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Re: misaligned cam

To: "E.Claure" <spanlab@ceibo.entelnet.bo>, mgs@autox.team.net
Subject: Re: misaligned cam
From: Barney Gaylord <barneymg@ntsource.com>
Date: Wed, 12 Sep 2001 23:08:28 -0500
At 10:17 PM 9/12/01 -0400, E.Claure wrote:
>.... The mechanic has put a doubt in my mind and really don't have the 
>time to take the front engine cover off. Can I check for this another way?

Yes it can be checked without removing the timing cover, but it's not a 
whole lot easier.  Check here:
     http://www.ntsource.com/~barneymg/mgtech/engine/cm201a.htm

>  would my car run at all?

Yes it would, just badly.  In general, a cam can be indexed (re-timed) by 
up to 6 degrees either way (+/- 6) from its nominal specification (equal to 
+/- 12 degrees at the crankshaft).

Retarding the cam timing will move the torque curve up the rev range, 
giving the engine more torque at higher speed, which may be good for a 
racing engine that spends very little time in the low speed range.  This 
increase in high end torque is a result of holding the intake valve open 
longer to allow the greatest charge of air in the cylinder before closing 
the valve for the compression stroke.

Advancing the cam timing will move the torque curve down the rev range, 
giving the engine better torque at lower speed, which may be good for a car 
driven around town a lot, and spending most of its running tine at lower speed.

Assuming your engine has a stock cam to begin with,  changing the cam 
timing in either direction is probably not good for street driving 
performance.  Checking the standard type of alignment of the timing chain 
and cam drive sprockets is as easy as removing the radiator, the crankshaft 
pulley, and the timing cover.  Checking the cam timing for any non-standard 
cam setup requires a degree wheel for the front of the crankshaft and a 
dial indicator to measure the opening of the valves.

See 8 page Instructions for Crane Tune-A-Cam tool kit:
     http://64.90.9.168/cranecams/pdf/803.pdf

Regards,

Barney Gaylord
1958 MGA with an attitude
     http://www.ntsource.com/~barneymg

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