Tuscan Challenge Engines

[thenick]

Hi all, I am bored at work and was just looking around the the net at some tuscan challenge cars and noticed that most of them run 4.6 RV8s. My question is, how do these engines differ from the 450 engine in my Chim given that they are both the same size RV8 but one is a hell of a lot more powerful than the other...

[Graham]

I may be wrong but i though the original Rover powered challenge cars ran a 4.5 motor before the move to the 4.5 ajp in the mid 90's.

Not sure on the full spec of the rover but it will have been something like

lightened and balanced
ported big valve heads
dry sump
smaller lighter flywheel and clutch
higher compression ratio
4* twin choke dellorto downdraft carbs
bigger free flowing exhaust manifold
no cats
probably running a lot more advance on the timing
different cam.
probably a few hundred miles between rebuilds and blow ups..
I hear quite a few spat pistons and cranks out of the block !!!

so no different to the chim then

Edited by Graham on Wednesday 18th April 14:15

[cre]

From memory (so it could be wrong!);
huuuuuuuuuge amount of difference between these engines, the RV8 challenge engines had steel cranks, carillo rods & cossy pistons, ultra big valve cylinder heads with bronze guides, wild (and I do mean WILD) camshaft with solid lifters and roller rockers, 4 twin choke (48 m/m?) dellorto's and were 4.5 litre.

there were a few other little bits that were different, but the above list is basically it. they were factory rated at 450 bhp (i think) but again this is the mythical blackpool donkey power, a really good one could knock on the door of 420 bhp although i did see one with aftermarket injection system reading 450+ bhp (in fact i still have the dyno sheet!).
HTH

Jamie

[Griffsmith]

What did the 4.5 ajp's make then? and how did they achieve their figures?