Hey, trying to change timing chain tensioner for the newest one since death rattle started to occur. But for god's sake I can't loose the tensioner! Looks like somebody did it before me and overtightened it that it made the aluminium o-ring crush, or do they come like that from factory?
Applying force will chew the tensioner's head off quickly. Any tips and tricks to get the tensioner loose without causing damage?
Using 27mm 6pt socket. I think it should be 45 ft-lb, that should come loose quickly right? There is 100% something wrong with my tensioner and how its tightened!

Thanks in advance!

 

It's always possible that someone may have cross-threaded it. However, it's normally on there super tight, particularly if it hasn't been removed in a while. A swivel joint, socket and a long breaker bar will normally break it loose.

 

The tensioner of my Mini came off just fine. It did not require excessive force.

 

So I finally got it loosened up! So much force and muscles were used... the old tensioner broke apart in my hand, changed for a new updated one and rattle is solved for now, hopefully for a longer period of time. I also deleted the muffler on the hot side turbo piping.
I have to say, the car runs much smoother, not because of that muffler delete, but from the tensioner change. May be a placebo effect.

Thanks for the help!

 

No, you’re probably accurate in the results from the new tensioner. 4 out of the 5 rebuilds Ive done each had a tensioner you could easily compress with fingers. Chain and guides looked to be in good condition, but the tensioner was allowing slack due to a worn out/weakened tensioner. Im thinking a lot of the T-chain issues are a result of an out-of-spec tensioner. Chains don’t stretch and as long as the guides aren’t chipped or broken, it should solve the issue. Good luck.

 

The new updated tensioner solved the issue. No more rattle on cold starts and the engine sounds and runs much better. The chain and rails looked good, I took the valve cover to replace the seal for a new one. I still can’t believe that mini/bmw haven’t solved the issue in the n18 engine, though it was only n14 related. I have the earlier n18 engine made in late 2012. Now I have to find out why my oil is always getting dark brown just after 1500-2000 miles, is it normal? What can be the cause of this? It doesn’t smell burned, using 0w40 ravenol, ll-04 rated.

 

Technically correct, but (for a layman) possibly misleading. Chains wear with time, resulting in increased play and increased forces on the guides. If wear is excessive, the chain may even "slide" on the sprockets, resulting in unsynchronized crank- and camshafts.

 

So I also have an n18 that I suspect to have timing chain related issues. When cold, if I rev it to 2500rpm or so it sounds god awful, like the timing chain is buzzing/slapping around.

What were your symptoms? I ordered a new tensioner to replace.

 

Sounds about right, replace the tensioner. I had this symptom, the engine was lacking in power and struggling after 2000 rpms. I always waited stationary for the chain to adjust, then drove off. And keep the oil level between min and max.

 

Okay great! And yes, thanks. I check my oil once a week and keep it topped off.

 

How often should the tensioner be replaced?

 

So I use to race motorcycles and the chain stretched. I had to take a link out of the drive chain just about every year or two. Why was that if they don't stretch? Also there is place on a motor-cycle to adjust both sides of the chain for stretch and it used to be like monthly maintenance.

https://advrider.com/f/threads/chain...a-link.756139/

 

Chain wear is very real indeed. I too have first hand experience with it. But technically, no single part of the chain "stretches" (i.e. increases in length). Instead, wear of the bushings and pins increases the gap between them, allowing the individual links of the chain to be able to move further apart from each other than when new. The sum total of this increased play (when pull forces are applied) is what is commonly referred to as chain "stretch".

 

Does it make a difference? In both cases, the chain wears out.... The worn out chain, wears out the sprocket. The chain slips on the sprocket, the engine is ruined.

 

No, it doesn't. That's why I wrote:
"Technically correct, but (for a layman) possibly misleading."
in my reply to Texasmontego above.

Could it be that you missed that?

 

If your tensioner has starter to fail it is a good time to think about doing the chain and sprockets, (motorcycle or car) as mentioned above the chain doesn't stretch a lot as its not under extreme tension but will wear on your sprockets. When I completed my timing chain job after 240k KM I compared my Cam Sprocket, Vanos, Crank sprocket to old vs new and there was clear wear and the chain was even about a 1/16" longer then the new one. (I have read that anything greater then a 16th can result in timing jumping or being off enough to bog an engine. Or worse, bend valves)

 

I read it, but you're wrong.
https://www.yourmechanic.com/article/how-long-does-a-timing-chain-last
Read the article and especially what I highlighted out of the article.

I'm telling you that I raced motorcycles. Old makes used chains. Same with Minibikes. These chains connected a drive sprocket on the engine and one on the wheel. Literally right out of the Motorcycle manual from the manufacturer its said, "Over time your chain will stretch with wear". There were two screws in the back sprocket connected to the axle with a lock nut, you unloosen the lock nut, turn the screws clockwise so they pushed the axle longer on each side one time, it accounted for the length of the chain stretching, then you tighten the nuts back down. If you suddenly buy a new chain, of if you bought two chains and now you are replacing it with the 2nd one in the box after 4 years, you put the chain on and now it is WAY TOO LONG. Despite the sprockets being 100% the same as the old chain. You loosen both nuts and you have to put them ALL THE WAY BACK to where they were when you put this same chain in the package 4 years ago.

