oil circulation

[ducati2242]

how quickly should a tank of oil circulate on  BSA single b34 ,  etc . I have sae 50 castrol classic oil in there but the return , when cold -1 c , is bubbly and spitty at best . I know the pump is good as for the first 5 seconds it pumps back solid stream . The engine is completely new inside . Pearson crank , bearings liner piston etc . Just not sure what should be seen returning . Its about half what returns in my b44 with 40 sae classic in it . thanks .

[JulianS]

The return will have bubbles because the return side of pump has greater capacity than the feed side (to keep sump dry)

[ducati2242]

The return will have bubbles because the return side of pump has greater capacity than the feed side (to keep sump dry)

Yeah but it would take 3 hours to circulate .I think I need thinner oil but not to sure what .

[JulianS]

You will get a solid stream when there is a build up of oil in the sump, after being parked and oil drains into the sump from the internals of the engine or through wet sumping. When the build up is cleared the return will be aerated oil.

50 is too thick for winter, especially with the recent low temperatures, the usual recommendation for B34 is, I think, 50 summer and 30 winter.

[ducati2242]

Ive been researching , internet is great , all night and have decided that as im only running it in , probably multi startups in the garage , im going to use a fully synthetic 20/50 oil . probably castrol but but will see what they have in the morning .

[ducati2242]

Not fully synthetic . Dont know where I came up with that . Fully synthetic wouldnt allow it to run in properly so i will need a non synthetic oil . 20/0 still sounds good though . Il keep the sae 50 for the summer .