3.9V8 to 4.6V8

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Originally Posted by Siska

For your 3.9 you could look for a Buick 300 crank. Takes a little bit of work and a few specialized parts, but will stroke a 3.9 to around 4.8.

Here is a couple of links I've found about it.

Affordable Aluminum Buick / Rover Stroker Motor, by Kurt Schley

And a company that supplies all of the parts that you will need,

D&D Fabrications: Engineering & Fabrication Services

I've spoken to Mark from D&D and he is a really helpful guy and really knows his stuff. I'm in the process of ordering some parts for the engine I'm building for my Disco.

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Thanks for that, though the first link while it talks about the 3.9, it seems to be discussing stroking a 4.0 and 4.6.

I was also hoping for something local - I think I need to reconsider what to do with the 3.9 - maybe a straight rebuild making it higher compression and doing some head and cam shaft work.

Cheers

Garry

On the top hat question, TR Spares in Syd had a 4.0 top hat rebuilt short motor for $3500- at christmas.

The 3.9 is smoother than the 4.6 due to its bore / stroke combination, and it's not quite so prone to cracking as the later 4.0 litre D2 blocks.

A 3.9 can provide reasonable performance, especially as you say when fitted with hc psitons, maybe tin gaskets and a high torque cam like the Real Steel Cyclone specially developed for 3.9 hotwire engines.

But in a heavy 4x4 it's torque that really matters and it's here that there's no substitute for capacity. However I wouldn't risk fitting a second hand 4.6 due to the all too common perosity problem - either a new hc short engine, or better still a top hatted seasoned block is ideal, but then the costs go up considerably.

From realsteel.co.uk:

305cu in/5l STROKER CRANKSHAFT- 4998cc
DW49951Stroker crank-cast 3.9/4.2 blocks £854.81
This crank has a stroke of 3.508”. Used with our forged stroker pistons, the capacity will increase to 4998cc. Crank must be used with our conrods, as the big end journals are wider than standard. Nitrided & crossdrilled. Long nose. Small diameter mains for 3.9/4.2 cylinder blocks. 2” big end journals. Weight = 19.6k. Made in England.

Real Steel's Rover V8 stroker kit will increase your engines horsepower and torque. The kit has been tested, and it is awesome! Crankshaft - a nodular iron crankshaft crossdrilled & nitrided, with increased stroke (3.508") Available for small main [3.9/4.2 block] and large main [4.0/4.6 block]. Con-rods - 6" steel “I” beam conrods are used, these are very strong, & give a better rod to stroke ratio. Pistons - Forged, high compression, 3.720"
pistons are strong and lightweight. Larger 0.927 gudgeon pins are used.
Fitting - Some grinding will be required, to enable the reciprocating components to clear the inside of the block. A small area of the sump will need to be panelled out to avoid the second conrod from the front of the engine hitting the sump during rotation. Rotate the engine completely to check that nothing is touching internally. A minimum of .060” clearance is required. Be careful not to grind through the “raised” oil gallery “tunnel”.


:)All the stroker stuff is on this site.:)