z-ya Posted November 25, 2013 Share Posted November 25, 2013 I would also suggest setting the lash at the lash cap. I had a similar issue with a Norris regrind. Setting the lash at the lobe resulted in a lot of noise, and in the end, too much clearance. I called Norris and their cams are ground in a way that the lash should always be measured at the lash cap. I set the lash per his instructions, and now valvetrain noise is normal. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted November 30, 2013 Author Share Posted November 30, 2013 Some fun facts about rocker arms,,,,, They're not all created equal....and that's all I'm gonna say about that. Measured the existing set. Pretty sure I found my culprit(s). One measured .004 off, another .005, and the worst one at .014". Even the brand new factory packaged Nissan arms - out of the 8 I got - one was .005" off and a couple were .003" off. Between the good factory ones, and the reground ones my buddy did - I've got a set that measures within .001". Wipe patterns today and install with the new cam (if I don't need to purchase additional lash pads). Will keep you posted... Quote Link to comment Share on other sites More sharing options...
Leon Posted November 30, 2013 Share Posted November 30, 2013 (edited) FWIW, I made sure all rockers used in my engine build were parallel and the engine was nice and quiet from the get-go. It has a bit over 1000 miles on it now. Edited November 30, 2013 by Leon Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted December 7, 2013 Author Share Posted December 7, 2013 OK - so a little distraught. I replaced the cam with the cam out of Clifton's old Z. I also had the rockers - all labeled 1-12 - with minimal wear...that were run with the cam originally. The freaking noise is STILL there. Wipe patterns dead middle on all rockers. I adjusted at the lash pad and not the cam. Set them for .006 and .008 cold. Ran the car for 20 min. Valves got louder. Car is hot now. Adjusted them down to .005 and .007 (at the lash pads) and the car wouldn't start. Readjusted them to .007 and .009 (hot) and the car still makes major valve noise. Granted - I did NOT measure these lash pads with the dial indicator for flatness - nor do I know if they were making noise when they were in Clifton's motor. Next step is to replace the rockers with the ones that measured out less than .002" and also measure the rockers that came with Clifton's cam. That'll be tomorrow. I'm really beginning to think it's something with the head - but I want to rule this out for certain first - as it does not involve removing the head. There was major play after the initial cold adjustment and then went after it when it was hot - but still after the proper hot adjustment - it's making noise like a sewing machine. Jeez Louise...I think a LS motor is in my near future. And I hate to say that - as I'm a L-series purist.... Quote Link to comment Share on other sites More sharing options...
madkaw Posted December 8, 2013 Share Posted December 8, 2013 Can you not pinpoint the noise with a stethoscope or something. I took an old valve cover and cut a hole in the top so I can look and hear. Didn't wind up using it but you can borrow it if you want Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 11, 2013 Share Posted December 11, 2013 What cam is it? Do you have the cam card? I hate to sound like a broken record here, but try setting the lash at the lash cap according to the cam card. Or call the cam mfg, they can tell you where, and how much. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted December 11, 2013 Author Share Posted December 11, 2013 z-ya - I don't have the cam card. It's the cam out of Clifton's old motor - along with the rockers - all numbered. I did indeed set the lash by measuring between the rocker tip and lash pad. As an experiment - I set it to .005 and 007 hot - the car wouldn't run. Dropped them back to .007 and .009 hot and the car runs - but still makes a buttload of noise. The old cam I had in there was a regrind from Delta Cams. I called and they said the lash could be set as low as .004 and .006 COLD. I have to think the cams are different. You can clearly see the lobe difference. Clifton had some wild super long duration turbo cam. Wipe patterns were still spot on with the existing lash pads - so I rolled with that setup. In a bit of a conundrum now. Not sure what to try next....LS7 maybe??? This is driving me freakin' nutZ! Quote Link to comment Share on other sites More sharing options...
madkaw Posted December 12, 2013 Share Posted December 12, 2013 So you haven't seen any visual wear marks on the lash pads that is unusual? I had more miles on my motor, but the uneven wear was easily visable on the lash pads. You could tell the rocker was weighted towards one side or the other on the lash pad. Even the bottom side of the lash pad wore uneven against the valve stem. Maybe you could clean things up and put some blue dykem on there and run it and check for wear? Have you tried a stethascope? Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 12, 2013 Share Posted December 12, 2013 Are the cam towers shimmed? Was the topside of the head ever resurfaced? It's a lot of work, but you may want to put a stock cam and lash pads back in there just as a test (you should be real good at it by now ) Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted December 12, 2013 Author Share Posted December 12, 2013 Cam towers are not shimmed. Head was cut just enough to flatten it. Very little was taken off. Topside was never touched. I am going to pull it back apart and try the rockers that measured out as close to 0 as possible. Also going to check the lash pads for abnormal wear as Madkaw suggested. Ever felt like you're chasing your tail??? Quote Link to comment Share on other sites More sharing options...
madkaw Posted December 12, 2013 Share Posted December 12, 2013 http://forums.hybridz.org/topic/110671-newly-rebuilt-engine-with-loud-tapping-noise-even-at-idle/page-5 I put up pics of my wear in this thread Quote Link to comment Share on other sites More sharing options...
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