[Land-speed] Dry Sump Tank Questions...

[Jim Dincau]

-----Original Message----- 
From: Larry Mayfield
Date: Saturday, October 19, 2013 9:25 AM
To: LSR ; monte
Subject: [Land-speed] Dry Sump Tank Questions...

I am considering the use of a dry sump system. Why? Well, the aspect of
fire caught my attention.  Ventilating the pan with a lot of oil at full
boogie makes a big mess and even bigger fire if it gets ablaze.  So, a
smaller blaze with a small oil pan for oil collection only.

If there is a link to something that can provide me with an education on
the kinds of questions below, I sure would appreciate it! I suspect
others would like it also!

http://www.petersonfluidsys.com/tech_faq.html



Just put your comments after the questions for me?

  I see there are at least two different types of tanks: round and
square. Seems to me that a square or rectangular tank provides for more
oil than a round one of the same basic dimension, however, there appears
that there are more round ones than rectangular. Any idea as to why?
Seems like a flat sided one would be easier to locate and mount.

       Quite some time ago I built a tank for our car which had flat sides, 
I angled the return line toward one side at the top so the oil could flow 
down the side in a sheet allowing it to de aerate. This design was a 
miserable failure compared to the round Peterson tank I replaced it with. 
The round tank with the return coming in tangentially de aerates the oil 
much more efficiently, the difference was night and day.

I have seen some in catalogs with removable tops or panels, both round
and square and I guess that would be for removable of debris; but seems
to me that if debris is present in the tank then the pump is probably
toast.  So, why would a LSR team need a cleanable tank like that?  Looks
like another place to leak.

You need to be able to clean the tank after any incident that leaves swarf 
in the tank.


Now, does the shape of the tank have anything to do with deareating the
oil returned from  the engine sump? Is round better for getting rid of
air in the oil? Why would that be?  Does the tank need a vent? Other
than the cap? I would guess so since air can be trapped in the oil as it
goes though the engine and it needs a place to escape.  However, if a
crankcase vacuum system is used though, would the vent be required?
Maybe a vent connected to the engine internally with a hose so that air
pressure is balanced everywhere?

See above reply on tank shape. See the link above for vent information. The 
vent size required for efficient de aeration is quite large -10 or larger.


Should the tank be located below the pump to prevent siphoning or
draining back into the engine pan when the engine is off?

The oil level in the tank should be above the level of the pump inlet to 
avoid loss of prime and cavitation issues. Oil draining from the tank into 
the engine through the pump is a dry sump system maintenance opportunity. I 
usually run the pump with a drill motor to return the oil to the tank if it 
has been sitting long enough to fill the pan..


For LSR type activities, are multi stage scavenge systems needed?  I
have see some with pick ups in the lifter valley, the valve covers, and
the pan in two or more places.   Are pumps driven at engine speed? Or
under/over driven?

The number of stages is governed by how much oil you are trying to manage 
and how much blow by you expect. Ask your pump supplier for a 
recommendation. In my case an F unblown gas four banger has two suction and 
one small pressure sections, the C blown alcohol motor has four suction and 
one large pressure sections. The Pumps are driven around 1/2 engine speed.


Finally, pressure regulators.  Since oil is incompressible, then the
pressure regulator is also a flow regulator as well.  I have an external
NASCAR regulator on my parts shelf, but where to actually put it in the
system? Seems to me that putting it just after the pump is draining flow
from the engine. The "extra" oil being dumped could be put directly into
the pan where the scavenge system would return it to the tank or
actually plumbed to the tank directly: that seems better, but, is it?
What if the OP regulator is at  the last place to get oil? Wouldn't that
be an ideal place because that way oil is delivered at full flow and
pressure to those places that absolutely must have both flow and
pressure: main bearings and rod bearings.

We use the pressure regulator built into the pump.

Standing by for any and all replies, no matter what they might be! I get
a lot of "you dumb f**k" so even those are ok.

larry

aka dipstick, dumb shit, idiot, no brains etc...

-- 
______________________________
drmayf
Worlds Fastest Sunbeam, period.
204.913 mph flying mile
210.779 mph exit speed
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