Brian, I don't think many of the 948 based XSP's were dry sumped. Mine wasn't.
The later 11 stud ones seemed to be, but these were usually special blocks
that were precursors to Cooper S blocks. I agree w/ your take on rebuild
frequency and red lines though. No sense reving much beyond where the cam
drops off and these are all long stroke motors when compared to the Ford Kent
series.
Roger
>>> Brian Evans <brian@uunet.ca> 04/16/01 10:28AM >>>
Most guys with small-block A-series find that the rods (998 Mini rods, in
most cases - same as full floating 1100 rods) are the weak limit, with the
limit being 7500 - 8000 rpm. At that, I'd limit the stock rods to no more
than say 2,000 miles, and use ARP rod bolts. Pistons should be Powermax
cast at the minimum, or forged racing pistons. Compression should be about
12:1
Heads, valves, rockers, etc. don't seem to give too much trouble, presuming
that a decent cam grind is used, and proper racing valve springs. I
personally use Iskenderian almost exclusively, but prefer steel top caps to
aluminium, as I've had several pull through. The 649 cam tends to run out
of steam about 7,000 - 7,500rpm.
The crank can be an issue. If you have a standard forged 948 crank, then
having it ground with generous fillet radius and then heat treated will
help a lot. If you have an original EN-40 racing crank, then you have a
dilemma: it's a really good crank - better than billet when new, but it's
really old and you don't know what's happened to it. These things have a
fatigue life, and the factory would life those EN-40 cranks at about three
races. We think we've got a wonder-piece and run them forever. All of the
main caps should be replaced with steel, or at the minimum have steel bars
reinforcing them. Always run a crank damper - you can get Fluid Dampers
that bolt onto Cooper-S crank pulleys now.
XSP's were dry-sumped, which helps the oiling issue a lot. I used to
restrict the flow to the head and rocker gear, but otherwise ran a pretty
stock internal oil system. I ran -10 lines to an external filter and oil
cooler, and fed the oil into the block at the stock location.
If it was my engine, using stock 998/1100 rods and well prepped standard
948 crank, steel bars on standard main caps, 649 cam, light flywheel, 998
Cooper damper, Powermax pistons, I'd use a red line of 7500 rpm and a
normal shift point of about 7000 - 7200. I used to plan to get two seasons
before freshening a motor like this. To go to say 8500 - 9000 rpm I'd use
a billet crank, Carrillo rods, about 14:1 compression, the best cam from
someone like Elgin who would custom grind something, a way better head than
I've ever owned to get flow that warranted all that RPM, steel main caps,
and a real good balance job. I'd probably freshen it every third race.
Hope this helps a bit - just a few thoughts on what I do.
Brian
>Roger- I've heard that the XSP's ran in Sprites at LeMans, and possibly
>Daytona, but have never had any 1st hand reports of it. Nice to know
>that they
>did, in fact, run there. Does the literature mention a reev limit? (of
>course,
>if it did you probably would have said so). The rods have 1100 stamped
>onto the
>big end (on the long side) and don't, it's true, look just like the
>948's in
>terms of the casting appearance (different materails, different casting
>technique). if you could find a way to get me copies of the literature,
>I'd be
>very grateful.
> Why aren't the mains the same as the 948's? They've got the same
>crank
>diameter, though
>the center main is reinforced as cast.-Are they wider?, I haven't
>checked one
>vs the other. And where do you find beearings for them if they aren't
>normal?-Just getting info on these motors has been difficult.
> No, I don't have the intake that you're refering to, but I do have
>access to an FJ XSP Intake and 40DCOE as originally run in FJ ca.1962
>
>Mark
>
>
>
>
>Roger Sieling wrote:
>
> > Mark,
> >
> > I have some old literature on these XSP engines. I also have a 948 based
> > XSP, which was in my Sprite when it ran at LeMans and Nassau Speed Week.
I
> > can tell you what limits the factory used at that time. The rods you have
> > shouldn't be the 1100 ones, but special steel ones that just look like
1100
> > full floaters.
> >
> > You will also find that main bearings cannot be bought off the shelf.
They
> > are special to that engine. Do you have the special intake mainfold for
> > 1-1/2" SU's with no chokes?
> >
> > Roger
Brian Evans
Director, Canada
MCI Wholesale Internet Services
|