Can Someone Translate These Cam Specs To Plain English....Please, Please, Please

[texasz]

There's a guy locally selling a ported & polished N42 head with these cam specs:

495 lift with 290 duration I think it was 107 lobe seperation.

Only pulled about 9 or 10 inches of vac. at 1000 rpm.

Pulled like a bitch in heat after 3000 or so rpm.

That head made 191HP to the wheels on a stock bore flat top bottom end with a header and standalone efi.

What does this mean in laymans terms?

[ChrisZ]

That you need to ship that head over here :classic:

I think it is what's called a stage II cam

Chris

[jmortensen]

Motorsport sells the Schneider cams and their stage IV looks similar, but it doesn't have to be a Schneider. Layman's terms: It is a medium sized cam.

[texasz]

Motorsport sells the Schneider cams and their stage IV looks similar, but it doesn't have to be a Schneider. Layman's terms: It is a medium sized cam.

Medium sized cam being good for top end or low end power? I really don't know much about cams if you can't already tell that.

[Oiluj]

Check out this document which explains what the terms mean and provides some additional information.

http://www.austincc.edu/wkibbe/camterminology.pdf

[jmortensen]

Medium sized cam being good for top end or low end power? I really don't know much about cams if you can't already tell that.

Medium sized cams are nice for a hot street engine. You'll lose a little bit of low end but pick up a lot on top. Mild cams are nicer for daily drivers, more torque at low rpms but don't quite have the punch up top. "Big" cams are more for race only engines and have the added issues of increasing wear and requiring a lot more compression to make them work properly.

[texasz]

Medium sized cams are nice for a hot street engine. You'll lose a little bit of low end but pick up a lot on top. Mild cams are nicer for daily drivers, more torque at low rpms but don't quite have the punch up top. "Big" cams are more for race only engines and have the added issues of increasing wear and requiring a lot more compression to make them work properly.

Jon, thank you for the info...that helps a lot!! This is exactly the kind of info I was after.

Now if I apply that info to a stroker bottom end you'd be in good shape it seems since with this cam you are giving up some torque it's no big deal because the stroker has so torque already.

[jmortensen]

It should do fine even on a normal bottom end and I daily drove my car with a similar cam for years, but yes, a stroker makes it even better. Here is a video of my 8.5:1 engine with brand new Mikunis (read: not tuned) and a very similar cam.

http://videos.streetfire.net/video/2000-autox-indisde-and-outside-I-think-my_8051.htm

[texasz]

Jon,

I've done a bit more research and calling on this and agree it does appear to be the Stage IV Schneider cam from MSA (I can't remember if the seller said it's an Isky or Schneider).

Anyhow, I just called MSA and the guy said that he'd really recommend the Stage II instead citing that the Stage IV power band is 3500-7000. This seems pretty darn high to me! Sounds like no power off the line unless you are rev'd up over 3500RPM and then you're likely spinning the tires instead of putting it to the ground.

Any experience/input on this?

Car use will be to autox, maybe road race (a buddy has been enjoying a track he recently found more than autox so I may give that a shot), and some street use (not a daily driver).

[Bruskiz]

Racer Brown article is a great read on camshafts. Datsun camshafts & valve timing by Racer Brown

Read it, take notes, read it again. If you want to cheat, jump to chapters 7 & 8 and he talks about selecting camshafts. I used the "weekend warrior" as a guide to getting Isky to do a regrind camshaft.

There is alot to camshafts then just adv duration and lift. Schneider 290/495 with lobe seperation angle(LSA) of 106 is going to have a rougher idle then Isky 290/490 cam with LSA of 109. Both cams are going to have a rougher idle then a 270 duration cam.

Decide on a cam for how you are going to drive most of the time, not an occassional track day or you can get a deal on it. One cam is not going to be perfect for street, autox, and the track. To me, 290 is too much duration for autox. To someone else, it may be perfect.

- Mike

[jmortensen]

Jon,

I've done a bit more research and calling on this and agree it does appear to be the Stage IV Schneider cam from MSA (I can't remember if the seller said it's an Isky or Schneider).

Anyhow, I just called MSA and the guy said that he'd really recommend the Stage II instead citing that the Stage IV power band is 3500-7000. This seems pretty darn high to me! Sounds like no power off the line unless you are rev'd up over 3500RPM and then you're likely spinning the tires instead of putting it to the ground.

Any experience/input on this?

Car use will be to autox, maybe road race (a buddy has been enjoying a track he recently found more than autox so I may give that a shot), and some street use (not a daily driver).

You DROVE it. What do YOU think?

As for my opinion, I daily drove and autoxed a very similar cam for years with a light flywheel and triple carbs, something a lot of people seem to think is impossible. The L6 has enough rotating mass in the crank that they aren't that hard to get off the line, even with a light flywheel. Stalling my car was a once a year if that sort of thing. You'd have to brainfart big time to screw up that bad.

I think people tend to undercam their Z motors as a general rule. I have seen several people buy the Stage III and then get rid of it because it wasn't big enough for their purpose (autox or track days). On the other hand I have seen one person, and only one, get extremely good results with the Stage III. I don't know if this is attributable to the headwork that he did, his super lightweight clutch setup, or his intake setup or what, but the guy does fantastic work and somehow got the Stage III cam to work well past the rpm range Schneider says it's good for:

http://forums.hybridz.org/showthread.php?t=145256

Excluding that extraordinary result, my experience watching others run the smaller Schneider cams has led me to believe that they're not big enough. I'd run the cam you have. If I had kept my L series I would have gone bigger, I was looking for something in the .520/300 range or so for autox/track days but no longer driving on the street.

[texasz]

Thank you for the added input Mike.

Jon, no I didn't drive it...the head is off the car and is what I'm looking at buying. So I've never driven nor even heard a car run with this head/cam.

The seller just said "that is was peaky and made most power above 4000 rpm. When the power came on, it really pulled. It idled rough, like a cammed V8. " Now if this is true I'm not sure that's a good fit, making most of the power above 4k seems pretty high to me. ARGH!