Guest 280ZForce Posted February 22, 2007 Share Posted February 22, 2007 Ok, I did some searching and I'm still unsure about what all the exact specs are for this infamous Z-Gad Isky custom grinded cam. So my question is what's the real differences between the (2) following Isky Cams and which is better for me: -Isky Stage 3 Cam for 280z Part #718149 (Scroll down to bottom chart on the link, 3rd one down) http://www.iskycams.com/pdfcatalog/2004-05/page176.pdf -Custom Z-gad Isky Grind Cam (true specs) --------------------------------------------------- what are their power bands and what will do me best for engine application? My current cam I have found out to be a Schneider custom turbo grind... all the could tell me was 260 duration, .488 lift intake/exhaust and 114 lobe center. My current build is listed below is as followed basically... My current project build will be either a 2.9 or 3.0L Stroker engine, custom forged Ross pistons, 240z race prepped rods, LD28 diesel crank, 2mm metal headgasket, full port and polished p90 head w/ a 3-5 angle valve job (intakes ported to around 1.75" and exhausts ported to approx 1.5" wide/tall), custom tailored lonewolf intake manifold w/ 1.75" ID runners, q45 90mm throttle body, GReddy turbo manifold, Holset HY35 externally wastegated. If you need to know anything else, let me know and I'll do my best to help out. Thanks in advance, any help would be greatly appreciated in this determining factor. -Justin Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted February 22, 2007 Share Posted February 22, 2007 The cam that I have from ISKY is a custom grind for a turbo car, I am building the same basic engine as yours. It is a L490 intake/L480 exhaust spec with a 114 deg lob angle. It is what they recommend for a stroked L turbo. Give them a call and they can recommend a grind for you. They don't have an turbo cams in the catalog, but have lots of cams that they will custom grind for you. I think that this is the same cam that ZGAD was running. EDIT - Here are the specs for Z-gads cam. Specs are.. Intake 490 lift 276 duration Exhaust 480 lift 266 duration 114* lobe center 44* overlap Cheers Doug Quote Link to comment Share on other sites More sharing options...
1 fast z Posted February 22, 2007 Share Posted February 22, 2007 There are PLENTY of different isky cams that arent even listed. Working directly with Isky is the way to go. Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted February 22, 2007 Share Posted February 22, 2007 EDIT - Here are the specs for Z-gads cam. Specs are.. Intake 490 lift 276 duration Exhaust 480 lift 266 duration 114* lobe center 44* overlap Cheers Doug Doug thats the same cam that I got from Ron. Justin call and ask for Ron he is a wealth of information and will recommend a nice grind for your application. I spent about an hour on the phone w/ him he is a super nice guy. Quote Link to comment Share on other sites More sharing options...
JIM73240Z Posted February 22, 2007 Share Posted February 22, 2007 is ron at isky? i have been dealing with nolan and he is on my $@it list. he is never there and i cant get an straight answer. i ordered the z-gad cam in september. got it. shiped it to lone wolf for work to be done with the rest of the head. figures, i orderd solid instead of internal oiled, sent back in october, still waiting. first lost, then out of stock. then fresh batch. should be shipped last month. not last month, this week (3-weeks ago). all i want is my cam. jimbo Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted February 22, 2007 Share Posted February 22, 2007 is ron at isky? i have been dealing with nolan and he is on my $@it list. he is never there and i cant get an straight answer. i ordered the z-gad cam in september. got it. shiped it to lone wolf for work to be done with the rest of the head. figures, i orderd solid instead of internal oiled, sent back in october, still waiting. first lost, then out of stock. then fresh batch. should be shipped last month. not last month, this week (3-weeks ago). all i want is my cam. jimbo Jimbo, Ron Iskenderian is one of the sons of the founder Ed Iskenderian. He is the only one in my opinion that you should deal with. Sometimes he is hard to get a hold of but when you do you better have 30 min or more to spare. I never dealt with Nolan, they do have over 100 people there though. Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted February 22, 2007 Share Posted February 22, 2007 thanks guys, I was not aware there was lots of custom turbo grinds available. They should really list them on their site products to maximize sales. My contact at the machine shop my stuff is at says they know Ron and Ed personally and have done business with them for about 30 years now and I know they sell a lot of their cams cuz that's their main source there, so they will have direct contact with them as far as regards to which cam I will be using. