Cakebreak Posted July 22, 2011 Report Share Posted July 22, 2011 I'e been looking at the Isky stage 3 cam (.490 lift and 290 duration), and the web cam .488 lift and 252 duration for my 79 620 (l20b) my daily driver. I was wondering if any of you guys use either of these cams and how they perform. And how much carb would you recommend? I've been looking at the Weber 38 dges.<br> Quote Link to comment
banzai510(hainz) Posted July 22, 2011 Report Share Posted July 22, 2011 Defdes on here and on The 510 realm has that cam 490/290. I think its a little big on the street also I think HRH on here has this. I have 2 488/252s at home but never run them. Numbers wise I picked these as duration is shorter. but heard mixed results on Webcams from the Aussies running the really BIG cams. One guy on here said it was OK running on the street. all else fails the Isky 475/275 is OK also. I have a 460 schneider on my truck the schneider dont make new cams anymore. just regrinds. Its OK in my truck with a 38/38 but sidedrafts are the way to get the power with the cam. cams cost money! springs,retainers,Lash pads ,new rockerarms! Quote Link to comment
Cakebreak Posted July 22, 2011 Author Report Share Posted July 22, 2011 Defdes on here and on The 510 realm has that cam 490/290. I think its a little big on the street also I think HRH on here has this. I have 2 488/252s at home but never run them. Numbers wise I picked these as duration is shorter. but heard mixed results on Webcams from the Aussies running the really BIG cams. One guy on here said it was OK running on the street. all else fails the Isky 475/275 is OK also. I have a 460 schneider on my truck the schneider dont make new cams anymore. just regrinds. Its OK in my truck with a 38/38 but sidedrafts are the way to get the power with the cam. cams cost money! springs,retainers,Lash pads ,new rockerarms! Thanks man! i have been hearing that the 490 290 is like an on off switch in traffic. How big of a carb would you recommend for a camed l20b being streetable of course. Quote Link to comment
banzai510(hainz) Posted July 22, 2011 Report Share Posted July 22, 2011 be honest I would be winging it. I have access to 32/36 38/38 duals 40mm mikunis 44mm mikunis I had a l20 long time ago that had a set of 40mm and ran great streetwise. However dont know the cam, as I was new to 510s I have a 40mm set on my beater 510 L16 with a 475/275. seems good to me,no choke to start. have a 44mm set on a L18 lttile to much but drivable. needs choke to start Quote Link to comment
ggzilla Posted July 22, 2011 Report Share Posted July 22, 2011 No such thing as too hot. The 490/290 is fine if you like to keep the engine revved up, including from a stop. The stock heavy flywheel will help get moving, as are stock truck diff ratios and stock small-diameter tires. > How big of a carb would you recommend for a camed l20b being streetable of course. All L20Bs are cammed!!! With the 490/290 and ported head, 2.5" exhaust either Weber 32/36 or 38/38 is OK. Dual 40s are always good and even 44s depending on the venturi size. Quote Link to comment
Sealik Posted July 22, 2011 Report Share Posted July 22, 2011 I have the Shadbolt 256/.491....which is actually .482 You can still get away with stock springs....BUT...they are really close to binding. You'll have a little more room with a Motorsprort retainer....which will raise the installed spring height. I'm running stock L inner and Comp outer, stock retainers with 180 lash pads. I just ordered the steel 150-180 retainers....so I can rev the crap out of the engine :) Keep the lash pads from possibly falling out....5 (ish) grand is my limit for now You can buy new or get your rockers refurbished....I bought new, but used my old rockers that I wet sanded down. I think anything over 260 duration would be a little too much for street/DD???? I spent quite a few hours port matching the head to the IM...and the carb adapters....and it seems it could use a little more fuel... :hyper: .... than the 32/36 I have on it now. The motor is quite responsive on the street...I've also advanced to cam to No 3 position The 38 is being shipped today...so.....we shall see. :D Quote Link to comment
john510 Posted July 22, 2011 Report Share Posted July 22, 2011 Cakebreak,im using the Webcams .488 lift 252 duration in my 510 with an L20b.Its very streetable.Good power from idle on up to about 5500 rpms.Definitely NOT a cam thats like an on-off switch.Smooth power throughout the rpms.Good idle.Im running 38 mm SU's an A87 peanut head thats port matched to the intake.About 2500 rpms is when the motor really starts to feel good.Pretty good gas mileage also.You cant use stock valve springs or retainers and lash pads were .180.I got springs and retainers from schneider. Quote Link to comment
