Custom Sump Design / Manufacture.

[Astro_Al]

Howdy, I think I need to fab up an 'interesting' sump.

Possibly dry, so fittings for several scavenge lines, plus baffles etc.

I'm looking to make bits of it as thin as realistically possible, other areas can have more depth. I'm looking for inputs on any aspect of it's design.

Where to put scavenge points (one at each corner seems like a plan?), what is a realistic minimum depth, how much volume should I aim for?

Presumably the oil capacity of a dry sump is not an issue? Or is it always a good idea to have some splashing around down there? Also thinking of an accusump inline as well.

Possibly crank scraper design - probably not worth the headache though?

Any inputs on the actual fabrication method is also good - I'm thinking Tig welded ali, possibly with a machined flange to mount it to the bottom of the block 'skirt'. I know heat distortion of the flange can be a problem, even when Tigging it.

etc etc...

Cheers, Al.

[FridgeFreezer]

Al, surely for your lump there are off-the-shelf dry sumps available?

[dollythelw]

Whats the recommended/stock oil capacity Al?

whats the stock sump made of?

[Astro_Al]

Al, surely for your lump there are off-the-shelf dry sumps available?

Yes John, there sure are, but none of them are designed specifically to clear a Mog 404 diff housing in a 100" wheelbase tube chassis...

Just figured for the price of them I could do something a bit more 'suitable' and gain a couple of inches extra clearance between the two.

A lot of the dry sumps I found are surprisingly deep - hence my questions about oil capacity etc (though I can't see why it matters in a dry sump...?).

Al.

[FridgeFreezer]

...for that matter have you even GOT the engine yet? If you haven't then I'd hold off on dry sumping until you've got it, otherwise you'll change your mind between now an then and end up with a different engine and a useless sump

Aren't they usually cast/machined?

[Lara]

Hi Al,

Dry sump design is a very important factor in an efficient system, you definitely need a scraper and make this strong as the forces are higher than you would believe. you also have to consider where the oil goes after it has been scraped, if it is not guided it will go straight back onto the crank, There are plenty of good books on this but the best I think is Smokey Yunick's book on the small block Chevy, not a Rover but for info like that it is perfect,

I have made quite a few dry sump systems and the sump have always been TIG welded ally with a scraper made of 4mm stainless. and a windage tray.

Use a Moroso pump, I like a 4 stage, 3 suction and one pressure, very sensible price etc. www.moroso.com

Make a valley in the bottom of the sump and a Pickup at each end and one in the cam valley of a V8. The suction from the scavenge will cause quite a vacuum also.

Oil capacity of the oil reservoir should be 15 litres or so on an endurance type engine and use a thin tall tank over a low wide one, this also needs to be well designed. look at www.stefs.com for good quality well designed off the shelf items.

Lara.

[Astro_Al]

I think the stock sumps are cast, but too deep.

It's not ordered yet John, but there's no going back now - the whole chassis is designed around it and the gearbox & bellhousing is bought. (Once the muppets send the right part... ).

Figuring out what is do-able will probably affect my engine order, so I want to figure it out now.

I'm not gonna make it before I get the engine, when I can throw everything together and really check the clearance.

Hopefully I can cut the flange off the sump it comes with and use that as the basis. It's just sheetmetal and pipe fittings after that - but since I really don't want to blow the thing up, I need to know some safe design inputs...

Jez - the stock sump and filter is 5.5 to 6 quarts. I'll be running a cooler and if it's gonna be dry, a nice big tank too, so that lot, plus possibly an accusump and a lot of lines means more...

Anyone??? Al.

[Astro_Al]

Damn - I'm always one post behind! Thanks Lara, great to get some tech from someone who's done it. My engine is Chevy too, so I'll defo check that book out, thanks for the tip - any more references you know of?

What do you go for in terms of a scraper clearance dimension?

Do you know if sump volume is a factor, or can I just make one as small as possible? (I guess the latter, but keep seeing ones that are 4 inches deep which puts me off...).

