How did you inspect the working components inside - crank journals, rod hournals, cam journals?  Also did you check the roundness of the rods or have them rebuilt?  Did the main bearings fit snugly in the case? You are losing oil pressure internally, where oil is leaking out inside the engine, and preventing sufficient oil pressure.  With every rebuild, it is imperative to check all working components with micrometers to ensure proper tight fit.  If not, you will have low oil pressure.

One other possibility is a bad oil pump.  I have seen one in the past where the gear spins on the drive shaft.  It didn't spin completely loose, so there was a little pressure, but certainly not enough.

Z

Marshall <kormak@TURBONET.COM> wrote:
K, here's the deal. I recently (1300 miles ago) rebuilt a vanagon engine
that was non-working(a head had died). Anyway, after throwing $1000 into
parts, got it running. however, it's operation is erratic. 300 miles
after an oil change, the high rpm oil sensor starts going off every once in
a while (mainly, when decelerating and hiting 45 in 4th gear). I finally
installed an oil pressure gauge, so i could monitor it. Turns out the
idiot light is correct, i have no oil pressure. BUT, here's the kicker. I
installed a fresh oil pump with the rebuild. It doesn't leak any oil. It
doesn't burn any oil. I've tweaked with everything trying to get this
thing stable, even the pressure relief valve. Any ideas of what may be
happening?
Marshall
86 vanagon

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