Oil Pressure Solutions Mi16

[findlay 0]

oh my heed!!

 

Despite the knowledge and experience on this site there isn't one person who can actually say... Do this to cure that

 

The problem is that we are all hypothesising on the situation and all experiencing different problems.

 

I think my solution this year will be sort out the bottom end, get a baffled sump and try a few viscosities of oil over the year. If I still have the same problem bin the Mi and go 8v turbo

[findlay 0]

Which reminds me...

 

Antoni, can the steel 8v sump and baffle that you have be bolted onto the Mi? If so I might well look at takking that off your hands

[C_W 3 1 Cars]

oh my heed!!

 

Despite the knowledge and experience on this site there isn't one person who can actually say... Do this to cure that

 

The problem is that we are all hypothesising on the situation and all experiencing different problems.

 

I think my solution this year will be sort out the bottom end, get a baffled sump and try a few viscosities of oil over the year. If I still have the same problem bin the Mi and go 8v turbo

Findaly, I've tried what you are proposing and it doesn't really help. I've tried a PS baffle, and every oil viscoicty you can think of (from Mobil 1 OW40 to Castrol RS 10/60, plus all other types in between).

 

However, I think the baffle must help a little, BUT if the problem really is the engines thirst for oil plus poor head drainage it won't matter what baffle is in the sump if it hasn't enough oil in it.

[Alan_M 66 1 Cars]

Which reminds me...

 

Antoni, can the steel 8v sump and baffle that you have be bolted onto the Mi? If so I might well look at takking that off your hands

Yes, it can. Thats what i've done with SRD baffles which look very similar to PTS ones. One thing is you need to use the 8valve sump bolts as the Mi16 ones are longer due to the alloy-finned sump having a thicker lip.

[zeolite 0]

Findlay...I have a sump lying in a box, a bit of steel, a pair of snips and a welder. If you can get a drawing it shouldn't be too difficult to fabricate a baffled sump.

Would welding in a small box for the pick up to extend into solve the problem?

I am not the greatest of welders but guess what Col does for a living?

 

pm me if you think this is a worthwhile idea.

[Alan_M 66 1 Cars]

The SRD and PTS baffles have three sides of a box around the pickup, as well as a horizontal baffle across 75% of the sump, preventing oil from sloshing about, and preventing crank windage (I think thats whats its called?)

 

I may have a pic of mine fitted to my Mi, before the sump went on.

[Batfink 201]

is there any way to create an oil pickup either side of the sump?? A T piece on the end of the oil pump or something then a bit of pipe to the other side.

Having never looked inside an engine its probably a stupid idea lol

[Batfink 201]

could the pump pump into a swirl pot attached to the block - then into the engine?

[C_W 3 1 Cars]

is there any way to create an oil pickup either side of the sump?? A T piece on the end of the oil pump or something then a bit of pipe to the other side.

Having never looked inside an engine its probably a stupid idea lol

It's feasible but the problem is it won't work unless the side that is out of the oil is not sucking air (ie it needs to block each on off depending on the cornering). I think someone mentioned something like an M5 has such a "centrifugal" type of pickup?

[Guest sillypugger]

so what about simply overfilling it with oil so that when the head is full then there is the right amount in the sump?

 

the biggest difference between this and the 8v is the head and i haven't heard of anyone getting surge with one of these - i noticed my pressure guage drop momentarily on left handers after my Mi conversion where it had never done it with the 8v.

 

as someone else said before i have also noticed that the drain hole at the cambelt end of the engine is smaller than the flywheel end and this may be causing insufficient oil to drain back to the sump as all the oil would gather here on a continuous left-hander.

 

obviously it would require a bit of fine tuning on the extra amount to put in.

[C_W 3 1 Cars]

I think on some track days I've put an extra litre in to try and stop the surge; it probably helps a little.

 

The difference between the 8v and Mi16 is that it seems the 16v has a much bigger demand on oil supply (followers, cams, spray bars etc), plus poor drainage.

[Guest sillypugger]

so if it has a greater demand for oil then you take that into account and add more - especially if oil that needs to be in the sump is getting stored in the head.

 

don't see what baffles can do in this scenario as it seems to be a lack of oil in the sump rather than a complete surge - the lack of oil accentuates the surge that occurs anyway.

[C_W 3 1 Cars]

so if it has a greater demand for oil then you take that into account and add more - especially if oil that needs to be in the sump is getting stored in the head.

 

don't see what baffles can do in this scenario as it seems to be a lack of oil in the sump rather than a complete surge - the lack of oil accentuates the surge that occurs anyway.

But you can't add too much; I've already probably added 1ltre over max in the past and it hasn't solved it. Having baffles help a little to control whatever oil is left.

