David, the bore and stroke of the 3.9 and 4.0 are identical. The 3.9 uses the
3.5
rods, small journal crank, and oil pump and distributor driven off the cam. $.0
uses late rods(longer), kighter pistons with shorter compression height, large
journal crank with longer nose, oil pump driven buy the crank, different cam,
and
no distributor. The interim block has the late casting but uses the earlier
internals except for the oil pump and cam. John
David Kernberger wrote:
> 8/29/00
>
> John,
>
> Excuse my ignorance, but is this "interim" block you speak of a 3.9
> or a 4.0? My familiarity is mostly with Buick/Olds blocks and only a
> little bit with Rovers.
>
> In general, what are the specification and feature differences
> between 3.9 s and 4.0 s? Are they the same bore and stroke dimensions?
> This is one little part of the Rover puzzle I would like to learn more
> about.
>
> T I A.
>
> Regards,
>
> Dave Kernberger
>
> -------------------------------------------------------
>
> >Greg, Its an interim block, probably a '94. Takes the small journal
> >crank. The
> >front cover off of that block is especially interesting, in that it has
> >the new
> >style oil pump that is driven off the crank, but will take a distributor.
>Are
> >you interested in selling? John
> >
> >Gregory Williams wrote:
> >
> >> Since we're on the subject of blocks, I thought I might launch a query. I
> >> picked up a 3.9 block in a deal last year. The gent that sold it to me
>said
> >> it was a 4.0. I inspected it pretty closely and found that it had the
> >> beefed up webbing of the 4.0/4.6 and the thick main caps as well. It also
> >> had bosses along the side of the block for crossbolts but they were'nt
> >> drilled and tapped for them. However, it had 5 bolt holes around each
> >> cylinder, 3.9 style rods and 2.3" mains. What is this? A 3.9 1/2?
> >>
> >> Greg
> >>
> >> -----Original Message-----
> >> From: Ric Smith [mailto:rsmith@coppercom.com]
> >> Sent: Monday, August 28, 2000 8:26 PM
> >> To: 'Jan Ben'
> >> Cc: 'buick-rover-v8@autox.team.net'
> >> Subject: Isky reverse rotation cams
> >>
> >> Jan, are you spinning the engine backwards like I am? Obviously reverse
> >> rotation cams don't help a normal motor. Isky does currently stock normal
> >> rotation cams for the 3.5 in about 4 obsolete grinds, mostly on 110
>centers.
> >> I had them do a custom grind for me but it was too peaky and the horsepower
> >> peak wasn't that good either so I advise conservative grinds for better
> >> torque. I'd check out RPI in UK for street cams for Rover trucks. Try
> >> www.rpiv8.com. It's good reading all over their site.
> >>
> >> I shopped for a 4.6 block for 3 years before I found a shop with just a
> >> block. They had dropped a nut down the intake and trashed one cyl liner.
>I
> >> paid just under a grand for the block with one hole resleeved and main
>caps.
> >> No crank, no top end, nothing else. I still need a windage tray for it and
> >> don't want to pay dealer prices. Any suggestions? ric.
|