Hello!

Posting this for my dad who is currently working on my mini. Apologies if the info is complete mostly just wondering if anybody has experienced this before.

2010 S Clubman

So one of the valves in the 4th cylinder cracked so we had that all re done nicely. He decided to replace the timing chain and tensioner since he had it all in parts. Current problem is that he can tighten all the bolts associated with the timing chain and it'll run fine for a bit and then it will get loose and go all out of whack. It may shut itself off, but if it doesn't and he turns it off then it won't start. So he has to take it all apart and retighten. Apparently, it is the camshaft sprocket bolt that loosens up losing the tension on the chain. He has tightened these things to the torque specifications of SEVERAL different online videos, guides, and mini specs but it just keeps happening. Kinda getting sick and tired of it so was wondering if anybody has had this happen or can think of something he isn't?

P.S. when it does run, it isn't misfiring anymore and it sounds better than ever!

Thanks in advance.

 

Do Not Drive It Anymore Until You Get This Figured Out. If the chain slips enough you will bend valves.

Did the tighten the crank bolt to the specified torque (50 Nm or 37 ft lbs) and then tighten a further 180 degrees?

if not it will slip.

 

Hello! He has not been driving it. He just runs it once he tightens everything and thinks it is ready to go. It'll slip while parked. He has tightened to several torque specifications trying to find the one that won't make it slip. Would you mind sharing your specifications for all three bolts just to see if he set them to those yet?

Thanks!

 

For some reason I cannot attach pictures so here is the text.
Hub to crankshaft Bolt: Oil threads lightly, 50NM, then 180 degrees
Vanos (intake) 20 NM then 180 degrees
Exhaust 20NM and then 90 degrees.

This is for the N14 engine. Might be different for the N18.

 

N18 is the same except for the exhaust cam. Ot is similar to the intake of 20Nm plus 180 degrees.

Can you/your father tell which sprocket has come loose?

 

I forgot to say. You must use new bolts each time.

 

yes it is the rear intake cam
this car is N14

 

thank you! and yes he is using new bolts every time especially since he keeps breaking them.

 

Breaking them? Huh?

 

Yes.
Here is a video.
He can line up the camshafts so that the numbers all line up pointing upwards. But the intake one has like a little bit left of the turn that it can still go (but the chain doesn't move when he adjusts). He can adjust them so they line up. Get everything running and when he turns it off and opens it up again, the rear one has slipped back down and forwards that same quarter turn. You can see in the picture. The red stayed up but the green one is lower. When this happens, the intake bolt is loose.

 

Here is a link to the video
https://drive.google.com/open?id=19a...Ivdj-jwS1Ian-7

 

First of all don’t use vice grips on the cams like that. You are creating a spot for the cam to shear and making metal shavings.

Are you using the Vanos dummy plug torques to like 5 nm (3 pounds)? I can’t remember but it’s really really low. If it is too tight it will do exactly what you are seeing.

During my first attempt I did not get the vanos seated correctly and the bolt loosened up. Make sure it is perpendicular to the intake and seated correctly when torqued.

 

Here's a link to a very detailed cam replacement procedure, for my '07 MCS --- https://www.newtis.info/tisv2/a/en/r...aft/1VnY7d2Xnh --- It includes all the info you need to set / adjust timing. Note that the vanos dummy plug torque spec is 0.6Nm which equates to about 5 INCH pounds --- much less than most small torque wrenches go to. Chances are, you've been tightening it too much, like jjcsnlynn suggested, causing all the grief. It's really important that things be installed and tightened as described in the procedure. And, just to be sure you use the correct procedure, go to the newtis home page and enter the last seven characters of your VIN --- just in case the '07 procedure is different from the '10.

 

I never thanked you. He was missing one step, the locking the cam bit. All good now! On to other problems. Thank you!