SleeperZ Posted December 12, 2011 Share Posted December 12, 2011 I've read so many camshaft threads, my eyes are swimming. But I found nothing on the question I have. I'm still tossing around options on replacing my wiped Schneider turbo cam. All the old rocker arms are in excellent condition, even the one that wiped the cam lobe. And cockerstar sold me a used camshaft that may be an excellent substitute for the old one. So if I decide to install this camshaft, what sort of prep does it need? I will probably have my rockers resurfaced, but what about the cam surfaces? Can any local machine shop do whatever may be needed, or does it need to ship off to a cam specialist? Thanks for the help. Quote Link to comment Share on other sites More sharing options...
PalmettoZ Posted December 12, 2011 Share Posted December 12, 2011 Hey Sleeper Z- Good camshafts only have surface hardening, and its not very deep. That said, most local machine shop (normal shops) cannot do regrinds on camshafts, and don't have the capability to do the hardening process afterwards either. A camshaft grinder is a very expensive machine for sure. If you send it off to be re-conditioned (or reground) make sure that the cam grinder you use can make a surface hardening for you after the grind, otherwise its a waste of money. If it were me, I would just install your used camshaft from Cockerstar and the old rocker arms if they are in good shape and don't show any visible wear under a magnifying glass. That would be the least expensive route. Probably would be just fine. If you want it bulletproof, have the rockers re-surfaced and cyrogenically treated, (Wolf Creek racing does this on an exchange basis) and get the cam also treated by him as well. This freezing process really works. Just my 2 cents. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 12, 2011 Author Share Posted December 12, 2011 (edited) I was not considering a cam regrind. I'm not familiar enough with camshaft metalurgy, is there a resurfacing or polishing to help the cam mate to the rockers? Supposedly we re-surface rockers like we hone cylinder walls, to retain lubricant to assist the break-in of the surfaces. What you seem to be saying is the used cam should be good to go. I think re-surfacing the rockers may help (?) even though they seem to be in excellent condition, no grooves or discernable wear save the wipe pattern. I am open to suggestions, I want to get some good use out of it even though I am currently a cheapskate and want to use "pre-worn" parts. Edited December 12, 2011 by SleeperZ Quote Link to comment Share on other sites More sharing options...
PalmettoZ Posted December 13, 2011 Share Posted December 13, 2011 Don't think there is any resurfacing treatment that you can do to help the cam mate to the rocker. Rocker arms are normally resurfaced to verify that the radius is correct, and the surface has the correct Rz (finish). You can't do anything to the cam unless it is re-ground and re-heat treated. I'm all about the cheapskate approach myself, and re-used the rockers on my 3.1 liter motor with a new cam. Still going fine. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 29, 2011 Author Share Posted December 29, 2011 Alright, I am playing with dialing this cam. It seems very similar to my old Schneider cam, with these specifications: Camlift .310 In/Ex Duration @ .050" camlift 240 In / 230 Ex I have measured the lobes of my pre-owned mystery cam to this: Camlift .293 In/Ex Duration @ .050" camlift 220 In/Ex The old cam stated it had 114 lobe separation, and to degree the intake peak to 112. I haven't measured the exhaust peak yet, but the intake was at 121, retarded 9 degrees relative to the old one. Should I run the cam at the number 1 hole on the gear, which is dead on TDC, or advance it as much as I can to get the intake peak closer to the Schneider? Yes, different cams, different grinders.... Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 30, 2011 Share Posted December 30, 2011 I would start in the # 1 hole. Set the lash and check the wipe pattern. Then check the cam timing. Do you have the cam card? If the timing is good, I would run it as is. If the timing is off, adjust it as well as you can with the sprocket you have. I was able to get very close with a Nismo adjustable sprocket. If you have shaved the head and shimmed the towers, and or are running a non stock head gasket thickness, you really need to verify the cam timing. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 31, 2011 Author Share Posted December 31, 2011 (edited) I don't have the cam card. I am trying to determine whether the cam is suitable for a slightly higher revving turbo engine for track use. I still have a stock turbine with a TO4B compressor, and I liked the power curve of the Schneider. Since this cam is looking remarkable similar in lift and duration, I am thinking I will use it, but with the standard cam advance, this cam is retarded relative to the Schneider. I degreed the peak of the exhaust at 84 degrees BTDC, so what is that separation? Cut crank degrees in 2, for about 102 degrees separation. That seems narrow; the Schneider is spec'd to 114 degrees separation. My peak measurements are pretty sloppy however. Anyway, I am tending towards advancing this cam, to more closely match the old one. It sounds like I should set up cylinder one with rockers and pads with the proper clearances and wipe, then make the measurements at the valve? Any tips or clarifications on what I am trying to do? Edited December 31, 2011 by SleeperZ Quote Link to comment Share on other sites More sharing options...
