[Shotimes] don's cams, a report

[Donald Mallinson]

They make dial indicators for this purpose.  I haven't ever done it, but 
I have read about it and watched it being done.  I didn't think that 
would make that much of a difference, but Doug and I are looking forward 
to the next dyno test where we find out what just making sure the cams 
are "straight up" will do.  Then he will start fiddling with 
advance/retard and computer stuff.

When I built a drag motor for my Catalina I did extensive research into 
cams for old Pontiac engines.  These are engines that have pretty much 
been a known quantity since 1965.   And yet to this day, I went to three 
MAJOR Pontiac engine builders,  One advances the heck out of all cams, 
another retards them, a third put them in pretty much straight up.  Is 
it any wonder that finding a good engine builder/tuner is still an 
exercise in pulling out your hair!

Don Mallinson

Ian Fisher wrote:

>Wow that's a mess for you and now me. How does one
>check the lobes? A dial indicator? I don't even know
>how to begin...
>
>I guess I won't install the timing belt this weekend..
>
>Ian
>
>--- Donald Mallinson <dmall@mwonline.net> wrote:
>
>  
>
>>I think you got the wrong idea, the ENTIRE cam was
>>ground off.  Not just 
>>one or two lobes.   As Doug explained it, when the
>>cam is reground, the 
>>grinder can either take the time to make sure that
>>the lobes of the 
>>original grind are straight up or he can eyeball it.
>> Apparently these 
>>were eyeballed.  Thus ALL lobes on each cam were off
>>the same amount in 
>>the same direction.
>>
>>The adjustable sprockets allow you to pretty much
>>put the cams where you 
>>want.  Doug says that just taking out the dowel and
>>using the slop in 
>>the bolt holes can get as much as 6-8 degrees, but
>>using the adjustable 
>>sprockets allows you to set up the cams the way they
>>were supposed to 
>>be, and start the tuning from scratch.  Then advance
>>or retard as needed.
>>
>>Ian, I would recommend that while the engine is
>>still easily accessable, 
>>that you check the cams and degree them to make sure
>>where they are.  
>>That is a good idea any time you put in a cam, but I
>>guess we got used 
>>to the idea that cheap aftermarket cams for Chevy's
>>and Fords were all 
>>done right.  Reground cams apparently may not have
>>the precession that 
>>new cams have.
>>
>>Don
>>
>>Ian Fisher wrote:
>>
>>    
>>
>>>If that is the case, why not exchange them for
>>>      
>>>
>>another
>>    
>>
>>>set? It seems like using adjustable sprockets won't
>>>get them timed properly very easily. If they are
>>>incorrect to start with adjustable sprockets will
>>>      
>>>
>>only
>>    
>>
>>>get you so far...
>>>
>>>This is interesting. Keep us posted. My +20 cams
>>>      
>>>
>>are
>>    
>>
>>>installed in my 3.2 which is waiting to be
>>>      
>>>
>>installed
>>    
>>
>>>sometime this month.
>>>
>>>Ian
>>>      
>>>
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>>
>>    
>>
>
>
>
>		
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