I'm starting to re-assemble my 1954 Sunbeam engine after having the big ends ground and the head skimmed and a friend has suggested that I use engine assembly oil to protect the bearing surfaces on the initial startup before engine oil is pumped around the engine. Aparently this oil stays on the bearing surfaces better as the engine is assembled whereas standard oil will tend to drain from the bearings so the engine will efffecively run dry for a little while. So, my question is, is this really a problem? After all most engines sit unused for a good 4-5 months over the winter and so must suffer from the same problem every year. I'd be grateful for your opinions/experiences.
I've built up many engines over the years, including several BSA Gold Stars, and have always used the oil they will be run with. Maybe they suffered some initial wear on first start up but nothing that I was ever aware of and the engines certainly didn't show any subsequent problems.
Sunbeam - Rapier or Alpine? (Had both). I used STP or Wynns to build engines, thick and sticky, so big end and main bearing shells don't fall off when bolting up.
When I used to be a Mechanic/Engine rebuilder I used a good quality Black Moly Grease liberally, meant it didn't matter for how long the engine sat before being started. Used it on all metal to metal interfaces actually, cams and followers, gears etc.
Honda recommend a 1:1 mixture of moly grease and regular engine oil on bearing surfaces for reassembly. Used this in the past without issue.
Yes, I realised that. On first start up it will provide some lubrication until the oil pressure builds up.
When you find this special sticky oil that stays on the surfaces then let me know and I'll run my engine on it.
I know.........I was just being facetious...........I had an S8 years ago for a short while - got it for nought because it was well clapped out, but couldn't be bothered to do it up as I had also acquired a Yam YDS3 which was a bit quick in those days.
