I'm overhauling a 62/63 stale-air 40HP for my beetle right now. I'm installing later heads (square rocker bosses) and 83mm big-bore pistons and cyls. I found that my deck measured .040" (2.25mm) and my stock head has 45cc's combustion chamber volume. This results in a 7.1.1 CR, which requires 87 octane gas minimum. I'm installing black cool tins under the cyls, and have checked the thermostatic bellows for proper opening @ 150*. If your head CC is 40 to 43cc's due to fly-cutting, then semi-hemi cutting the heads and/or 'sinking' the valves will increase the volume to lower the CR. The 77mm stock cyls don't have the luxury of having shims available, but the 83mm big-bores will use the same shims as a stock 1600cc engine with 87mm cyls. Boston Bob told me that the limited length of the intake manifold won't allow you to shim the cyls very much, if at all. I'm sending you my spreadsheet in a pmail. Thanks for the reminder to use later rockers, Marc.
Mike B. ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, April 30, 2008 12:44 AM Subject: [vintagvw] 40 horse expert 1961-1965 beetles > Ok,I going to restore my uncles 1963 beetle. I have the original engine > which I'm going to rebuild.It came with boxes of the parts. I have a > pair of > fresh(less then 2000 miles on them) rebuilt heads with the long rocker > studs.It > is my understanding, that back in the day these engines had a high > cylinder > head failure rate.Now,I also have a pair of remanufactured 1965 40 horse > heads and the correct cylinder head studs to up grade the engine case .I > have a > few opinions here ,should I use the long stud heads,up-grade with the > short > stud rocker kit and shim the barrels to lower the CR. Or maybe just use > the > 1965 heads,have them semi-hemi cut to lower CR ,install the correct > cylinder > head studs and go that way.What do you think? Engine will have new oil > pump,piston & cylinders,rebuilt rods,cam,lifters,new bearings etc.Car > will be driven > only for recreation. > > > > **************Need a new ride? Check out the largest site for U.S. used > car > listings at AOL Autos. > (http://autos.aol.com/used?NCID=aolcmp00300000002851) > _______________________________________________ > vintagvw site list > [email protected] > http://lists.sjsu.edu/mailman/listinfo/vintagvw > _______________________________________________ vintagvw site list [email protected] http://lists.sjsu.edu/mailman/listinfo/vintagvw
