Hi all, im currently getting my L20b rebuilt and worked and ive been suggested to run shorter con rods with an offset pin to maintain the correct piston height at the top of its stroke. Has anyone done this? Keep in mind im using the stock L20 crank so this is not a stroker build

I can't imagine why (or how) you would successfully do this (assuming by "pin", you mean gudgeon pin)

Unless you mean offset grinding the crank, which is actually stroking the engine.

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

You'd need to find some Z20E conrods which are longer than the L20B rods, & use Z20E pistons to suit the longer rods. It's worth a few HP (less than 10, according to Graham Wilkins) & I haven't been able to find any con rods, though I got some 86 mm pistons from E-Bay. The closest thing I could find was a supplier in Florida, USA, who wanted about $200 for the rods & $400 for the shipping. OR a Chinese manufacturer who'd make them with a minimum order of 10 rods. Maybe if you're going for a full race engine, all this malarkey would be necessary, but if it's only a street engine, the difference would be almost negligible, or unnoticeable. I hate to say this, because I don't know who suggested the rod swap, but it sounds like a wallet lightening exercise to me.

Shorter rods can be beneficial in a turbo charged application but if you are after 6" rods have a look at RB30 rods and change the little end bushes

Yea Dave i meant gudeon pin

Thank b310, yea it sounded like that to me which prompted the question. I couldnt see much benefit for cost but on the other hand it needs rods and pistons anyway

Thanks dizzy

Ok so quick update, the builder cant find a suitable combo that will work with the rest of the motor and the block has been decked so that throws another spanner in the works so now the plan is standard length rods with a lightweight piston, if available. So shouldnt need to find any shorter rod combos