« Previous Entry | MAIN | Next Entry »
December 01, 2003
Nelson...
Well, "knock" is pretty well tied to compression ratios and timing along
with octanes of course, but you already know
this.
You are looking at a cam with numbers
similiar to a Kent #276. The lift numbers
may be the other way around but this is
a minor point (usually a bit more lift for
exhaust rather than inlet, when cam is
assymetric, 'cause exhaust valve is smaller I guess?).
This is a very fast road cam, similiar to
what an APT VP3 or Kent #286 would be for a 1275, more or less.
Minimum compression ratio for such a
a cam (for suitable "squeeze") would probably be around 9.5-1 and on
today's
unleaded premiums (91-93 PON)
this should work I would think
without having to modify
the stock distributor advance curve in
terms of rate or total, assuming header
and/or at least a free flow exhaust.
On yesterday's leaded
premiums (100+ RON) you'd be looking
at a compatible CR of up to 11.0-1 with
about the same ignition advance curve,
running a set of plugs at least a step
more cold than stock.
What compression ratio is the engine
currently running as this will have quite
an effect on combustion temperatures
as the cam "comes in" (cylinder "filling").
Cap'n. Bob
'60 :{)
PilotRob@... 27113
Posted on December 1, 2003 05:05 PM
Posted to category(s) Carburetor | Cylinder Head | Electrical System | Engine (external) | Engine (internal) | Exhaust System | Ignition System | Restoration | Technical Info | Transmission | Tuning
