franky240z Posted September 25, 2012 Share Posted September 25, 2012 Howdy all. I've a cam 300/300 duration valve lift 0.453" inlet valve lift 0.451 exhaust Timing inlet open 43btdc closes 77abdc exhaust open 77 bbdc closes 43 atdc Full lift 107 deg atdc inlet btdc exhaust Am I right in thinking that the lift is a little low? Reading the specs it reads like it should be a nice 4-7000rpm grid, or have I missed something!? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 25, 2012 Share Posted September 25, 2012 Kind of hard to tell what the true duration is unless you give the openings/closings at 0.050" lift, as ramp up on the lobes can vary a lot. I am assuming your duration numbers are based on the cam lift alone, and look typical to what you read, 4k-7k rpm. Virtually identical to the cam I am installing/dialing right now. Quote Link to comment Share on other sites More sharing options...
franky240z Posted September 26, 2012 Author Share Posted September 26, 2012 This is the data i've got Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 27, 2012 Share Posted September 27, 2012 This is a cam that when measured with conventional 0.050" lift specs is really at most a 275 duration. More likely 260. That coincides with the lift. If you look at Isky's site, they will show you both gross duration and duration at 0.050" valve lift.Schneider does this as well I believe. There is no reason to run 300 duration with a small lift like that. Quote Link to comment Share on other sites More sharing options...
franky240z Posted September 27, 2012 Author Share Posted September 27, 2012 So not quite enough 'cam' then? Does anyone run something similar? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 27, 2012 Share Posted September 27, 2012 I have a similar cam I bought used and just degreed according to the cam card. I've been struggling with getting it to work satisfactorily, and this weekend will be it's last chance. I will report on the results. Quote Link to comment Share on other sites More sharing options...
franky240z Posted September 27, 2012 Author Share Posted September 27, 2012 Should also put, 2.4, worked head, 40mm carbs, 1+mm bore, 10.0:1 compression. Quote Link to comment Share on other sites More sharing options...
Xnke Posted September 28, 2012 Share Posted September 28, 2012 The cam I am running is advertised at .480" lift, 280* duration...but at 0.050" lift it's only 232* duration, and it's only .455" lift. It's fine for driving daily, but I feel like my horsepower:fuel milage parity is a little off. Wide powerband, but pretty much NO power under 1800RPM, pulls pretty good till the redline at 7200 though. Call it 3-7K. Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted September 28, 2012 Share Posted September 28, 2012 (edited) Add 100th lift it would be ok, these cams are for people that dont want to set up the springs and piston to make them realy work Edited September 28, 2012 by PMC raceengines Quote Link to comment Share on other sites More sharing options...
franky240z Posted September 28, 2012 Author Share Posted September 28, 2012 I already think i'll have to get something a little lumpier. I'm running a 4.44 subaru plated lsd so no having much push low down isn't an issue. its not a daily driver either. Ideally i'd like something that came on about 3500ish rpm and pulled nice to 6800. As its a fun/toy car I do want a fun feeling engine. Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted September 28, 2012 Share Posted September 28, 2012 260@50 310d 550Lift on 106c is right on the money with 10.5 comp ported head and 3 45carbs and a good set of pipes Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 28, 2012 Share Posted September 28, 2012 See how those specs correlated? 300=250, 310=260...Im with PMC, without added lift the duration is pretty much useless. Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted September 29, 2012 Share Posted September 29, 2012 (edited) Long deg duration low lift cams rev well , and last well as the speed on the rocker is much slower .But dont make the same torque and power as the high lift race cams we use, having close to 600th and 314d @ 50 will be 260+ on 106c or 108 .... this type of cam makes power from 4300 and makes peak torque at 5500 and peak power at 7500 , this is in a L28 with 89mm bore and 3, 45,48 carbs , now when i say it makes power from 4300 i mean thats when its on the cam ,but they make plenty before this and are fun to drive , , Edited September 29, 2012 by PMC raceengines Quote Link to comment Share on other sites More sharing options...
franky240z Posted September 29, 2012 Author Share Posted September 29, 2012 I just want a lively feeling engine, i'm staying at 2.4 +1mm. 40mm carbs, lightened/balanced bottom end and flywheel. What do you think might suit? My current cam? Quote Link to comment Share on other sites More sharing options...
zbloke Posted September 29, 2012 Share Posted September 29, 2012 I just want a lively feeling engine, i'm staying at 2.4 +1mm. 40mm carbs, lightened/balanced bottom end and flywheel. What do you think might suit? My current cam? I really think you'd benefit from some more lift, I have a similar-ish spec engine to yours in my Z and I've got a cam with 297 deg. duration and 490" lift, drives well and pulls hard from approx. 4200rpm to the redline.......and sometimes slightly above it Only real way to know if your current cam is sufficient is too build the engine with it and see if you like it, just make sure when you do your dummy build/mock up you have enough piston to valve clearance to go to a bigger cam without carrying out any further mods, if you don't like it Quote Link to comment Share on other sites More sharing options...
franky240z Posted September 29, 2012 Author Share Posted September 29, 2012 i'm fitting new rockers though, I guess new ones would be ok with a cam change under 1000miles? Quote Link to comment Share on other sites More sharing options...
franky240z Posted September 30, 2012 Author Share Posted September 30, 2012 I think this is what I want. Just a little more lift.. Brand Isky Racing Cams Manufacturer's Part Number 718196 Part Type Camshafts Product Line Isky Solid Flat Tappet Camshafts Summit Racing Part Number ISK-718196 Cam Style Mechanical flat tappet Intake Duration at 050 inch Lift 264 Exhaust Duration at 050 inch Lift 264 Duration at 050 inch Lift 264 int./264 exh. Advertised Intake Duration 306 Advertised Exhaust Duration 306 Advertised Duration 306 int./306 exh. Intake Valve Lift with Factory Rocker Arm Ratio 0.530 in. Exhaust Valve Lift with Factory Rocker Arm Ratio 0.530 in. Valve Lift with Factory Rocker Arm Ratio 0.530 int./0.530 exh. Intake Valve Lash 0.010 in. Exhaust Valve Lash 0.010 in. Computer-Controlled Compatible No Grind Number Z-196 Valve Springs Required Yes Camshaft Manufacturers Description Fits the Datsun 280-Z 2,800cc engine. Competition camshaft, thicker valve lash caps ISK-LC-263 required. Quantity Sold individually. Notes Rev lube included. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.