Re: L20 crank into L18? Good, bad or ugly?

[MarkBnyrd]

Nat,
Its been very entertaining reading some of the advice from the lads,  however i think it may be rubbish. true the L20 B crank has 5mm bigger main journals as does the Z20 , and this is a good thing because then you wont break the crank after about 5 rallies. to do it properly you would need to get the L18 line bored ($150-300)  and use the normal L20 main bearings, get the crank nitrided and it will take 100 rallies+
If you are on a budget you can use late 1600  or L24 conrods Z20 or Z22 standard pistons and with a few "adjustments" to the block you can have up to 2092cc in an  L18 block 100 %reliable with standard bits as if nissan made it themselves !
I wouldnt worry to much about calculating  stroke rod ratios, bore flex , good or bad crank to piston angles????
I can tell you this because its been done like that for 20 years in australian rallying with the usual datsun reliability, it turns out to be stronger and more reliable than with an L18 crank because you dont have to rev the date out of it. this is a very good thing in the bush, being able to get it up on cam straight out of every corner and up every hill , torque is what you want and bigger crank is gold !
if anyone wishes to stress about rod angularity or scuffed pistons then try a Z 22 crank ( 92 mm stroke instead of the L18s 78 mm) with  1600 rods, very short custom pistons, an 89mm bore, all resulting in a 2.3 L  L18 that is happy to rev all day to 7500. this engine may be on the edge but i have built 2 like it , and datrally in melbourne once did one with a 94 mm sroke and 90mm bore giving 2.4L. and geuss what, they all lived happily ever after!
My 2 engines like this have each done 2 years of rallying (causing many tears for wrx and evo competitors) without anything but regular oil changes.
so it sounds like an exelent and safe bet  to put in the L20 crank so let me know if you are after more info ! and please tell me about the rest of the car.
                        mark  [EMAIL PROTECTED] 

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