I have been in contact with Paul at Mahle today for an update as sadly a human error led to a large batch of Big End bearings being incorrectly made which just shows that even F1 divisions make human errors .
I was gutted to have the thought that I'd have to stick stock bearings in it as it would seem they may be a weak link in the engine but the new R53 ones should be ready mid- late Feb 2011 and he is going to push Allen today as I have stickers coming too
The Pistons will not be ready until next year due to forging issues and they are very busy with Jap stuff
Copy of my original post :::;
I would urge you all to read this as an example of the approach Paul Grosvenor had to a simple enquiry from me . He has had no dealings with me before and it takes a lot of time replying to e-mails as you all know I'm sure but to say I was very happily surprised with the details given to me would not do it justice .
I WILL definitley be buying the big end bearings and Pistons from Mahle for my Winter re-build !
many thanks for your enquiry about BMW MINI pistons.
Unfortunately I cannot give you any exact data on power / torque figures for the rods and pistons. As a very rough "rule of thumb" 50% increases should not present a problem if the engine mapping is correct - anything above this and you could very likely begin to experience problems. Piston / rod problems are more often caused by detonation rather than power / torque as it can cause massive cylinder pressure increases. Additionally you should consider that the bearings in the BMW MINI are an aluminium type bearing and increases in power / torque or detonation can also cause fatigue in these items causing failure, particularly the big end bearings.
Also you should consider that when using the engine in a motorsport environment you are really using it out side of the design parameters i.e. sustained periods of maximum RPM and full throttle, for normal road use full throttle and high RPM are used for only very short periods of time.
Our Motorsport division is currently finalising designs for both pistons and bearings for the BMW MINI (both the Mk1 and Mk2 version). The bearings are UK manufactured in our F1 Race Unit and are either available now or in the next two weeks depending on model. These bearings are cast bronze with a lead indium slide layer which is a massive improvement over aluminium and is exactly the same material as we use in Race bearings supplied to factory teams. The pistons will be a forged replacement for the standard items in MAHLE proprietary low expansion alloy to limit "piston slap" with phosphate and graphal coatings to reduce friction and micro welding problems. They will also come supplied with MAHLE manufactured steel nitrided rings. We expect these items to be available to purchase in around 6-8 weeks.
Sorry I cannot give you any accurate figures, but I hope the above is of some help and if I can be of any further assistance then please do not hesitate to contact me.
MAHLE Aftermarket Ltd.
National Sales Manager (Engine Components)
Springvale Avenue, Springvale Business Park, Bilston WV14 0QL West Midlands, Great Britain
Phone: +44 (0) 1902 357-123, Fax: +44 (0) 1902 357-113
Mobile: +44 (0) 7788 59 59 34