I own a GP with 59K miles. I recently returned from a six week business trip and immediately heard a new sound in the engine bay. The sound occurs while at idle and in every gear. If I put pressure on the throttle, the sound begins at approximately 1500 rpm and sounds like a rock in a rotating tire, getting faster as the rpms increase. The sound continues all the way through the rpms. When I took the car in for service, the shop identified an oil leak and recommended I change the oil pan gasket. At the same time, I had the 60K Inspection II performed. I went to pick the car up but decided to have the mechanic ride with me in case the sound could still be heard. The sound was still there. The mechanic listened to the sound, pulled out a stethoscope with a metal rod attached to the end in order to listen to the engine vibrations, and began listening/looking for the sound. Immediate recommendation was to pull the valve cover, check the valves, springs, tensioner, etc... The tensioner was found to be loose and was replaced. The sound is still there. The mechanic called the local Mini dealership (Passport Mini of Alexandria), explained the sound he was hearing as he was having trouble diagnosing the sound and was told this is a common aliment and you just have to live with it. No further explanation other than there is no fix. When I talked to the mechanic this afternoon, he said he had checked everything he could and was still baffled and did not want to keep pulling things off and replacing them if he was not sure where sound was emanating from. He said, to him, the sound was definitely coming from between the top of the head and midway down and that the lifter gap was was fine. He said but he was not sure what to do: - the chain might have stretched (not too sure about that one) and may need replacing - the timing guide might have worn out and need to be replaced - the rubber mounts at the top of the lifters might have decayed and need replacing - that the oil pump is from a cooper and may not be not be up to supplying the performance (original) head with enough oil (he also was surprised that the head was not a BMW manufactured piece - I have have owned the car since it had 16 miles on it and have not changed the head. Not sure if this is always the case but wanted to add it anyway.) Steps already taken: - Timing chain tensioner replaced as it was loose (when it was pulled, the end was stuck pressed into itself and not moving in/out) Anybody else ever deal with a similar issue? Any recommendations (other than going with a big bore head from Revolution Mini )?

 

Here is a video of the noise. Maybe this can shed some light on the issue: http://www.youtube.com/watch?v=VTa39Krzg8w

 

Since the sound is in sync with engine speed then it cant be a loose screw or nut bouncing around. It might be a stuck lifter?

 

I can't authoritatively comment on your issue without hearing it, but from the impression you are conveying, the timing chain tensioner would be my first suspicion.

What I can tell you is that BMW never manufactured engines for any MINI. As far as I know, they have never made an engine for a FWD application period. I've had my engine out of the car and on my workbench (where I split the trans). I've looked it over from every angle, and there are NO BMW markings on any part of the engine itself, although every bracket, pipe, wire, hose, cable, etc seems to have the famous Roundal on it.

 

Is this a MINI mechanic you're dealing with? Did you have the serpentine belt changed? What size belt? Did they install it correctly? Is there a hole showing on the tensioner tab? Did they replace the serpentine belt tensioner? Two suggestions: hook up a timing light and look at the belt and tensioner while it's idling. If that doesn't show anything wrong, get a piece of dowel rod and carefully place one end on the valve cover and other parts of the engine you can safely reach while you put your ear to the other end and find where the noise is loudest.

 

The R53 motor, which is what you have in your GP, was made in Brazil by Tritec. All of the accessories were added at the MINI factory once it was in England.

I doubt that the timing chain has stretched as it is internal and fully lubricated. It is designed to last the life of the motor.

I find it interesting that it happened after it had been sitting for six weeks. I'm wondering if the oil drained down from the chain tensioner and can no longer hold enough pressure to effectively tighten the chain? Possibly an air bubble?