Need to find the spec on a 4.2 v8 + 3.9

[Fingers Mclean]

Hi Guys
where can i find the spec for the 3.9 v8 compared to the 4.2 i know there the same engine,,but i would like to know what bits and bhp difference there is between the two..
Any ideas>
cheers Ali

[hairyasswelder]

From the book, you and your Range Rover (Haynes)

V8 3.9 1989-1992 3,950cc 94.0 bore x74.1 stroke 188bhp@4750 235ft/lb @2,600rpm 9.35:1 compression ratio

V8 4.2 1992-1995 4,278cc 93.98 bore x 77 stroke 200hp@4,850 250ft/lb @3250 8.94:1 comp ratio

RPI website may be of some help for the physical differences

HTH

Steve

[hairyasswelder]

Forget that 'cause I just cross referenced it with another book and they do not agree  :?

Range Rover ,the first generation states
3947cc 93.98x71.1mm  
BUT all other info tallies  :?

Confused
Steve

[Range Rover Blues]

The 4.2 is a stroked 3.9, that's all.  The CR is lower but off the top of my head I can't tell you exactly.

BHP is just shy of 200 IIRC, 0-60 only just over 10 seconds with a EEC kerb weight of 2100kg or thereabouts.

[Fingers Mclean]

Thanks guys ..I'am Just thinking i have two engines sat here a 4.2 and a 3.9 both with auto boxes so which one do i use mmmmm :lol:  :lol:  :lol:

[Range Rover Blues]

If it's in good nick then use the 4.2, more torquey for sure.  If they are different at all I'd suggest mating it with the 3.9 Auto box though as the changes might be a bit higher, allowing the engine to rev a bit more.