letitsnow Posted December 31, 2011 Share Posted December 31, 2011 I don't have much advice other than run it, if it's gutless down low, advance it some and try again. You might call isky and ask them too. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 1, 2012 Author Share Posted January 1, 2012 I don't have much advice other than run it, if it's gutless down low, advance it some and try again. You might call isky and ask them too. The cam seems way too retarded to just install the rockers and test it. Seriously, I'm starting to think this particular cam was indexed wrong when it was ground. Compared to my old grind, with the cam gear notch lined up with the thrust plate and the dampener at TDC, this thing is 20 degrees off. The 0.05" intake (at the lobe) opening is more than 20 degrees AFTER TDC, where my old grind was 8 degrees ATDC. The duration is slightly less, so even with the closer lobe centers, it's going to run like crap if it doesn't contact the valves. I'm thinking I will ignore the index mark, and degree the thing as advanced as I can without going more extreme than my original grind. It looks like I will have to skip a tooth or two on the cam gear to do this. I'd really appreciate feedback from some experienced L28 cam degree'rs, this is my first shot at this.... Quote Link to comment Share on other sites More sharing options...
letitsnow Posted January 1, 2012 Share Posted January 1, 2012 If the old can ran well, then starting there is probably a good point. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 1, 2012 Share Posted January 1, 2012 Really the only thing to do is dyno it, that is the absolute quickest way. With an adjustable camshaft like the Tomei you can make adjustments of 1/2 a degree (camshaft) right on the dyno and make another run. You really don't need to retune any fueling, making the quick run makes OBVIOUS changes to the torque curve you can see when you are as far off as you think you are. The issue is the turbo will skew this somewhat, and I might actually suggest you run the engine with the wastegate wired full open to minimize the effect of boost on the engine's torque production. One you have optimized it, put the turbo back into operation and you should be golden. Alternative would be to get a G-Tech PASS and make runs on a flat surface. It will give you a printout as well that you can compare. Sorry I'm big on the G-Tech but the second generation unit has proven to be so useful to me I can't help it! Heck, the FIRST generation box was a revelation to me for checking brake and tire improvements...not something it's supposed to do. And apparently more geeks were doing it as well because they incorporated all that stuff into the PASS model. Not cheap...but I digress. According to what JeffP got out of several manufacturers the Rockwell Hardness of the components is about 60-65 and one is slightly harder than the other to put the wear on an easily changed piece (I guess that would mean the cam is 65, and the rocker follower is 60...) Both components are sufficiently hard that sliding friction should not affect them if lubricated properly. But you know how that goes these days! A side note here is that Paeco in Birmingham AL formerly would hardface the lobes. Weld on super hard metal like you would put on Backhoe Buckets and Scraper Blades. Seriously hard stuff. They would guarantee no wear or damage to the lobe once this was applied. Basically it was so hard it would eat whatever other component it was running against. They would use this on hard to find lobes, or journals to restore the components to standard size. They would do this on rod or main journals as well. Push comes to shove, ultimately, if they still offer this "Paecolloy" service you could have them build up the lobes and then have them ground where you want. I'm sure the grinder will absolutely LOVE you taking a near-billet cam that is hard as hell into them to be ground... Also, the stones used to grind the cam should really be dressed properly. When you do a profile of the cam surface, you can sometimes see where the grinder laid the stone against the cam before engaging the drive. This leaves a flat spot over several degrees. Over time, that can cause issues as well. The guy who can go in depth about this is JeffP. He did work for Sig Erson for a while, and when working on the "Secret Project" got a LOT of information about the current state-of-the-art in the business. In discussions with Ron @ Isky, he actually quickly corrected us about 'Crappy CWC Cam Blanks' in that technically they have "Far superior metallurgy than the old Japan Cams...But there's something about that Nissan Japan Chilled Billet Process that makes them just WORK better than anything else in these L-Engines." Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 1, 2012 Author Share Posted January 1, 2012 Yeah, that Tomei adjustable cam gear would be nice. A dyno would be nice too, but I have no way to control fuel at the moment, being in-between fuel management computers right now. I will be installing MS3 and using maps from Zmanco as a baseline. So I just need to get close to an appropriate cam timing right now, unless using this cam is too risky, then I can just install the A grind I have, along with the spraybar and towers. It's all on the extreme cheap right now, I just want to make sure I'm not wasting the small amount of money I've already thrown at this. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 1, 2012 Share Posted January 1, 2012 That Tomei can be had off E-Bay for under $200 DELIVERED (direct from Japan via EMS post, I got mine in 4 days from sale close!) Trick: Drop Ship direct from Japan. The sale I found was posted on E-Bay AUSTRALIA. And the exchange rate helped about 15% at the time. It think it hurts now. What you can do if physical clearance of the cam is your concern and you don't want to pull the head to clay the valves is take some larger diameter solder and lay it over the piston dome through the spark plug hole, and slowly crank the engine over by hand. If you feel it hit, you know you're close...but by measuring the indentation you know EXACTLY how close you are. This one isn't rocket science, when you are near TDC you can rock it back and forth and move the solder a bit to make sure you get the thing 'worst smashed' so you know the closest point. Then you can alter your timing and see if you make it better. I don't think more than one link is ever advisable. I did one link one time and the customer loved the results-it was a tiger up to 5000rpms. Seriously moved the torque down in the RPM range. But it was terrible at 5000 and up. Power came on around 2200 N/A. That was a stock A-Style as I recall. Problem with the turbo is that you will mask the timing changes quite a bit. I'd still suggest after checking physical clearance, you wire the wastegate open and at least do 'butt dyno' runs with no or as little boost as possible. This will get you closer faster than if you even boost to 3-5 psi. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 2, 2012 Author Share Posted January 2, 2012 I degreed this mystery cam a little more accurately, and it's not as bad as I thought. Mystery Duration IN 306 (0.008" clearance) 220 (0.050" clearance) This has a much softer ramp up. Duration EX 297 (0.010" clearance) 230 (0.050" clearance) Schneider had 240/230, more intake duration. The main difference in the cams it seems is the lobe separation, I calculated 105 cam degrees, the Schneider in comparison states 114. What is striking to me, at 0.050" lift, the intake opening of the Mystery cam is 25 degrees ATDC, the same 8 degrees of overlap to the exhaust closing, but almost 30 degrees later. Gotta wonder if the exhaust valve is going to hit the piston it's so late. The intake with stock timing degrees to 120, 8 degrees retarded relative to the Schneider, if I understand the specification. I am thinking this cam was ground for a high RPM motor; I'd prefer to keep the RPMs less than 7k (stock L28ET, new dampener). A bit of advance may not hurt, perhaps up to 8 degrees matching the intake lobe peak of the intake to the Schneider (112 degrees). I appreciate the insight TonyD, good suggestions on "dynoing" the engine. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 3, 2012 Author Share Posted January 3, 2012 Found the cam grinder online, forwarded these questions on, maybe I can get the info from the source.... http://www.gude.com/ Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 3, 2012 Share Posted January 3, 2012 Oh, Bill! He's over in Elsinore about 20 minutes from me. Used to do a lot of Z-Cams, but has been into Hondas of late. Gets his billets for them cut locally at a machine shop right there in Elsinore as well. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 6, 2012 Author Share Posted January 6, 2012 Got an answer from Bill: Run it in the #2 cam hole pulls from 2800 to 7800 good all round cam mild enough for street mean enough to win in scca this cam in my 240 z ran 14.70 in the ¼ mile no other changes. Bill Sounds interesting.... Quote Link to comment Share on other sites More sharing options...
chuckles Posted January 10, 2012 Share Posted January 10, 2012 correct me if I'm wrong, but aren't cams ground for turbo cars totally different than ones for a NA car? Is this a NA or Turbo cam? Don't know what Bill was running, but I assume 14.70 in the 1/4 was not with a turbo motor and cam in a 240. I could see that with na 2.4. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 10, 2012 Author Share Posted January 10, 2012 I don't know if it was specifically for a normally aspirated engine, but it has next to no overlap. If you compare the durations and lift, this cam is milder than my old turbo cam. All I really wanted was a reasonable lift and performance above 6000 rpm, and I think this will do it. I am advancing it a little, resurfacing my rockers and checking the wipe, then buttoning it up and moving on to Megasquirt. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 11, 2012 Author Share Posted September 11, 2012 So I now have attempted to operate this cam with my new MegaSquirt install. I'm glad I cam back to re-read this thread, as this "mystery" cam is acting retarded. After timing the thing nuts on the number 2 cam gear position, it won't idle as there is no vacuum. I advanced it a single tooth, and it was a little better but still crap. Before I give up on it completely, I may have some luck advancing it more than 1 tooth, say 2 or 3, so here goes. Quote Link to comment Share on other sites More sharing options...
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