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Too much oil in sump

General engine tech -- Drag Racing to Circle Track

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stealth
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Too much oil in sump

Post by stealth » Fri Jun 19, 2020 12:41 am

Has anyone measured the power loss from overfilled pan sump?

Dyno results?

What’s your experience with lowering oil level?

Thanks
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Re: Too much oil in sump

Post by hoodeng » Fri Jun 19, 2020 1:14 am

Many years ago i had an experience with a 4/71 Detroit diesel that had excessive oil consumption between services, the engine was not that big on hours and performed faultlessly otherwise.

Detroit offered a reason that possibly the crankcase was being over filled at service, No was the reply, it was only filled to the top dot on the dipstick. They came back with, put in the normal fill for that type of sump which was 20l ,run and then dip it, i don't remember exactly where it was on the stick but it was definitely below the low mark.

They supplied a new universal dip stick assembly, that came with a long blade with instructions to dip it till oil rested on the full mark, cut the blade to length and rivet into the cap, that stick was noticeably longer than the one used previously. Result, oil consumption within spec.

Cheers.

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Re: Too much oil in sump

Post by digger » Fri Jun 19, 2020 3:15 am

There’s an engine masters video Ep32 I think about this. You need to sign up for free subscription

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Re: Too much oil in sump

Post by Kevin Johnson » Fri Jun 19, 2020 5:53 am

hoodeng wrote:
Fri Jun 19, 2020 1:14 am
Many years ago i had an experience with a 4/71 Detroit diesel that had excessive oil consumption between services, the engine was not that big on hours and performed faultlessly otherwise.

Detroit offered a reason that possibly the crankcase was being over filled at service, No was the reply, it was only filled to the top dot on the dipstick. They came back with, put in the normal fill for that type of sump which was 20l ,run and then dip it, i don't remember exactly where it was on the stick but it was definitely below the low mark.

They supplied a new universal dip stick assembly, that came with a long blade with instructions to dip it till oil rested on the full mark, cut the blade to length and rivet into the cap, that stick was noticeably longer than the one used previously. Result, oil consumption within spec.

Cheers.

Enthusiasts tend to collect multiple examples of an engine to have spare cores. Often there are a few different dipstick lengths. It is easy for them to be switched.

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Re: Too much oil in sump

Post by mag2555 » Fri Jun 19, 2020 6:09 am

Since your talking about dyno results and your on a speed site I will asuume your looking for results from rpms up to 5500 or better, not 2000 rpm like the average Diesel!

Nothing is carved in stone with results that I have seen due to the verience per motor in the size of the cranks counter weights and the shape of there leading edge.

One thing I have seen that is carved in stone is that H beam type Rods keep a bunch more oil hung up around the Crank then I beam type Rods do!
All drag race motors with a good baffled sump oil pan can safely run one Qt down from the stock full mark and a tight fitting Crank scraper can be worth 8 to 15 hp at rpms above 5500.
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Re: Too much oil in sump

Post by rebelyell » Fri Jun 19, 2020 9:13 am

Too much oil in sump causes aeration/foaming leading to dropping oil pressure and air in oil does Not protect bearings.

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Re: Too much oil in sump

Post by Coloradoracer » Fri Jun 19, 2020 9:25 am

There's a fine line between just enough and too much oil in the sump. Most manufacturers put more oil in the sump than is actually needed because of cooling, and to ensure there is adequate lubrication available at all times under all conditions. That doesn't mean the level is ideal, just that it's sufficient to do what they want it to do. It's been proven that running the least amount of oil possible yet ensuring there is enough there to maintain proper circulation is worth some power. However, that doesn't mean it's the best way to deal with it. I remember seeing a dyno test that they had less than three quarts of oil in the engine and made substantial gains in power as a result. However, doing that to you daily or your race car could very well leave you with a blown engine due to lack of oiling. A dyno is a fixed thing. The engine doesn't move. It can't take into account acceleration forces, deceleration forces, cornering, etc. To get away with lower oil volume in the pan, you have to address oil return in a big way. You must also ensure that the oil pan itself lends well to keeping the pickup submerged at all times, regardless of the attitude of the car. No easy task, as there is always going to be some issues with this with wet sump engines. Dry sump engines have very few issues, but come with their own disadvantages, which include the need for an external pump, tank, and plumbing...not to mention cost....

