Hey

So I recently got me a nice set of pistons, connecting rods, and a crank from a 4.6 gems range rover with 98,000 miles on it.

I currently have a 1997 4.0 GEMS Discovery 1, that I have taken about 400lb of weight out of

I want to get more power out of my already mildly tweaked 4.0. I figured the best way to do it is to put in these new connecting rods and crank.

Currently I have a decatted exhaust, cold air intake, ported inlet manifold, and I must say it runs very well!

My plan is to do a TON of "while I'm in there" tweaking, port polish the head, polish combustion chambers, replace ALL gaskets and any bolts that don't look good.

As for the crank, I plan on using 4.0 pistons, 4.6 connecting rods, and 4.6 crank. This should make my compression fairly high, around 10.9 to one. To compensate and eliminate knock, I will be running 5 gallons of 110 octane to every tank of 93.

The computer will be a stock 4.0 ecu BUT I have a 4.6 range rover gems control unit on the way... NOT SURE IF I NEED THIS, help here? My plan was to take the chip that controls fueling and spark and put it on the PCM of my 4.0 ecu so my security and whatnot will still work just fine.

This should be a VERY fun project!! Any tips? I've done the head gasket before (fairly easy, rovers have TONS of space) but I have never had the oil pan off or the engine out of the car.

Thanks!
-Alex

 

personally; I like the lay out with the exception of the 11-1 compression ratio.
I would run the 4.6 piston, buy the time you deck the heads and block you will probably be in the high 9-10. area.
it would be capable of running on 93 octane.
you are running a GEMs it can also be chipped unlike Boshe systems,
you may want to look at a chip to get all the benefits out of the work you are doing.
JMHO

 

what cam are you going with?

 

I think if I work on the combustion chambers a bit, polish and reduce a little area, I should be able to run 93 with little knock, and a 93/110 mix if I want max power with no ignition retardation.

 

I'm working with piper cams to make me a nice 4.6 cam with a lopey idle and fairly high lift/overlap. It's a custom grind, still talking with the representative about it.

 

cool
-couple of places (crane is one) sell a mounting plate so that you can get away from rocker shaft. that is cheaper / easier if you are going to go with rollers.


-look into bleed down lifters. just ordered some rhodes
-some sbc valves are the same as ours, if you are changing.

 

Where did you get your bleed down lifters? I don't think my cam would be THAT hardcore to warrant $1,500 lifters, thats more than I paid for the whole truck ._.

I wonder how much they would run me for a TVR 5.0 crank/pistons/connecting rods. Pretty sure they run the exact same bore as the 4.0/4.6 rover v8.

 

Rhodes or summit
#9896.... <$200
Not too expensive .....problem is junk like roller arms ...that is a lot of scratch for a bit of friction reduction. Might be worth it if it were going in a track vehicle, but iffy on disco
Stroker kits are 2500 on up
You can do 5.2

 

"I wonder how much they would run me for a TVR 5.0 crank/pistons/connecting rods." about $6k

 

Did you ever build this? I just finished this exact build, but with stock 4.6 pistons, and a new oem 4.6 cam. Besides Bosch pink top fuel injectors and a decatted exhaust, everything else is stock. I gotta say I'm pretty pleased with the power. I've only put about 200 miles on it so far, but every time I drive it I feel a little more power from it loosening up. With the 4.0 I had 245/75/16 standard load tires, and it couldn't even hold slight inclines on the interstate. I also consistently got 9-10mpg (lots of hills here). Now it has 255/85/16s D-load tires and I can accelerate up inclines on the interstate while in overdrive. I'm also getting 11-12mpg. It still has all stock gearing, and even with 33s it is staying that way. The 4.6 compensates enough for me.