proxlamus© Posted April 23, 2007 Share Posted April 23, 2007 Welp I finally got rid of my P90a and those annoying ticking lifters ( i hate hydraulic lifters ) I upgraded to a Schneider cam with .488 valve lift and a 260 duration, vacuum dropped from 19in. hg. at idle to 12in. hg. definatly sounds beefy. I also installed the heavy duty valve springs so the old stock springs don't crap out. Not a huge difference in power, but a GREAT powerband up to 6,000 where I have my rev limiter set. Im not used to the solid lifters so it still sounds kidna noisey even after a 0.010 intake and 0.012 exhuast hot lash adjustment. Wipe pattern is good. oh and I have a HKS 2mm headgasket! score! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 23, 2007 Share Posted April 23, 2007 Time to raise the rev limiter... Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 23, 2007 Author Share Posted April 23, 2007 think I can do it safely now without much problems Jon?! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 23, 2007 Share Posted April 23, 2007 Yep, I'd go 7200 or so. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 23, 2007 Author Share Posted April 23, 2007 haha oh lordy that scares me. are the stock springs the limiting factor with a safe rev limit on the Z's?! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 23, 2007 Share Posted April 23, 2007 The fact that the stock turbo cam is too small to make any power over 5500 is really the limiting factor. I had my original valve springs to 7500 rpm with the first tiny little upgrade cam I installed with stock springs. There wasn't much point to revving that high, but it got there without floating the valves. Now that you can use the extra rpms effectively I think the next limiting factor for you is the harmonic issue with the crank that is supposed to kick in around 7500 rpms. Apparently you can drive right through that spot, but it will cause damage over a relatively short period of time with a NA engine, or so goes the commonly spouted theory. I have not actually experienced the damaging effects of this harmonic issue myself... Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 23, 2007 Author Share Posted April 23, 2007 wow. Ill rev it to 7,000 then =) har har thanks Jon! Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 23, 2007 Author Share Posted April 23, 2007 weird im gettin a weird mis-fire now around 5200 rpm and on. I checked the valve lash which is great on a hot spec.. think maybe I need to change the gapping on my spark plugs? Im using the same plugs I used before.. hmm I only drove the car around the block to feel the power band, but normally the rev limiter kicks in at 5,200 and cuts hard at 5,800 so I assumed that stutter was the rev limiter. The feeling is described as a hesitation and continues to hesitate at any higher RPM. AFR is about 10.8 (to be safe) I also pulled out the timing gun which read 24 degrees at idle which is what megasquirt is reading so I didnt mix it up a tooth or anything. any idea's? Quote Link to comment Share on other sites More sharing options...
Ivan280zt Posted April 24, 2007 Share Posted April 24, 2007 Get that a/f to about 11.8 (I run 12.0 at 20psi pump gas) and make sure that you are at least running ngk bpr7es with gap between 25-30. I made few passes down the street with same a/f as yours is right now and it killed those plugs in hearbeat. Now would be also good time to upgrade your ignition box too (unless you already have one). What timing are you running under full boost? Quote Link to comment Share on other sites More sharing options...
Daeron Posted April 24, 2007 Share Posted April 24, 2007 anecdotal comment, I one time accidentally (i forget the circumstances, this is NOT like me) gassed my bone-stock 75 280 up to ahh.. significantly over 7000 before the valves started floating on me... I made a comment to a friend of mine tonight, who was looking at potential upgrades and mods to his '05 SRT-4 tonight. I said to him, "I don't know a great deal about camshafts, but I know how little I know, and I know I am learning more every day. One thing that I do know, is that for my purposes, almost any aftermarket cam for a turbocharged car, is considered "experimental equipment" to say the least." My point was that since turbo'd cars have only really been popular with a widespread, upgrade-minded public for about fifteen or twenty years, and that quite frankly, the REAL know-how on camshaft selection had NOT disseminated to the general public yet.. OHC engines have been around and highly developed in a backyard environment for several decades, now, and alot of people have learned alot from their friends who worked in a machine shop. As a result, we all know more of the intricacies of camshaft specs than we did say, thirty years ago. I'm talking average gearhead knowledge level is up.. but in regards to turbo motors, the VAST majority of us don't really grok what makes it tick just right. The elimination of the valve overlap, although it simplifies the number of factors to be considered, merely makes cam tuning more subtle and difficult to get matched to the engine being built. Not to talk down or negative about anyone and their choice of AFTERMARKET cam, by any means.. I initially started making the comment thinking about the remark made that the stock cam not making any power above 5500 RPM; Braap, tonyD and company are all well aware of the nuances that different specs can give to an engine's flow, but as far as us normal little people are concerned I think we have a long way to go. Thank god for the internet, and hybridZ, right??? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 24, 2007 Share Posted April 24, 2007 I initially started making the comment thinking about the remark made that the stock cam not making any power above 5500 RPM; Braap, tonyD and company are all well aware of the nuances that different specs can give to an engine's flow, but as far as us normal little people are concerned I think we have a long way to go. I'm basing what I said on the many many dyno sheets and threads that I've seen here in the last few years. The turbo cam is advanced 4 degrees from the NA cam so that lowers the rpm where peak power occurs (cam timing is backwards from ignition timing). Seems to be around 5500 from what I've seen. NA cam seems to peak at 6000, maybe 6250. I've also swapped cams several times in my own Z, ported the head, and used different induction systems and seen their effects. I don't have the experience of a BRAAP or a TonyD and I definitely value their advice, but I don't consider myself a little person and I don't think you should either. I've got experience that tells me what I said is generally correct. If you think I'm wrong then we can argue that point. But don't say that we should wait for someone more qualified to decide the issue for us, or that I shouldn't have made the statement I made in the first place. That's not giving either of us enough credit. Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted April 24, 2007 Share Posted April 24, 2007 and your quite welcome for those upgrades Mr. Ryan and I do believe it's a 260 duration, not 250. I told you that you'd like that cam. You can contact Schneider, but you may be able to adjust the valve to 0.006 intake and 0.008 exhaust to help quiet things up. I demand vids! hehe Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 24, 2007 Author Share Posted April 24, 2007 actually I was reading the specs on the sheet you faxed me Justin, it says COLD valve lash .008 intake and .010 exhuast! whooa I was still using the .010 intake and .012 exhuast! ouch better change that! justin what valve lash pads did you use?! I am still using the stock ones. OH yeh, wangsman on Zcar.com recommended I use diesal engine oil.. whatt!! why diesal oil?! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 24, 2007 Share Posted April 24, 2007 actually I was reading the specs on the sheet you faxed me Justin, it says COLD valve lash .008 intake and .010 exhuast! whooa I was still using the .010 intake and .012 exhuast! ouch better change that! Different cam manufacturers advise different lash adjustments, but it's better to run them a little loose than a little tight. The old saying is "Quiet valves burn". My aftermarket cam came with a recommendation of .006 and .008 hot and that's the tightest I've seen. Usually I think .008 and .010 is more common. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 24, 2007 Author Share Posted April 24, 2007 UGH and one more thing, I called schnieder.. they recommended a lash pad thickness of .150 or .160. I am running the stock lash pads. Obviously I need to upgrade to .150 or .160, can I keep the stock retainer?! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 24, 2007 Share Posted April 24, 2007 I thought you said you checked the wipe pattern and it was good... if the pattern is good then you don't need to change anything. If you're unsure then you should check it again or have someone who knows how to do it check it for you. I have a big problem with Schneider or any cam manufacturer telling you what size lash pads you need. They don't know how far the valves are cut or the seats sunk into the head, so I don't believe that they or anyone can tell you without testing what pads you need. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted April 24, 2007 Share Posted April 24, 2007 OH yeh, wangsman on Zcar.com recommended I use diesal engine oil.. whatt!! why diesal oil?! If it's a CWC casting they have a higher chance of failure (it seems) due to the metal used. You've probably seen the pics of the worn down cam lobes on CWC castings. Diesel oil was probably recommended because it might have those additives removed from conventional gas engine oil that is blamed for the flattening of these cams. This is all word-of-internet that I've ran across... so take it as such. Mario Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 24, 2007 Author Share Posted April 24, 2007 k. I used a sharpie and colored the rocker arm and swung the lobes around the rocker arm, everything looked fine to me and the lobe didnt go out of the contact patch on the rocker arm. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 24, 2007 Share Posted April 24, 2007 If the wipe pattern is right then you don't need new lash pads. Did you check every valve? It's kind of anal, but you might try that and see if one is off. Bad machine work can sometimes result in that type of situation, or sometimes if one valve gets burnt or something someone will do a quick fix and cut that one seat, and then all the valves aren't at the same position in the head. Other than that I'd just warn you to be careful about going too tight on the lash. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 24, 2007 Author Share Posted April 24, 2007 No I checked 2 and figured they would be the same. OK i guess its time to dismantle the head again. LoL Thank you Jon, thank you everyone. I'll pull the car in the garage in a few minutes and check it out. Its snowing like crazy right now here in Denver. Quote Link to comment Share on other sites More sharing options...
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