'10 Mini, JCW Coupe, R56, N14, yadda yadda.

TL:DR: Can the oil pump chain make an awful racket?

This past week during cold startup (30-40DegF outside) a very loud rattling was present while revving through certain RPMs (in motion, or stopped). Symptoms subsided when the motor was warm. With the car stopped in place and a partner helping with the accelerator, we recreated the noise and with my hand on the valve cover, there was significant 'shaking' from the passenger side (on the portion of the cover above the vanos unit.

This noise was loud enough to mimic the sound you'd typically hear from an exhaust heat shield, but it was coming from around the timing chain it seemed (great!).

I've previously replaced the timing chain (20-30K mi ago), and recognized the pattern of symptoms (did not replace oil pump chain at that time). So I pulled everything apart to have a look at the timing chain tensioner, and timing chain guides. Both looked real good. No debris, broken parts.

I turned my attention towards the oil pump chain, and noticed a ton of slack--so much that I could pretty much pull the chain up and skip teeth with it, or get it to hit the housing while rotating. Pics are attached. Could this be my issue?





There is the oil pump chain

Picture of the top, not really helpful

Here I have a sharpie pushing the chain easily. Can get 3/8" deflection with just my fingers.

 

Is chain slack in spec?

 

I'm interested in this thread as I am about to change my timing chain. I'm waffling on whether to change the oil chain or not.

What is the slack spec? And how do you test it?

 

I’ll check the manual (Bentley) to see what it says tonight.

if you need the camshaft tool for your repair, DM me and I’ll send it your way once I’m wrapped up

 

Mini tech procedures can be found here --- https://www.newtis.info/tisv2/a/en/ a brief version using more popular special tools is in this screenshot, from a Promini web site a couple years ago, currently "being updated". Info is still good.

 

mine made noise at varying rpms till warm , and it was the timing chain that was dead.. changed the chain, sprocket, guides , tensioner

 

From what I noticed on all of the minis I worked on, the oil pump chain has some slack to the point I could remove the pump if tilted enough. The pump itself does not require too much force to turn and it is not timed. just make sure there is a black cover with a notch the keeps the chain rather a little tighter.

 

update:

timing chain and guides replaced; oil chain left as is. The bad sound went away, and the wavering idle issue I had is now gone. im very happy.

also: don’t break bolts off into the motor when you are going this. It sucks to get out.