LS6 high oil consumption

[sbwrench]

Just an update: Long block done with fresh (stock) heads.New rings. All bearings looked good. Surprised to find .010 under mains and rods. Engine builder forgot to mention that. Resealing rear half of T56. Confirmed oil level in pan. 6.25 quarts to full on stick so any additional will be remote filter and lines. Engine should go back in car tomorrow so I will confirm position (level) in the car. Break in will be the 60 mile drive to the autocross. I'll let you all know how it runs. Appreciate advice and thoughts on this.

[Kevin Johnson]

So now that you have calibrated your dipstick for the full mark, you can put exactly 6.25 quarts in the engine, run it briefly to let the lines and filter fill and stop. Check dipstick and measure the quantity needed to bring the static fill level back up to the 6.25 quart level. Jot that total down somewhere for when you purge the system completely and need to buy oil. Don't add that amount to the 6.25 quart fill or you will have over-filled your system and that would explain the flooding of the windage tray and smoking the track.

[Kevin Johnson]

So now that you have calibrated your dipstick for the full mark, you can put exactly 6.25 quarts in the engine, run it briefly to let the lines and filter fill and stop. Check dipstick and measure the quantity needed to bring the static fill level back up to the 6.25 quart level. Jot that total down somewhere for when you purge the system completely and need to buy oil. Don't add that amount to the 6.25 quart fill or you will have over-filled your system and that would explain the flooding of the windage tray and smoking the track.

When I read this again after a few hours I can see how it could be misunderstood.

1) Start with system completely empty of oil. Pan empty. Lines empty. Filter empty.

2) Pour in 6.25 quarts of oil to engine. Let it sit for a couple minutes. Check dipstick and confirm that the fill line corresponds correctly.

3) Start engine and run for a few minutes.

4) Shut off engine and let it sit for a few minutes.

5) Check dipstick and note or mark where oil level is at.

6) Slowly add measured amounts of oil while repeatedly checking dipstick. When 6.25 quart fill line is reached, jot down the added amount of oil -- call that quantity "EO", for extra oil.

7) You should be good to go. When you buy oil, you will need 6.25 quarts plus the quantity EO.

You can modify this in the future by prefilling the filter and so on but you need to be methodical prior to this in order to avoid over-filling the system.

[sbwrench]

Understood. Thanks again. I believe I have confirmed the track smoking was a function of the cracked cylinder heads as opposed to an overfilled sump but I'm getting what you are laying down. Engine going back in tomorrow and I will confirm it's angle in relation to the earth to see if there is anything to consider there as well.

[sbwrench]

Finished and back in car. 7.1 quarts total fill. Initially fuel fouled right side plugs. Swapped out the O2 sensor that has been bathed in oil for the past 6K miles and it cleaned right up.Runs great and no more smoking!! Swapped in an LS7 clutch/flywheel package while it was all apart. Very nice upgrade. Great pedal feel. I've got about 50 miles on it. Autocross tomorrow. My first one!! I'll do final inspection this evening. Kevin, engine sits about 2 degrees nose up in car and level side to side. Used new motor mounts on reassembly to rule out any deterioration and change in engine position. Thanks all for tips and advice.

[Kevin Johnson]

Kevin, engine sits about 2 degrees nose up in car and level side to side. Used new motor mounts on reassembly to rule out any deterioration and change in engine position. Thanks all for tips and advice.

Looking at a technical drawing of an LS oil pan it should be at 2.5 degrees so you are very close. Good luck tomorrow!

[machinedave]

Glad to know its back on the road and not smoking. Have fun at the autocross tomorrow!

[MadBill]

Compared to the G loads of cornering & braking (1.0 G = 45°), surely the installation angle could have no effect apart from a slight potential error in the dipstick reading if the stick isn't near the middle?

[Kevin Johnson]

Compared to the G loads of cornering & braking (1.0 G = 45°), surely the installation angle could have no effect apart from a slight potential error in the dipstick reading if the stick isn't near the middle?

I am afraid that the results of my comments were that the images of the pans mentioned were pulled from the website. They are still available on the internet but I think it is better at this point for this to be a learning exercise about engineering aftermarket oil pans.

When you slice out sections of OEM engineered oil pans you really have to consider what the elements removed were intended to do.

There are many threads across websites on modifying existing LS pans for Mazda installations by slicing out a section that that has a slope with respect to the oil pan rail of about 10 degrees ergo about 12.5 degrees to the tarmac when installed. So now a vast expanse or surface has but a 2.5 degree slope with respect to the road.

You absolutely need to be concerned about drainback rates, surge rates under braking and the migration of oil on a surface that is affected by the lateral forces of acceleration or the engine mounted in the vehicle and the reaction forces of the fluid with internal walls of the pan which are dependent on the relative attitude or orientation of that system, itself under acceleration.

Remember when the consumer products industry made the amazing discovery that foamed chemicals will cling longer to vertical surfaces than neat fluids? A change in the effective viscosity of the product. The same idea needs to be transferred over for (or rather, recognize the existing engineering for) the draining of foamed oil back to the sump. The residence time of oil in different phase conditions and different areas of the engine (here the pan) really does matter, particularly in a competition engine.

[Cubic_Cleveland]

How did the track day go?

[sbwrench]

I must preface my auto cross results by saying I brought a large caliber hand gun to a knife fight. It was sponsored by the Florida Corvair Club so let's not count those cars. The rest were a smattering of Miata's, including two spec race cars, a couple mini coopers a Boxster and a couple others for a total of 24 cars being driven by 30 drivers. Now keep in mind I have never auto crossed before so I guess that counts for something. Anyhow I had fast time of the day at 72.2 seconds and the next closest was a 73.8. I had a blast, learned a bunch of stuff and the car made the 120 mile round trip and 6 runs all in second gear with the same mount of oil in it that I started with! Win, win.

[Cubic_Cleveland]

Awesome buddy! Good to hear you've got it sorted.