Thanks for the links - I'll check em out.

Al.

[Daan]

Very important is also deairation (hope thats spelled right). Are you planning a swirl pot? On my last project air in the oil caused at least 3 engines to nuke.

Daan

[02GF74]

to avoid distortion when welding, bolt the sump to the block or a sturdy piece of ply wood?

[Lara]

Damn - I'm always one post behind! Thanks Lara, great to get some tech from someone who's done it. My engine is Chevy too, so I'll defo check that book out, thanks for the tip - any more references you know of?

What do you go for in terms of a scraper clearance dimension?

Do you know if sump volume is a factor, or can I just make one as small as possible? (I guess the latter, but keep seeing ones that are 4 inches deep which puts me off...).

Thanks for the links - I'll check em out.

Al.

Hi Al,

Scraper needs to be about 2mm clearance but no closer, make a card template and go from there.

Sump does not have to hold much if the windage tray is doing its job and directing the flow of oil from the crank to the oil trough and pickups. The big US ones are big because they can be, but if you look at a good NASCAR or F1 type sump you will see a very small unit.

I will give you a list of good books tomorrow if I remember.

Lara.

[Astro_Al]

to avoid distortion when welding, bolt the sump to the block or a sturdy piece of ply wood?

Yeah, it will be bolted to a metal jig, ta.

Daan - not too sure yet... Investigating! What did your (expensive!) experience conclude on that - what would you do? Might sound stupid but would running the oil flowing into the tank through a mesh help to remove bubbles caused by an oil/air mix being sucked from the sump?

Getting the scraper right scares me.

Thanks Lara - good stuff. Sounds like I can do something interesting.

Al.

[02GF74]

curiousity has go the better of me .... what is a scraper?

[Lara]

Hi Al,

Don't be afraid of the scraper I will send some pics, it is not rocket science!

The gauze idea is good and it is common practice on good systems!

Tall reservoirs help also in deaerating and conical bottoms leading to the pickup tube are the ultimate.

Lara.

[Tonk]

best bolted to a heatsink to avoid distortion, i reckon a quick machining afterwards would be best to get it dead flat

[minivin]

curiousity has go the better of me .... what is a scraper?

think of a more simpler crank like an ol' british bike crank, it's made up of two flywheels which tend to be cylindrical. These flywheel's tend to suffer with oil hanging-up on them which then tends to get flung up the bores and the oil scraper ring has to do even more work.

To prevent this from happening a scraper tends to be cast into the crankcases or bolted in so that it sits close, but not touching the crank flywheels so that it can scrape as much oil of the flywheels as possible, to prevent oil fling

[Astro_Al]

>"Don't be afraid of the scraper I will send some pics, it is not rocket science!"

Oh but I am! The '2mm' thing makes me happier though, I was envisaging a few thou... Duh.

Pics will be much appreciated.

>"The gauze idea is good and it is common practice on good systems!"

Cool - I had a good idea!

>"Tall reservoirs help also in deaerating and conical bottoms leading to the pickup tube are the ultimate."

Tall res should be do-able. I prefer my bottoms nicely curved, but a cone could suffice in these circumstances. Are they available commercially in this style, or shall I make my own? The tall res idea also makes me more confident against pickup starvation at extreme angles (like on my garage floor where this thing is destined to stay... ).

Tonk - I'm glad to see you are already figuring out the best way for you to do this...

Man - I nearly didn't bother posting this here, I thought custom dry sumps wouldn't be very 'LR4x4'. Glad to see I was wrong - thanks for the great input guys.

Al.

[Daan]

if you were to make your own tank: use a swirl pot internal of the tank which drops its oil onto 1 or 2 plates with a lot of holes which in turn drops the oil in bottom of the tank. make the tank as high as you possibly can package.

Easyer is to use an existing dry sump tank which usually has this build in. But they can be hard to package.

[02GF74]

Man - I nearly didn't bother posting this here, I thought custom dry sumps wouldn't be very 'LR4x4'. Glad to see I was wrong - thanks for the great input guys.