 

The deeper sump capacity and lowered pickup may help, but crf450 tried this and it only helps a little I think.

[Batfink 201]

surely a swirl pot would be a better option than a accusump - would probably take up the same amount of room -

you probably need about 30seconds of oil to be safe

so anyone know the true flow rate of oil through the engine? its variable isnt it as the pump it driven of the crank????

hmm - might be a difficult one to match the flow rates of two pumps - maybe you would need two electrical ones

[Rob Thomson 6]

Over-filling is dangerous because the crank starts to hit the oil, and when that happens the oil gets aerated - and then the oil doesn't work so well so temperatures go up and everything gets f*cked. At least, that's the extreme case but I accidentally over-filled mine once (by about litre) and even during gentle road use the temperatures were higher than I've ever seen them, and the oil pressure dropped very noticeably. I drained the excess immediately.

 

As mentioned somewhere in the waffle above, you can easily calculate the flow generated by the pump at different engine speeds. Having reviewed my figures with more accurate pump dimensions, I reckon it flows 8 litres/minute per thousand (engine) rpm. That's assuming no cavitation and no other loses, but the true flow isn't going to be much less than that.

 

Obviously once the pressure relief valve opens not all of that flow goes through the engine. My oil pressure stabilises at about 2,750, so that's about when the valve starts to open. In other words, I reckon my engine needs about 22 litres/minute when it's revving.

 

Isn't a swirl pot otherwise known as a dry sump?

Edited October 5, 2004 by Rob Thomson

[Antoni1.9 0]

Hi Rob,

 

How did you calculate the oil flow rate ?

 

Cheers

 

Antoni

[Rob Thomson 6]

Damn - I knew someone was going to ask that!

 

The pump works by catching oil between the outer edge of the two gears and the body of the pump and moving it from the inlet to the outlet. Obviously the gears are counter-rotating so this happens on both sides of the pump.

 

Obviously there are some loses. The seal isn't going to be perfect between the teeth of the gears and the walls of the pump, and between the upper and lower surfaces of the gears and the other walls of the pump. Also, a small amount of oil will pass back through the centre of the pump as the gears turn. Anyway, I'm informed that these pumps are about 98% efficent so I'm ignoring what loses there are as being negligible.

 

Anyway, to work out the capacity all you have to do is work out the volume of oil that's moved by one chamber of the gear (measured to be about 675mm3), and then multiply it by the number of chambers per gear (8), the number of gears (2), and the pump speed (22/29ths of the crank speed).

 

I'll work you through the numbers if you want, but only after I've bought my lunch!

[C_W 3 1 Cars]

Obviously once the pressure relief valve opens not all of that flow goes through the engine. My oil pressure stabilises at about 2,750, so that's about when the valve starts to open. In other words, I reckon my engine needs about 22 litres/minute when it's revving.

The point at which it opens varies according to oil temperature and viscosity. At a cold fast idle, mine is at the e nd of the gauge, but when very hot can ned 4000rpm to reach it's peak.

[Rob Thomson 6]

Oh yeah....

 

The answer comes out in cubic millimetres, but divide by a million and you'll get litres.

[Rob Thomson 6]

The point at which it opens varies according to oil temperature and viscosity. At a cold fast idle, mine is at the e nd of the gauge, but when very hot can ned 4000rpm to reach it's peak.

Yep - the less viscous the oil the more flow is needed before the pressure in the system is high enough to cause the relief valve to open. This happens at about 2,750 rpm on my engine with averagely hot oil.

[smckeown 1]

well im seriously considering spending the dosh on the Pace dry sump system. Maybe end of this yeat, early next year

[Rob Thomson 6]

I was planning to give them a call when I've got five minutes. Just to discuss exactly what extra bits are needed and what mods are needed to the engine. I'm not going to pay that much money without thinking long and hard about it first!

 

But anyway, anyone reckon I should ask if they'll do a group discount? Who might be interested?

[smckeown 1]

defo me. jon murghia seems to be able to get discounts, plus he had the full kit list

[lagerhead 0]

Has anyone actually killed or damaged an engine due to oil surge?

 

When I was going round Brands with an instructor from Palmersport, he said that the pressure on their engines was all over the place as well and so long as there was some flow from the pump he wouldn't worry too much (don't quote me on that one though!)

 

I was at Rockingham last weekend running full slicks (so much fun!) having had a crude baffle plate welded in my sump and, whilst there was certainly some fluctuation, didn't have the stop light come on which was better than my previous visit with road tyres and no baffle.

 

I'm going to keep my set-up the same for a while and see what, if anything happens.

 

Cheers

 

Andy

[C_W 3 1 Cars]

I think a few people have had experiences of engines dieing on track. I think if you do get surge and you make sure you don't load the engine then it's not as bad as it could be.