On 10/27/18, dbeierl <dbeierl@gmail.com> wrote: >> >> If >> the lifters are quite worn and bleed down faster than normal, I wonder >> if that causes the heads' oiling circuit(s) to lose its' prime. > I wouldn't think lifters would wear much internally, since the piston > basically only moves at starting time and then only if it was under an open > valve. But because of the extraordinarily small clearance between piston > and bore they're subject to getting sticky. The restoring force from 60 > psi of oil pressure is a lot less than you'd think given the small piston > area. When one does bleed down all it does is allow the valve to close and > ooze ?half a cc? of oil out the end. > > Can't speak to the rest except to say I'm used to thinking of "prime" as an > issue in suction systems rather than pressure one.
Right. I see your points regarding general lifter behaviour. I looked online for an oil passage flow for this engine but didn't find one. Ya, my mind was focused on "priming" because as far as I know, the pump was allowing oil to seep out overnight due to "borderline" oil pump gear end play. (a not uncommon issue per se when mating a diesel Vanagon oil pickup tube to a I4 VW gas engine oil pump. Even with new parts). As it was, oil pressure stayed at zero until the engine held at ~ 2500 RPM. After reducing gear end play to ~ .002 (measured with Plastigauge), even if the engine sat unused for 3 days, first start, I'd see oil pressure right away. The difference was "night and day".
-- Neil n Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca> 1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy> 1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/> Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay> |
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