Huge Oil Retention Problem - Please Help

[Monky]

Hi all,

Trying to get a better understanding of my cars setup and wondered if anyone could help.

I did a lot of research on my engines build and know that it is running a tomei baffled sump (stock sump with tomei baffles) and a N1 pump, if anyone could answer these questions I would appreciate it:

1) I'm aware that I need to run my oil level higher than normal, just before the hump on the dipstick, is this correct? I still have a stock sump only with Tomei baffles. Are you only meant to overfill oil on track with a stock sump?

2) Very very occasionally I have noticed oil pressure dropping in the lower gears on WOT (running circa 600hp) to around 2.5 bar, I assume this is oil surge. Even though I have the tomei baffles I take it this still isn't enough and ideally I need an extended sump? Most of the time circa 6bar.

Most importantly:

3) When I check oil when cold the level is 100% fine, I then turn the engine over and literally re-check it there and then it barely registers on the dipstick. Now I know their is oil in there 100% but why does it do this? Is it something to do with the baffles and is the sump literally being sucked dry, is the oil stuck in the head? The car also has an N1 oil pump. I know that some fit drains from the head back to the sump but do I have an issue? It has a restrictor as well.

I'm just worried about what I should be doing as the engine has had a small fortune invested and it wasn't be the previous owner so hard to ask the questions. It just seems strange that it's not registering on the dipstick. If I overfill to the hump, run the car, re-check then the oil level is 100% fine but only when I overfill. If I don't overfill it shows nearly nothing and takes a whole night of standing for it all to drain back.

Any help really appreciated as I am a little confused!

Thanks,

M

[Monky]

Below is a picture of a stock sump with the tomei baffle kit. I've circled in red where I think the dipstick goes.

If the dipstick does go here then no wonder it shows no oil after running. All the oil is retained around the oil pick up in the square and it must take a while for the oil to drain back where the dipstick would go. This would maybe explain why it shows no oil after turning off but does show oil after leaving it over night. Does that make sense?

Edited June 6, 2009 by Monky

[Moodles2]

1) I'm aware that I need to run my oil level higher than normal, just before the hump on the dipstick, is this correct? I still have a stock sump only with Tomei baffles. Are you only meant to overfill oil on track with a stock sump?

The kink in the dipstick is a good point to overfill to, from how the dipstick sits there is still alot of real estate between the kink and the crank

[R31Nismoid]

Are you running a catch can with return setup?

[RRob]

Remote oil filter or oil cooler draining back?

[Monky]

Hi guys,

Thanks for the replies.

@ Moodles - Do I still fill to the hump even if I have the tomei baffles? From what I was told you only do that if you have a completely stock sump, i.e stock baffles where as I have tomei baffles. It's roughly another litre to the bottom of the hump so I can add it if needed I just wasn't sure as people on the GTR forum using the tomei baffles were telling me to fill to the normal level regardless?

@ R31 - No catch can, it just has the normal breather pipes with the last vented to atmosphere, there is no oil coming from this pipe, no residue at all. I thought at first the oil was being retained in the head but surely it would come out from the breather pipe. I've read of people empyting a litre of oil into there catch can on a drag run due to oil retention in the head but seeing as I have no oil collecting it surely can't be this, the head must have a tomei restrictor.

@ RR - The car has a remote oil filter kit yes and it also has an oil cooler but surely it can't retain 1.5litres +?

To give you an idea, I leave the car overnight so oil has been allowed to drain. I check in morning, engine cold, oil level is 100% at the max line. I literally run the engine for 5 seconds, turn off and re-check and oil level on the dipstick is just touching the very bottom, as in not the low level marker right at the bottom?

Does anyone else get this exact problem with Tomei baffles? The Tomei baffles have trap doors so I assumed it just took a long time for the oil to seap back through to the dipstick area.

Will get there in the end just a little concerning at the momemnt!

[Moodles2]

@ Moodles - Do I still fill to the hump even if I have the tomei baffles? From what I was told you only do that if you have a completely stock sump, i.e stock baffles where as I have tomei baffles. It's roughly another litre to the bottom of the hump so I can add it if needed I just wasn't sure as people on the GTR forum using the tomei baffles were telling me to fill to the normal level regardless?

The tomei baffle has trapdoors as part of their design, which kinda makes the overfilling not as important compared to it's importance with the stock baffling while at the track. But I think with the stock oil pickup there's always the possibility of oil starvation when the oil is pressed against the wall of the sump with high g-forces.

[RRob]

Is the oil filter mounted high in the engine bay?

I would set the the oil level to the full mark just after its been shut down.

[Monky]

Hi all,

Right I found out whats going on! It's what I thought with a slightly different twist.

Basically the oil isn't getting up to temperature, therefore it takes a huge amount of time for the oil to drain past the baffles back to the area where the dipstick goes in the sump.

This makes it looks like there is no oil after starting. I'm looking into getting a oil thermostat or maybe using something like a 5w40 instead of the 10w50 to help the oil get up to temp quicker. At present I have to sit for over 30mins at 2k to get the oil to 60 degrees! Once it's up it stays up but if you don't do this it will never get up to temp, I guess due to overcooling?

Also the oil cooler is a laminova unit, does anyone know if you can get thermostats for them?

Cheers for all your time.

M

[blind_elk]

The oil isn't going to heat up in just 5 sec of running time. It's cold, and will take quite a time to return to the sump.

You NEVER bother checking oil levels immediately after shutting down the engine - you need a few minutes, even when the oil is hot. When it's cold, you need even more time.

The viscosity of the oil makes little difference as to how quickly it will get up to temperature. That is controlled by the shear that the oil is subjected to, as it squeezes past all the clearances. The engine willl heat up faster if it is doing some work - drive the car around the block; the oil will heat up quicker.

