What is the most effective windage tray for a SBC?

[rustbucket79]

Rustbucket79; Looks like a few different opinions on trays and oil pans.
It may well depend on the combination of pan, scraper etc. I do believe there is some power in windage work.

Years ago when I was young and had more time than money,(I'm still short on both) I built an oil pan for a 355 sbc. I used a stock pan, bolted it onto a short block and cut the whole bottom out of the pan. I then bent the passengers side above the rail in and created a scraper out of it. I took another stock pan and some other sheet metal to make a large kickout stepped around the starter, and made a windage tray that was circular around the crank and cut slots in the tray and bent the edges up to catch oil spinning around the tray. the circular tray went in under the scraper on the passengers side. The pan was approx. an inch deeper than stock, It showed a quart and a half low on a stock dipstick with five quarts. I lowered the pickup tube the right amount. I ran that engine with that pan on it for years. The test came when I sold that engine in a diff. car turn key. When I made the pan I got in a hurry to finish welding and got the pan warped at the front of the pan rail requiring a good amount of silicone to seal it to the engine. And it wasn't very pretty!! It developed a leak a year later and the new owner took my (MASTERPIECE) off and put a stock pan on it. The car never E.T.ed quite as good. I don't have specifics on air densities to compare back to back, However it never repeated the best E.T. It ran before the pan switch. And he consistently ran about a tenth slower.
This was on a 7000 rpm. max engine. The crank had not been knife edged and may make windage reductions more significant.???
Windage to me is still interesting and a gray area.
Sorry about the rambling on and on but I thought you may be interested in this.

Thanks; Randy

Wasn't rambling on to me, that's the kind of innovation that makes this site so unique. It certainly sounds to me that your effort was worth some power. Thanks for taking the time to post.

[rustbucket79]

Just to add a bit more as I wanted to wait until today to answer.
Although this is a BB I think it is relevant.

I just took a 540 off the dyno.
It is a 7000RPM street engine
With a supposedly well designed "entry level" pan with a screen & scraper it had a small problem
At about 55-5800 oil pressure started backing up big time
It was 30 LBS down from 70 by 6500 where I aborted the test.
Added one quart over what was recommended
Same deal except is lost over 10HP & was worse

Drained 2 quarts same deal only it picked up almost 20HP
Pulled the pan, added studs & the Moroso windage tray that looks like a stock GM type.
More HP by a few, started at 75lbs & was 70 at 7000
Opinion is the windage was blowing the oil out of the sump at RPM
This was obviously not a drainage issue as seen by the worsening problem by adding oil.

I would suggest at the least a tray of some sort to keep windage out of the sump

I do not agree that this type of tray is going to cause return issues at all

On another personal note & just for a bit of venting so I will feel better,,,
I have no idea why a well known & reputable pan manufacturer sells a friggin pan without including a tray knowing this can be an issue

But I can say they are not alone.....

Thanks for the response Mike, the oil pressure falloff that was later corrected with a tray certainly show's the inadequacy of a bolt on pan, thinking that's all you need. A rookie might run that same pan and burn up some bearings if he wasn't paying attention. Gook information to have.

[panic]

Some ideas:
http://victorylibrary.com/mopar/baffle.htm

[Kevin Johnson]

Dedicated scrapers typically give back 2% to 3% at peak power for a NA engine -- appears to hold true for multiple engine configurations and with or without a tray.

Power return with a scraper typically begins at ~ 2750rpm. You'll need a sensitive dyno and careful experimental technique to avoid confounds that could mask these results. Be aware that inertial dynos and steady state dynos will show differences in the power returns from windage control. Windage is highly complex and changes in character as rpms increase. Losses due to windage can be from friction as well as increased rotating mass as well as work performed by pumping, etc.

Video research performed at MIT shows extreme foaming of engine oil can occur at just a steady 2000 rpms -- hence the need for windage trays. But properly designed trays. The ejected oil reaches an equilibrium with foam generation and dissipation that can be upset by improper tray design.

For kickout pans it is probably best to run a floor mounted scraper as in the Ford FE or Porsche 944/968 pan. Another good option is to run a scraper which operates in the 90 degree quadrant following TDC (downstroke). A good example of this type can be found in the 1995 Dodge Neon 2.0 block (only year they ran them). If you put a scraper over a kickout at the 9:00 position the scavenged oil will be forced back into the rotating assembly.

Within bay pumping leads to scouring of the pan floor. Same idea behind oil being blown out of the sump well proper. Shield the draining oil from these windage effects. Look at the shielded drainage tunnels in the Nissan SR20.

