*The stock con rods are marginal once engine out put approaches ~180 Bhp. There are aftermarket ones available from Crower, Cunningham, Carillo and others, but all are built to order. Figure about $200 and up per con rod.
*Con rod and main bearings are another issue. Tri-metal Clevite are somewhat available, Pretty much custom. Or, convert to Chevy rod bearings.
*Pistons are limited for off the shelf sets. These are usually 9.8 to 1 Max and have a small flat dome. Old Mondial sets do show up every so often and cost typically upwards of $300. These are cast and not ideal for serious performance engine. Wiseco can make custom ones for about $600 per set, which is not expensive, considering they come with rings, pins and are forged pistons. Cylinders 1 and 4 are offset relative to cylinders 2 and 3, keep this in mind as it will affect valve to piston clearance. Valve to piston clearance must be considered due to how tight everything fits in the combustion chamber. Compression rations much beyond 11 to 1 are complex due to the clearance problems.
*Excessive valve overlap will cause the intake and exhaust valves to touch. They run very close
to each other.
*If oil pressure is increased, oil flow to the 6 feed holes for the cam housings must be restricted. If this is not done, there will be excessive oil in the cam housings and wont drain back rapidly enough into the crankcase.
*Use a Lancia Scorpion or Montecarleo oil pump and pan as it has proper baffling to control. Otherwise oil starvation could result.
*ARP head stud set for a FORD Cosworth Sierra will fit the FIAT / Lancia if one is willing to use M12 studs. This requires drilling a tapping the holes in the block for M12 x 1.75 threaded holes.
*If possible, use the Vx or TC130 cylinder head. These have better flow as delivered with 43.5 mm intake valves. Vx cylinder heads have sodium filled exhaust valves.
*Good cylinder head work, which is required for increased performance, is expensive. Figure at least $1000, not including parts for the work required.
*What intake system is being considered?
*What exhaust is being considered?
*What cams are being considered?
*It is difficult to get more than 200 Bhp normally aspired from the FIAT/ Lancia TC. Much more is possible via supercharger or turbo.
*Keep in mind, the Abarth X1/9s used the Lancia transaxle, but they had problems with transmitting the power from the Abarth twin cam which was eventually fixed.
*Add up the cost for all this, and one can easily exceed the cost of a Honda K20A drive train, which is designed to produce, 220+ Bhp in the Type R version as delivered complete with cable shift, 6-speed transaxle with Torsen LSD. Two Xweb members have done this K20A conversion.
*Less expensive versions of the K20 drive train can be had from an RSX or even a TSX. K20A type R is a JDM or euro only drive train.
*The cable shift transaxle can simplify the shifter linkage and result in a better shifting.
*The Honda B16/B18 drive train offers very good power for the money spent. For well under $2000 and the drive train fits well in the X with few modifications. And there is a long history of reliable power and parts for the B16/B18.
*Also consider the Toyota 4AG drive train from the series one MR2 and GM's Eco-Tech drive train.
*Many other FWD based drive trains have been stuffed into an X beyond the Lancia Beta drive train.
*This is not meant to discourage doing a FIAT / Lancia twin cam conversion, its more of a realty check of some things to consider.
This message has been edited by Rupunzell on Oct 26, 2008 8:47 AM