Aluminium dry sumps

[Munkul]

I realise I do a fair bit of rallying, servicing, building cars and I have for 20+ years and that's the only scenario I've seen anyone wanting a split tank to open in a hurry, and the only real reason for having a split tank

Fair enough, you may be right, but a large proportion of those instances will be game over already when you've already lost oil pressure...

It's not the only reason, the main reason would be to split for cleaning the baffled internals after you had a big problem. Not necessarily to "have a quick check to see if it looks good" 5 mins before a stage...

 

[gt6s]

Its not a sump its a dry sump tank used in conjunction with a dry sump pan

OOPS You are right I got that from the thead title MY BAD

 

[PhillipM]

Perhaps, I've seen plenty of engines drop pressure with an issue like a tank pickup weld cracked, fitting leaking on the tanks, or hydraulic line internals breaking away and causing debris in the bottom of the tank, etc, without dying. And racers being racers, if they know what's causing it half the time they'll just keep going if they think they'll get away with it.

As someone else said, if you're buying your sump and tank systems, if you engine has spat a bearing you're likely to just replace the entire hoses, oil cooler, tank, etc, and maybe even the pump unless you send it for a rebuild anyway for the people that are spending the kind of money a dry sump setup is without fabricating it themselves.
In fact most engine builders will require it for them to warranty the rebuild.
Anyway, either way I can't say I've ever seen an issue with v-bands on sump tanks, I don't see why it's such an issue, it's easy, fast and light, you can use an off the shelf o-ring or sealant, very little machining, very low cost.
There's no pressure there so if it's not sealing you've screwed something up when you made it.

 

[cr500dom]

Or both clearance holes, with cap screws and Nylok nuts.


Not until they drop the throttle in a big slide. Broken ribs are not unheard of. I learned that, being a smarty pants in my old hot rod. Very easy to get sideways with big power, but once the wheels stop spinning lateral grip comes back veeery quickly.

Yes but that’s instantaneous and as you say, you are off the throttle so no engine load.
That’s a very different oil supply requirement to pulling 3.5g Lateral for 8-10 seconds at high revs under load.

 

[hotponyshoes]

I've seen quite a few lotus 7 style cars with dry sumps.
Mainly for ground clearance.

I thought about fitting one on mine but just ended up cutting down the pick up pipe and making a shallower wider aluminium sump in the end.
But that's a rv8 engine which doesn't really have any sort of oil supply anyway...

Although we have killed a couple of engines so maybe I should do something about that...

 

[PhillipM]

Part of the reason I fitted one to the buggy was exactly that, ground clearance. That and bouncing up and down or driving across 45 degree side slopes doesn't really help with oil control...

 

[bricol]

I've seen quite a few lotus 7 style cars with dry sumps.
Mainly for ground clearance.

I thought about fitting one on mine but just ended up cutting down the pick up pipe and making a shallower wider aluminium sump in the end.
But that's a rv8 engine which doesn't really have any sort of oil supply anyway...

Although we have killed a couple of engines so maybe I should do something about that...

I owned a dry sump system for a crossflow - intended to fit it to my trials car for increased clearance - but similar to you, I made a longer, shallower sump that had the same clearance as the next lowest component, the bell housing.

Sold it without ever fitting it.

 

[Morrisman]

I thought about fitting one on mine but just ended up cutting down the pick up pipe and making a shallower wider aluminium sump in the end.
But that's a rv8 engine which doesn't really have any sort of oil supply anyway...

The 3.5 in my old Morris had barely 5psi at idle. It soon picked up once the throttle was touched.
I converted it to electric water pump to shave a few inches off the length.

 

[hotponyshoes]

The 3.5 in my old Morris had barely 5psi at idle. It soon picked up once the throttle was touched.
I converted it to electric water pump to shave a few inches off the length.

View attachment 373701

Mine picks up on throttle but drops off when hot. You can almost use the oil pressure gauge as a reverse g-force meter when cornering on the track.
Luckily it's pretty nippy through the corners so it's not without oil for long

 

[8ob]

I've seen quite a few lotus 7 style cars with dry sumps.
Mainly for ground clearance.

I thought about fitting one on mine but just ended up cutting down the pick up pipe and making a shallower wider aluminium sump in the end.
But that's a rv8 engine which doesn't really have any sort of oil supply anyway...

Although we have killed a couple of engines so maybe I should do something about that...

