windage trays and crank scrapers
windage trays and crank scrapers
(OP)
I am hoping to put both on the 225 slant six i am building. I am having trouble finding any and was wondering about designing a set. also I am wondering about how much difference they really make. I am not building a HP monster but I want to pick up as many "free" HP as possible by reducing internal friction and loads as this gives better power and efficiency.
The crank scraper is the biggest question how close to the crank should it be?
The crank scraper is the biggest question how close to the crank should it be?





RE: windage trays and crank scrapers
Cheers
Greg Locock
RE: windage trays and crank scrapers
RE: windage trays and crank scrapers
RE: windage trays and crank scrapers
RE: windage trays and crank scrapers
The biggest improvement with a wetsump was going to a substantially increased capacity and lowering the oil level.
The pan should have all the gated gizmos and a windage tray to seperate the sump from the rotating mass. ALL the return oil should be directly routed to the pan and not allowed to drain back (via hoses, etc.). It's always a good idea to clean up the inside of the block in the sump to make drain off a little better. Lotus/Cosworth painted some blocks in this effort. I did not find it superior to just cleaning off the flash and irregular surfaces and I did not have to worry about paint chipping off.
A note here about why I mount the windage tray on the pan instead of the block---high frequency vibration tended to crack mine when block mounted---I've seen successful block mounts so my problem may not be universal. Also I have used "diamond cut" SS screen with indeterminate results.
Dry sump is truly the correct way with all upper end oil return via external hoses or extra scavenge sections on the pump if it is possible/legal. Take a look at last months Circle Track for a nice little article about the NASCAR engine dry sumps.
Phil---0.005" would be nice but not very practical in an engine with 0.003" to 0.005" end play. I always ended up in the area of 0.015". I had the opportunity to observe the bottom end of an I-6 Ford with a clear plastic pan installed. From what I could see the scraper should do it's job even if it had a eighth inch clearance.
I no longer use scrapers, per se. If I cannot use a romotely located dry sump tank I use what I like to call my "integral dry sump" wetsump design with the oil level as far away from the rotating mass as possible and a 3 qt. accumulator. Running two or three qt. "low level" can be scary and dangerous unless ALL the wetsump mods are made in one package. If you lower the oil level in a stock setup you will gain power but with a good chance of damaging your engine.
Rod
RE: windage trays and crank scrapers
Another good setup is a piece of one way screen either bolted or welded in the pan. Depending on the pan depth, it should be about one third to one quarter of the way from the top surface of the pan. Basically you just need a hole big enough to get the oil pump pickup in and out.
RE: windage trays and crank scrapers
RE: windage trays and crank scrapers
A good wet sump will beat a poor dry sump.
the higher the engine speed, the more advantage you will get out of a good dry sump.
A good example of room can be in 2 different types of boats.
I have a centre mount ski boat with a fairly warm 350 SB Chev. The crank misses the bottom of the boat by about an inch, and with a good designed wet sump, reliable oil pressure cannot be maintained at speeds above about 5000 RPM, so a dry sump is essential for continuous high speed operation.
I have worked on a ski race boat that had a 350 SB Chev on an outboard leg. It had about a foot of clearance between the crank and the bottom of the boat. The sump was something like 7" long by 7" wide by 9" deep. With a decent tangential scraper and a tray, it was in effect a gravity scavenged dry sump, so I would expect nil gain from a dry sump, and probably a loss due to the power used to drive a scavenge pump.
The scrapers in both sumps are a copy of a late 80's Cosworth F1 dry sump pan and scraper.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
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RE: windage trays and crank scrapers
try www.crank-scrapers.com
RE: windage trays and crank scrapers
I wish I could use a dry sump on the mini as I rather like nice cool de-aerated oil but, an Accusump will just have to do. The Lotus-Cortina is restored as it was raced in the late '60's and has a "gravity scavenged dry sump"---THANKS PAT, I've been searching for a name for that thing.---Many of the so called "restored" vintage race cars these days reflect what the cars 'could have been' and not what they really were. Since I built this car in 1967, I can more nearly restore it to that condition...anyone can take an old street car and, with sufficient $$$ , can make a replica race car but, IMO, it will never be a "vintage" race car.
Rod
RE: windage trays and crank scrapers
Even for a SBC, I generally make my own pan scraper and tray, as they really need to be purpose designed to fit the chassis, application, and exact internal configuration of the motor. I have even been known to fit a two piece sump, so the scraper, then sump top half, then tray, then oil pump then bottom half or pan can be fitted in that order. That allows a full length scraper, and a tray that only has a very small hole for the oil pump shaft, and of course an oil return in the very middle, where even 3 or 4 Gs would not let oil slosh back up through the hole
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: windage trays and crank scrapers
I can make a custom high capacity pan. Build the windage tray into the pan. (welded or bolted) Use an accusump type device incase my level calcs are a bit off, and because it will preoil the engine. Polish the crank and do some edgeing and radiusing.
