Hi everyone. I am hoping to find more specfic information concerning "proper" cam chain tension during installation on a N14 DOHC Turbo. I have the cam locating kit with all the required tools, pretension tool, crank and cam tools. I have found two specific ways to set cam chain tension while torquing cam/crank bolts. One is using the inch lbs setting per Bentley manual which does not provide much actual cam chain tension, second method is a specific length to set the cam guide tensioner tool. Note: the specific length method more closely matches the actual OEM tensioner as installed in a running engine. Also, Bentley does not reference the correct "rest" position of the Intake cam vanos sprocket and there is one, the dot must line up in the exact center of the machined "hill shape" machined area of the chain sprocket itself - appears to be very important to me to accurately time the cams. Please not, I have timed the cams both ways, hence my concern one vs another. I am not concerned about "cam chain wear", only accurate location of the cams during actual engine running condtions.
The major concern I have is the cam chain tension must be correct to position the Vanos sprocket correctly at rest due to it's spring tension within it's assembly. I have built many engines, some make a 1000 hp, some do not (only added this statement to reflect I have the ability to perform the task, machine parts to better perform the tasks, but no real information available to make an informed decision).
There are mods out there in other engine platforms to modify cam chain tensioners from losing applied tension. Every performance dohc motorcycle engine build typically gets a manual cam chain tensioner to prevent possible camshaft movement during engine rpm increase/decrease that can and will happen with a oil fed tensioner and increased valve spring pressures, oil viscosity issue or possible oil pressure loss for whatever reason. I see there is a updated cam chain tensioner, cam chains redesigned etc. What I don't see is anyone actually disassemble Vanos units or Tensioners to improve their performance, just parts replacement.
I purchased a '07 Cooper S, non running for cheap, rebuilt the engine, replaced all worn components (engine was oil starved at least once - hence the $500 purchase price for car). But, I have concerns with cam timing methods that appear conflicting and can cause assembly/running issues. I found during engine running the ECU appears to command a specific Vanos "setpoint" of 36, which I don't like assuming that is a "degree" setting of the cam in relation to crankshaft. Maybe it is. Also, I have concerns with excessive wear in the Vanos sprocket assembly allowing oil pressure to bleed causing incorrect cam timing - again it appear replacing parts as preventive maintenance is the norm. Maybe I am overthinking the cam chain tension preload, but I don't believe so. And I am thinking of contacting professional engine builders of these engines to see if they will share knowledge that they worked hard to obtain and may not what to share readily. Sorry for such a long winded post, but building engines correctly is paramount to me.

Thx!

 

not sure if I follow your issue, but the intake vanos sprocket has no orientation perse'. it is already preloaded and the oil pressure controls it.

you mentioned "cam chain tensioner" what are you referring to? the timing chain tensioner or the camshaft vanos sprocket?

newtis.info has also information that might help you get the engine back on its tires.

 

One of my concerns is how internal wear of the vanos intake sprocket affects actual cam timing. Its obviously a "controlled" oil leak system, meaning no seals to prevent leakage. Yes, I have disassembled one. A spring returns the sprocket to a "rest" position, oil pressure is applied via vanos solenoid/oil pressure created by oil pump regulated by ECM. Assuming the ECM determines location of camshaft relative to a specific requirement programmed with the table of the ecm. Just how precise is it? Seemingly not very precise based on TIS documents stating how to verify after timing camshafts. The use of feeler gauges and the amount allowed is not precise compared to use of dial indicators, very large degree wheels to improve accurate measurements in the world I usually build engines for.
So, oil viscosity, oil pressure and hot/cold running temperature can and will affect cam position. Cam position affects idle and off idle engine performance etc. I have found conflicting information concerning "correct" cam chain tensioners vs updated cam chain design. I am beyond that at this point - longer tensioner design appears to be used with redesigned timing chains.
I have personally seen and documented a vanos sprocket not fully return to rest position upon engine shut down and subsequent restart. Also, it seems the whole design lacks refinement. I find it unacceptable the allowance in the cams not returning to the exact timed location per the TIS documents, no wonder the engine has rough idle issues and yes idle is influenced by many other factors as well. It appears the industry has just accepted the design short comings and maybe adapted via tuning software. One of the few upper level engine builds documented uses "stock" vanos sprockets/soleniods/tensioners.
Seems tuning parameters aren't readily shared. I tune cars, mainly Ford products, diesel and "gasoline" engines and motorcycles and we share info readliy, so I understand the "big" picture here. This post generated no real design information, how much the vanos sprocket actually changes cam timing, does the ECM really constantly vary the timing and to what parameters relative to crank degrees.
I am most likely fixing this car to OEM level and send it down the road prior to other expensive items fail. This basket case was purchased very cheap, $3000 later in hard parts and specific tools - the lack of outright performance doesn't equal the effort unless a person is a diehard Mini fan or has deep pockets to replace high dollar items like HPFP, throttle body, cracked intakes and the need for carbon cleaning from DFI. The intent was to make a first car for a family member, but I have zero faith in the vehicle.
While I appreciate the dedication everyone has to the brand, just not my cup of tea. Good day to all. This should at least be an entertaining read.

