dumb question about cranks and oiling
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Anonymous
Don't forget too that you don't drive a car stationary - when you accelerate or turn that oil is sloshing around in the sump and therefore can indeed get hit by the crank, hence the knifedging to minimise the drag.
That's really the reason for a deep sump oil pan - not to hold more oil but to move the oil further away from the crank. Once it dips in you get a windage cloud as Dave described, like a rope twisted around the crank, that costs horsepower and increases crank inertia (hurts revability
).
So a smart move is to baffle the sump for a start - cheap and easy. Racing pans do this. you could get pretty fancy with swinging trap doors etc, I will just make a simple one for the deep sump oilpan I built for my SB.
You can also use an accumulator to keep oil out of the pan (like a semi dry sump!), I'll be using one of them but mostly for starvation and startup protection.
I've heard mixed feedback on windage trays. It's true most people use them, but I've also heard of tests where they gained no power at all. I guess it depends on how bad the original installation was. One of my concerns is that of course you have oil draining back into the sump and if you are not careful (hi vol pump and small resrtictions in the windage tray) you can actually trap oil in the tray and make things worse. So as mentioned if you are using one I would open up the louvres, especially on a stroker where the crank gets closer to the tray.
I like the idea of a crank scraper too. I'll be using one of those for sure, I'm still thinking about the windage tray. It's basically a piece of sheet metal that strips the crank of any oil it picked up. Some modern engines have them built in already.
That's really the reason for a deep sump oil pan - not to hold more oil but to move the oil further away from the crank. Once it dips in you get a windage cloud as Dave described, like a rope twisted around the crank, that costs horsepower and increases crank inertia (hurts revability
).So a smart move is to baffle the sump for a start - cheap and easy. Racing pans do this. you could get pretty fancy with swinging trap doors etc, I will just make a simple one for the deep sump oilpan I built for my SB.
You can also use an accumulator to keep oil out of the pan (like a semi dry sump!), I'll be using one of them but mostly for starvation and startup protection.
I've heard mixed feedback on windage trays. It's true most people use them, but I've also heard of tests where they gained no power at all. I guess it depends on how bad the original installation was. One of my concerns is that of course you have oil draining back into the sump and if you are not careful (hi vol pump and small resrtictions in the windage tray) you can actually trap oil in the tray and make things worse. So as mentioned if you are using one I would open up the louvres, especially on a stroker where the crank gets closer to the tray.
I like the idea of a crank scraper too. I'll be using one of those for sure, I'm still thinking about the windage tray. It's basically a piece of sheet metal that strips the crank of any oil it picked up. Some modern engines have them built in already.
Gavin Chisholm - 414ci W2 Stroker SmallBlock Panther Pink '71 Challenger convertible - in bits
Car progress can be viewed here
Car progress can be viewed here