[Shotimes] don's cams, a report

[Ian Fisher]

I've seen it mentioned that some cam sets in the past
(vendor unnamed) were ground using one mtx intake cam
and one atx intake cam. This led to huge variances due
to the differences in lift between the cams. As I
understand it, Colt Cams (who grinds the +20's, +40's,
etc) was aware of this issue and was trying to avoid
it.

If Doug is using Josh's adjustable sprockets, he will
have a nice range of adjustment (spec's listed on
Josh's site) but I don't see how anyone can compensate
for misground lobes. If one is brought into spec, it
puts all of the others out of spec. The problem may be
exacerbated if more than one lobe is way off. As I
think about it though, I'd assume that they'd all be
off. Doug has mentioned on the forum that many cam
grinders chuck the cam without a means of placing them
"straight up" first. If the cams are chucked the way
that I imagine they would be, I assume that all of the
cuts would be the same once the cam is chucked. If
it's out of position than you'll have a problem. This
is all conjecture on my part though. I'm not really
sure how it's done..

FPS "degreed" a set of stage 1 cams for a friend of
mine. AFAIK, they didn't install adjustable sprockets
so I have no idea what they actually did. 

This is very interesting but for now I'm not going to
jump to conclusions. Obviously I hope that my +20's
are ok but I'm not ready to throw them out just yet..

Ian

--- Robert Bruce <rbruce@bellatlantic.net> wrote:

> This extremely disturbing!  I was considering
> getting a set.  I assume Doug degreed one cylinder
> per cam.  If he had degreed
> differences between cylinders, would the results
> show varying amounts of advance/retard?  Wonder what
> the timing spacing between
> cylinders looks like?  I hope we can learn the
> reasoning behind these variances.  Inconsistencies
> of this amount are just not
> acceptable for parts that command as high a price as
> these.
> 
> How many degrees of adjustment are available with
> the custom sprockets?  
> 
> Robert Bruce
> 92 w/ a mod or two 
> 
>  
> 
> -----Original Message-----
> From: shotimes-admin@autox.team.net
> [mailto:shotimes-admin@autox.team.net] On Behalf Of
> Ian Fisher
> Sent: Friday, September 30, 2005 6:32 PM
> To: Donald Mallinson; SHOtimes; Mike Kopstain
> Subject: Re: [Shotimes] don's cams, a report
> 
> 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
> 
> --- Donald Mallinson <dmall@mwonline.net> wrote:
> 
> > Many of you may remember that Josh's +20 cams were
> > installed in my '89 
> > along with EH intake and BBB.  Dyno testing showed
> > Zero HP gain (maybe 2 
> > hp at most) and a loss across the board of 15+ lb
> > ft. HP was also lower 
> > than before until rpm's got to 6500 rpm!
> > 
> > The car is in Douglasville and Doug Lewis reported
> > last night that the 
> > cams WERE timed correctly according to the cam
> belt,
> > sprockets etc.  
> > That was the first question we had.
> > 
> > What he found out right away is that the cams were
> > ground way off from 
> > straight up.  Two of them were 11 and 12 degrees
> off
> > one direction, and 
> > two were off 9 and 4 degrees the other direction
> (I
> > think) so he has 
> > installed adjustable sprockets and will properly
> > time the cams and see 
> > what happens.
> > 
> > Just thought I would report that the initial
> > installation was OK, done 
> > by Mike Kopstain and friends.
> > 
> > Anxiously awaiting good news from the next dyno
> > session!
> > 
> > Don Mallinson
> > _______________________________________________
> > Shotimes mailing list
> > Shotimes@autox.team.net
> > http://www.team.net/mailman/listinfo/shotimes
> > 
> 
> 
> 
> 	
> 		
>
______________________________________________________
> 
> Yahoo! for Good 
> Donate to the Hurricane Katrina relief effort. 
> http://store.yahoo.com/redcross-donate3/ 
> _______________________________________________
> Shotimes mailing list
> Shotimes@autox.team.net
> http://www.team.net/mailman/listinfo/shotimes
> _______________________________________________
> Shotimes mailing list
> Shotimes@autox.team.net
> http://www.team.net/mailman/listinfo/shotimes
> 



		
__________________________________ 
Yahoo! Mail - PC Magazine Editors' Choice 2005 
http://mail.yahoo.com