Now perhaps you know more than Suzuki Motorcycle, and the Your Mechanic Article, however, why put a "chain tensioner" on their in the first place. That is exactly what the chain tensioner does is automatically turn those screws that I used to have to turn manually. Still not enough-- ok, here is ANOTHER article. https://www.testingautos.com/car_car...-replaced.html

Here is how you do this on a to handle the same problem, chain stretch. I used pound out a link on the motorcycle chain which accomplishes the same thing. Now does that mean the chain isn't wearing as well, no it is wearing as well;however, the chain can be 100% tight on the sprocket between links the entire time. You can even take out a link and wear that all the way down to with very little effect on the sprocket. After that, it gets dicey.

 

There must be a misunderstanding:

I fully agree that chains wear and that they can (and do when in use) be stretched to longer length than when they are new. I have first hand experience of this as I have changed several bicycle chains in my life due to this. I even use the term "stretch" myself to describe the wear of a chain.

It was Texasmontego's post above that left the impression that chains do not wear (or any wear has no effect on the operation of the engine). I didn't want ill-informed readers to pick up that statement and take it for granted. So I responded to his post explaining in a more technical sense the process of chain wear. And it really is the case that no individual part of the chain gets longer but instead the play (due to material being worn off) between parts increases the length of the chain when pulled apart (!).

PS.: The sites you link to do not go into depth on how a chain wears and the effect wear has on the length of the chain and how forces are transferred from the chain to the sprockets. Here is a better, illustrated source of knowledge. It deals with bicycle chains but the principles are the same:
http://pardo.net/bike/pic/fail-004/000.html

 

Ok, that's fine. Whether the roller pins wear, (thus causing the chain to stretch) as the article you just linked or whether the "EXACT mechanics are immaterial" (my point) and so thus the end-result is the chain stretches, the end result is the same. The total length of the metal chain with fixed links stretches. Stretches as in "becomes longer" than the original length of the chain when new. A longer and long chain eventually exceeds the ability for the tensioner to account for the wear and then the engine blows up.

BMW Mini says the timing chain on the Mini Cooper is a "no maintenance" item which in a properly maintained car will last the LIFE of the vehicle. I think I called the service support technician here about 9 months ago and that is about his verbatim quote. This is a lie and anyone with a bicycle chain to a motorcycle or lawn mower drive chain (old fashioned) needs to realize that BWM is crazy for advertising this or believing this (which they still do, to the best of my knowledge) unless they are telling us the life of the engine is under 100K miles. Someone needs to sue them into the next century over it. Plenty of cars and engines that will outlast the Mini Engine with metal timing chains that will last a long time, longer than the Mini engine, but I don't know any of them that tell you they will last forever and never even have to be "inspected". In fact, I've owned Toyota and Honda and all of them have "inspections starting typically 75-120 K miles. This use to be a routine problem with Nissan engines as well.

 

BMW has released instructions on how to measure chain wear and even provides tools that indicate whether the chain has to be replaced:
https://www.newtis.info/tisv2/a/en/r...aft/1VnZ6aRFHk

 

Or there is this tool for checking the timing chain status. This tool also comes with most of the cam lock kits.

https://www.fcpeuro.com/products/min...waAux4EALw_wcB

 

Well my mini master service technical here at Austin-Mini says it is not required...I think that is my point. I guess technically it is not Mini because I believe they outsource their service to that national chain who I can't remember right this second.

However, what are you using to manual crank the engine.with the plugs removed? I'm guessing that is another tool to buy for that right?

Eventually I will pull my value cover off and take a look because I think the normal (51+%) failure point from my reading is the top chain guide starts failing (or disintegrates) and this test as I am seeing will "NOT" necessarily see that problem. Well unless it has completely disintegrated already or the looseness is why it rattled to break.. However, I think that part could still fatigue fail with "chain length" within tolerances and cascade an issue. I'm not sure I trust that procedure as to anything significant. I really think the weak issue/fail issue is again the use of excessive plastic (it looks like teflon from pics I have seen) in the car. I don't believe that the chain length ALONE is the problem.

 

@mini-is-for-me you can manually rotate your engine by removing the front right tire, where you will gain access to your crankshaft pulley (that connects to your AC pump and various other parts. In there you will find a (I believe 18mm bolt) you can then turn this bolt which rotates the crank, and the cams.... 1crankshaft rotation = 2 camshaft rotations.
No special tools required to rotate the engine, it should rotate smoothly with out the plugs in it, make sure to rotate it the correct direction clockwise not counter clockwise.
(more info here https://www.northamericanmotoring.co...e-by-hand.html)
I recently did a timing chain in my car, and it wasn't the top chain guide that had failed, it was the cassette that had broken at the bottom where it sits just above the crankshaft sprocket.

 

I can confirm that if the three bolts on the crank pulley are tight, trying to turn them results in the crank being turned.

(For me it was a pia to get the crank pulley to not turn so i could fasten/unfasten the bolts.)

 

To lossen the crank bolt, you will need to either get, or manufacture a special tool. I made mine out of a piece of 1/4" flat bar, drilled out the center, (big enough to let my 18mm socket through) then 4 holes that line up with the pulley hole layout, then use your pulley bolts to fasten your tool back in place, brace it against the engine, and then either a 24" extension and 24" breaker bar, and a lot of muscle and puckered buttholes later it will come lose... I went through the top after removing the engine mount on that side and found that to have less pucker factor.

Tool looks like this https://new.minimania.com/part/G2NME...l-Gen2-R55-r61

I made one, that was much shorter and cheaper, and worked great.