I am working on a m20 stroker. Has stock eta crank, rods, pistons, etc. The head will have all new OE parts including the 325i double valve springs, and either a 284/284 reground "e" cam or a 284/284 reground "i" cam (probably i) I will have a custom chip made with a higher rpm limit but I want to know what would be a resonably safe limit? the cam should pull up to 7k but I don't know if the engine will handle it.
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itll be fine -
6900rpm.
Stock i valve springs float at about 7100rpm. Stiffer springs will crack the head and break rocker arms, so stick to 6900.Adam Fogg- '88 M3
Common sense- It's the new 'gifted'Comment
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Awesome, Thanks for the info guys. 6,900 is more then enough for me. I don't plan to push the engine to it's max rpm but I like to know it's there if I ever needed it :)Comment
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Originally posted by AdamF 88iS
Where did you hear about HD springs failure? 4+ years running BMP HD valve springs with their cam..Redline my slut everyday to 6900.No problems.But then again my head was brand new...not used/rebuilt.Comment
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I didn't hear it, I experience it at work. People break rocker arms and get cracks below the valve springs all the time. Just search for 'broken rocker arm' on this site and E30tech, lots of stories; but none of them on E cars with soft springs.Originally posted by nitro325isAdam Fogg- '88 M3
Common sense- It's the new 'gifted'Comment
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