Oil pressure and lat.G

[kcapitano]

Hi everybody

I'm a long time reader, but I've never posted a question before. My team has been struggling with oil pressure during cornering and I'm hoping someone can shed some light on our problem.

My team blew up two engines this past year and both had the exact same failure. Both engines destroyed their connecting rod bearings and both bearings showed significant signs of overheating. Our theory was that this was due to loss of oil pressure, and during recent testing we noticed were losing almost all oil pressure beyond 0.5 G's Lateral.

Oil pressure vs. RPM

Oil pressure vs Lat.G

Has anyone seen this before in their own car?

We are currently running a CBR600F4i with a custom wetsump. The oil pan has a baffle above it that is supposed to allow oil into the pan but not out.

Unfortunately there is another variable. When we blew up our engines we were using the wrong type of oil. It was less viscous than the specified oil. Could this have led to the failures?

We also have similiar data as shown above from a previous car that never blew up an engine, which makes me wonder if this is even a problem we should be worried about.

Thanks for reading, any advice is kindly appreciated.

EDIT: fixed links to photos

[jlangholzj]

Pictures don't show up But I'm sure it looked something similar to our graphs (psi vs RPM and vs lat AND lon G). We tested a stock pan, a modified pan, a modified with an accusump, a home-built pan with modified baffling and finally a non-modified pan built specifically for our R6. Bike engines obviously don't encounter much lateral G force so they're not really baffled for such.

I suggest looking at the size of your pickup and how big/orientation of it as well as running 2-3 skid-pad's in a row while running Das on the PSI. You'll be able to tell if you need to baffle the right or left side more.

Obviously the best choice to solve the problem will be a well-designed dry-sump but we found this last year that we can at least squeak by with a modified wet-pan

[Rex Chan]

Regarding the viscosity of oil - what oil temps are you running? Personally, I wouldn't be worried about running a slightly runnier oil if you're not running it super hot (140C+). We run a CBR600RR 03-06, and the Honda manual says 10W-30, but we run Valvoline SynPower 5W-40 - so runnier cold, but thicker hot. Modern oils are supposed to have all sorts of additives to protect the metal, and not just rely on the thickness of oil.

Regarding the oilP vs. RPM plots, they look very bad. I wouldn't run any engine that did that, though we have never run sustained latG for that long (skidpad?). It was explained to me that low/zero oilP = no oil flow into plain bearings = faster wear.

We run a CBR600RR with wet sump. The old sump design (40mm, 2005-2011) ran perfect pressures, but the new one (16mm, 2012) is not so good (I'll call it acceptable, but we're trying to find the cause of the problem).

Oil Pressure vs. RPM: Old 40mm Sump (20Hz)

Oil Pressure vs. RPM: New 16mm flat sump (50Hz)

Pics of the new flat sump

If you email me, I'd be happy to send you our MoTeC i2 data (Std for 40mm sump, Pro for 16mm flat sump).

[jlangholzj]

here's what our data looked like for the entire endurance at FSAEL-12 Just to give you an idea as well.

pressure vs rpm:
http://i260.photobucket.com/al...zj/pressurevsrpm.png

pressure vs Lon G
http://i260.photobucket.com/al...zj/psivslonaccel.png

Pressure vs Lat G
http://i260.photobucket.com/al...zj/psivslataccel.png

[SNasello]

Can you post an oil pressure vs. time graph for this instance? It is difficult to judge how quickly it drops off. Perhaps also lateral G and RPM in there.

To be honest, You still have some oil pressure there, but the low pressure could be causing excessive bearing wear. How much oil do you run in the engine? Do get a similar result when you run in both directions? 30s sustained cornering is a long time, but a series of slaloms or fast transitions could be a concern.

What does your oil pan look like? Does the pressure pump only suck oil from one pickup? I could imagine that your sucking oil away from the pickup faster than the pan is refilling.

[jlangholzj]

Originally posted by SNasello:
Can you post an oil pressure vs. time graph for this instance? It is difficult to judge how quickly it drops off. Perhaps also lateral G and RPM in there.

