JK_DC Posted August 4, 2006 Share Posted August 4, 2006 I am not sure what camshaft I have and I am way overdue on a valve adjustment. I have a performance cam so I don't think stock settings will work. The markings on the cam are J23 EP40 C2. My 1 and 2 lobes are worn pretty good and the clearances were maybe .002 cold on those, not sure if that will wear it though. I tried stock settings but it sounded terrible so I'm wondering if anyone knows if those numbers/letters mean anything or at least list the different manufacturers so I can contact them. I looked at schneider and isky, but don't see those #'s listed. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 4, 2006 Share Posted August 4, 2006 It's pretty hard to figure out what cam you have. You could measure lift with a dial indicator and then try to find someone advertising a cam with the same lift. Or you could degree the cam and see if you could match that to someone's advertised cam timing. Tough to do, and even if you do the measurements some cams are notoriously far from what's listed on the cam car. My aftermarket cam wants everything .002 tighter than stock, so IIRC its .008 and .010 instead of .010 and .012. Don't go too tight trying to get the noise to go away, its better to have the noise. There is an old saying "Quiet valves burn". Quote Link to comment Share on other sites More sharing options...
JK_DC Posted August 4, 2006 Author Share Posted August 4, 2006 okay...thanks for the info. I have been searching zcar also and they say about the same thing. Since it was pretty quiet and then got really obnoxious clicking I thought it was far off. I seem to remember when I first got the Z it was clicking then got a valve adjust at the dealer and the clicking went away. I guess they did it too tight. It sounded like a diesel engine it was so bad. It was worse with the windows up. I think I have a little valve slap at stock settings. I will go .002 tighter and leave it at that. Can the lobes wear with too little clearance? Or is that from the rockers? The mechanic reused them on the rebuild even though I wanted new ones- 15,000-20,000 miles on them. I've always used synthetic oil and changed it regularly so it shouldn't wear so much in 30,000 miles. What are the symptoms from a burnt valve? This is the first adjustment in 30,000 miles on a rebuilt head so it has been too tight for awhile. It has been running fine, revs easily to 7k in 1st and 6.5k in 2nd. Thanks Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 4, 2006 Share Posted August 4, 2006 I think you're taking me a little too literally. The engine shouldn't be clacking like a diesel, but just tightening the valves until they make no noise is a recipe for disaster. It does seem that aftermarket cams are noisier than stock cams IME. There is one cam manufacturer which has had more lobe failures than any other reported here, and that is the Schneider cam that MSA sells. It could be that you're losing a lobe, and I would suspect that more if you had a Schneider cam. I don't know how people diagnose a lobe going flat until the car is really down on power and something is obviously wrong, unless there is a lot of metal in the oil or something. Just don't know the answer on that one. Lobes and rockers shouldn't wear from too little clearance. Cam lobes wear from incorrect lash pads, bad metallurgy on the cam itself, or damaged rocker arms. Symptom of a burnt valve is loss of compression, and if you do a compression test and put a couple squirts of oil in the cylinder it doesn't change the readings on the gauge. Quote Link to comment Share on other sites More sharing options...
JK_DC Posted August 5, 2006 Author Share Posted August 5, 2006 I tightened them to .008 and .010 today and it sounds a lot better. There is still valve noise but it isn't excessive, sounds a little noisier than the stock cam did. I was able to turn the idle down to 800, before it didn't like it less than 1000. The reason I said it looked flat was because there was an 1/8" of metal less on some of the lobes and it was rougher when sliding my finger across them. Not sure of the terminology, but the metal on the lobe was visibly lower than the metal surrounding the lobe on the outside. But like you said I'll run it until I run into problems or until I want to upgrade to a stage 3 cam. Quote Link to comment Share on other sites More sharing options...
dapiper Posted August 7, 2006 Share Posted August 7, 2006 Your cam is shot, probably due to bad lube. Check your cam oiler for plugging. Quote Link to comment Share on other sites More sharing options...
bradz240 Posted August 7, 2006 Share Posted August 7, 2006 "The markings on the cam are J23 EP40 C2." To identify your cam you can check with cam grinders. My local cam grinder identified mine for me. He knew is was a datsun cam before I unwraped it. Brad Quote Link to comment Share on other sites More sharing options...
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