Now, when the engine is cold it has very good oil pressure, 20psi or so at idle and about 50psi cruising, but as the engine warms up this drops off quickly.
After 5 minutes or so of cruising the oil drops down to about 15psi at around 3500rpm and practically 0 at idle. Holding it pinned (about 4500rpm) the guage filckers between 0 and 2psi or so.
Letting it sit for half hour or so then jumping back in and getting straight on the throttle its got ok pressure again (say 20psi flat out) then that tapers off quickly.
I always put this down to drainback issues, or the pickup coming out of the oil, i've never had the engine out/sump off so im not sure where the pickup is. The engine is in backwards and on about a 15 degree lean, but it does have two small drain back tubes from the heads to the dog clutch.
But it hit me like a brick wall today. The engine is in a cover, in the hull, and has absolutely no air flow over the engine or sump. Before i put the scoop on inlet temps were obviously ridiculous, the scoop made a huge diffrence to performance.
Running the engine without a cover to test would be irrelevant, as theres still no airflow over the sump/block.
Im wondering if the oil is just heating up to a stupid temperature really fast??
I dont particularly wish to pull the engine out to fit an oil temp guage (wont get one in there with the engine in) so is there an easy way to work out if its way to hot? Would an IR temp gun on the side of the sump be a rough guide?
Even with the stupidly low oil pressure it makes no funny noises, sounds happy as, so im thinking it may be getting heaps of flow and just very little pressure, and i've never really woried about it.
Just thought i would throw the idea out there while i think about it.
Cheers.
Edited by Bomber Watson, 17 August 2012 - 08:17 PM.
