Zkrazy Posted November 20, 2009 Share Posted November 20, 2009 I need to shim my cam up 15 thousandths, do I need bigger lash pads? It seemed automatic to me to put in 15 thou thicker pads but I can only find them in 10 thou increments and they aren't cheap (no job). It's still cheaper than a new cam if the wipe pattern isn't correct. It's an Electromotive cam, anyone know anything about them? Quote Link to comment Share on other sites More sharing options...
woldson Posted November 20, 2009 Share Posted November 20, 2009 Why are you shimming? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted November 20, 2009 Administrators Share Posted November 20, 2009 You are correct. For whatever distance you shim the cam, you should make up for it in lash pad thickness. As you found out, you have .005" discrepancy between tower shims and available Nissan lash pads, (Nissan is out of a few sizes as well, no indication of when or if they will be replenished). Here is another source for lash pads in .5mm, (.020" increments), vendor is a member here. http://www.zccjdm.com/catalog.php/azcarbum/dt43033/pd944870/KAMEARI__CHROMOLY_LASH_PADS. With stock cams, there is sooo much room for error on wipe pattern, .015 will be safe. After-market cams are generally more aggressive, as such will take up more of the available wiping surface area so it become more critical. The more radical the cam, the more critical it is. Verify where your wiping pattern is on your rockers before you added the shim. Make sure there is no abnormal wear. If wiping surface has any divots or heavy wear, any change to the wiping surface area, (shimming cam, changing lash pads, valve job, swapping rockers to different lobes), will quickly wear out the rocker and the cam lobe. If the wiping pad is in good overall condition, and if the wiping pattern is perfectly in the middle, you can go +.010" or +.020" lash pad and should be fine. If the wiping pattern is biased towards the "valve" side of the wiping pad, use the .010" lash pad. If the wiping pattern is biased towards the "adjuster/pivot" side of the wiping pad, use the .020" lash pad. Disclaimer Those guidelines will only work if the wiping pattern was properly set up for the cam in the first place, rocker wiping surface and cam lobes are in good serviceable condition, there is enough room to safely “shift†the wiping pattern across the pad either way .050†or so either way, and is not a replacement for verifying your cams wiping pattern is still "ok" after the shim and lash pad change. Hope that helps, Paul Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted November 20, 2009 Share Posted November 20, 2009 Are the lash pads case hardened? I needed a thinner one for my P90 when I was setting up the pattern, so I filed it with a hand file to take off a few thousandths in the groove. I didn't have any other pads to use. I have about 8000 miles on it now and it still holds the lash setting. So if you have one that is too thick, I think it's OK to file it a little, very carefully and measure with a micrometer as you go. Correct me if I did a bad thing... Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted November 20, 2009 Administrators Share Posted November 20, 2009 Are the lash pads case hardened? I needed a thinner one for my P90 when I was setting up the pattern, so I filed it with a hand file to take off a few thousandths in the groove. I didn't have any other pads to use. I have about 8000 miles on it now and it still holds the lash setting. So if you have one that is too thick, I think it's OK to file it a little, very carefully and measure with a micrometer as you go. Correct me if I did a bad thing... Dave, Yes they are hardened. How, to what degree of hardness and to what depth, I do not know? (You actually filed one?!?! You are very patient. I tried once...) You should be able to remove that rocker and visually inspect the lash pad for abnormal wear, if it looks ok, you should be fine. Quote Link to comment Share on other sites More sharing options...
Xnke Posted November 20, 2009 Share Posted November 20, 2009 BRAAP, the lash pads are hardened, but not that hard. I have turned them in a lathe with carbide tooling, they cut beautifully. I'd imagine they were something like 4140 prehardened, or something. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted November 20, 2009 Administrators Share Posted November 20, 2009 BRAAP, the lash pads are hardened, but not that hard. I have turned them in a lathe with carbide tooling, they cut beautifully. I'd imagine they were something like 4140 prehardened, or something. Thanks for the info. Quote Link to comment Share on other sites More sharing options...
theghosttanker Posted November 21, 2009 Share Posted November 21, 2009 you need to shim 015? The rule of thumb is that you don't need to shim your cam at all if you have taken less than 020 off the head, and a lot of people here claim to have taken even more off without shimming. If you are thinking you need to shim 015 because you took 015 off, just skip it. Quote Link to comment Share on other sites More sharing options...
Zkrazy Posted November 22, 2009 Author Share Posted November 22, 2009 The head was just shaved .010, the block .004. Now the cam is to the left of the alignment mark but I'm on the 3rd hold of the sprocket. After the block but before the head was shaved it was right about in the middle, not to the right like it should be, on the 1st hole. The chain isn't very old either. So I need to shim up the cam to get it's timing correct. I removed all the lash pads and they vary; most are .160 but three are .162 and one is .163. I think I'm going to get the .180 set and hand file them to match each valve as it was, + 15. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 22, 2009 Share Posted November 22, 2009 Magnetic Chuck in Surface Grinder makes short work of the lash pads... Quote Link to comment Share on other sites More sharing options...
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