I went with a dry sump for the 7 type I am building I am using a ford 302 and managed to get the engine to sit so much lower in the chassis with the added benefit of nothing mechanical hanging lower than the chassis rails, also meant using a special bellhousing with ap 7.5" clutch on a much reduced flywheel diameter, also to tilt the gearbox over a tad. All good fun

Bob

 

[Shox Dr]

I thought one of the main rasons to dry sump a motor was to stop air pressure changes due to variable volumes of oil, effecting HP. I know in Harley tuning cicrles its a huge HP drain if the crankcase has too much oil in it, down to the pump not scavenging enough.

 

[bricol]

I thought one of the main rasons to dry sump a motor was to stop air pressure changes due to variable volumes of oil, effecting HP. I know in Harley tuning cicrles its a huge HP drain if the crankcase has too much oil in it, down to the pump not scavenging enough.

Not to stop air pressure changes, to stop oil pressure and flow changes - ensure a reliable, constant, flow of oil - doesn't take much air on the high pressure side to lose the oil film of a bearing under load - and "rattle rattle, bang bang".

 

[bricol]

Caterham used an "apollo" tank with the K-series engine- the crank tended to whip air into the oil in the wet sump, so the oil is passed through a cyclonic separator, the air escaping the oil being restricted in its passage back to the cam cover area via suitable hose. The oil then fed back into the end, hopefully more oil than air. There's a small chance it helps with maintaining an oil flow when the pump momentarily sucks air from the wet sump under cornering loads.

Not sure about that theory that some owners state - when it sucks air, the pressure drops, flow stops . . . but I've run one for over 20 yrs so far. Which reminds me I have two brand spanking new Accusumps under the house to either use or sell . . .

 

[minimutly]

Well yes, but why would have air on the hp side? Because the wet sump contents isn’t where it should be usually. Either the oil in the sump is being pulverised by the crankshaft half way up the crankcase instead of on the bottom, or more likely it’s still in the cylinder head(s), the high rpm the tuned engine is turning meaning gravity hasn’t been ably to push it back down into the sump.
I was standing next to a 2l 16 valve on my dyno, when the cam cover vent let go with a gush of hot oil all over the exhaust - I didn’t look, just ran out. The head had filled with the oil that should have been in the sump...

 

[PhillipM]

Have the same issue with the buggy given it turns 9000rpm. So much in fact that one of the head breathers vents straight back to the tank instead on a seperate fitting - it's why you see some tanks with extra intake fittings on the top too.

 

[minimutly]

Have the same issue with the buggy given it turns 9000rpm. So much in fact that one of the head breathers vents straight back to the tank instead on a seperate fitting - it's why you see some tanks with extra intake fittings on the top too.

Hmmm. And of course, given the volume of a typical 16v head, over half the sump contents could be up there, if the time at 9000 rpm is long enough. Then you turn left or right...

 

[PhillipM]

I think it's more the throwing the engine up in the air over a jump and back down that's the issue

 

[Morrisman]

Well yes, but why would have air on the hp side? Because the wet sump contents isn’t where it should be usually. Either the oil in the sump is being pulverised by the crankshaft half way up the crankcase instead of on the bottom, or more likely it’s still in the cylinder head(s), the high rpm the tuned engine is turning meaning gravity hasn’t been ably to push it back down into the sump.
I was standing next to a 2l 16 valve on my dyno, when the cam cover vent let go with a gush of hot oil all over the exhaust - I didn’t look, just ran out. The head had filled with the oil that should have been in the sump...

Something I was told when I built my first Chevy 350 in the Philippines 25+ years ago, was to go over the whole block and the heads with a die grinder, inside and out, remove all the casting flash, seams, ridges and rough edges, especially on the oil return holes. Open them up, smooth them out, let that oil flow. It's surprising how rough and ready some of the cast in holes are.

And it saves on cut knuckles when assembling too.

Probably not a problem in die cast modern alloy motors though.

High volume oil pumps, to be avoided at all costs. People think they are essential in a hi-po motor, but what they do is fill your top end with oil.

 

[PhillipM]

Unless you have vtec or a rotary, in which case they are essential.

 

[Keithmac]

I know of VW engines that have suffered oil starvation on long corners (track-days and Nurburgring), they either go Dry Sump or more commonly Accusump (sp).

Doesn't take long to knock a set of Main/ Big End Bearing shells out..

Aprilia RSV was Dry sump, new version is Wet sump. Harley Davidson have done away with Dry sump on the newer engines iirc.

I wouldn't call it a Boy Racer mod at all, very involved converting a car to Dry Sump.