Lotus Elan

Racing with a wet sump ?

PostPost by: cabc26b » Sat Nov 29, 2008 1:44 am

I have to believe that any of you all racing under FIA regulations have this figured out- SO..... What is the reliable set up to keep a twin cam oiled with a wet sump. I am considering going this route on my s1 if there is a way to avoid changing main bearings every week end (lI have heard is a possibility w/o dry sump). Any suggestion would be much apprecialted

George
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PostPost by: twincamman » Sat Nov 29, 2008 3:20 am

a sliding or rotating oil pick up and baffling the sump ----haven't done it myself-- just heard it can be done ---ed
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PostPost by: rgh0 » Sat Nov 29, 2008 7:31 am

I use a baffled sump that works just fine. Historic racing in Australia does not allow dry sumps either. The last engine I pulled from my Elan had 3 years of racing with the 8300rpm limit I use and bearings were perfect so it must be working Ok

Basic design required is a central pick up - the earlier screw in block pickups are perfect in combination with the early 120E blocks that I normally use in my competition engines. Then baffles either side of the pick up with swinging trap doors. Finish it of with a windage tray and it works just fine.

You can add extended wings on the oil pan as the Escort and Cortina guys seem to do but it all gets a little tight for space in the Elan and I dont think it is really necessary anyway with the baffling and trap doors.

I think I have posted some photos at some stage on the yahoo elan group but pm me if you would like some. Col Croucher at www.elantrikbits.com has produced a good and very detailed set of build instructions which he sells through his web site. This is a good resource if you dont feel confident in developing it from scratch yourself. And yes I am biased as I helped Col with the development of his design based on my experiences which in turn I got from talking to an old racer one day at a track meeting many years ago

cheers
Rohan
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PostPost by: bcmc33 » Sat Nov 29, 2008 12:20 pm

Rohan,

I have some pictures of your baffle design and intend to copy it next time the engine comes out.

The bit that ?baffles? me is the tray ? what exactly is it?s purpose and why is it called a windage tray?
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PostPost by: Old English White » Sat Nov 29, 2008 12:48 pm

... Georges ,
A blaffled sump could do nothing without a good high pressure/high capacity oil pump ...
There are different opinions about expanded sump , but racing on track , if possible , I'll have one (same as on RS/Mexico Escort's S1 , but can't be used directly) , as on my friend Jean-Pierre on his Elan GTS , like many others.
"OEW" has a baffled non-expanded sump(as described by Rohan) with a proper oil pump , and does not suffer from that on track , but even if its owner allways wanted to , she isn't a real racer anyway.
Christian.
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PostPost by: Elanintheforest » Sat Nov 29, 2008 1:12 pm

Brian, I had to look up what 'windage' is, and found this on an American performance site:

Windage is the power loss caused by the friction of the oil in the engine coming into non-lubrication contact with the moving parts inside the engine. For the most part, this is oil splashing against the counterweights of the crank as it spins. If there is poor oil control inside a race engine, windage can cause some pretty significant power loss. First, as rpm increases, the amount of powerloss for a given amount of windage increases dramatically. As a liquid, it's the same concept as water in a swimming pool providing little resistance if you slowly dip your hand into it. The feeling of resistance becomes much different if you do a belly flop off the high dive into that same pool. Second, life inside a circle-track race engine is much different than any road-going engine cruising down the interstate. In racing, high-g turns, rough racetracks, and good, old engine vibrations put much more kinetic energy into the oil collected in the bottom of the pan, which makes oil control much more difficult.

The windage tray is a piece of sheetmetal with louvered holes stamped init. The direction of the louvers is important. Oil slung off the crank can easily pass through the louvers into the sump, but there is no line-of-sight path between the oil in the sump and the crank. This makes it much more difficult for oil in the pan to splash back on the crank.

The word windage seems to have been adapted from it?s original definition, which is ?the retarding force of air friction on a moving object?


Well, I've leaned something!

Mark
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PostPost by: bcmc33 » Sat Nov 29, 2008 1:50 pm

Mark,

Thank?s for the info.
Windage to me related to my rifle shooting days, but the synonym is not so difficult to understand when related to any resistance of moving parts.
So, in a nutshell, the windage tray is to stop oil slopping about and hitting the rotating crankshaft which would create significant resistance at very high rotating speeds.

