[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]
Gene Berg said that he liked the chrome-moly pushrods because if you get the engine hot the increased valve lash would create noise that is obvoious to the driver. He said (and I may be paraphrasing here) "I prefer to be warned, how about you?" I have a set for my 2110 that I'm building (but I have no practical experience as of yet.) The Amazing Kelly Pitt. > Subject: Re: [T3] Further research and experimenting material! > > Chromoly push rods expand about half as much as stock alum. PRs. I know, I > tested them in my oven and used my 12" dial calipers. Alum @ 200F grew > .016", CM @ 200 only grew .008". Same length push rods. > > Tom > Tom's Old VW Home > http://home.att.net/~drsowatt/index.html > > ----- Original Message ----- > From: "Hal Sullivan" <tristessa@pon.net> > To: <type3@vwtype3.org> > Sent: Tuesday, November 06, 2001 10:37 PM > Subject: [T3] Further research and experimenting material! > > >> At 08:32 PM 11/6/01 -0600, Jim Adney wrote: >>> The way I see it, however, the biggest contribution comes from the >>> differental thermal expansion of the various parts and the fact that >>> the cylinders and head studs are steel while the pushrods are >>> aluminum (which expands 3x as much as steel.) >> >> Now *this* I want to check out. I'm using chromoly pushrods in one of my >> aircooled VWs -- I'm going to have to start measuring my valve lash both >> cold and hot, keep a chart of what I find. >> >> I've heard theories that the reason for the valve clearance is due to the >> different expansion rate of the aluminum pushrods relative to the rest of >> the engine. Following that theory, chromoly pushrods should expand at the >> same rate (or nearly so). If that's the case, would the 004/.006 > clearance >> be as necessary in engines that use chromoly pushrods? >> ------------------------------------------------------------------- List info at http://www.vwtype3.org/list or mailto:help@vwtype3.org