Originally Posted by hobby28
I am building a dirt track street stock engine, what is recommended on windage tray? Are you better off with a stud kit and mounting the tray to the mains or is it better to buy an oil pan with a built in windage tray? I have to buy fasteners either way.
The following assumes you’re using a wet sump configuration. You need a very good pan with a left turn kick out, tray, baffles, and perhaps a crank scraper depending on the kick out shape. I like a full length windage tray but most of these are limited to the pans that fit modified mounting where the stock cross member is eliminated or location modified.
The type of engine mounting and the distance from the pan to the track will have a large effect on the available choices that can be used.
In any circumstance a constant left turn car needs as deep a pan as possible with a right side kick out that locates the pump pick up within. The constant left turn forces the oil to the right side of the pan. The right side kick out in the sump proper catches this oil preventing it from climbing the pan wall thus escaping the pump pickup as the pickup extends into this cavity. Some pans also include a rolled relief on this side just below the pan rail as a place to trap oil being thrown off the crankshaft toward the right side of the crankcase. This roll catches that throw-off so it can’t be pulled around with the crankshaft as part of the windage. From the roll the oil runs down the side of the pan into the sump, this is very effective at taking the oil mist out of the windage. If the pan of your choice does not have this feature then a crank scraper is necessary to perform this function. Many scrapers that are sold have a conformal shape to the crank, while effective they do have to be “adjusted” to insure clearance. However a simple piece of angle welded to the pan side a little lower where shaping around the crankshaft isn’t necessary is every bit as effective in peeling oil out of the windage and returning to the sump.
I like a full length louvered windage tray, most end sort of the front crank throw. The full length which requires a deeper shaped pan helps strip oil from the crank and isolate it so that it flows to the sump instead of being pickup by the windage and carried with the crankshaft. A forward extension of the tray also helps baffle oil from flowing forward under hard breaking which can cause the oil to flood the front wall of the crankcase and get into the path of the spinning crankshaft.
This link to Milodon shows what I consider the ideal wet sump for circle track use look at pan 31514. It has many good ideas that can be used as much as possible in other oil pans if your installation cannot accommodate this exact pan assembly. Milodon Circle Track Oil Pans
The windage scraper to go with pans that do not have the crank throw-off relief see part 32640 on the next link. I'm also a big proponent of the oil pump support bracket part number 17100.
Also needed is a rear pan baffle in this case I’m using Milodon part number 32500 as an example, there are other makers of these parts as well. The rear baffle fits under the pump often giving much needed clearance between a high volume oil pump and the rear crank counterweight; but its intended use is to prevent oil from climbing the rear of the pan upon acceleration keeping the oil from flooding the rear seal area as well as from getting into the spinning rear counterweight. http://www.milodon.com/2012-Milodon-...%20Gaskets.pdf
Don’t forget to use a quality all steel intermediate pump drive shaft.
Mock up this assembly to be sure of all need clearances. You will find the thinking about how to manage oil in the designs of these parts to be extremely effective. The problem they solve is not only to get the oil out of the spinning crank where power is used by the crank to push its way through the oily windage but it is also a problem of maintaining just enough oil on the cylinder walls without overwhelming the rings while insuring the oil from circulation returns to the sump to rest long enough to allow trapped vapors to escape and through the use of traps and baffles keep the oil where the pickup is and out of the crankshaft. In regard to controlling oil on the cylinder walls and underside of the piston, you will notice that many recently “clean sheet of paper” designed engines like the Chevy LS have dried out the crankcase so much that an index oil stream onto the bottom of the piston became necessary for cooling the piston and lubricating the cylinder wall and rings. So it is possible to get the bottom end too dry. However, I don’t see that as much of a problem on the Gen I engines with their looser tolerances and clearances still it’s something to consider when building your engine.