[Kevin Johnson]

If possible, immediately shut down and drain and examine the oil from the pan after a 7k pull where pressure was seen dropping. Good possibility that excessive air entrainment is the cause rather than neat air entering th pickup. Surface foam will dissipate quickly due to the surface active agents in the oil but deeply entrained air will take quite some time to clear (minutes). Boroscope in the crankcase is another possibility -- this was the technique employed at MIT.

Just to add a bit more as I wanted to wait until today to answer.
Although this is a BB I think it is relevant.

I just took a 540 off the dyno.
It is a 7000RPM street engine
With a supposedly well designed "entry level" pan with a screen & scraper it had a small problem
At about 55-5800 oil pressure started backing up big time
It was 30 LBS down from 70 by 6500 where I aborted the test.
Added one quart over what was recommended
Same deal except is lost over 10HP & was worse

Drained 2 quarts same deal only it picked up almost 20HP
Pulled the pan, added studs & the Moroso windage tray that looks like a stock GM type.
More HP by a few, started at 75lbs & was 70 at 7000
Opinion is the windage was blowing the oil out of the sump at RPM
This was obviously not a drainage issue as seen by the worsening problem by adding oil.

I would suggest at the least a tray of some sort to keep windage out of the sump

I do not agree that this type of tray is going to cause return issues at all

On another personal note & just for a bit of venting so I will feel better,,,
I have no idea why a well known & reputable pan manufacturer sells a friggin pan without including a tray knowing this can be an issue

But I can say they are not alone.....

Thanks for the response Mike, the oil pressure falloff that was later corrected with a tray certainly show's the inadequacy of a bolt on pan, thinking that's all you need. A rookie might run that same pan and burn up some bearings if he wasn't paying attention. Gook information to have.

[panic]

Dedicated scrapers typically give back 2% to 3% at peak power for a NA engine -- appears to hold true for multiple engine configurations and with or without a tray.
Power return with a scraper typically begins at ~ 2750rpm

Those are fairly flat generalizations, considering the wide range of oil level vs. lowest counterweight sweep, displacement vs. case volume, etc.
Why would an RB-based 440 with 10.72" deck, knife-edged 3.75" crank with reduced CW OD have the same windage and control as a B-based 463 stroker with 9.98" deck?

How much improvement will a scraper provide on Bill Jenkin's ideal dyno engine (6 foot deep bucket)?

[Kevin Johnson]

KJ: "Dedicated scrapers typically give back 2% to 3% at peak power for a NA engine -- appears to hold true for multiple engine configurations and with or without a tray.
Power return with a scraper typically begins at ~ 2750rpm"

Those are fairly flat generalizations, considering the wide range of oil level vs. lowest counterweight sweep, displacement vs. case volume, etc.
Why would an RB-based 440 with 10.72" deck, knife-edged 3.75" crank with reduced CW OD have the same windage and control as a B-based 463 stroker with 9.98" deck?

How much improvement will a scraper provide on Bill Jenkin's ideal dyno engine (6 foot deep bucket)?

Yes, I know the generalizations are sweeping. This is just what has been reported back. I can make up some data? I make scrapers for hundreds of different types of engines.

At higher rpms the pressure differential that forms around the rotating assembly actively draws oil into it which is counter-intuitive physics. This is why windage clouds form despite having occlusive windage trays. The ejected oil from the rods and mains is enough to sustain a cloud so perhaps Grumpy's ideal engine will as well.

A more ideal engine would be running with little to no atmosphere in the crankcase. Ala Formula 1.

Also, the extrema of the sweep of the rods typically exceeds that of even unmodified counterweights -- haven't run into a counter-example yet.

[randy331]

Kevin, what angle, should the scraper be to the crank? 90/45etc. Or would it work best to start out at a 180* angle to way the counterweights rotate, then sweep away from the crank. Also, will it be different depending on where in the pan you have it, and the size of the pan etc?
Thanks ahead of time for any help.

[Kevin Johnson]

Kevin, what angle, should the scraper be to the crank? 90/45etc. Or would it work best to start out at a 180* angle to way the counterweights rotate, then sweep away from the crank. Also, will it be different depending on where in the pan you have it, and the size of the pan etc?
Thanks ahead of time for any help.

I think two ideal angles are in play. To release the oil adhering to the surface of the rotating assembly one should use a tangent with as thin a lipophobically coated blade as possible -- asymptotically approaching a mathematical tangent, in other words. This minimizes the hydrodynamic friction as well as the energy used to shear the oil molecules away from oneanother. You are essentially allowing the oil to follow the path of least resistance -- which it "wants" to do.