You can play with the oil level in your engine to see if you gain any power, but I'll tell you this, unless you are able to find 50 or more hp, it's very unlikely it will translate to any difference in performance on the track. I run a dry sump on my stuff, but that's because a wet sump was not practical for what I have. But if it comes down to it, I'll take a little too much oil over a little too little.....The old saying goes, it's better to have it and not need it than to need it and not have it.....
Mark Goulette
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Re: Too much oil in sump

Post by Coloradoracer » Fri Jun 19, 2020 9:26 am

rebelyell wrote:
Fri Jun 19, 2020 9:13 am
Too much oil in sump causes aeration/foaming leading to dropping oil pressure and air in oil does Not protect bearings.
In extreme cases, yes....99% of applications out there won't have an issue with this.
Mark Goulette
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Re: Too much oil in sump

Post by rebelyell » Fri Jun 19, 2020 9:49 am

Like many things, it's not too much; until it is.

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Re: Too much oil in sump

Post by Walter R. Malik » Fri Jun 19, 2020 10:42 am

stealth wrote:
Fri Jun 19, 2020 12:41 am
Has anyone measured the power loss from overfilled pan sump?

Dyno results?

What’s your experience with lowering oil level?

Thanks
On the dyno ... lowering the oil level in the pan definitely will have more power however, if in the vehicle that oil-pickup ever becomes uncovered, you will be sorry.
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Re: Too much oil in sump

Post by DeezNutz » Fri Jun 19, 2020 11:08 am

Several class racers (NHRA Stock/Super Stock) will drain a quart or so, or put in less than normal amount of their favorite super lightweight oil for a heads up run or for qualifying. They usually have done alot of measuring and mock up on the engine stand to determine exactly how much oil to keep the pickup covered.
It's just for a all out pass, not the whole event. And it does work!

Less oil windage=horsepower
More oil windage=less horsepower

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Re: Too much oil in sump

Post by mt-engines » Fri Jun 19, 2020 11:15 am

I see a lot of responses that do not answer the OP question like usual.

I have seen many times on the dyno, even in good wetsump pans where 1-2qts Les can be 20 HP and give better oil pressure in the pull.

Even at the track I have seen this.

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Re: Too much oil in sump

Post by rebelyell » Fri Jun 19, 2020 3:25 pm

stealth wrote:
Fri Jun 19, 2020 12:41 am
Has anyone measured the power loss from overfilled pan sump?

Dyno results?

What’s your experience with lowering oil level?

Thanks
As digger said
Yes, it has been done on Engine Masters
I have it recorded on DVR from Motortrend, However

I just checked; it is Engine Masters Season 3, Episode 3 "How Oil Kills Power" © 2020

consecutive dyno pulls with hp, tq & oil pressures graphed; pulls at varied oil levels.

So long as pickup remains covered while reducing windage, you're golden. Baffles, gates & doors in pan are big help on street /road course. Everybody ain't straightline racing; many ain't dry-sumped.

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Re: Too much oil in sump

Post by stealth » Fri Jun 19, 2020 8:25 pm

mt-engines wrote:
Fri Jun 19, 2020 11:15 am
I see a lot of responses that do not answer the OP question like usual.

I have seen many times on the dyno, even in good wetsump pans where 1-2qts Les can be 20 HP and give better oil pressure in the pull.

Even at the track I have seen this.
Thank you....

So my pan is huge, but dyno operator wanted me to fill well past where I thought it should be. I had at least 7 quarts in there and he wanted more. So I put in another two to bring up to bottom of tray in sump. The whole experience was bad, but wondering what that might have cost me in hp.

Friend of mine like mentioned run very low amount of oil in pan at drags an don’t seem to have issues. The biggest issue is at shutdown area, not down track or launch under full power.

I learned a lot about so called experts in this field.
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Re: Too much oil in sump

Post by Kevin Johnson » Fri Jun 19, 2020 9:25 pm

stealth wrote:
Fri Jun 19, 2020 8:25 pm
...

So I put in another two to bring up to bottom of tray in sump.

...
If you examine many OEM oil pans, the static fill level just reaches the "[windage] tray." "Windage tray" has many OEM names.

The designer/manufacturer of the pan is best equipped to answer where the oil level "should" be. There have been marked differences between OEMs* in the designs of sumps and oil levels for the same basic engine.

* Read as OEM engineering departments.

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