p wrote: >>i keep hearing about tappet adjustments closing right up or needing doing every5-10 hrs or so even one example where compression was being lost on that cyl which had gone tight anyone got any answers as to what is going on here <<
They are probably talking about VW valves. VWs used in aircraft lead a hard life. The valves wear and the valve seats wear leading to "recession" into the head, which effectively tightens the valves, usually the exhausts more than the intakes, due to the higher temps involved. Hydraulic lifters alleviate that, but there is some debate as to how well some VW implementations (all aftermarket on Type 1s) work at the high speeds we airplane guys run them at. Marvel Mystery oil probably helps reduce the frequency of adjustments, although I should point out that I've never flown behind a VW engine, and therefore could be completely clueless. The Corvair has hydraulic lifters, so valve adjustments are done after a rebuild, and never again until the next rebuild... Mark Langford, Huntsville, Alabama see KR2S project N56ML at http://home.hiwaay.net/~langford email to N56ML "at" hiwaay.net --------------------------------------------------------------
