats my guess. Lets hope it did not bend anything.
When you say bend i assume your referencing valves correct? I am under the impression that if the timing chain snaps becomes broken then the valves in the head would bend and have to be replaced upon the repair of the timing chain.
MiniToBe, have you looked at the cylinders and valves with a borescope? Or at least done a compression test? I know you know what you're doing, having rebuilt a few of these. Do you have reason to believe that the valves are OK, or are you just going to fire it up and see what happens?
MiniToBe, have you looked at the cylinders and valves with a borescope? Or at least done a compression test? I know you know what you're doing, having rebuilt a few of these. Do you have reason to believe that the valves are OK, or are you just going to fire it up and see what happens?
I did not use a bore scope as the one I have isnt the best. but here are the things I did:
1- visual inspection of the rocker arms (all were making contact with the lobes).
2- after cleaning the mess and after locking the camshafts, I spun the engine and was getting pressure on 1 and 2.
3- since the piston design was different than N14s in such that those have impressions on the exhaust side as well. I felt this engine could be a non interfering engine.
4- I deduced that once the chain snapped, the camshafts automatically closed valves (or at least pulled away for the lack of better terms) and the valves were unharmed.
let's take numbers
once all were sealed up and fresh oil was poured, it was a cold/dry start and the numbers were 120 120 130 140...The numbers led me to believe that valves are not bent (at least to let me move forward with getting this car running)
after pumping quick start and numerous tried to start it finally----------STARTED lol but the happiness was short lived :( it runs for few seconds and then shuts off. I plugged my million dollar tool, and noticed the rail pressure was no more than 4.5MPa...I bought a HPFP and will swap it and see if that fixes this issue.
I bought a used one which came out off of a wrecked mini for $65. I'll try it amd see...i also have another running N18 engine i can take the pump out of it. Not a biggie
You have compression so it looks like something lucky happened. Yes there's indents in the pistons but that just allows for a bit longer valve open time, it isn't enough to save the valves if the cam has them open when the piston gets to the top. Last year the timing belt on the Subaru decided to give up while I was doing 70 on the highway, bent the valves on 3 out of 4 cylinders and that was far from a high performance engine.
Anyway, it looks like a happy ending so far as the valves and head are concerned, excellent.
After the first start, the car would always try to start and eventually start. it would idle fine but once i push the peddle, it chokes and dies.
Connected the diagnostics and started looking at numbers and clearing codes. One code kept coming back relate to the intake camshaft!!! I replaced the Vanos and the code still came back.
finally, I pulled the valve cover out and what a site.....the intake camshaft was maybe 30 deg retarded. I did use the locking tools the first time and was spot on!!! what happened? At any rate, I readjusted the timing and put buttoned everything up. I started the car and it didnt even hesitate a second. it fired right up and no lights are present (at the moment).
Once I sell the convi, this will be hitting the road
There's a locking pin in the phaser, so that sounds like what is fighting you. You'll need to make sure that it is in the correct position, too. This problem kicked my tail for two days when I was working on an N20 that has the same setup (I think). I was doing the software and the engine builder swore there was no such locking pin, but we kept seeing that behavior where the engine would park at a different timing after it got enough oil pressure to move the locking pin.
you mean the VVT gear/sprocket? there is a mark on it but not in reference to the camshaft. I did over 10 N14 rebuilds and never once "moved" on me. any angle of the sprocket would be fine, but I always try to match was was before.
The VVT setup is completely different between the N14 and N18. BMW started implementing a feature where the phase of the cam could be locked when the engine was running so it could be phased when cranking again before there was normally enough oil pressure to phase it. This allows faster and easier cranking for start/stop.
This is all on the fringe of my understanding since I fought this problem on the electrical side. I was contracted to a race team at the time, so it was someone else's job to turn wrenches and I didn't see what exactly was done. I'm also assuming the VANOS is the same hardware between the N18 and the N20. The headline features are the same, but I haven't seen exact details. I'm just hoping I can give you a starting point (and to let you know you aren't crazy since it is possible the timing did change on you!)
1-location of the car
2-time of the month
3-overall condition and options
4-mileage
5-history if available
in some deals, I run thin margins which might not be feasible for a dealer. It took me three years to get where I am right now and for sure this site helped a lot. desire is something needed, but you also need tools (including bmw/mini software) and patience. some cars stuck with me for a year because the color wasn't that desirable!!!
at any rate, you can PM your specific plans, and I can share some insights
1-location of the car
2-time of the month
3-overall condition and options
4-mileage
5-history if available
in some deals, I run thin margins which might not be feasible for a dealer. It took me three years to get where I am right now and for sure this site helped a lot. desire is something needed, but you also need tools (including bmw/mini software) and patience. some cars stuck with me for a year because the color wasn't that desirable!!!
at any rate, you can PM your specific plans, and I can share some insights
05-11-2018, 05:19 AM
