Silent Posted November 23, 2005 Share Posted November 23, 2005 ever since a year ago the car has been getting slower and slower, and now i know why, not that the carbs are leaking, but the cam is screwed. went to run the valves today, pulled the valve cover and found this! now i have to find out what cam it is, the only markings i can see on it is CWC D1. what the hell caused this? not breaking it in? improper lash spacing? Quote Link to comment Share on other sites More sharing options...
Cruez Posted November 24, 2005 Share Posted November 24, 2005 Hard to tell in that pic... Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted November 24, 2005 Share Posted November 24, 2005 what the hell caused this? not breaking it in?improper lash spacing? improper lash spacing Quote Link to comment Share on other sites More sharing options...
5foot2 Posted November 24, 2005 Share Posted November 24, 2005 wow! did the follower really wear a grove, leaving a flange on each side of the cam lobe, or am I seeing things? I've pulled a few bad cams out of SBC motors but the lifter contact face is bigger than the cam lobe so the lobe dishes the lifter face as it wears. This is pretty cool. Quote Link to comment Share on other sites More sharing options...
Silent Posted November 24, 2005 Author Share Posted November 24, 2005 wow! did the follower really wear a grove, leaving a flange on each side of the cam lobe, or am I seeing things? I've pulled a few bad cams out of SBC motors but the lifter contact face is bigger than the cam lobe so the lobe dishes the lifter face as it wears. This is pretty cool. you're not seeing things, thats what happened. so the general consensus is the valves were to tight? and thats what caused it? in that pic, where the "ends" of the lobe are supposed to be, and it looks like it's missing the center section, well IT IS!!!! the green square is what is missing. Quote Link to comment Share on other sites More sharing options...
speeder Posted November 24, 2005 Share Posted November 24, 2005 Improper thickness lash pad allowed the cam to wipe off the rocker's contact area. Looks as if a thicker lash pad should have been used to move the contact area away from the pivot. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 24, 2005 Share Posted November 24, 2005 I agree with speeder. Looks like the wrong lash pads to me too. Maybe someone installed a cam without changing the pads. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted November 24, 2005 Share Posted November 24, 2005 [img']http://home.kc.rr.com/jcgillespie/cam18fnwtf.jpg[/img] That's crazy I've never seen that before! Quote Link to comment Share on other sites More sharing options...
Silent Posted November 24, 2005 Author Share Posted November 24, 2005 ahh piss. alright question, who makes the cams for MSA? because i don't want the same cam Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 24, 2005 Share Posted November 24, 2005 Schneider Quote Link to comment Share on other sites More sharing options...
JaysZ Posted November 24, 2005 Share Posted November 24, 2005 i thought the schnieder was a pretty decent cam? no? Quote Link to comment Share on other sites More sharing options...
WHP Posted November 25, 2005 Share Posted November 25, 2005 I just had the same thing happen with an Isky L490 cam! The lash clearance was set correct for sure I confirmed it twice. The guy that did my head work was experienced, but I wonder if he failed to have the spring perches milled off resulting in excessive valve spring pressure? I can't imagine he got the wipe pattern wrong on all cylinders. I called a Nissan expert that swares by Isky cams and he said he has seen a few do this due to bad metalergy. He breaks in the new cams at 2000 rpm with only one spring, then puts the full springs in. I put a stock cam/head back on and lost almost 20 mph on top end. Guess I'll redo my good head again. I was using a spray bar and internal oiling and checked with the valve cover off and it was oiling good. Hey Silent, better flush and change your oil about 5 times! Quote Link to comment Share on other sites More sharing options...
speeder Posted November 25, 2005 Share Posted November 25, 2005 I've heard the metallurgy story on Isky cams also - but I will tell you with 99% certainty that this problem is improper valve train geometry - a setup problem. Could be spring coil bind, on just the one position, and that should be checked also. "Experienced" machine shop people have been known to be ignorant of the need to check the wipe pattern on EVERY rocker when setting up a new cam and/or reassembling after a valve job that alters valve stem heights. This is especially critical with a performance cam, whose higher lift/duration widens the contact patch on the rocker, giving less tolerance for error. Machinists generally understand the concept of getting the spring seat pressure and coil bind clearance correct, but lash pad selection is a "Datsun" thing. Quote Link to comment Share on other sites More sharing options...
