Bronze distributor gear, or guides in used oil analysis
I've been running a bronze dist gear with our 2004-vintage LT-1 with Erson 253/259 solid roller (with AFR 210s that have bronze guides), and am concerned by the copper and lead content shown in the used oil analysis. Inside the filter (cut open properly, not hacksawed), there's some shiny bronze sheen to it. Can't really feel it between the fingers. Oil from the pan is normal appearing & no sheen.
Used oil analysis shows 27 units copper (vs all 350s they've tested being 10) and 31 units of lead (vs all 350s being 11). There's 1 unit of tin vs. universal average 350s having 2 units of tin. Very low chrome, aluminum, no insolubles, no fuel dilution (wideband tuned since new, 14.7:1 cruise and 12.5:1 WFO).
Oil pressure is great (30ish idle, 55-60 at cruise), no bad noises, car burns 1 quart per 1000 miles, leakdown is 3 to 3.5% across all cyls.
The lead and copper concern me, making me wonder if it could be bearings.
I'm changing over to composite dist gear.
Welcome your thoughts.
'69 Z/28 - Dad's orig. owner, 44K mi., match #s DZ302 & M20 preserved in glass case. LT-1 w/ 210 AFRs, 0.640" lift 253/259 @ .050" Erson roller and Tremec TKO600 in car for more fun & 11.7s @ 121 MPH on drag radials & pump gas.