The V8 Owners Forum -

Hello,

I drive an offroad truck that has a 4.2 rv8 in it. Runs perfectly, just on really steep climbs i'm loosing oil pressure. Which nearly put me on my roof this weekend just gone as i had to switch off the motor (i run hydraulic winches from the engine) !

I'm running a dizzy type oil pump unfortunately, but not a lot i can do about that With standard RR sump.

I've got an accusump which i use, but this is only a limited supply of oil and runs out.

I have a dry sump pump, but that can only be installed when i change truck due to lack of space.

So....i'm left with the option of making a decent sump !

I've been looking at this thread for a while now - http://www.v8forum.co.uk/forum/viewtopic.php?t=6193 and wondering if there were any others showing custom sumps ?

In the one made by topcatproduction, there are 2 layers - can you explain the reason behind this ?

The main difference between my truck and a race car, is that once a race car has gone round a corner it generally comes back onto a straight - allowing the oil to "equalise" around the sump...whereas i can stay on a near vertical climb for some time.

Cheers

Gordon

Do you have any clearance to increase the depth of the sump?

I think most of the chaps on here who modify their sumps with baffles/gates/etc... the engines are in lower 'sports cars' (me included) so don't have the option of a deeper sump.

The later engine 4.6 serp, has a deeper sump pan. Although they hav a different design at the front with one of the corners chamfered off. May be able to 'modify' it to fit?

The aim of the game is to try and stop the oil moving away from the pick up, weather the oil is being moved by a hill or by latteral g force the same fixes would work for either.

The way I see it you have a couple of options:
fit a bigger capacity accusump/ or fit 2 so it would last longer?
modify your current sump making it deeper.
fit a dry sump system. I looked at fitting a dry sump system, had an idea of using my current oil pump as the high pressure pump to feed the engine but plumb the oil pick up pipe into the bottom of an external oil catch tank, which is fed from a scavenge pump sucking out the oil from the sump. In the end I couldn't do it becasue I don't have room to mount an external scavenge pump, (i'd have though your 4x4 would have room?) and couldn't find a reasonable priced scavenge pump, for the pump alone was looking at 6-£700!

When I modified my sump I did some tests on it. Just filled it with oil to the max mark and 'sloshed' it round and held it at various angles to stimulate g force acting on the oil, the standard baffle doesn't really work as a baffle, more like a windage tray to stop the crank wipping up the oil so you could look at making your own better fitting baffle plate lower in the sump somewhere arround the max oil level to try and help stop the oil moving away from the pick up pipe.

Tom.

You could make the oil pickup flexible, so it follows the oil around the sump.....

Chris.

Would toy not be able to run your winches off their own sump and drive the pumps with an aircon magnetic drive pulley so you can turn them on and off as required.

Thanks for the answers.

Yes i do have some space below the engine to make it deeper.

2 accusumps .... would work i guess, but i'm not keen on it.

dry sump - as i mentioned in my opening post, i have a pump to install but it won't fit in this current truck (not enough space for an extra pulley on the front )

winches - there is an hydraulic pump run off the engine, they don't use the engines oil - sorry for confusion.

This was a little mistake we made on sunday :


Oops.... but self recovered with our electrical winch and carried on the competition.

Gordon

I'm a bit confused TBH. The standard sump pans are deep at the rear so going uphill should only really be suited by the design at a glance. Sure you have enough oil in the sump so that when the accumulator has gulped up it's load + everything else circulating? You might be able to make the pickup go a tad further back in the sump and reduce the diameter to prevent sucking air?

for the dry sump, if there is no room on the front of the pulley, why not fix it to the back side of the ballancer, I am going to assume the pump drive pulley is about 50mm which is a problem, but could be overcome by using a bigger pulley on the drive and pump, as long as the ratio is kept similar,

Haha I've been looking for those pics for the last 2 days for someone else!

The idea behind having 2 layers is for more chance of oil getting stuck in there. Basically a bit like a simple maze, as soon as the oil starts to go into the sump it stands less chance of being forced out due to gravity, whether it be G's or degrees on an incline etc!

The thing you're up against is getting the oil into the sump in the first place, when you're working on an extreme angle, facing downhill would be the worst, the oil in the sump will be fine with baffles etc until it runs out and the returning oil sits right up the front of the sump being thrown around by the crank. Due to the quantity you should still get some making it back to the pickup pipe but it's a tough one to get right!

spend wrote:I'm a bit confused TBH. The standard sump pans are deep at the rear so going uphill should only really be suited by the design at a glance. Sure you have enough oil in the sump so that when the accumulator has gulped up it's load + everything else circulating? You might be able to make the pickup go a tad further back in the sump and reduce the diameter to prevent sucking air?

I agree - i shouldn't really be loosing suction where i am ? Possibly, i have an issue with the pickup ? Which i'll be able to see when the sump comes off.

RE : oil level - yes it's ok, checked with a full accumulator.

Which style of pickup seem to work better ? The old one with like a skirt that comes down, or the newer one ?

G

I prefer the newer one, there is less open area to gulp air in basically, and if you baffle the sump you don't have to leave such a big space in the middle.

zim wrote:
This was a little mistake we made on sunday :


Oops.... but self recovered with our electrical winch and carried on the competition.

Gordon

Mmm, I can see why you have issues with oil pickup...... you need the same system they use in bulk fuel tanks with a floating pickup, that should work upside down...........

Given the volume of oil moving about, there is no way any wet sump could maintain high angles for any period of time without worry.

There is simply too much oil moving about.

And the external oil pump doesnt need driven directly off the crank, it could be mounted remotely and driven off an auxiliary belt.

Really, a dry sump is the only option.

Unless somehow you could design a sump with 2 sumps inside and 2 seperate pickup points. Although how that would be achieved Ive no diea

stevieturbo wrote:Given the volume of oil moving about, there is no way any wet sump could maintain high angles for any period of time without worry.

There is simply too much oil moving about.

That could easily be solved I think by having additional remote reservoirs piped to the sump & mounted forwards, so that gravity simply increases 'available engine oil capacity' on an incline, then tips it back to the remote when level again.

Not my idea unfortunately, I can't remember where but I saw a spider like satellite reservoir schematic in some obscure book in the past and it's always stuck in my mind as being much more elegant than winged & trapdoor sumps IYSWIM?

I can't see how that would work for any long period of time though- if the truck is stuck on a steep slope and needs to sit running for a while the oil would drain out of the extra tanks in several seconds, even a minute may not be long enough, and as Stevie said you can't defy gravity no matter how clever your sump design- no matter how many clever shapes etc you have if sitting on an angle the oil will not go uphill which is the problem once the level drops to the level of the pickup pipe.

The best and most cost effective solution (and should be quite viable if you have longer springs etc fitted) could be to simpy fit a deeper sump, \_/ in shape from both directions, so long as the truck doesn't sit at anything over about 50° (which would be rare to sit at that angle for any long amount of time) it should be fine. The only downside would be ground clearance, but if your axles and steering are further away due to a lift kit it should be do-able.