Silent Posted November 25, 2005 Author Share Posted November 25, 2005 ahhh crap. i knew something was funky because everytime i would stick it on the dyno, the power would keep getting lower, and lower and lower. started at 192 now it's down to 142. guess it's best to happen in the winter time instead of the middle of the summer during racing season. are the cam packages from msa pretty decent? or would i be bettr off to piece one together? last question, is the max lift the stock spring can take is 450? 460 would be pushing it right? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 25, 2005 Share Posted November 25, 2005 I seem to remember that it is pretty common for people to run the .460/260 cam from MSA with stock springs. That is a pretty small cam though. I always want to question why people even bother with all the hassle to put in such a small cam. Search for speeder's post on valve stem seals if you go bigger than .460 too. He has a great post about some alternate stem seals from a Ford Ranger which will give you a lot more clearance so that the retainer doesn't hit the valve stem seal at full lift (which is a problem over ~.470 lift). Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted November 25, 2005 Share Posted November 25, 2005 In my opinion the Schnieder cams that MSA sells is probably one of the best things they sell. I have the MSA 2003 cam which is a Schnieder .460 lift 270/270 cam, the kit comes with new rockers, lash pads and springs and it is claimed to provide good power from 3500 rpm to 6000 rpm. When I was running su's that cam gave me gobs of torque and it pulled hard all the way through its stated range, when I switched to 40mm Mikunis I had to modify the carbs considerably to work well with the cam as it is to small for the carbs. In my opinion the primary cause of the cam wear problem you have experianced is from A) improper cam break-in improper cam geometry. I had a car many years ago that the cam was not properly broken in on and within a matter of months the lobes started showing wear like you have on yours. One last thing (my opinion again) unless you truly have no clue you should never completely trust someone else's work, when they are done take it home and recheck everything yourself, even the best mechanic will not treat your engine the same way he treats his own. Dragonfly Quote Link to comment Share on other sites More sharing options...
Silent Posted November 26, 2005 Author Share Posted November 26, 2005 this is the cam i was planning on getting. im lookin to stick with the stock head till im completely maxed out on it, as in modded su's ported intake, port matched intake on the head. but nothing to extreme. im not even sure what cam is in my car or anything about it till i pull it. hence why i asked about the 460 lift on stock springs without modifications, IE changing springs. im not going to balls out radical till i get my n42 done Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted November 26, 2005 Share Posted November 26, 2005 You can run stock springs on a .460 lift cam with no problem, with a higher lift cam you do not need to change the springs so much as to machine down the spring perch in the head then shim the springs accordingly. The book "How to Modify Your Nissan/Datsun" by Frank Honsowetz has pictures and detailed information on making modifications to your head to accept larger cam profiles i.e. machining down the spring perches etc. if you don't own the book it is one of the best purchases you can make if you want to stick with an L series engine in your car. When I was running the su's I was using ZTherapy's rebuilt 4 screw round top carbs that were flow matched and using SM needles. If you have junky or worn out carbs the best cam in the world will not do you any good, so keep that in mind before spending your money. Dragonfly Quote Link to comment Share on other sites More sharing options...
Silent Posted November 26, 2005 Author Share Posted November 26, 2005 You can run stock springs on a .460 lift cam with no problem' date=' with a higher lift cam you do not need to change the springs so much as to machine down the spring perch in the head then shim the springs accordingly. The book "How to Modify Your Nissan/Datsun" by Frank Honsowetz has pictures and detailed information on making modifications to your head to accept larger cam profiles i.e. machining down the spring perches etc. if you don't own the book it is one of the best purchases you can make if you want to stick with an L series engine in your car. When I was running the su's I was using ZTherapy's rebuilt 4 screw round top carbs that were flow matched and using SM needles. If you have junky or worn out carbs the best cam in the world will not do you any good, so keep that in mind before spending your money. Dragonfly[/quote'] i have that book, read it front to back about 12 times so far. guess before i go off and spend the money on the cam kit, i need to find out what is in the car first. thanks so much for the info guys! Quote Link to comment Share on other sites More sharing options...
speeder Posted November 26, 2005 Share Posted November 26, 2005 I have gone the "machining the spring seat" route with Isky springs and I can tell you there are better solutions. If you buy the Schnieder springs and retainers from MSA you don't have to machine the seats and you will have a spring that will support .550 lift or something rediculous like that at the specified height/set valve seat pressure. I'm currently running .515 lift on the Schnieders/unmodified seats with no issues. The valve stem seals then become an issue, and the Fel-Pro Ford items take care of that. Quote Link to comment Share on other sites More sharing options...
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