240zprace Posted January 28, 2004 Share Posted January 28, 2004 would the stock srings handle a 488 lift cam? Quote Link to comment Share on other sites More sharing options...
Clifton Posted January 29, 2004 Share Posted January 29, 2004 They are no different than other L head springs. It "may" take it even though .460" is supposed to be the max, but it's the valve float that will cost you power. Springs are only $100 and worth it. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 29, 2004 Share Posted January 29, 2004 Couple of problems you might encounter: The stock coils will bind with a "true" .490 lift cam. If you get aftermarket springs, you may run into a situation that I encountered with Schneider springs and retainers. The retainer just barely hit the valve stem seal at full lift. The retainers were turned down in a lathe to fix, my machinist said that he didn't feel comfortable with anything less than .050" space between the bottom of the retainer and the stem seal so they were cut down to allow .075 IIRC. Neither Schneider nor MSA says anything about this. Not sure if they are simply not aware, or if they are choosing to ignore the problem When I originally built my first engine with this cam, I went to a sh!tbag crook of a machinist who "made" the stock springs and retainers work by cutting the valves a LOT. This led to having 0 margin on the valves, and they warped due to the heat of combustion. This had another negative effect, because when I cc'd the chambers during the 2nd build there was a 4cc difference between the same chamber with the new valve vs the old valve. So the original farkwad also cost me some compression with his crappy work as well. Did I mention that I paid this crook for new valve springs and retainers??? On the second build I had to purchase new valves and springs and retainers to fix, and since the valves sat much lower in the head, new lash pads were also necessary. Not that tough to figure out, but unless you have a big supply of lash pads you pretty much just have to experiment until you get it right. My advice is find a "good" machinist to do the work, preferably someone who has dealt with the L series engines in the past. My situation was the exception rather than the rule (I don't think most machinists are crooks) but I thought I'd throw that out there for your benefit. EDIT--All of the above happened with an E31 head with 280 valves, so I think that everything above correlates to your P90. Jon Quote Link to comment Share on other sites More sharing options...
speeder Posted January 30, 2004 Share Posted January 30, 2004 I'll soon be setting up a P90 with the Schneider #62002 spring/ retainer set that MSA sells. Just wondering - at what valve lift does the retainer - to seal clearance become marginal? Schneider claims that this spring set will support valve lifts of .600 plus when spring heights are set per their specs. My new cam has .515 lift - much bigger than any I've used with these springs previously. Quote Link to comment Share on other sites More sharing options...
240zprace Posted January 30, 2004 Author Share Posted January 30, 2004 speeder, i'm going with a web cam and springs/retainer from top end motorsports in hollywood. from my encounters the web cam is the cam to go with. i've got a friend that expieremented several cams and he liked the web cams better and screen name sss510 that post on here said he loves the web cam too. so, i think i'm going that route. Quote Link to comment Share on other sites More sharing options...
speeder Posted January 31, 2004 Share Posted January 31, 2004 My cam is by Elgin. It was recommended to me by a friend who runs a well set-up, high - horsepower turbo. They, along with Iskendarian and Web-Cam are all good stuff, and all can make you a cam to do anything you want. This particular one seemed to suit my needs the best, and someone else already did the research. Jon, do you happen to know what lift your cam makes? Just when I think I have everything planned, I have something else to stress about! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 1, 2004 Share Posted February 1, 2004 Mine was stated at .490 and when my machinist checked it he said that that was accurate to a few thou. I think it was actually .488 IIRC. If you're reusing your old valves you may not have the interference problem, because they will sit higher in the head. Jon Quote Link to comment Share on other sites More sharing options...
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