At higher rotational speeds windage changes in character and you want to disrupt the pressure differential that is forming around the rotating assembly which is actively drawing oil into it. For this I believe the optimal angle is a normal to the surface of the rotating assembly. There are side effects to this, however, in the increased energy consumed by the system trying to return to its previously disrupted equilibrium.

I generally believe that the windage flow following a rotating assembly has a complex function with multiple nodal points of varying distances from the central axis to the crank. At these nodes -- some of which assuredly lie outside the swept path of the rotating assembly -- it should be possible to achieve a local maximum of energy saved by disrupting the flow versus energy lost by its seeking to re-establish it. Oh, is that a pan kickout, perhaps? I think many OEMs have happened upon the practical side of this relationship. Local maxima do not neccessarily mean global or function-wide maxima.

In answer to the last two questions, yes.

[Tony B]

On dry sump pans, to get the screen to "work", it had to be 1/4" off the floor, and 1/2" below the rail. When it was hung out like that, you would find pieces of the screen in the return filter. Obviously, even the directional screen was becoming solid at high rpm's, which showed to throw it in the garbage, and let the pump (vacuum) do it's job.
On a wet sump pan, a screen (necessary evil, like the wet sump) will keep the windage from beating the oil in the bottom of the pan back up on the crank (which is a large toranado of oil). It will have to be a directional like the Stef's, to work. A solid tray like the Chevy one will let the oil keep bouncing right back on the crankshaft.
ALL pans, wet or dry benefit from kickouts (the ones you have to install the bolts from the bottom).TB

[Kevin Johnson]

On dry sump pans, to get the screen to "work", it had to be 1/4" off the floor, and 1/2" below the rail. When it was hung out like that, you would find pieces of the screen in the return filter. Obviously, even the directional screen was becoming solid at high rpm's, which showed to throw it in the garbage, and let the pump (vacuum) do it's job...

Likely harmonics rather than the physical force of the oil droplets -- did you try supporting the screening with a perimeter framework?

Also try putting a scraper in the first quadrant. With less atmosphere the droplets will be directly expelled radially and tangentially. Side note: This pattern leads to problems with oiling of the orthogonally oriented wrist pins. A certain percentage, greater propensity, will be carried around with the rotating assembly leading to a greater force from that clockwise direction. A scraper at that position will absorb the greatest brunt and the draining oil can be shunted to the pan wall then to the floor and then the scavenge ports. Because of the focused patterns aligned from bay to bay there will almost certainly be damaging resonant frequencies that would have previously been dampened by the diffusing effects of the windage atmosphere which tends to travel up and down the crank.

[ChrisU]

the best windage tray is no windage tray. Generally no benefit in these, more often a loss of power. A big pan with lots of space around the crank usually makes the most power.

That's the best post on this thread... but it doesn't look like anyone paid any attention.

Maybe that is good in some ways?

[Kevin Johnson]

the best windage tray is no windage tray. Generally no benefit in these, more often a loss of power. A big pan with lots of space around the crank usually makes the most power.

That's the best post on this thread... but it doesn't look like anyone paid any attention.

Maybe that is good in some ways?

Well, about 40 years ago that same thing was being said re the big block Mopars. Surprise. 13 hp gain out of the box on the stock motor.

Windage trays need to be properly designed. They serve specific functions. There are very good reasons the OEMs have completely re-engineered many old platforms to minimize windage losses.

[Jeff]

Had a 318 Spin #1 rod on customers 97 dodge pickup . He knows how to abuse a vehical and laughs about it. Not sure what caused it, exept lack of oil but why? Both wrist pins tight on 1&2. After reading the post on oil pressure drop, I feel better that I ordered a windage tray for it this time. They were out doing some serious off roading when it let lose. Can tell it starved for oil on 1&2 ,everything in the rest of the engine other then bearing material from 1 was fine.
In the same time fram he broke an axle and seperated a ball joint.

[ewgant01]

No windage tray is the way to go, just run a larger sump pan with less oil. The windage tray will catch oil and hold it closer to the crank, actually doing opposite of what the windage tray is made for. Oil gets back into the pan through the use of gravity. Just like pouring fuel through a funnel, the fuel can only go so fast and when it is poured faster than it can run out it builds up.
A scraper however is a good idea, but it takes a lot of work to get it to fit close without hitting.