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

[farna@xxxxxxx]

That cam might give it more power on the low end. The cam Lunati ground for me years ago was a good mid range came. It had 264 degrees duration and 0.470 lift (added 20 degrees and 0.100"). I don't recall tach readings, but it ran pretty much like a stock engine up to 40-45 mph, then had a good bit more power from there all the way up to around 75-80 mph. Could easily cruise at 70 and still have a little passing/hill pulling power left over. Cruising at 75 wasn't out of the question. 

You'll have to talk to someone familiar with cams. I'm sure Doug didn't come up with that grind himself. It may be what it takes to get better low speed performance vs. the cam I had. 


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Date: Thu, 11 Feb 2010 23:50:53 -0800
From: tom jennings <tomj@xxxxxxx>

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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Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
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