 

Here is the official procedure for N14 engine:
https://www.newtis.info/tisv2/a/en/r...aft/1VnY7d2Xnh

Note, when you install the tension tool for locking down the cam bolts, the procedure says to apply 0.6Nm torque for proper chain tension.

 

I just replaced the head on my N18 (not an N14, but pretty close), and was dumbfounded when my BMW dealership tech buddy told me that the cam sprocket positions with relation to the cams did NOT matter. I am an experienced mechanic, and have done MANY timing chain and timing belt replacements, and there were ALWAYS reference points on the cams and/or timing gears. Some timing chains and belts I have done even had reference marks on the chains or belts themselves. When we dis-assembled the timing chain to remove the head (of course we locked it all down with the proper tools first), I also marked the vanos cam sprockets in relation to the cams and head, since I thought my buddy was crazy. LOL. Then the new/used head went on, and the reference marks were of course not on that head nor the cams. So.....once the "new" head was on and torqued down, and the engine was still locked with the proper tools, I noticed a "dot" on each of the cam timing gears/vanos assemblies. I aligned those dots in a straight up position, then tightened the cam gear bolts, of course using new bolts and proper torque and angle specs. I have no idea if that matters at all, but it made me feel better, and the engine runs just fine, no check engine lights or anything like that. As far as a preload before installing the vanos cam sprockets, I guessed at it, as I had no torque wrench that would read as low as .6 NM. I figured it was just finger tight. 500 miles later, and with an ill-advised intake cam swap since I was sent a later model head with the wrong HPFP drive on the end of the intake cam, all is well.

P.S. Did you know that each head and cam setup might use different rocker and valvetronic eccentric followers based upon measurements taken at the factory when that whole mess is put together? Yup, neither did I! LOL. Turns out that one of either 4 or 5 different numbered rockers and/or valvetronic followers may be used, depending upon measurements taken during the manufacturing process. Live and learn, they say.....

I believe the answer to the cam sprockets not having a reference point to the cam position lies in the "infinitely adjustable" cam timing, and on the N18 at least, that applies to both intake and exhaust cams.

 

Yes, I understand and reseached the "mini" 2nd generation engine designs (not a fan). Note: Vanos sprockets have a rest position relative to themselves only. Correct that the sprockets can be installed in any relative position to the cams after cams/crank are locked in place. The rest position of the vanos only sprockets is to ensure they are not damaged. I have found that the cam chain tensioner tool preload/procedure doesn't work very precisely. And that is confirmed by https://www.newtis.info/tisv2/a/en/r...mshaft/4SWA1nT
The fact that after timing cams and rotating the crankshaft 720 degrees, there is an allowable tolerance that translates to too much camshaft degree tolerance for me! I have timed a N14 twenty plus times using different preloads, the only time the camshafts return "perfectly" with no tolerance is to simulate the actual engine running cam chain preload. Others will argue, which means nothing as far as I am concerned. They are not building any engines for me with the allowable tolerances in the "newtis" procedure. In other engines I build we use dial indicators and large degree wheels to ensure cam timing is accurate, not multiple degrees off.
Each to his own - "your mileage my differ".

 

I'm not sure if this is posted in the right place but here it is. I have a 2008 mini cooper s clubman. It has a N14 engine. I'm replacing the timing chain. I'm following all the proper steps as far as locking the camshaft down etc. The problem I'm having is when I went to remove the crankshaft hub after removing both bearing bolts the top bearing bolts and both cam sprockets but the flywheel locking pin came out. I didn't realize this and turned the hub and flywheel. Now when I went to put the locking pin back in the hole in the flywheel cant be found as I turn the crankshaft bolt the flywheel moves to the left or to the right about 1/4 turn before it feels locked even with the pin not in but in the amount of space the fly wheel does turn there is no hole for locking the flywheel. What is the procedure with the camshaft locked with the embossed info facing up to turn the crankshaft to line up the lock pin holes. How do I make sure the crankshaft and the camshaft are in time with each other

 

If you're gonna be turning the crank and don't know the cams are closely synch'd, you better remove the cams THEN lock the flywheel. Only then will it be safe to install and lock the cams. Turning the crank with cams that aren't synch'd is a great way to bend valves. Be sure to use sprocket and crank bolts that haven't been torqued to spec.