On this board I've seen comments relating engine performance to camshaft design. "The engine #'s would improve with a more modern camsaft design..." What constitutes a "modern" camshaft design? Something like Elgin? (Depending on application) He advocates more duration at medium lift with less total lift over the nose. Where does one get a "modern camshaft design" for the NH? Yeah, I'm trying to spec a cam...trying to keep the lowend torque, and OK (but not stock) idle quality. Not shooting for 6000RPM racecar, but would like to improve highend performance while keeping good lowend torque. Thx!
Halfway decent article here: http://www.chevyhiperformance.com/techarticles/49158_camshaft_engine_basics/index.html Devon
Just keep in mind that if you're playing camshaft games...the Nailhead uses non-tapered cam lobes and non-convex lifter bottoms. Better make sure the cam company knows that before they grind you a "special".
There's a good article on the subject here: http://www.enginebuildermag.com/Article/47626/flat_or_tapered_cams_and_flat_or_crowned_lifters.aspx Somewhere out there in cyber-land is a forum with some great posts on camshaft design....I believe I have it bookmarked at work. Anyway, the cam guru was the guy that designs cams for Camcraft. It was great reading. I'll post it if'n I find it. Until then, a google search for 'camshaft design' or 'camshaft design software' will give you enough info to achieve a new level of enlightenment!
anyone on this board using a "modern camshaft design" in a NH? Any modern cam specs that are known to improve performance? I'm very interested in enlightenment, but not in re-invention. Thx!
The original cam design for the super cats was done by Duntov,,, one of the best being the 091 cam.... gonna be hard to beat for all around performance....:laugh: :Smarty: there are several Duntov grinds that were used in different years, at least one that was a little ''hotter'' but you would not be able to tell by driving the car.....Me, I will stick with the 091.....:Brow:
I'm all for re-invention!! Imagine swapping out your old-tech-camshaft-and-lifter arrangement for some new-fangled programmable-microprocessor-controlled valve actuators!! Some day that day will come....:beers2: But back to your original topic... Roller rockers will, to some extent, do what you are asking.... not hurt drivability by increasing off-the-seat duration, but provide extra valve opening, ie 'area under the curve', for better breathing. Tom once told me the nailhead cams already have fast-opening ramps to open the valves quickly, so there is a limit as how much that can be improved on. The extra ratio of the roller rockers will improve the opening rate. With the result being valves that will be open longer.... But all this needs to be MATCHED to other engine parameters....like port flow, bore/stroke ratio, and intake and exhaust systems being used. That's where the cam design software is useful.... Take a look at the Camcraft webpage, http://www.camcraftcams.com/ Read what is there, then do a search on their designer, Charles Reichard. I'd like to see what he could come up with for Nails.
Given the lifter position (centered on the cam lobe) and the non-industry-standard "true" flat tappet/non-tapered cam lobe--and--the lack of high-pressure additives in common motor oil: A roller lifter is the only adequate response to getting modern camshafts designed.
Never mind.... I just figured out you were talking about the original Super Wildcat cam part number ending in 091... Right?
yep, and i have it some where,,,, got it from Walt,,,,I have run it in the past, and it performs very welll.....
I've been debating having TA grind me a hydraulic roller for my motor. But then I'd have to deal with the Nails tight VP clearence issues, plus it would be at least $800 to make the swap. Maybe sometime in the future...
Andy, personally , I lean toward A good cam [i picked Postons,nh400 because it was closest to the o91] and a set of Toms roller rockers for $800 spent.... rather than a roller cam and roller lifters and all the complex gear they intail.... and my gut feeling is that Toms roller rockers will pick up more power ....and be nicer to the valves,and valve guides in the process....
I'm going with a cam similar to Carmen's W30, and the Comp Cams grind Erik has in his 425. It ought to make good power, have a nice idle, and not have VP clearence issues. It specs out at 222*/234*, .496"/.512", and 108* lobe seperation. We'll see if Tom's rockers are in the budget.
yep, too many times we overlook the factory performance grinds .... Duntov engineered cams for all the gm divisions and was one of the best....if not the best....
Andy, just a word of caution. I feel you will be disappointed with a cam that is close to the "W30" grind. If you are keeping the DynaFlow the idle will be rough, little vacuum for power brakes, especially at idle, low end torque will peak at around 3500RPM's. Now Erik's grind should be closer to what you should be looking for. What's wrong with the cam in your car now??? "My Rockers" will enhance the performance of ANY cam they are installed on without all the "While I'm at it's" that will most definitely come into play. 108* separation is too close. You will need more like 112*-115*. And you may think you'll get the advertised lift, just dream on it won't be anywhere's near that. And if it is you WILL have V/P clearance issues. Just my thoughts. Tom
Hey Funky... Schneider has some nice grinds avail too: http://schneidercams.com/364401425hydraulicliftercamshafts.aspx They're not too wild on the duration, have 112* lobe centers and several have lower lifts that would work great with some roller rockers. Okay, Tom, pick one out for us!
Thanks for your opinion Tom. I plan on keeping the Dynaflow for the time being, but a ST400 is definitely planned in the future. I want a lumpy idle, and I already planned on probably using an electric vacuum pump. I don't think the torque peak will be that high. The split duration profile should level it out, plus I'll be running a shorter tire with the 3.23's. I know there's a better cam for my application. I'm trying to get BOTH the sound I'm after AND still maintain decent streetability/low end power. If all I was after was the sound I'd throw in a cam speced at 250/250 @.050 on 107* centers with notched pistons. If all I was after was power I'd probably throw in a cam speced at 223/235 @.050 on 112* centers. The cam I chose is kinda a compromise. And there's nothing wrong with the current cam, aside from being stock. But the motors going to be out so I figured now was as good a time as any. I'm going to either start squeezing more power out of my Nail or throw in a BBB. I figured a cam swap was the logical choice. I had considered your rockers but they aren't in the budget as of yet. And I also realize I won't achieve the advertised lift, which is why I speced it out as high as I did. I'm more than happy to hear some more advise, I'm always open to criticism. Shoot me a PM if you've got anything else to add! Thanks again :beers2: .