Sealik Posted July 23, 2011 Report Share Posted July 23, 2011 Cakebreak,im using the Webcams .488 lift 252 duration in my 510 with an L20b.Its very streetable.Good power from idle on up to about 5500 rpms.Definitely NOT a cam thats like an on-off switch.Smooth power throughout the rpms.Good idle.Im running 38 mm SU's an A87 peanut head thats port matched to the intake.About 2500 rpms is when the motor really starts to feel good.Pretty good gas mileage also.You cant use stock valve springs or retainers and lash pads were .180.I got springs and retainers from schneider. Your cam is pretty much the same as mine.... You can use the stock retainers/springs/180 pads....IF...there is no coil bind... and IF the lash pad is at least 60% in the retainer... and IF you are not revving over 6 grand. Many IFs....not recommended....but doable....as I can attest to.... :D EDIT John...do you have the specs for those springs on hand...? Quote Link to comment
datzenmike Posted July 23, 2011 Report Share Posted July 23, 2011 The stock L20B cam is 0.413 lift and 248 duration. It makes about 100+ ft lbs of torque at 3,200 RPMs and 112 hp at the engine or about 90 RWHP (on a good day) @ 5,600 Quote Link to comment
datsunwizard Posted July 23, 2011 Report Share Posted July 23, 2011 If you are comparing cams ( and more so cams from different manufactures), you need to know, at what lift at the valve the duration is measured at. Example, a cam that is advertised at 280 degrees duration at .025" lift, but the same cam could show a duration of 250 degrees at .050" and if the cam is measured at 0 lift, it could be advertised at 300 degrees. So it boils down to, if the amount of lift at the valve is not shown with the duration spec, the stated duration is meaning less. Some manufactures go as far as listing the duration and then in the fine print will show the "effective duration" ( a lot less duration) which is at some measured valve lift. There is no standard spec on valve lift when measuring duration, so the manufactures use what ever they want, which can make it very difficult to compare between cams. Quote Link to comment
datzenmike Posted July 23, 2011 Report Share Posted July 23, 2011 This is apples and oranges comparisons. Also no valve starts to open exactly at the stated duration, for one thing the valve lash has to be taken up first before the valve can begin to move. If you had a degree wheel on the crank and a dial indicator on the valve stem you could probably get a better guess at what you have. Some makers specify their duration at 0.050" lift. Quote Link to comment
DISLEXICDIME Posted July 23, 2011 Report Share Posted July 23, 2011 My .last built l had a 480/280 in it and it was fun . But slodats 490/290 was as you saod an on off switch but wshen it came on holly crap it was fun. But trying to drive in traffic was not fun. Both cars ran 38mm su's and where over 11.1.1 Quote Link to comment
datzenmike Posted July 23, 2011 Report Share Posted July 23, 2011 A rule of thumb is that for every 10 degrees of added duration the power and torque moves roughly 500 RPMs higher up the scale. If the L20B makes peak torque at 3,200 then going to a 290 from a stock 248 will (besides increasing the torque) make the car pull stronger up near 5,000 RPMs. The trouble with this is that at the old torque peak at 3,200 RPMs, the added 20 or so degrees on the valve closing side of duration means the intale closes much later than it used to. Stock closing point is 52 degrees past BDC and the piston is well on it's way up the cylinder on the compression stroke. Adding 20 more degrees say to around 70 degrees ABDC means the compression will actually push air back out the intake valve into the port or even the intake. This reverse of direction is disruptive and the cylinder does no fill effectively and power drops off. This added duration benefits very high RPMs where the air speed is so high it is not easily pushed back by the compression stroke and the air crams itself into the cylinder just before the valve closes. Quote Link to comment
hang_510 Posted July 23, 2011 Report Share Posted July 23, 2011 I'e been looking at the Isky stage 3 cam (.490 lift and 290 duration), cams cost money! springs,retainers,Lash pads ,new rockerarms! new rocker arms cost more than the cam :rolleyes: im running an isky .480/280 on the LZ22 (9.5:1) dual weber 45's wanted something still streetable, would run on 87, but effective in the canyons (it really is on 91) :w00t: pulls hard to 6000+ Quote Link to comment
d510addict Posted July 23, 2011 Report Share Posted July 23, 2011 Is there a cam that is a flat out performance increase over the stock l20b cam? or do they just push the power/torque peak up and down RPMS? I do not know much about how lift/duration actually change things, but want to build up this W53 head I have for my new l20b. Quote Link to comment
