My guess is it depends (what a decisive answer, huh?). I would think a low viscosity oil would allow the rings to seat quicker UNLESS it is highly fortified with friction modifiers and film strength enhancers.
[ June 19, 2004, 03:03 PM: Message edited by: pscholte ]
pscholte is right. Lower viscosity will allow engine to break in faster. A lot of depends on oil as well. Synthetic or mineral will make a significant difference. Full engine break in with synthetics take about 6k-10k miles. Using mineral based oil of the same grade break in will be in about 8k-12k miles. I mentioned long time ago that there are special break in oils available in Europe of strange grade 20W-20. In case of engine rebuild I would've run Mobil 1 0W-20 for 30-45 minutes and drain it. In a new engine you don't really need to worry about it. I think that all car manufacturers already use special break in oil or special additives to ensure proper break in.
quote:Originally posted by Mamala Bay:
web page ...Interesting article on Engine Break-In...I think some would agree on the new engine materials used regarding ring seating..
That is an interesting article, but it really pertains to bike break-in. Seems like there's a world of difference in breaking-in a bike compared to a car engine.
Actually the instructions for the dyno break-in are exactly the same as used on my race car engines. I break in the cam (if flat tappet) change the oil and filter (to get the assembly lubes out) and get it back up to temp and then follow the the break-in procedure.
Seems logical (and obvious) that a "thicker" oil would leave a denser film less prone to wiping removal, the same way a car might hydroplane on very wet mud at 30 mph while it might not with dirty rain water at the same speed. And if the remaining wiped oil film is thicker, it's more effective at preventing metal parts from contacting, thereby increasing time required to obtain the same amount of wear. But as others have noted, the various anti-wear/film strength/friction modifying additives complicate such simple logic.