[Healeys] Cam drive sprocket (gear)

Michael Salter msalter at precisionsportscar.com
Sat Oct 20 20:13:27 MDT 2007


Hi John,
It is probably a little more complicated than that. I don't remember how
many teeth there are on the cam sprocket but you will probably find that
combinations of moving the cam to another keyway and then installing the
timing chain to move the timing back to as close as you can get to the
original spec will produce an increment of maybe 1 or 2 degrees.

Michael Salter
100S (1955)
3000 Mk111(1965)
100 (1953)
AHX12 (1953)
Bugeye (1961)
http://www.netbug.net/blogmichael/

-----Original Message-----
From: healeys-bounces+msalter=precisionsportscar.com at autox.team.net
[mailto:healeys-bounces+msalter=precisionsportscar.com at autox.team.net] On
Behalf Of John Snyder
Sent: October 20, 2007 10:58 PM
To: healeys at autox.team.net
Subject: [Healeys] Cam drive sprocket (gear)

Here is a question that has me baffled.  I'm rebuilding one of the first
3000
engines.  HBN7L 605 chassis.  The camshaft drive sprocket has 6 keyways in
it.
Each keyway is numbered 1 thru 6.  There are corresponding numbers on the
front of the sprocket near the teeth, w/ #1 at the big "dot" used for timing
the cam.  Comparing this sprocket to a later one with only one keyway, the
#1
is located the same as the single keyway and big dot.

This engine was built by Hollywood Sports Car in the early 1960s, and the
guy
who raced it says it dyno'ed at 206 HP.  I know that changing the cam timing
slightly can increase horsepower, but think that rotating the cam 60 degrees
(1/6 of the circumference) would not allow the engine to run.  Why does this
sprocket/gear have 6 keyways?

John Snyder
1959 BN7
1960 BT7
1961 BN7 MK2
1962 BT7 MK2


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