Daily Archives: June 24, 2020

I have been really enjoying one of my Father’s Day presents

Mrs. the Poet bought me a year subscription to Motor Trend On Demand and I have been bingeing on Engine Masters videos, both ones I had seen and wanted to watch again and the ones I couldn’t watch because of the expensive paywall. Well MTOD had a fantastic Father’s Day special that basically had an entire year for a bit less than the price of a single month under their old plan, $11.99/yr. Now the Sprint-T budget won’t allow for lots of fancy engine parts, but it will allow for parts that make the engine fit the car better and also make more power engine live longer. Especially when I can make those parts for next to nothing and also make the model parts for next to nothing and super simple.

One of the things that I’m having problems with is the oil pan on the LS engine. Most of the factory pans hang down way too much. There is also the consideration that most of the factory pans are also rear sump which puts the front hoop crossmember right where the sump of the oil pan goes. Plus ungood. So, I’m either going to have to buy or make an oil pan that avoids the frame crossmember and also doesn’t hang down too far under the engine so the engine can mount as low as possible. There was an episode with an oil pan comparison that had a brilliant idea for making a pan with extra wide kickouts that keep the oil that gets scraped off the crank by the crank scraper or just gets thrown off the crank by centrifugal forces from bouncing off the side of the pan back onto the crank, robbing horsepower. Normally to do that and still have access to the pan bolts on the bottom of the block you have to weld big tubes inside the pan for a socket to reach the bolts or nuts on studs, but this pan they were using had the whole bottom of the pan unbolt to access the pan bolts and bolt the top part to the block, then the bottom part bolts on to the top. Much easier than welding tubes through the pan, much easier than trying to snake bolts through the tubes onto studs that cost more than the bolts used with regular non-kickout pans, and better sealing because of less distortion of the pan rail. On the Mini Sprint-T I just need to make a multi-layer pan with identical layers of 0.040″ with a layer of 0.010″ sandwiched somewhere between to simulate the flanges where the top and bottom bolt together and stick it to the bottom of the engine where the oil pan gets stuck.

What I had in mind was a pan that went as far below the block as the flywheel does and as far out to the sides as the frame with maybe an inch or so clearance between the inside of the frame and the side of the pan. This would allow for a huge amount of volume for the oil to basically collect away from the crank then flow back to the oil pickup that attaches to the oil pump, with swinging doors to trap a pool of oil around the pickup while other baffles keep the oil away from the crank to prevent it from whipping air into the oil. As was shown in the episode keeping oil away from the crank inside the pan made for more power and more importantly more stable oil pressure while the engine operates. Then the only limitation on how low the engine could sit in the frame would be stuff attached to the engine like the transmission pan on the transmission. A wild thought just occurred to me, is it possible to dry sump a transmission to make it not stick as far down and also run more fluid for cooler running? I’m pretty sure there is, but more research needs to be done.

Anywho, back to the engine pan. One thing I can see that would improve the mega-wide but shallow pan would be rolling beads inside the bottom to divert the return flow inside the pan away from the crank and towards the oil pickup and also stiffen the bottom against vibration. I can also see making the full-scale pan from just two pieces of sheet stock with the ends folding down from the top, and the sides folding up from the bottom, and making the flange where the two bolt together follow that contour. Or not, I’ll have to see when I build the full-scale pan. But for the Mini Sprint-T the sheet for the flange will get glued flat somewhere between the top and the bottom sheets, just to show there are a top and bottom. Measuring the model block I have shows just 0.2″ from the bottom of the block and the bottom of the flywheel cover, or about 5″ deep and about 18″ long, and keeping it rectangular at 34″ wide gives a volume of 53 quarts at the top of the pan. That would allow for lots of oil at very low levels that keep most of the oil away from the crank to prevent the crank from whipping air into the oil. Running the oil only 1″ deep is 11 quarts and the crank would be about 3.5″± away from the oil, which is still a lot of oil. Significantly more than the factory pan and also much further away from the crank.

Edit from 6/29: I measured my drawing of the frame and discovered that at the front of the engine there is only 22″ between the frame rails and there is 18.5″ from the front of the 1.5″ diameter crossmember to the front of the engine with the flywheel/flexplate behind the crossmember. Working that out at 1″ deep gives a little over 7 quarts (actual conversion is 6.66 liters) of oil in the bottom 1″ of the pan. This is more than the LS7 wet sump pan, so I’m counting this as “all good”. Filling to the top of the pan/bottom of the block gives a bit over 9 gallons or roughly 37 US quarts. I’m going to start at 7 quarts plus filter(s) and see how the oil pressure does while driving and add oil as needed. I don’t foresee actually racing at 7 quarts as I think the engine will need more oil to keep the pickup submerged while the engine is running to prevent sucking air into the oil system. Since oil is heavy I plan on running as little as I can without uncovering the pickup.

Well I have rambled on long enough. The tl;dr is I enjoy my Father’s Day gift and it has inspired me greatly.