Hi Brad. I have a 71 also. Choosing to leave it stock for awhile and ignore the
AEG163 S head ala Viz, 45DCOE, 286 new on the shelf -for now. Trying to just
have
a simple, sweet stocker this time. I've had the full race and semi
before and we'll see just how long it takes for me to break down and DO IT. Oh
well.
D r e a m M a c h i n e :
Balance it. APT stuff. 286 cam is too hot, especially with 1.5 rockers. Try 276
and stock or offset-bushed rockers for less added stress on the valve operating
system as a whole. Do Vizard's mods to a good head and use rimflows.
Compression no higher than 10:1, even tho these engines really dig high
compression. 40DCOE or a 45. LCB and a nice steelpack for the audibilities - or
an RC40 for a sleeper. Alden Yellow and optimized radiator with aux electric
fan. Oil cooler depending on where you live. 5-speed to give the engine a fair
break.
I wrote a treatise for the Mini web about balancing power demand and longevity.
You could call it stress management. Be judicious about adding stress. Analyze
those activities that reduce stress, such as balancing,
porting, better exhaust header and cooling the fluids. Consider those that are
neutral, like improved ignition systems higher output oil pump, degreeing-in the
cam. Counter with those that add stress, like high-lift cams and rockers,
high compression, forced induction, and higher-rev power band. Balance is more
than just what your pistons weigh.
The improved head and rimflows will give you better breathing while not adding
stress. Gotta leave the guides alone. Okay- polish them, but leave them full
length. This should make up the difference between hot and hotter cam.
Yea!
If the trade-offs are fair to the engine and the power band is relatively
unchanged, you could have a happier, sweeter, considerably more powerful motor.
Engine Stress Management can also be related to factors that raise or lower
temperature. For everything that adds, do something that reduces. A 10:1 CR
raises heat!
With a close-ratio 5 speed box, the engine will last a lot longer (cast iron
doesn't blush). Damn - that was a good little saying!
Higher efficiency and lower stress are the best goals, tweaking reasonably for
rational use.
David McCartney
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