Making engine displacement smaller ?

[John_S4x4]

Although not very common, I believe that some tuners have made engine capacities smaller. I presume this is normaly done by making the crank stroke shorter and hence usually end up with a higher reving engine. I can't say I've heard of the bore being made smaller, by say changing pistons and liners. I know this type of engine modification might be done for getting an engine to fit into motorsport class rules (eg going smaller capacity and then turboing the engine with the normal 1.4 capacity factor).
Has anybody got more info or heard of somebody doing this....I'm am thinking more about 4 cyl engines here.

[GreenV8S]

The story goes that the V8S bonnet is the shape it is because TVR designed a V8 stroked down to 2 liters and then supercharged back to the original power level, this was apparently intended to avoid huge duties that the Italian government imposed on engines over 2 liters. Obviously the modern take on this is to replace the titchy 3.9 V8 with a bigger modern one and *then* supercharge it ...

[chuntington101]

its common with SBC to use a crank from the 350 in a 400 block! this gives you a displacement of 377 cubic inch.

as for raducing the bore, no never heard of that. and can see is being very hard to do!

thanks Chris.

[stevieturbo]

Reducing the bore would be pretty straightforward, by just replacing the liners.


Although decreasing engine size would be en expensive route to go, unless that engine in question was an extremely good unit in the first place, in terms of cylinder heads.

it would probably be easier to source a smaller engine in the first place.

[aldi]

www.bobnorwood.com/The%20Fastest%20Little%20Sports%20Car%20in%20Utah.htm

This is quite an interesing article about someone doing the land speed record for various classes using an Mk2 MR2 shell with reduced capacity mk1 based engines, down to 1.5 and 1.0L IIRC. Quite a good read.