Sump Idea - Maybe To Reduce Surge?

[rallysteve 22]

Okay, this might be a stupid idea and i might have thought of it after a few pints, but I cant really see any reason it that it would not work.

 

The problems with surge on the mi engine is due to cornering forces moving the oil away from the oil pump pick up right? Fitting a deeper sump etc like Petert describes very well on his website is one way of helping by having more oil in the sump to begin with.

 

Fitting baffles help to stop the oil from moving away from the pickup on initial turn in, however during a sustained corner, oil will flow from the crank etc onto the wrong side of the baffles.

 

So why not, baffle around the the pickup to stop oil flowing away from it, then fit a small scavenge pump external on the sump to return oil forced to the far side of the sump back to the pickup end?

 

I cant really see how this could not improve the situation even if just a bit. A dry sump kit is way out of my budget, but dont want to ruin the mi16 engine I am re-building first outing on track.

 

Opinions?

 

Steve

Edited March 15, 2011 by rallysteve

[Cameron 16]

I think the problem with this is that the majority of the cost of a dry sump kit is actually in the pump itself. It's a good idea in theory but to be honest by the time you've got all the work done - designed and made the baffles, welded them in the sump, welded the scavenge unions in - then bought the associated parts - fittings, oil hose, oil pump, drive pulleys, mounting brackets etc etc - then you're probably not far off the cost of a sry sump kit anyway!

 

It would be a good solution, and race fuel tanks use a similar method of combating fuel starvation, but I don't think it's worth the effort and cost when a dry sump kit wouldn't cost much more.

[rallysteve 22]

Cheers Cameron.

 

I see where your coming from, am i not right in thinking you are looking at £2k for everything needed for the dry sump kit on an XU?

 

Apreciate your comments though, just working the idea through in my head.

 

I was thinking of using an electric oil pump such as this mocal one:

http://www.merlinmotorsport.co.uk/p3652/MOCAL-ELECTRIC-OIL-PUMP/product_info.html

 

If i can find someone who would weld in the baffles to the sump then I cant see the cost being that high, there wont be too many unions involved (4?) and less than a meter of pipework.

 

Cheers Steve

[Tesstuff 222]

Never heard of oil surge at the speeds you would be doing Steve. 35mph is perhaps a little below the danger level

 

 

When I had my BX 16v Phase 2 in 1994, I did loads of track days and fast runs across France and oil surge was never an issue, so is it something that happens as it gets older?

 

I used to do Mallory with the BX and that has a longggg right hander, which I presume would have showed the problem?

 

Baffles me(pun not intended)

Edited March 15, 2011 by Tesstuff

[rallyeash 155]

don't really hear much about surge in the 405/bx's generally only seem to be in 205's + 309's.

 

i thought the main issue was the oil drain back from the head down to the sump was poor, although the sump is an issue also.

[Tesstuff 222]

don't really hear much about surge in the 405/bx's generally only seem to be in 205's + 309's.

 

i thought the main issue was the oil drain back from the head down to the sump was poor, although the sump is an issue also.

 

Presuming that is the case then, the engine didn't seem to suffer until it was transplanted, suggesting once out of its factory fitted environment the problem can surface.

 

So using logic, would that suggest the engine doesn't sit correctly in the other two cars or perhaps some other critical change once transplanted.

 

Or are they just older and it shows itself then?

[rallyeash 155]

in there original envoironment there not fast enough i spose its brought to attention more as theres bags of track 205 mi16s but very few 405s and bx's

[stu8v 68 1 Cars]

I thought you only suffered surge because half the oil was still stuck in the head after a high RPM run? I'm looking at extra drains on the head back to the sump.

[welshpug 1,662]

I suffered oil surge on a L/H corner in my ZX, was around 35 mph.

[unariciflocos 49 1 Cars]

Instead of using fittings and pumps, wouldn't it be far easier to just have some trap door baffles around the pickup and then have a windage tray inclined to the pick-up so that all the oil that returns from the engine is directed over the pickup, sort of like a funnel?

 

Pumps and fittings sounds way too complicated for me.

[rallysteve 22]

Okay, looks like this might be turning into another big debate about what causes the oil starvation in the alloy 16v so might as well roll with it.......

First of all we might as well clarify the terms 'surge' and 'starvation'.

 

Starvation This is what actually kills the bottom end bearings, it is the starvation of oil which reduces the oil pressure to a level below what is required by the bottom end bearings. The only cause of this must be the fact there is no oil at the pump pick up. The reason for there not being oil at that point is the basis for the uncertainty and debate.

 

Surge This is the effect of corning g-forces on the oil within the engine, resuslts in the oil being forced towards the outside of the corner in simple terms without going into depth with centrifugal/centripetal forces. This surge could be evident anywhere in which oil resides and is not pressurised, e.g within the oil drains of the head or within the sump.

 

From what I have read/been told so far here are the following 'causes' of the starvation and how I understand them to affect things (not necessaraly correct though )

 

- Oil moving away from the oil pick up within the sump under hard or sustained cornering, (particually on a RH corner as the oil pick up on the XU in on the right hand side of the engine)

This affects all transvere mounted engines under cornering and longitudinal engines under acceleration and braking. Although engines with wide sumps could suffer from starvation due to g-force in both axis). This must be the cause of the pressure loss, however it is where the oil has gone that is the mystery.

- Oil being held in the cylinder head resulting in a low sump level.

I dont believe this to be the main problem, as far as I can tell over filling the sump by the amount held within the head would solve the problem, but from what I have learnt doesnt. Also the Gti6 engine shares and almost identical head design but does not suffer starvation in the same league.