ggzilla Posted July 23, 2011 Report Share Posted July 23, 2011 Yes, they can do that. A higher lift with more agressive openings will keep the power band in the same place just bump up power. Cam & valves wear out quicker. Quote Link to comment
banzai510(hainz) Posted July 23, 2011 Report Share Posted July 23, 2011 Cam & valves wear out quicker. ???????? owner needs money before cam wears out and sells car/truck Quote Link to comment
john510 Posted July 24, 2011 Report Share Posted July 24, 2011 Your cam is pretty much the same as mine.... You can use the stock retainers/springs/180 pads....IF...there is no coil bind... and IF the lash pad is at least 60% in the retainer... and IF you are not revving over 6 grand. Many IFs....not recommended....but doable....as I can attest to.... :D EDIT John...do you have the specs for those springs on hand...? I dont know the specs on the springs,i took my cam specs to Schneider and they matched up my Web cam to there closest matching cam and thats how we came up with compatible springs and retainers.I do remember the Schneider springs were a little taller and might of had less coils.I played with the stock springs and the Web cam before i put the head back together,they were pretty much stacked solid when i got the cam onto the bump.The part # for springs is 68020 schneider springs,retainers #73003,if that helps.Also the retainers were quite different than stock. Quote Link to comment
Cakebreak Posted July 24, 2011 Author Report Share Posted July 24, 2011 Thank you everyone for all of your help and advice! So i've decided that the Isky 490/290 is out of the question, I am now deciding between the isky 480/280 .050- 232 and the Web cam 488/252 .050- 230 but probably the web because of the duration. Who sells good rocker arms? Quote Link to comment
Sealik Posted July 24, 2011 Report Share Posted July 24, 2011 Thank you everyone for all of your help and advice! So i've decided that the Isky 490/290 is out of the question, I am now deciding between the isky 480/280 .050- 232 and the Web cam 488/252 .050- 230 but probably the web because of the duration. Who sells good rocker arms? Good luck on finding NOS rockers. They do come up on Ebay now and again.....there are a total of 3 available now. With shipping I paid a little under 200 bucks. Best bet would be to get yours reconditioned........ Here are my old ones....after I wet sanded them Quote Link to comment
Hybridchemistry Posted July 27, 2011 Report Share Posted July 27, 2011 Good luck on finding NOS rockers. They do come up on Ebay now and again.....there are a total of 3 available now. With shipping I paid a little under 200 bucks. Best bet would be to get yours reconditioned........ Here are my old ones....after I wet sanded them If there is a Pick n Pull near you, pick up a set out of just about any Datsun. I picked up some arms from a 280z that looked like crap but were able to be cleaned up and will be going in our LZ engine. Just be wary of pitting and chipping on the side. Quote Link to comment
Dirttrack510 Posted February 26, 2012 Report Share Posted February 26, 2012 I run an old Cal Cams camshaft that is marked as being .510 lift and I'm still running the stock springs, It's on my race wagon. So far, so good with no binding issues, but it's close. I rev that thing to around 7200 RPM's. It idles great too, I have it set at 600 RPM. :D Quote Link to comment
datzenmike Posted February 26, 2012 Report Share Posted February 26, 2012 IIRC the stock springs are good to just under .480 lift so either the springs were changed or the cam has less lift? Quote Link to comment
Ratty260z Posted February 26, 2012 Report Share Posted February 26, 2012 zccjdm.com makes new billit ones for Z's just email them and they can help you out for rocker arms. Quote Link to comment
Sealik Posted February 26, 2012 Report Share Posted February 26, 2012 I run an old Cal Cams camshaft that is marked as being .510 lift and I'm still running the stock springs, It's on my race wagon. So far, so good with no binding issues, but it's close. I rev that thing to around 7200 RPM's. It idles great too, I have it set at 600 RPM. :D .510 lift?....you should measure that cam to confirm???? Must be running aftermarket/thicker lash pads to obtain correct wipe pattern? Aftermarket retainers?....that will raise installed spring height and reduce the possibility of the springs stacking solid Valves sitting farther in the head....?....Racer Brown quote ..."Stock Datsun valve springs are quite light and generally are not suitable for valve lifts in excess of 0.440 to 0.460-inch. Besides they stack solid at a lift of about 0.500-inch. They're fine for stock camshafts, but they are the engine speed-limiting factor with camshafts having higher valve velocities"... When I installed my Shadbolt cam (listed at .491/actual lift was only .484) it looked like my stock springs were close to coil bind Quote Link to comment
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