M42B18 rebuild

[Winrace12]

Hello everyone!
Thought i wanted to let you in on my process of rebuilding a M42 engine.
Last year I bought myself a 98 M42 swapped (old engine ended up getting rod-knock earlier owner said) 318TI to start doing some trackdays and to just have som fun with. I did some basic mods to it
like coilovers, pads, bucket seats etc and had a blast for a whole year without any major issues. By the end of the year the engine was idling rough, used some coolant and leaked oil everywhere.
So I decided to pull the engine and give it a refresh with new gaskets etc. Swapping in an M50/52 was no option due to the strict rules here in Norway (illegal to swap for a bigger motor). After tearing down the motor i realised
it needed much more than just gaskets (you will see in the pictures below). So far this is the list of parts i've ordered.

• Gasket rebuild kit
• Cylinder head bolts
• Termostat
• Waterpump
• Radiator
• Gear-linkage rebuild kit
• M3 gear lever
• M40 flywheel and clutch
• Pilot bearings
• Oilfilter, airfilter and fuelfilter
• Ignition coil
• Igition cables
• Spark plugs
• Crankcase ventilation-valve
• Vaccum hoses and some intake hoses
• 2nd hand refurbished cylinder head
• 2nd hand used piston
• Rod bolts
• Rod bearings
• Piston rings
• Knock sensor
• Water pipe and o rings
• N52 torx head exhaust studs
• E34 steering coupler
• E36 M3 master cylinder

Pulling the engine:
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[Winrace12]

Engine disassembly:

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After removing the cylinder head I realised that the engine was far more hurt than i first thought.
All of the exhaust valves were bent, and on cyl. 4 the valves had hit the piston as well as the cylinder.
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As there were no good options for buying a used engine, I took the risk and decided to buy a used cylinder head, a used piston and rebuild the engine. I bought a refurbished head and used piston for 400 dollars and got to work.

[Winrace12]

I cleaned and sanded down the block, and painted it afterwards. Starting to look much better already.
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Now i am waiting for my flex-hone, rod bearings, pistonrings and cylinderhead to arrive to continue. More updates to come.

[thenjnick]

Wow definitely showing its age. It came a long way, and it looks great painted black, nice! Awesome pictures too


Sent from my iPhone using Tapatalk

[Winrace12]

Rotating assembly back together after cleaning, honing and new bearings/rings.




Also started painting some other parts


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[ggme36]

thats cool dude, well done, looks mad

[Onestiffslide]

Nice progress! I like it when people take pride in their work especially on a engine rebuild. Its 20yrs old but its yours and you should put 110% effort into making it the best. My girlfriends dad and her brother did an engine in their civic hatch. They put it back in just as dirty as it came out. Hardly even replaced any of the old parts.
Cant wait to see progress!