[Moodles2]

Earl's do make an inline thermo (here) and a sandwich type thermos (here) and B&M make a cheap (got mine for $110) inline thermo (here) which I added onto my existing system

[femno]

I also know why your oil is taking ages to drain to the front of the sump.

When you install Tomei baffles, you need to remove the P/S driveshaft from the sump, and drill out the 5 or so small holes between the front/rear wall. You can see them in the picture above.

From factory they are there to stop oil drianing to the back of the sump during acceleration.

You need to drill these to about 5-6mm to allow the oil to drain from the back to the front where the Tomei baffles are.

Im guessing this may not have been done when the baffles were installed.

[Monky]

@ blind - Thanks for the reply :-). I never check oil levels after immediate shut down as obviously it needs time to drain, I'm talking 10-15 minutues later not instantly. The 5w40 I was referring too was Shell Helix, currently using Silkolene 15w50 so the rates are quite different and thought it may be worth a try. What I'm saying is that even after 1 hour of motorway driving the oil temp gauge will only show 30 degrees unless the gauge is faulty but this would explain the length of time the oil takes to drain back over night. I just check levels when cold and make sure 100%, I then monitor oil pressure while driving.

@ Moodles - Star! Did you find you were running abnormal oil temps, i.e. too low? I'm going to test the gauge/sensor first, make sure it's accurate then look at blocking the oil cooler to see if the temp rises.

@ Femno - Again thanks for the help, I didn't install the baffle kit. Everything was done by the previous owner, and he had the engine built at RB Motorsport here in the UK. They have a good repuation here and would be surprised if they didn;t do this but I will ask the questions regardless. It's not a massive problem as I know there is plenty of oil in there but not being able to check true level inbetween driving is a pain as you can imagine!

Is it even possible to run at 30 degrees oil temp after an hour of motorway driving, surely it would be higher? I would expect at least 50 degrees even with a good oil cooler installed. I've had oil temp gauges on many cars and have never seen this low even with an oil cooler installed.

Cheers,

M

[MrStabby]

I have an oil cooler with thermostat. According to the factory gauge, the oil is up to 70 degrees after 10 minutes of driving.

[GT-RZ]

yea i dont think 30deg is possible... unless you got some dry ice hidden in there think about it. that's room temperature. or am i missing something ? i know my oil gets up to 80-90deg pretty fast but i dont have any extra cooling.

[Moodles2]

@ Moodles - Star! Did you find you were running abnormal oil temps, i.e. too low? I'm going to test the gauge/sensor first, make sure it's accurate then look at blocking the oil cooler to see if the temp rises.

My oil cooler install was a no-expenses spared job (passenger side so lots of braided hose), so I spent the extra $200 for the inline thermostat + extra speedflow -10 fittings I needed. Before oil cooler it took 5 minutes for my oil temp to get to 70c, with oil cooler+thermo installed it's exactly the same. There's about 6l of oil in my system, the normal 4.5l RB26's take and approx another 1.5l in all my lines + core.

Some people without thermostats just put a plastic bag over their oil cooler, or some sort of other covering during winter (even using numberplate).

[Monky]

@ MrK - Thanks, going to get one as well :-)

@ GT - I can't believe it's that cool either, but then why does it take so long to drain past the baffles, i.e. overnight unless femno is on the money with the holes but I can't see someone like RB getting it wrong, awaiting there reply.

Does anyone know if it's physically possible for the oil to be at 30 degrees after an hour of driving, if not then no doubt then temp sender is foobared.

@ Moodles - Again thanks, I'll replace the sender first, make sure the gauge is 100% accurate then re-evaluate everything. It gets quite cold here so a thermostat is really needed although I can't believe the gauge is reading right, although it would explain the oil taking so long to drain but even at cold temps it shouldn't take that long to get passed the baffles.

M

[Monky]

I also know why your oil is taking ages to drain to the front of the sump.

When you install Tomei baffles, you need to remove the P/S driveshaft from the sump, and drill out the 5 or so small holes between the front/rear wall. You can see them in the picture above.

From factory they are there to stop oil drianing to the back of the sump during acceleration.

You need to drill these to about 5-6mm to allow the oil to drain from the back to the front where the Tomei baffles are.

Im guessing this may not have been done when the baffles were installed.

Just heard back from RB Motorsport, they did indeed drill the 5 holes into the sump wall. Strange one eh, I'm using 15w 50 silkolene which is pretty gloopy but even then it shouldn't take this long, they said no more than 5 minutes when the oil is up to temp.

M

[Duncan]

Is it even possible to run at 30 degrees oil temp after an hour of motorway driving, surely it would be higher? I would expect at least 50 degrees even with a good oil cooler installed. I've had oil temp gauges on many cars and have never seen this low even with an oil cooler installed.

Cheers,

M

no its not, it will be at 60-80 degrees within a few minutes even on a cold day. So as far as that goes it's more likely there is a problem with your oil temp gauge. I have trouble with mine, even on the track it never reads about 70 but I'm sure it gets to 110+. The 2 main parts are the sender which must have a good earth (because it reads by showing a resistance compared to chasis earth) and to a lesser extent voltage into the gauge. Or maybe the gauge is stuffed physically.

[LotusGTR]

My guess would be that if you put your hand on your engine after running it at motorway speeds it would be too hot to touch. My guess would be the oil would be the same temp, therefore not 30 degrees. Also, you'd expect the oil and water temp to be pretty close to each other. I have a stock water temp gauge with no calibrations so can't say what it is at full temp, but is sure ain't 30 degrees.