Originally Posted by Brynjaminjones
Thanks for the advice guys.
On the topic of suitable oil type:
My engine builder usually builds drag racing engines for a living. He specifically told me that he tightened up the clearances vs. what he would normally do for a racing engine, as this is in no way meant for racing. He explained that the wider clearances in a racing engine are in order to build a thicker wedge of oil.
He did tell me briefly what the clearances were in my engine but I'm not clued up on what the normal range is. I think he said around 0.001"- 0.003" for the main bearings.
I ordered all the parts myself and everything is pretty much a good quality stock replacement.
The pistons are cast aluminum.
He did tell me that 20w-50 is what all his drag racers use, which is why he does too. I'd guess in this case that I could do to drop down a touch in oil weight as they would have wider clearances than I do.
Based on all the above, would you guys agree?
Linctex, the oil filter in this is on its side, so I think a regular style filter should be okay.
If the bearing clearances are 0.001" to 0.003" I'd think a good full synthetic 5W-30 would work good for normal street driving. Lots of V8 engines with 400+ HP have been or are specified for 5W-30 and have similar bearing clearance. You're in the UK that doesn't get that hot either, so no real need for 20W-50.