Hey all,


New to the forum, not TOO new to MINI's... unfortunately I broke down earlier this year and upgraded my 2009 R56 Base and swapped to a 2009 R55 S. Potentially a big mistake. Here's why-


So for the first month I had the car (64k on it when I bought it), it started rough on early morning cold startups. Diagnosed it down to the HPFP and brought it to my nearest dealer (Cincinnati MINI) 100 miles away, sputtering and coughing the whole way. Fortunately they couldn't even get it started to get it into their shop when I left it overnight and it finally threw a HPFP code, so I was in the clear for a free warranty pump.


Once that was sorted, the Tech called me and told me of a couple things it ought to have done, all of which I declined (I'm a mechanic by trade, but I like to squeeze anything under warranty out of dealers and save my wallet, especially a $900 HPFP). One of those items was the timing chain tensioner, as he said it was bleeding off pressure- which it appeared to me as if it was as well, since every few days while the car was stagnant it would rattle for a few seconds and then the tensioner would pick up the slack.


(Also according to previous history records, the chain and guides were changed at 15k by a MINI dealer.)


So I bought a new one and installed it a couple weeks ago, and yet the rattle still exists for a few seconds until oil pressure is built back up and the tensioner picks up the slack. I know this is a common problem on MINIs specifically, but we do fix timing chains on GM and Ford V6s all the time, and timing chain wear on those will leave a constant rattle, not a startup rattle that fades off... the most recent we've been changing on Ford 3.5 twin turbo engines are sourced to the OCV/VVT valves bleeding off pressure. Could something like this be occurring on the R55/R56 engines? Maybe another part on the same hydraulic oil circuit losing prime and regaining it after a little runtime? After all, the chain is totally silent after that. Would love to get some thoughts on the issue. Thanks fellas!

 

Also to mention- I've done two synthetic oil changes in the past 5,000 miles with Rizlone additive, with SeaFoam flushes through the PCV at both of those times to prevent/reduce carbon buildup on the valves, one of the main causes of typical timing chain wear.

 

do you know if you had the 78mm tensioner or the 82mm one?

is the car manual?

 

Not sure on the tensioner length... I wasn't aware there was more than one. My parts suppliers only listed one aftermarket number.

But it is a 6sp. manual.

 

yep, there are two lengths out there...do you hear the noise go away if you press back on the clutch?

 

I'll have to check on that then and make sure I got the right one...
I haven't noticed it changing while depressing the clutch, but I'll check on that.

 

also, post a vid or audio so we can hear it too

 

Yep, the older lentgh and the newer lentgh. Now we have the newer lentgh in the fix part and the replacement part: All goes back to here:

11317607551 is the newest 82mm and replacement tensioner when you do a chain repair. And 11314609482 is the older 82MM and for people that are swamping in a new tensioner if the chain is stretched but not strectch too much where the chain needs replaced. We no longer carry the 76mm version, some places do. MINI NLA'd that version and most aftermarkets did also.

https://www.northamericanmotoring.co...nsioner-7.html

 

Great, thank you for the clarification. I bought a pretty generic Duralast part, so I'm guessing it was made to the OE specs before the 82mm. I'll be picking a new style tensioner up and installing it first chance I get. Thanks!