bottom-end (not the same as "Pretty Girls of FIAT")

[maytag]

Taken from another active thread, that got me thinking:

NOS ports for a wet system sound like fun but how much power can be added before a stock 1800 bottom end self destructs? Maybe forged pistons would help?

Has anyone found the limitations of the bottom-end of these motors? Both in HP and in RPMs? With all the available bolt-ons to help the motor breathe, and the availability of adjustable cam-gears, added to my own willingness to spend the time balancing the assembly (something I'm good at, finally! ) what's the ultimate limiting factor of the motor?

Just spit-ballin' here, but I'd think that even with bigger valve-springs, the top-end is gonna start to float long before an iron bottom-end starts to break-up. ??? Maybe 8k? 8500? anyone here gone this far?

I sure love the thought of this motor screamin' at serious revs!
I once built an air-cooled Ducati twin (that everyone said shouldn't rev past 9k) that'd rev to the moon! well past 11k.... (I've got video posted online, if anyone cares ) and there's something to be said for RPM's!

[mdrburchette]

You don't hear much about bottom end problems with these engines, in fact, unless someone breaks a timing belt, there just isn't much that go wrong with the internals. With that said, my 1608 is sporting race valve springs from GC, custom JE pistons and custom Crower rods. I have turned it past 8k rpms and all the parts I used are good for at least 9k, but the power curve starts to fall off at 7k so there's not much of a reason to go further.

[maytag]

but with the right cam & breathing mods, has anyone been able to extend that power curve?

[mdrburchette]

My power curve changed with the 42/82 cams I'm running. They don't start to come in until after 3k rpm and will pull strong until around 7k, then start dropping. I have not dynoed my engine since repairing an irratic ignition problem and changing to dual IDFs so I don't have the exact numbers.