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 23, 2007 Share Posted February 23, 2007 One day, ooone day, someone will post the specs that actually have any mean whatsoever for a cam. That is, the 0.05" duration. For example, the cam I am running right now, has 295/292 duration, but is WAY too small, and will make max power maybe 100-200rpm higher than stock. Why is this? Because the 0.05" duration is only 212/210. Check this link for examples of why advertised duration means nothing. http://www.crowcams.com.au/templates/Catalogue-Datsun-OHC.shtml Dave Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted February 23, 2007 Share Posted February 23, 2007 For the L490L480 custom turbo grind (Z-Gad) Duration at .050 Intake-242 Exhaust-232 Doug Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 23, 2007 Share Posted February 23, 2007 Thank you. That sounds like a nice cam to me. Interesting that he cut down on overall duration. In order to get an adequate 0.05, this then requires a relatively high ramp rate, and also limits the maximum lift you get. I think.. I am still learning about cams. I'm not sure why you would do this instead of increasing the advertised duration, and reducing the ramp rate, and getting more lift. Or am I incorrect in my assumption that a lesser change between adv and 0.05 means a lower ramp rate overall? Dave Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 23, 2007 Share Posted February 23, 2007 One day, ooone day, someone will post the specs that actually have any mean whatsoever for a cam. That is, the 0.05" duration. That may give a standard of measurement, but is GROSSLY misleading, especially in a forced induction cam. .050" lift is flowing a LOT of air under pressure. And with the assymetrical ramps Nissan uses (Ron can tell you loads about that little quirk) the numbers at .050 are as useless as the gross numbers used by others because different grinders (if they grind assymetrical at all) may alter the ramp rate as well. Also important are the valve opening events, and the stagger from the ramps that minimize overlap, or increase it. There is a link to a website somewhere that has all the old Racer Brown technical articles. Anyone trying to understand how a camshaft works in an L-Engine should really read that site (http://www.datsport.com/Racer_Brown_Menu.html) What Racer Brown pioneered in the early 70's was relearned and quantified by Ron in the later 70's after he got out of the USAF and got his engineering degree and started doing cam development work for Electramotive's racers. Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted February 23, 2007 Share Posted February 23, 2007 Here are my specs: Isky Custom Ground *Lift 490 intake, Lift 480 exhaust *290 intake duration, 280 exhaust duration *1/14 lobe center He said this cam will keep overlap down, help increase throttle response, and assist in my quest for no turbo lag. Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted February 23, 2007 Share Posted February 23, 2007 Here are my specs: Isky Custom Ground *Lift 490 intake, Lift 480 exhaust *290 intake duration, 280 exhaust duration *114 lobe center He said this cam will keep overlap down, help increase throttle response, and assist in my quest for no turbo lag. whats the overlap on your cam and .05 duration? Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted February 23, 2007 Share Posted February 23, 2007 hmmm I think so I have to pull the cam specs to double check. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 23, 2007 Share Posted February 23, 2007 That may give a standard of measurement, but is GROSSLY misleading, especially in a forced induction cam. .050" lift is flowing a LOT of air under pressure. And with the assymetrical ramps Nissan uses (Ron can tell you loads about that little quirk) the numbers at .050 are as useless as the gross numbers used by others because different grinders (if they grind assymetrical at all) may alter the ramp rate as well. Also important are the valve opening events, and the stagger from the ramps that minimize overlap, or increase it. Tony, Perhaps my statement over-emphasized the importance of 0.05 duration. Don't get me wrong, I still consider it a much better indication of the characteristics of a cam that advertised duration, but, what we are really trying to do is to deduce some information about the entire cam profile. Ie, we are trying to understand the ramp rate, be it asymmetric (between exhaust/intake I assume you are referring?) or not. I don't understand your point about the numbers at 0.05 being useless because Nissan grind their cams with assymetric ramp rates. What difference does that make when considering an aftermarket cam manufacturered by person X? More to follow, should do some work. Oh and those racer brown articles look very interesting. Dave Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted February 24, 2007 Administrators Share Posted February 24, 2007 Dave, If I understand where Tony D. was coming from in that post, (Tony, don’t hesitate to correct me if my assumption is wrong), you pretty much summed up what he was alluding to, in that what we are really concerned with is the lift area under the curve, not just duration at one lift point. Comparing duration specs at .050” only, without any other info, whether the cams are symmetrical or asymmetrical, is barely marginally useful info. With Datsun