Listers,
I'm planning an eventual rebuild for my BJ8 engine that will incorporate
a few performance mods (mild porting, carb work, etc.). I'm considering
doing some of the mods prior to pulling the engine, to see what kind of
effect individual mods have.
Anyway, I'm thinking about installing a high(er) ratio/lift rocker set from
Rocker Arm Specialists. I see they come in 1.5, 1.55 and 1.6 ratios.
Does anybody know if--for sure--which of these will "drop in" to a
stock (no head or block skimming) 2912cc engine? I know you should
dry build the engine to check clearances when you do this, but if anybody
has dropped-in a, say, 1.5 or 1.55 rocker set with no ill effects would you
let me know? My cam has an advertised lift of .432" (250deg duration),
as opposed to the nominal lift of .368" (per the book, anybody know if
this is "advertised?") I assume both are total lift, after multiplication by
the rocker ... can anybody confirm? Looks like my cam grind has higher
lift and shorter duration than stock (it was the mildest of 5 available grinds
from Crower Cams). It's a good cam, very stable idle and good low-end
torque, but seems to tap out over 4,000 rpm.
Maybe with the higher-lift cam I should use the 1.5 rocker? The stock
rocker is a nominal 1.5, but I've heard they are all over the place and
usually closer to 1.45 ... can anybody verify/dispute?
Another note: in checking the Bentley manual, I note the valve rocker
clearance for "Competition (Mk. II and III)" is .015", not the .012"
listed on the rocker cover. Anybody know what "Competition" means?
(BTW, the "Mk. II and III" are italicized in the manual)
Ah, heck with it, anybody know what the best lift/duration cam and
rockers are for a really torquey, quick, street machine?
bs
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Bob Spidell San Jose, CA bspidell@pacbell.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
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