slownrusty Posted June 21, 2006 Share Posted June 21, 2006 Guys – Please do not feel like I am getting greedy! But I have decided to swap the cam in my upcoming Turbo upgrade project. I called Webcams (spoke to a very friendly Debbie) and based on the recommendation by them they have an AWESOME turbo grind…but I need to figure out the lash pads cap thickness that I have to buy from Nissan Motorsports, as the base circle on the Web cam is less than the stock cam.. I also called Nissan Motorsports spoke to Paul (who was helpful) and for selecting the lash pad caps I just cannot read off the Web cam card specs, as they guarantee that a few valves might end up being out of range. I feel that the cam might be a true ingredient in unleashing some more power and also widening the power band…..so I would really love to pursue this and know I can do it, with some assistance from you guys who have been down this road. So my question to you guys is how (what is the procedure) do I actually measure and calculate the lash pad cap thickness that is required to run with the new aftermarket cam? I understand that it could be a mix of different caps pads thicknesses as well? Many thanks in advance. Regards - Yasin Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted June 21, 2006 Administrators Share Posted June 21, 2006 This thread covers how to set up your valve train with an aftermarket cam, including how to determine correct lash pad thickness… Custom Cylinder head building.. What’s involved… http://forums.hybridz.org/showthread.php?t=108398 Then, don’t forget this thread as well… Using a degree wheel to degree in your L-series cam… http://forums.hybridz.org/showthread.php?t=111523 Here are some pics from that thread… Hope that helps… Paul Quote Link to comment Share on other sites More sharing options...
KTM-EXC Posted June 22, 2006 Share Posted June 22, 2006 If you dont mind me asking... How much for the cam?? Quote Link to comment Share on other sites More sharing options...
510six Posted June 22, 2006 Share Posted June 22, 2006 http://www.webcamshafts.com/ A regrind is 158 bucks.Great write up on how to setup lash pad thickness, I usually use a black marker and check the wipe pattern on the rockers. Quote Link to comment Share on other sites More sharing options...
slownrusty Posted June 22, 2006 Author Share Posted June 22, 2006 Thanks for the links and tips guys...I will definitely follow them...in the mean time can you please give me a good range of pads to buy for the mock-up like say 5 of this thickness, 3 of that thickness and 4 of this thickness...that should be get well on the way. Many thanks - Yasin Quote Link to comment Share on other sites More sharing options...
Zmanco Posted June 22, 2006 Share Posted June 22, 2006 Yasin, you might ask the cam shop what they recommend. I just sent my core up to Delta Cam to be reground. They say that for the grind I chose, .180" lash pads are all I need. So I've gone and ordered a set. I'll know more when I actually get it all assembled and check it out, but they say that they've done enough of this grind for Zs that it should just bolt together. We'll see Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 22, 2006 Share Posted June 22, 2006 I never understood how anyone could claim to know what lash pad you need. The depth of the valve can change, eg after a valve job, or if the seats are sinking into the head. I had to change the lash pads when I installed new valves. Can't remember how much, but I definitely had to go bigger because the valve was sitting futher into the chamber. Needless to say do the wipe pattern and make sure, regardless of what Delta or whoever suggests. Quote Link to comment Share on other sites More sharing options...
slownrusty Posted June 22, 2006 Author Share Posted June 22, 2006 Jon - Your response is exactly what Web and Paul at Nissan Motorsports said to me, the only way to know for sure is the "wipe pattern" (makes me feel like I'm in the toilet...LOL!)..there are too many variables to have a "one size shoe fits all" scenario.. Yasin Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted June 22, 2006 Administrators Share Posted June 22, 2006 I never understood how anyone could claim to know what lash pad you need. The depth of the valve can change' date=' eg after a valve job, or if the seats are sinking into the head. I had to change the lash pads when I installed new valves. Can't remember how much, but I definitely had to go bigger because the valve was sitting futher into the chamber. Needless to say do the wipe pattern and make sure, regardless of what Delta or whoever suggests.[/quote'] Jon, THANK YOU!!!!! Guys, listen to what Jon is saying here. We, (Rusch Motorsports), are a specialty Datsun L-series shop specializing in custom high end L-series cylinder heads, and we see this on EVERY SINGLE HEAD that comes through our shop. If a valve job has been done on the cylinder head at any point in its life, AND/OR the head has had the top surfaced, (material removed from under the cam towers also alters the required lash pad thickness if cam saver shims weren’t used), either or both of those conditions will require different lash pad thickness. Typically with OE cams, there is quite a bit of latitude as for cam wiping pattern is concerned, for example, up to .060†lash pad thickness variation with no issues of wiping pattern issues, but with aggressive cams, that room of fudge factor diminishes. Get up into the .560â€+ lift range and if the cam is ground with very aggressive opening and closing ramps, (they usually are at this level), there may be only a .020 window of lash pad thickness that will work, so it is imperative that you check and double check for proper lash pad thickness or you will ruin the cam and rockers in very short order. To put this in perspective, these engines are getting quite old and it is not uncommon for some, if not 95% of them, to have at least 1, 2, even 5 valve jobs since new, and you can rest assured that not all of these previous valve jobs were done at shops that make sure the head is ready for the customer to just bolt on to his short block without any cam wiping issues. Not every machine shop will check cam wipe patterns for the customer, or tip the valve stems, and even of the ones that do tip the valve stems, not all of them will grind the same amount of material from the stem tips as the material removed during the valve grind, which would help keep your original lash pad thickness spot on. In short, when someone asks how to verify or measure for proper lash pad thickness, please do NOT throw out a blanket statement such as “just use what the cam manufacture suggests!†Those recommended lash pad thickness are given for brand new, OE valve train geometry, i.e. as delivered from the factory new. Just how many of us have brand new OE L-series heads that we are installing a new cam in? Sure, those circumstances can be duplicated, but I can guarantee you that 75% of the shops that did those valve jobs on these old Datsun, did NOT do that, (a lot of Datsun owners in past 20 years would use the cheapest machine shop around to save a buck), so the recommended lash pad thickness is a just ball park at best. Cam wiping pattern still NEEDS to be checked on each and every valve if you want to give your cam a fighting chance at living more than 2000 miles. Again, thank you Jon for bringing that up. Quote Link to comment Share on other sites More sharing options...
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