131mirafiori forum

hi,
I just want to know what the diffrent between 1600TC cylinder head compare to the 2000TC one. what I know all the valve are same size maybe combustion chamber a bit diffrent. ???
thanks.

It depends which 1600 you are talking about - there are 4 different twin cam 1600's

1608cc 125.###### series found in fiat 125's 124 special, 124 coupe BC and 124 Spider BS - these are sightly different as the early engines had a slightly different cylinder spacing in the block. These heads will bolt on to the later blocks but there are some differences in the water galleries that require the head to be modified to work on the later blocks. The ones off coupes (and spiders?) may have 42.4mm intake valves

1592cc 132.#### series found in 124 coupes, spiders, and fiat 132  these are a 132 series 1756cc block except with 80mm cylinders and the same bore spacing as the 84mm bore engines - i.e. the valves in cylinder 1 and cylinder 4 are not on the bore centreline. will have 41.8mm intake valves

1585cc regular port - found in 131, lancia beta, fiat ritmo/strada 105TC, early lancia delta, early fiat regata 100s, probably a few others. 1980's heads may have 43.5mm intake valves, early ones will have 41.8mm

1585cc reverse port - found on mid to late 80's delta, regata, prisma and some others. All fuel injected version from 1985 on will have these heads where the intake and exhaust ports are on the opposite sides to all the "old" heads -  from what I can tell, mostly to allow better fitment to FWD cars (exhaust at the front) and solve the problem on the old style heads where the rear of the head did not receive as much coolant flow as the front and could run hot. intake valves are 43.5mm and the combustion shape is quite different.

For all types there may be slightly different size ports depending on exactly what car the head was for.

Otherwise if we are talking regular port heads - the differences compared to 2L heads are small, some of the 1600 heads may have slightly smaller ports, but that can be a good thing if the head is going to be modified as it gives you more to work with. Also the combustion chamber may be slightly smaller, but only a few cc, fiat use pistons with different size domes and valve cutouts to get the compression ratio required rather than changing the volume of the combustion chamber in the head much at all.

hi testament,
thanks for your explanation on the cylinder head. actually my 131 engine is 1585cc now running with 2000cc cylinder head from fiat 132 with a bit port and polish. what about if I use gear box from 2000cc engine is it more powerfull interm of pick up and top end speed or become worst?
thanks.
selem

The 5 speed gearboxes are the same for all 131?s and 132?s I think. The only difference is that on later cars the 5th gear is 0.83:1 instead of earlier 0.87:1, just a little bit taller.

there's a fiat 132 gearbox with 0.78:1 5th gear ratio....

no - some early cars had the colloti (124/125 type) gearbox, later cars had the ZF gearbox which is stronger, and that also came with two different rear output styles. Not sure on all the ratio differences but most of the differences would be between the different boxes rather than different ratios in the same box. e.g. all 2 litre manual cars had the same ratios as far as I know (131 or 132/argenta)