To be honest, You still have some oil pressure there, but the low pressure could be causing excessive bearing wear. How much oil do you run in the engine? Do get a similar result when you run in both directions? 30s sustained cornering is a long time, but a series of slaloms or fast transitions could be a concern.

What does your oil pan look like? Does the pressure pump only suck oil from one pickup? I could imagine that your sucking oil away from the pickup faster than the pan is refilling.

there is NO oil pressure there....those are some ugly looking plots. As far as testing I would suggest doing some skidpad and finding out how your pressure behaves in steady state cornering. The actual "time in corner" is somewhat irrelevant as you shouldn't see that big of a drop in pressure. We would make about 5-6 revolutions in one direction, then stop, allow the oil to fully settle and then make 5-6 revolutions in the opposite direction.

I'd also suggest that you try the stock wetsup and see what the plots look like then. if your custom pickups are flowing at a higher rate than stock, you could be running into problems as suggested.

Just remember that as soon as the pickup comes uncovered, you'll loose pressure. So try and place it as dead center as you possibly can and don't make it any larger than you need to. The stock R6 pickup is only about 3/4" square and we ran into similar issues when running a much larger pickup than that.

[Jan_Dressler]

Originally posted by Rex Chan:
We run a CBR600RR with wet sump. The old sump design (40mm, 2005-2011) ran perfect pressures, but the new one (16mm, 2012) is not so good (I'll call it acceptable, but we're trying to find the cause of the problem).
[...]
Pics of the new flat sump

This "new flat sump" is a dry sump if I am not totally mistaken?
Concerning the "not so good" pressures with this system... According to the comments on FB, you use -10 scavenge hoses and -12 for the inlet, which is the same as we do. IIRC we are also using the same (Dailey) pump. So: Why do you have both scavenge inlets in the rear section of the engine? That is one thing we do in a different way. And: Where does the outlet of your external PRV go to?

Jan

[Rex Chan]

Jan - yes, the new "flat" sump is a dry sump. And yes, AN-10 for scavenge to Dailey Eng 2 stage, and AN-12 to oil tank and feed line to inetrnal CBR600 oil pump.

There's probably 2 reasons why the pickups are at the rear:

1. The old 40mm dry sump had the pickups in the same location, so we wanted to minimise the changes from the change in sump design.

2. The old sump probably had it in those locations due to reasoning that we would need oil most under sustained accel (rear pickups) and lateral accel (side pickups). Braking should not be sustained, so we use the tank as a buffer.

Our current thinking about how to fix the problem is baffling around the pickups to trap oil near the pickup, as our flat sump is very flat on the inside too.

Also, we made a video of the oil tank level, and the oil is quite low for a lot of a lap, so we should make a bigger tank too.

[Jan_Dressler]

We always had the pickups "diagonally", one at the front at one side, the other one at the rear at the other side.
Sustained acceleration: Each of the two stages of the pump has about 2x the flow rate of the pressure pump, so it should be sufficient...

Oil tank capacity: We have about 2+ liters in the tank.
Never had any problems with the whole system in the past 4 years.

Jan

[kcapitano]

Thank you to everyone who has responded so far. You have been very helpful.

Here is a plot of oil pressure, lat G, and RPM during the oil pan testing we did.
Time plot

I believe we run about 2.5L of oil in the engine, but I'm not sure on the exact figure. It's less than the stock oil amount because our oil pan has much less volume. In any case, the oil is always filled to the sight glass.

Our problems seem to be mostly in right hand corners. We notice a small drop in oil pressure in left hand corners, but it usually holds steady around 40psi.

We are currently using the stock oil pickup from the 600F4i and it is located pretty much in the center of the pan. The pan itself is just an open reservoir, so nothing special. Aside from the baffle placed above the oil pan it's a completely stock system.

We tried running with no baffle and got the exact same results as shown here, so I think we may have better results looking at the pickup design. I'm thinking a design with multiple pickup locations (maybe one in each corner of the pan) with pickups that are self closing once they come uncovered will be a good bet. Does anyone have experience running this type of system, or suggestions on custom pickup designs?

Thanks