- Oil pressure being wasted by the conrod location on the crank

I belive the 8v and gti6 engine use a different style of conrod location on the crank which results in less oil pressure being lost at this crucial point. However i believe someone (CRF450 i believe) tried fitting the 8v rods to the 16v but the starvation was not cured.

- Oil being whipped into a foam by the crank at high engine speeds

gti6 engines are fitted with a windage tray to help combat this problem, however the 8v is not. Although this might help slightly it does not explain why the starvation occurs mid corner not as a result of high engine speeds.

 

Therefore I can see the most plausable issue is to attempt to equalise the oil level in either side of the sump whilst it is being forced to one side by g-forces. By pumping oil from the LHS to RHS of the sump and fitting a large baffle just leftwards of the oil pickup, I believe the required minimum amount of oil could be kept around the pick up pipe thus keeping a consistant oil feed.

 

Please feel free to add your own understandings and arguments.....

 

 

Steve

[unariciflocos 49 1 Cars]

Surge causes starvation.

 

Someone should make a transparent sump and fit a camera in the bay to film what's actually happening there. Until then we're just guessing.

[hcmini1989 16]

I was thinking about this the other day and you could be onto something here mate,Why not utalize the powersteerng pump for this ?.Instead of an electric one.I dont know wheather it would shift enough oil but worth ago i suppose.

[PVFCpug 6]

Why not engineer two pick ups! one on each side or is that too obvious.

[Cameron 16]

No need for a transparent sump, what happens is obvious.

 

The oil moves to the opposite side of the sump due to cornering forces, meaning the level around the pickup is reduced. The pickup sucks up as much oil as it can but there comes a point where the level drops below the pickup and you get oil starvation.

 

I think the main contributing factor to this is the crank. The oil doesn't just move to the outer side of the sump, when it gets there it moves up the inside of the block then gets sprayed all over the shop by the spinning crank. There are other factors such as the quite large capacity for oil in the head and the limited draining of the head, I was never convinced that the con-rod location was a significant factor but I'm waiting to be proved wrong.

 

Fitting the deeper sump and extended pickup help, as you've got more oil to get through before the pickup runs dry, but IMO this is a crutch and I've never been that impressed by the solution.

 

Fitting the XU10 baffled sump and windage tray is a great solution, as it dramatically reduces the amount of oil that gets thrown about by the crank.

 

Fitting a GTi6 head has worked for me, but I also fitted the XU10 sump while I was at it which would also be helping things. I haven't had any surge so far, despite hammering round Oulton all day last year. But that doesn't stop me from checking the gauge!

 

I think a combination of the above is the best option if you don't want to go to a dry sump, although it involves a fair bit of work.. You need to drill and tap the main bearing bolt heads or weld on threaded studs to fit a windage tray, and the GTi6 head conversion also involves a lot of work. I really don't like the idea of fitting an electric pump to pump oil from one side of the block to the other, sorry, it's so much extra complexity for something that can be solved with much easier methods.

Edited March 15, 2011 by Cameron

[DRTDVL 4 1 Cars]

RallySteve: One of the Renault guys i know helped me and made this to combat the surge problems

 

 

 

We extended the front of the sump which gives us an extra 960ml of oil also. We used one of the tin sumps as it's easier to weld (we had to change the location of the oil drain plug).

The top plate uses 3 grub screws loctied in place on each of the spacer bracing bars with 3 small holes drilled in it to allow the oil to drain that gets caught between the ribs. The Pump plate bolts onto the pump using the existing pump bolts, a stud conversion was done on the bolt closest to the front of the pump to allow for a spacer so we didn't need to bend the metal.

 

 

 

Those photos where when it was still being developed.

 

 

Edited March 15, 2011 by DRTDVL

[Batfink 201]

I'm sure sandy has said in the past that when the mi16 heads are fitted with solid lifters and a reducer in the oilway to limit the oil going into the head there are no issues with oil starvation - even with slicks

[rodionski 3 1 Cars]

Could you please refer to that oil supply reducer to the head?

I am about to convert to solid lifter and would appreciate the hint. Thanks in advance.

[brumster 135 1 Cars]

No-ones mentioned the pixies

 

 

Get rid of those feckers and your problem's solved

Edited May 25, 2011 by brumster

[Henry 1.9GTi 36]

LOL

 

I run the extnesion on the pickup with the GTi-6 baffled sump and still got massive surge, indicated by starvation to my oil pressure gauge

 

However, after having another go and fitting an extended pump baffle along with extending the gti-6 baffle up by 1-2cm and fitting a chain gaurd, I havnt seen any surge. Windage tray would be next.

 

Must go faster!

Edited May 25, 2011 by Henry 1.9GTi

[KRISKARRERA 2 1 Cars]

I've had it in the 405

[petert 591]

Could you please refer to that oil supply reducer to the head?

I am about to convert to solid lifter and would appreciate the hint. Thanks in advance.

 

Here's a pic. from my phone. Hopefully it's clear enough. The standard hole is approx. 3mm, mine is 1.5mm. I also tap the back M6 so it can be easily inserted/removed. I used brass as that was the closet stock size I had. Some would argue it's too heavy and should have used aluminium!

[rodionski 3 1 Cars]

Peter, thanks! Is this the part that should be inserted instead of the head oil filter?

I think i would need the measurements for this plug and comments on where and how to put it in.

Many thanks in advance!

[petert 591]

There are two. They sit in the gallery behind each cam pulley. Undo the plugs with an allen key then you'll be able to extract the old ones. I wind an M6 bolt into them. It destroys them but how else do you know if the gallery is clean. For a thorough clean, once you've removed the non-return valves, use a length of 6mm rod to knock out the bungs on the dizzy end.

[rodionski 3 1 Cars]

Oh that's what they are. Then I know what you mean. Many thanks again!