Re: [AMC-list] question on this cam grind, specs
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Re: [AMC-list] question on this cam grind, specs



What's the valve lash?
You can alter the cams action a little bit by playing with lash.
Is it ground straight up? I.E. same as the stock cam?

Maybe your missing something in the equation?
Don't shoot me, I'm just trying to decypher why Galvin would call
it an RV cam if it is not? 
  I wonder, did they back in the day make a "hotter" cam and
this one got ground to the wrong specs and slipped through the cracks?

  Call and ask, maybe you can get exact info as to who ground it
and talk to them?

Mark Price
Morgantown, WV 26508
1969 AMC Rambler, 4.0L, EFI, T-5
2004 Grand Cherokee Laredo, 4.7L, Quadratrac II
"I realize that death is inevitable.
I just don't want to be around when it happens!"

----- "tom jennings" <tomj@xxxxxxx> wrote:

> From: "tom jennings" <tomj@xxxxxxx>
> To: "Rambler AMC, Nash, Jeep and family" <amc-list@xxxxxxxxxxxx>
> Sent: Friday, February 12, 2010 2:50:53 AM GMT -05:00 US/Canada Eastern
> Subject: [AMC-list] question on this cam grind, specs
>
> So I bought one of Doug Galvin's performance cams for the 195.6 OHV. I
> asked
> for specs (cam card) before I bought, he didn't have any one hand, but
> one
> would come in ythe box; he said it was basically an "RV" cam, more
> torque at
> 1000 rpm up at the expense of torque over 3500 rpm, not a bad tradeoff
> in
> this car. Thought I'd take a chance and look at the cam card when it
> came,
> seemed like a safe bet (I can return it unused).
> 
> The TSM specs only duration and opening time, which I assume is seat
> to
> seat. The software I use (SCDynoSim) does the math for me, but I hand
> checked it and it's correct. The cam card with the new cam specifies
> lift,
> duration etc at .006, .050, .100 lift.
> 
> So if I compare stock cam seat-to-seat, vs. .006" lift of the new cam
> (is
> that good enough for ballpark?) I get:
> 
> factory: 244 duration (I opens 13 btdc closes 52 abdc;   E opens 55
> closes
> 10) overlap 22 degrees    (SEAT TO SEAT)
> new:     348 duration (I opens 64 btdc closes 105 abdc; E opens 105
> closes
> 65) overlap 130 degrees (at .006 LIFT)
> 
> Numbers rounded to nearest whole. Lift on the new cam is about .020
> higher.
> 
> The new cam doesn't seem right for an "RV" cam. All that overlap!
> That
> sounds like it will have no vacuum, and that duration seems pointless
> at low
> speeds, reversion and all that.
> 
> Am I nuts or is this a bad cam for a slow turning long stroke motor?
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