Cam Dynamics 7000 Plus cam help

Posted By: ProStock1320

Cam Dynamics 7000 Plus cam help - 08/29/09 04:23 AM

This one is for you "back in the day" old DC catalog kinda guys.

So I'm looking at a DC cam chart and see P4007277 listed as a Cam Dynamics Stock "Cheater" cam with .467/.483 lift but duration is 352/380 ??? If memory serves, there are only 360 degrees in a circle, right? What am I missing? Someone please enlighten me! Thanks.

Posted By: DrCharles

Re: Cam Dynamics 7000 Plus cam help - 08/29/09 04:40 AM

Remember the cam turns at half crank speed.

The only reason for these cams is to meet stock lift specs while cramming in the maximum possible duration. They have almost square lobes that just slam the valves open and closed so are very hard on valvetrain parts...

A few years ago, one of the car mags (think it was Hot Rod but not sure) had one lying around and wanted to try it... wish I'd saved the article. Anyway they said it would not idle under 1800 rpm and made basically no vacuum, because both valves are open most of the time, but it would rev really high.

Posted By: ProStock1320

Re: Cam Dynamics 7000 Plus cam help - 08/29/09 05:15 AM

So do you half the duration number to obtain modern cam duration numbers or is there another method?

Posted By: Dodgem

Re: Cam Dynamics 7000 Plus cam help - 08/29/09 02:26 PM

Friend used to use those cams on a tractor puller back in the day and those 440's would pull to 7500 at least.
I remember trying to get my head around how there could be more degrees than in a circle!! but alas cam deg are in crank deg and cam is turning 1/2 speed so 380 deg on the crank is 190 on cam circle.
But it in a block and map it out with your degree kit

Posted By: ProStock1320

Re: Cam Dynamics 7000 Plus cam help - 08/30/09 02:56 AM

I know a stock eliminator guy down in northern Calif that says this cam makes gobs of power. I'm trying to figure out how 190* of duration can do that and what this thing equates to in modern cam terms. Is there a tech bulletin or white paper on it somewhere? I do see Dr C's note about an article Hot Rod(?) may have run. Anyone got another source? I'm thinking about sticking one in the boy's 383 AMC Hornet.

Posted By: Dodgem

Re: Cam Dynamics 7000 Plus cam help - 08/30/09 03:52 AM

My old engine book and DC books that listed that cam are gone. now everyone tells me no such cams existed!!! LOL!!
I'll bet they were 305/320 duration @ .050 at least.
Be fun to try one!!

Posted By: Dodgem

Re: Cam Dynamics 7000 Plus cam help - 08/30/09 03:54 AM

Hears some stuff
http://flag.blackened.net/mopar/camchart.html

Posted By: Moparteacher

Re: Cam Dynamics 7000 Plus cam help - 08/30/09 03:55 AM

Chrysler used to measure duration at .006" lift, and if you go back far enough they measured the the intire lobe from start of the ramp to ramp. That's where you get the large numbers.

A common duration figure, @.050" lift, for a stock eliminator cam starts at about 260 degrees.

These cams are extremely peaky; they work in a very narrow rpm band.

Posted By: mr_340

Re: Cam Dynamics 7000 Plus cam help - 08/30/09 04:00 AM

The .006" spec is an SAE spec, usually called the "advertised duration". I have one for a 340 that's never been used. I never measured it but the lobe has a flat nose on it. It looks like the lobes are designed to cause the valvetrain to fly off the end getting more lift and land on the other side of the ramp.

Posted By: sixpackbee

Re: Cam Dynamics 7000 Plus cam help - 08/30/09 11:28 AM

Quote:

I'm thinking about sticking one in the boy's 383 AMC Hornet.

Be advised that you can not just stick a stocker cam in. They are very large at all lifts and have big dwell numbers so they eat up piston to valve like crazy. My old 360 stocker with the piston in the hole .051 and the valves sunk had little P to V.
Also because the acceleration/decell ramps are so steep they require a ton of spring for a hydraulic lifter. To really take advantage of a cam like that ceramic lifters are a must. I like to have seat pressures of around 220 and 420+ over the nose. My 340 stocker goes through a set of springs about every 30 runs or so.

Posted By: Lil Wedge

Re: Cam Dynamics 7000 Plus cam help - 08/30/09 09:21 PM

I ran this cam in a 440 six pack back in the early 80's ,stock cast pistons, stock 906 heads, ran Direct Connection springs,retainers, 1.86 installed height, 100 lbs closed and 300 lbs open with stock rockers which were more like 1.42 which kept it closer to legal lift. Ran it 2 seasons, ran 11.80's 3600 lb Super Bee, Stuck it in a tubbed out 3000 lb. Duster,same trans and converter, only TM7 and 750 Holley and went 11.00 in good air,11.30's in the heat, bracket raced it for a couple years. Great Cam. Piston to valve clearance is critical. I know a couple guys who unintentually put their own valve reliefs in their pistons

Posted By: ProStock1320

Re: Cam Dynamics 7000 Plus cam help - 08/31/09 05:28 AM

Sounds like some of that old 'Mopar black magic' that used to get whispered about. Thanks for all the good info. I most certainly will watch the piston/valve issue and the spring thing. Anybody want to venture a guess on rpm band or convertor choice?