The last thing is the scraper. it was mentioned more than once to mount it tangently to the arc of travel. mounting directly to the bottom of the block would seem to be paralell to the arc. so can i bend the scraper to get the angle i need or would that be causing more problems than mounting it on the pan rail.
RE: windage trays and crank scrapers
The one on the side where the crank is moving up, only clears by about 1/8" or less.
These two overlap at the bottom, and bolt together with 1/8" spacers between them, so the opening faces toward the direction of travel. I use at least 1" of overlap.
I then carefully bend the closest piece, or top of the opening at the overlap so as to fit with about 0.020" clearance to the counterweights and rod bolts or whatever comes closest at that point.
I do not use a sump gasket between the block and the tray, as variable compression of the gasket will change the clearance. I do use a thin bead of silicone rubber to seal that surface as it will squeeze down to a consistent steel to steel contact, but still stops leaks.
Not finished yet.
I then make a channel or gutter to fit to the bottom of this, so it catches the oil coming out of the gap at the overlap. This channel falls from each end toward the oil pump pick up. It has hole directly over the pickup. Of course the hole is large enough comfortably carry the maximum oil flow, but no larger than necessary to do this. Of course it is at the lowest point in the channel. I also like to peen the edges of the hole down slightly to make a bell-mouth.
That takes care of the windage and oil return, and helps a lot with lateral surge.
To stop oil surging out of the pan (especially in a longitudinal direction) under G force, I also use flat plates, parallel to the ground, welded to and sealed to the pan, just above running oil level. This stops the oil running to the ends of the sump and coming up around the gaps between the end of the main scraper/tray and the sump.
I keep the pan as short, narrow and deep as possible, while maintaining chassis and ground clearance, and reasonable capacity.
Reasonable capacity varies greatly with the application. I like to see at least 6 (preferably 8)litres of oil in a SBC endurance engine, but 4 can be enough for a methanol SBC drag motor. With low capacity sumps on a drag motor, I would change the oil between runs.
Of course there are impossible compromises like the wet sumped, centre mount ski race boat, where there is no room for decent capacity, but a need for reserve capacity as it is an endurance motor where the skiers can normally outperform the boat.
Still not finished.
I make my own, simple cone shaped pick up that has little legs that sit on the bottom of the pan, thereby keeping the pick up as deep as possible, while ensuring it cannot close off against the bottom of the oil pan. I go to a lot of trouble to ensure there are no leaks between the pick up and the pump, as I want to ensure that no air will be sucked into the oil.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: windage trays and crank scrapers
My pan is as low as is possible, usually about 2" from the ground (I use a little heavier plate with longitudinal ridges on the very bottom since it does touch now and again). On the Ford inline fours it is not the best idea to use a plate between the block and pan but instead I use a scraper plate braced and welded to the top of the windage tray at a ~30 degree angle to the crank centerline suitably notched to clear the crank and four rods by about a ~1/16" using the main caps/bolts as a brace/stop with suitable drainage holes in the appropriate places. Below the windage tray which is bolted in full pan width and 3/4 length with a 1 1/2" hole for the pickup and a 1/2" hole at the front for the "dipstick" and centered forward I have a 10" by 10" box with four hinged (inward only) doors. The pan is widened to the left to add an additional 2qts. capacity for a total of 7qts. (I only put five in). with the Accusump, filters, -010 AN lines and 19 row Mocal heat exchanger it all comes out at about 10 or 11 qts. total.
I have also seen several other setups that bolted to the main cap studs but, they have not worked well for me.
Rod
PS: 10-4 the seal up the oil pickup against air leaks. I cannot tell you how many engines I have seen that were ruined before their time by a small air leak at the oil pickup/pump.
RE: windage trays and crank scrapers
The windage tray serve many functions when combined with the bedplate.
RE: windage trays and crank scrapers
Did you forget to attach a link?
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: windage trays and crank scrapers
It's patent document from EU patent office. It can be accessed through patent search website. Try this link ie.espacenet.com and type in EP1482133.
RE: windage trays and crank scrapers
Your ID on this site now makes more sense to me.
I like the design. Congratulations on the patent.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: windage trays and crank scrapers
Many other designs (Porsche Cayenne's engine for example)make it difficult for the production people to assemble conrod from the bottom of the engine.
With the use of pressed plate, access is not a problem and the design is applicable to many existing cylinder blocks.
RE: windage trays and crank scrapers
http://ie.espacenet.com/
Rod
RE: windage trays and crank scrapers
RE: windage trays and crank scrapers
RE: windage trays and crank scrapers
Can you describe more about the design that lost hp?
One thing I have seen in "classic" scraper design is a lack of drainage ports for oil that collects on the top of the scraper. That forces the oil to go for at least another trip round once the volume builds to the point where it pushes over the edge of the "shelf."
RE: windage trays and crank scrapers
The louvers must not serve as the primary oil scrapper as the amount collected is not as much as the primary one.