Jarrid said..
> 8000 RPM engine needs much or all of the following.:
> Balance everything.
> Cam profiled to the requirement.
> BIG valves.
> Clean up the ports.
> Port match.
> Have the crank thouroughly tested before any machining.
> Carrillo rods.
> Lightened pistons.
> Chevy lightened wrist pins.
> Lightweight double valve springs.
> Titanium valve keepers.
> Lightweight custom datsun 510 valves.
> Main oil passages in crank dilled and cleaned.
> Lightweight flywheel with lightweight clutch (7 inch).
>
So the crank itself is not in danger of breaking at these revs? Did you
treat it in any way? I've also heard of steel center main bearing caps being
a must.
> 7000 RPMs could use stock rods (get some of Ramons ARP rod bolts),
> a cam, some porting, balance and stiffer valve springs.
> Anything you can make lighter in the valve train is a good idea.
> 7000 RPM engine is going to need more carb than stock.
> DCOE webers are nice, a 36/36 DGV would be OK.
> Puting in oversized chokes (Bill Lewis) in a zenith 36WIA/WIP as well as
> larger jets would help out alot.
> I wouldnt use the stroms unless I had to for smog.
> 2500 RPM to 7000 RPM usable range is doubtfull unless your
> criteria is that the engine can operate within that range.
> In practice a 7000 RPM alpine engine will have a very big hole
> below 3000 RPM.
> I have what I would call a 7000 RPM on my alpine now, and if you
> make the mistake of letting the revs drop below 3000 RPM,
> the engine sputters and spits through the carbs. Fuel injection
> will fix this, but the engine still doesnt make torque till 3500.
>
>
I don't really need power from 2500, just not for the engine to splutter if
I end up down there. I do autocross and motorkhanas sometimes(I think you
call it solo there), and sometimes I can get caught out and can be in the
wrong gear. It sounds like this will limit my choke size of the webber DCOEs
to around 32mm, which again will limit my upper end power and revs. But as
you say I can't have everything. This is all such valuable info to know
before I embark, taa guys.
> 6 inch rods are longer.
> Your smokey yunich book will say that you want to increase the rod to
stroke
> length ratio. Ideally we want an infinitely long rod, but thats not going
> to
> happen, to we use the longest rod that we can accomodate with pistion pin
> height offset. Added benefit is that the piston gets very short and
> lighter.
>
>
Did these rods still fit down the bore, or did you have to assemble from the
bottom of the engine?
> >What is the magic article on the 2000cc rootes engine?
>
> SAOC had an articcle some years back telling of making a low$ high
> displacment
> rootes engine.
> It consisted of Avenger 96mm pistons, some other rootes conecting rod and
> alot
> of faith in the integrity of your block.
> Yielded 1944cc if I'm not mistaken.
>
> What is not apperant though is how do you seal the .180 thou overbore
holes
> in you block.
>
Yes, I have read this article. I wondered about how many blocks would be
needed before one would actually not break through. Here in NZ I know of
engines running cf bedford pistons (165 thou over), holden 161 pistons (160
thou), volvo (175 thou). Again, they all use custom made head gaskets, and I
think one may actually be o-ringed.
Back in the late 50s and early 60s there was a lot of humber 80s racing here
(just really rebadged hillman minxes) and ford zephyr pistons were the norm.
They actually took out the NZ national saloon title for a few years, with
jags being next in line. It wasn't until the ford mustangs arrived here that
they were knocked off their perch. Sunbeams weren't used for racing much
here, as there were far fewer of them and they were much dearer here. Theres
still humber 80s racing in the classic scene today, but also alpines and
rapiers. The shell i'm using is a humber 90, which is really a rebadged mark
2 s/minx. It is a bit heavier than the alpines (but a lot of the extra
weight are frills which are easily removed) but it looks much slower which I
find appealing. I'm running about 920kg at present and have yet to lighten
the doors or glass. Also parts are much easier to come by. Alpines are a bit
precious here now if you want to race hard, out of my budget anyway. The
first car I was racing was a Humber Sceptre mark 2, even rarer, which is why
I changed. But it's the sceptre motor (which is the same as an alpine series
V) that I'm using.
Greg Locke
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