Long term Project Planning - Range Rover

[softdash3.9]

Hi everyone, thought it was about time I started posting again now that I am back in V8 mode , in the last coupleof years I have been busy moving and carrying out improvements at my new house, here we are 2 years later (did include a 30m x 15m Toy shed )

My Range Rover Classic is still in regular use, but I am starting to think about what to do when she retires and join my other toys

My RRc is a late sofdash with a semi serpentine engine, small journal crank, distributor, non crossbolt mains, but with all the crossbolt castings present.

Running on LPG

The block went porous and I had thick wall liners fitted, so scope to up the piston diameter.

My current thoughts are along the lines of.........

Increase capacity to 5.0 or 5.2, raise the compression ratio to take advantage of the higher octane in LPG (but kep the ability to run petrol (Super inleaded as a reserve)

Polish/port heads possible large valves

So I suppose my initial questions are:-

What is the optimum CR for LPG

What is the maximum CR I can run keeping the ability to run petrol

What is the best method of stroking the engine (offset groung 4.6 crank?)

What conrods to use

What Pistons to look for

No doubt there willbe more to come

Any help would be apprecieted

[TokyoP6B]

is available from Woody Cooper at: www.thewedgeshop.com

This uses a Buick 300 crank ( 86.00mm stroke ) + you will have to specify to Woody what piston diameter you need ( bore )　＋and what heads and block you are using ( compression/bearings/seals ); the crank uses 2.5 inch mains , and that will take you to a shade under 5 litres with a 95.00mm ( ? ) bore

Tell Woody what you want + he will supply the Kit as a "bolt-in" proposition without you having to worry about what pistons work with what rods, you may need a longer keyway cut in the crank snout and a flywheel made up too

X-bolting: can easilly be done but use an upgrade to the stock Rover x-bolts, also suggest ARP studs for the heads and ARP bolts for the conrods

Getting everything balanced is most important with a stroker motor , if you are using a clutch and pressureplate get that balanced as an assembly too

I've just built an "interim" 3.9 block, same as yours, to 5,040cc, cannot assist with your compression question other than to say that much above 10.5:1 your engine won't like running on petrol....

You say your engine is "small journal" but if it has the crossbolting bumps cast into the block it will have provision for x-bolting and can be machined to the bigger 2.5in mains of the later model blocks ( and Buicks )

GW