Found this on the web:

http://www.expertvillage.com/video/5866 ... -plate.htm
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PostPost by: cabc26b » Sat Nov 29, 2008 5:07 pm

Gents;

Thanks for the advice and pointers , much appreciated. The engine builder I use never got the wet sump figured out reliably back in the day and so uses dry sump on the motors, I generally go with what he recommends, however, there are a lot of places I want to consider going that don't want you showing up with a reliable oiling system. go figure. So this is my call -

No question I want to use the HP/HV pump - the story on the stock pump is that one it loses it's prime it can take 30 seconds have Oil pressure come back up ( like after and oil change) . is there a opinion on the gears to use for this or a supplier

My guy has tried the swinger from Bean , he had two thinks to say - its a moving part so some times it would stop moving and so became a maintenance item. the other thing is that if you went through a sequence of left-right turns at high speeds the oil and the pick would lose synchronicity and the pump would suck ail - almost a guarantee at VIR on the climbing esses and I think can happen at Road Atlanta going down into turn 5

So - The Design of the sump seems to be where art and science convene - more specifics would be helpful , Rohan - can you send me pictues of your baffle , I have heard that there are other over-the-counter solutions so open to these as well if you know of one that works . Christian, can you elaborate on the escort pan ( is this on that has the depth in the rear) ? or about what your friend Jean-Pierre uses to get the system reliable ( I have not heard about him braking down so would like to gain some insight on this one)

Thanks for the help guys .

George
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PostPost by: memini55 » Sat Nov 29, 2008 5:20 pm

George,
Col Croucher has written an indepth article on the sump balling system and has ot posted on his website if you want to take a look. I know he has put lots of labor into refining his design.
Might be worth a look.

Best of luck
Mark

http://elantrikbits.com/baffle.html
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PostPost by: Rob_LaMoreaux » Sat Nov 29, 2008 7:48 pm

My engine came with the later pickup and sump which had been baffled somewhat. I added a windage tray designed to get the oil into the pickup side, then I added an oil accumulator and a low oil pressure light.

This seems to be working well, but I don't have that many miles on the engine yet.

I do like the looks of the sump developed by Rohan and Col, but since I can use the accumulator I went that route.

Rob
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PostPost by: ceejay » Sat Nov 29, 2008 10:12 pm

Hi Guys.
I just noticed the discussion about the oil surge problem with twinks.
It was a little over two years ago before I decided to cure this stupid oil surge problem for good... the elan was off the road for about a week and a half while some fabricating and metal surgery was done inside the sump of the twin cam. To cut a long story short, the job was soon finished, and since that day, oil surge is just a faint distant memory.... But you know what, I thought about it for several years or so before I got my butt into gear to build the baffled sump system.

And the result... nothing short of brilliant, it is just like the CV drive shaft thing, do it once & do it right and you can almost forget about it, I now know that I can drive as hard as I want around any given corner and not be hassled by oil surge, it just ain't gonna happen.

We have also given several of the "How To Build Sump Baffle Manuals" away with CV drive shaft orders and for the next few days the manual has been reduced to $29.95 as a pre Xmas special, if you are interested.
Visit: http://www.elantrikbits.com/baffle.html
You wont have to go re-invent the wheel, buy it, read it, build it.
Col.
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PostPost by: rgh0 » Sat Nov 29, 2008 11:32 pm

ZIP file with photos and some notes attached of my approach to sump baffles. i have renamed as .doc since .zip extensions are not allowed. So download, rename to .zip and then you will be able to open it.

cheers
Rohan
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Lotus Twin Cam Sump Baffle.doc
This is a ZIP file - you need to download and rename with .zip extension to open
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PostPost by: lotusanglia1965 » Sun Nov 30, 2008 12:14 pm

sorry,i'm windows thick,i've downloaded,but how do i rename with.zip extension?i've tried right click on it on the desktop and added .zip to the title? help!
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PostPost by: bcmc33 » Sun Nov 30, 2008 1:40 pm

I have WinZip to recognise the five jpeg files but it will not open them. I've tried all I know (not much) and keep getting the following message:

Lotus_Twin_Cam_Sump_Baffle.zip: The archive is either in unknown format or damaged
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PostPost by: cabc26b » Sun Nov 30, 2008 3:16 pm

Thanks Rohan, I will look these over. I will most likley will take a look at Col's set up as well. Anywhere else to look ?. [/i]
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