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Re: Cam Timing

To: "John McCauley" <jege@dock.net>, <mgs@Autox.Team.Net>
Subject: Re: Cam Timing
From: Chris Delling <saschris@flash.net>
Date: Sun, 11 Jan 1998 17:29:08 -0500
John-

The cam specs you give make no sense at all.  As described your performance
cam would be very mild - the car might not even run!  

Most "perfromance cams" are ground to give 270 degrees or more duration.  I
also have never seen a cam for an MG that was designed to open the intake
before 21 degrees - this includes the stock MGB cams.

Please verify your cam specs, and provide a more detailed description of
your engine - i.e. year of car, carburation and exhaust used, and any
modifications from stock.

Most performance cams won't have "any guts" below 3000 R.P.M. or so.  The
real hairy cams don't begin to make power until 4000 R.P.M.  In general you
will give up low end torque.

Timing in the cam isn't real hard.  Once you have established "true TDC" on
the crank, you use a dial indicator to measure the when full lift occurs on
the cam.  When the cam is at full lift, it should correspond to the spec
given for the cam, say 108 degrees after top dead center for example.  If
it doesn't, you will need to use offset keys, or a vernier type timing gear
to properly adjust it so it does.

Get back to me with cam specs (or cam model number if it's a Piper or Kent)
and I will try to give you some more specifics.

Regards,

Chris Delling

At 05:14 PM 1/10/98 -0800, John McCauley wrote:
>I have just installed a performance camshaft in my new engine, and it has
>no guts.  I have been told it is the cam timing, so I puchased a degree
>wheel.  I have installed it on my car and it is set to top dead center.  I
>can't make any sense of how to use it beyond that.  
>My cam specs are: 
>Duration at .050  229 deg.
>Intake   opens 8   closes 41
>Exhaust   opens 41   closes 8
>Cam rise .295    L/C 108 deg.
>
>I would appreciate any help you could give me.
>
>Thanks,
>Greg McCauley
>
>


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