[VintageLambo] Re: Engine manual, Camshaft timing

Laust: My intent on posting the Crane Cams recomendation was only to show that your settings are well researched and are on track. Any information that you can post will be appreciated. I"d like to know where you have introduced each injector since space beyond the carbs. seems very limited. Is it possible to post a picture. I did not see this on your website. Regards, Nash --- In VintageLambo@yahoogroups.com, "lgpdk " wrote: > Nash, > > It appears that "Crane Cams" are more conservative than I was in my > clearance recommendation. However measuring at 15 degrees is more > relevant for "colder cams" and the exhaust valve to piston clearance > actually increases by advancing the (exhaust) cams. > I found my old Excel spreadsheets on the summary of the Power/Torque > vs. cam advance simulations as well as on finding the angle for > minimum valve-piston clearance (older Excel version and quite small, > 100kB). These are mostly numbers and graphs with no comments, > therefore can be hard to read, but I will be happy to post them if > there is interest and someone, Fred? Jack?, can tell me how. > > Best regards, > Laust > > > > > --- In VintageLambo@yahoogroups.com, "nashbap " > wrote: > > Laust: > > > > Thank you for clarifying the settings. > > > > For those who are interested in this discussion, the minimum > piston > > to valve clearance recommmended is 0.10in. for the intakes and > > 0.12in. for the exhausts as per the Crane Cam website to be > checked > > 15 degrees before and after TDC in the overlap zone; presumably > for > > Detroit iron. > > > > Regards, > > > > Nash > > > > > > > > --- In VintageLambo@yahoogroups.com, "lgpdk " > > wrote: > > > Nash, > > > > > > That is right, I used 6 cam degrees (=12 crank degrees). I ran > the > > > simulation for the standard cam setting for the engine and was > > > encouraged by seeing the shape of the curve being close to what > has > > > been published. At that time I was also encouraged to see that > the > > > peak HP was close to 350 HP. I then increased (and decreased) > the > > > cam timing individually, I think up to 8 cam degrees and found > that > > > the 6 degree advance on both cams provided the best result > without > > > almost no side effect, except the risk of valve piston > > interference. > > > I then calculated difference in valve piston interference (0 to > 6 > > > deg cam advance) to be 1 mm. With that knowledge I measured the > > > actual cam – piston clearance (I have forgotten what it was) and > > > decided that it was safe to take 1 mm out (and I stand by a > prior > > > statement that a final .060" clearance should be safe). I used > cam > > > centers as the parameter to adjust, which takes the valve-lash > > > uncertainty out of the measurements (you don"t have to question > > what > > > valve lash is assumed for the quoted 32/64 inlet > opening/closing). > > > In the case of the inlet the cam center would be (32+180+64)/2- > 32 = > > > 106 ATDC. Since the cam top is flat, the center is found as the > > > angular mean between same height between a rising and falling > edge. > > > Using cam centers pre-supposes a symmetric motion as a function > of > > > cam (and crank) angle, which I strongly believe is true and > > > certainly did not have contradicted in the results I got. > > > Since I did many things to the car I cannot separate this effect > > > form others, but I certainly am very impressed with its low-end > > > torque. It effortlessly and smoothly motors uphill (around > Laguna > > > Seca Golf Club) in 5th gear with four people at 1000 rpm. The > > > smoothness I am sure is helped by the fuel injection which does > not > > > require high air-flow to get good fuel spray. ><