If you have any specific to home made sump - post ya questions here - I look at kit car builder forum and the guys do DIY sump mods, dry si=umoping etc, all the time.

re: scraper - gotcha - seem to remember reading that polishing the crank and knife edging it is done to prevent the oil sticking to it.

dare I ask about swirl pot now?

[Astro_Al]

I was also wondering about an engine cut-off upon oil pump failure - any ideas how to wire that sucker up???

What about startup - do I need to get the pump flowing before turning the engine over? How about just switching the pump on with the ignition 1st stage, so it'll always be running when you try to start the engine?

Actually, scrub that, there's no key, so ignition 'stages' don't really exist (like key positions). Just an ignition switch to make the circuit and then a start button. I guess I just wire the pump into the ignition switch?

Ta, Al. B)

[GBMUD]

I was also wondering about an engine cut-off upon oil pump failure - any ideas how to wire that sucker up???

What about startup - do I need to get the pump flowing before turning the engine over? How about just switching the pump on with the ignition 1st stage, so it'll always be running when you try to start the engine?

Actually, scrub that, there's no key, so ignition 'stages' don't really exist (like key positions). Just an ignition switch to make the circuit and then a start button. I guess I just wire the pump into the ignition switch?

Ta, Al. B)

IIRC Landrover 101s had a system where the engine would not run without oil pressure. It was a PITA I suspect but you know what V8s are for self priming, I guess it was to prevent squaddies ignoring the red light and driving anyway.

With a remote oil pump you could easily make the engine require oil pressure before you get fuel pump or ignition?

Chris

[Astro_Al]

So what you're saying is:

1st switch position: enable oil pump.

Check if oil pressure -----> if yes then enable ignition circuit.

2nd switch position: Ignition circuit.

After which point the starter button will become useful.

So you have to switch on the oil pump and achieve pressure before the ignition circuit will be enabled. And any loss of pressure will instntly cause ignition loss?

[is this a good idea for a road-legal car?] I'd rather blow up an engine than kill someone...

Probably...

I don't mind the physical oil system, but I hate this stuff. I once wrote a book: "Auto-Electrics And Why It's Not My Bag, Baby". Fridge - you can sort me out, right?

Do I need to let the oil run for a time before firing it up?

Al.

[GBMUD]

I was thinking of one ignition position. This turns on the oil pump. When the oil light goes out then a relay turns on the fuel pump/ignition coil and you then hit the starter. You could make the oil pressure switch enable the starter if you wanted - but that would obviously not save the engine if oil pressure were lost while driving.

How about a buzzer in place of the oil light? Then you can choose to kill the engine or continue driving in a life critical situation.

Oil pressure usualy comes up pretty much instantly so there need be no real delay between turning on and starting.

Chris

[FridgeFreezer]

Uh Al, oil pumps tend to be driven by the engine, dry sump ones from a belt on the front. Unless you're adding an electric booster pump (Think Auto) or an accumulator (Think Auto again) you won't get oil pressure until the engine has at least cranked over a few times.

Cutting spark (/starter/fuel pump/headlights/electric seats/neons) when the oil pressure light comes on is easy, but IMHO not a good idea as I'd rather cruise to a stop with vacuum assistance for brakes and PAS than save a few seconds of minor wear on the engine. Assuming it's the oil pressure and not a dodgy connection/switch which I reckon is more likely to happen. You're introducing a point of failure.

Best option is as suggested - loud buzzer or big flashing light. Keep it simple

[Astro_Al]

Yeah - I think you're right John. It does seem a bit dodgy... Doesn't take long to seize though...

Big idiot light it is then.

Yes, I am thinking of a accumulator. Quote from someone with this already:

"Yes - I have an accu-sump ( wet sump ) oiling system.

I flip a toggle switch to start the oil being pumped from the accusump though the engine. after about 45-60 sec I turn the engine on or over and start the car. Mimimal pistion slap of the small block chevy"

Sounds good to me. Oil at startup would be bonza!

Al.