Hi Dave,
Took even longer on mine due to running on WMO and sump-gunk, a good coupla 100hrs....Mine used oil until everything seated in nicely, this was with a semi controlled cooling system, averaging around 90C...My other unit, has seated in quite nicely now, only around 20-30hrs, running very cold on a 200L ebullient cooling system(Seldom gets to running temp), this one runs quite cool in comparison... Temp seems to have had little to do with it. One thing to note though - I am now not using synthetic oils or detergent based ones... I have oil filters installed/retrofitted on both units.... I like the "old school" way of using the sump apron to settle out the crap... On initial run in, using 20w50 on the first engine(Along with WMO fuel), it took an age.... After rebuild, with straight 30W oil on my second unit(Dreaded Dino Juice), things were much, or seem to be much quicker...
My 10c worth...
Cheers
Ed