cams, we are lucky to get advertised duration and duration at .050”, and lobe separation information, (for the domestic V-8 cam market, you can find graphically plotted cam profiles from many manufactures, as well as lift, jerk, acceleration graphs, and that is much better way to compare one cam to another. The BEST way is through actual dyno testing in the engine you are building). I would agree that the .050” duration spec makes it easier to compare one cam grind against another, but it really doesn’t give you any idea as to how “aggressive” the cam grind is, i.e. lift area under the curve. For example, (this is a very broad general example so don’t pick it apart , it is merely used to express a the concept), lets say you find 2 cams with similar .050” duration specs, similar lift figures and similar lobe separation, but one cam makes a lot more power EVERYwhere in the rpm range compared to the other. The camshaft that produced more power had the same duration at .050", but it had more duration at say .100” and .250”, but LESS advertised duration!!!…. That cam was ground with a more aggressive profile which allowed it to make more power, though at the expense of accelerated valve train wear. Keep in mind that everything is a compromise, whether you are building an engine for max power or building a suspension for max lateral acceleration. From this you can see that the .050” duration spec really didn’t help much. So we take ALL the info we can get on the cams and use that to make our comparisons. This is where it gets goofy. Cam manufactures don’t use a common lift value for their “advertised” duration specs. Some use .002” valve lift, some will use .012” valve lift and everything in between. At that low of valve lift, just .002” of valve lift change will show a HUGE difference in duration due to the slope of the opening and closing ramps. But when comparing cam specs just from one manufacturer, you can use the relationship between the advertised AND .050” duration specs to get a relative indication of the ramp rates, i.e. the aggressiveness of the cam profile. Also keep in mind, the more aggressive the cam profile, the more exacting you need to be with lash pad selection. If the cam has a pretty aggressive profile, it will use the majority of the rocker arm wiping surface. The less aggressive cams will use a narrow portion of the rocker wiping surface. Schneider cams are an example of smallish wiping patterns so there is quite a bit of fudge room for lash pads that will “work”. The .520” hot street cam we have ground by Rebello has a wide wiping pattern and as such, will only allow two maybe three lash pads to be used before the wiping pattern is close to running off either end of the rocker. Stock cams can get away with as much as 5-7 different lash pad thicknesses before the wiping pattern becomes compromised. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 24, 2007 Share Posted February 24, 2007 Paul, I agree with everything you said. We do want the entire profile information, and everything is a compromise (area under the curve vs wear). I wasn't aware that advertised duration referred to anything other than the point at which the valve starts to lift at all. That changes my view of things if it is true. The more information you can get out of the cam manufacturers, the better, and the more informed your decision can be. Thanks for more succinctly and completely making my point. Dave Quote Link to comment Share on other sites More sharing options...
blairjj Posted February 24, 2007 Share Posted February 24, 2007 I think that somewhere in this I'm beginning to detect a hint of Calculus... (area under the curve). I've had the math but knew little of its relation to Camshaft theory. Must check on a few sources as I'm now hopelessly interested... Jay <= has the "knack" Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted February 24, 2007 Administrators Share Posted February 24, 2007 Paul, I agree with everything you said. We do want the entire profile information, and everything is a compromise (area under the curve vs wear). I wasn't aware that advertised duration referred to anything other than the point at which the valve starts to lift at all. That changes my view of things if it is true. The more information you can get out of the cam manufacturers, the better, and the more informed your decision can be. Thanks for more succinctly and completely making my point. Dave Dave, Yes, we are indeed on the same page, and yes, camshaft advertised duration is given at differing points of actual valve lift depending on manufacturer. Here are a few sources which will shed a little more light on the non standard “advertised†duration issue… http://www.summitracing.com/streetandstrip/dictionary/dictionary.asp http://www.harveycrane.com/duration.htm http://www.dynospotracing.com/cams.htm Hope that helps… “May the Torque be with you….†Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted February 24, 2007 Share Posted February 24, 2007 clean this up a bit and make it a sticky Quote Link to comment Share on other sites More sharing options...
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