Hello from Estrie Québec Canada !

Hello there so my car is a BMW 335xi 2008 it has the n54 engine the car is a coupe 2-door and it has a manual transmission ..long story short I had the car for around 5 years and more I had a bunch of Maintenance I had to do deal with it obviously I didn't choose the the right one and end up at the end that I might have spun the crank hub .. I always like it this engine but I also taught that there is a lot of bad engineering inside just by looking around with the driving belt which has the crank pulley and if the belt gets oily the crew the crank pulley is not well made to stop the belt from slipping inside the crank and passing through the Seal of the crank and damage the engine and basically that's what happened in my case... I managed to make by myself swapping the engine with a using engine that I bought somewhere on the market, which ended up when I first crank the used engine that took all my time to swap in ... Resulted in a hard knocking sounds .. and I feel really disappointed but obviously big things I've learned it out of all of this specially I never done a swap in my whole life and started on the BMW ....

Know the game has changed I have bought Darton sleeves for the engine and I am on my way to start building the engine ....the new sleeves can handle 1000hp and tons of psi...I have the hard decisions to make now on how much I want to stroke the bore ? Minimum 81mm (de-stroke) 84mm (factory OEM ) and more for stroked options let's say 85.5mm

Trying to have suggestions from others is hard to get since nobody really did de-stroke ,and only couple ones had stroked ...

I'm stuck here with the new bore size..Wich I understand that it will inflict new bearings size ,crankshaft worked and rebalanced ect .....

I will try to post pictures soon here I am currently learning the engine fundamentals course engine building assembly ...

I would love to have any recommendations on what I should do .. the car has been sitting down for too long and I might going to loose it if I don't take any decisions soon ! Thanks!

Hi Michel,

Welcome to HPA. What engine management are you running?

@chris250 sadly im am running an oem ecu , i really wish i could run an aftermarket standalone ecu