zo6style

Car: '06 C6Z LS7
Use: Track (Club Racing)
Engine Mods: Cam, Lifters, Push-Rods, Valve Springs, SS Exhaust Valves, New Valve Guides, (Spec by Comp), Headers, Oil Pump (Katech Red).

Problem:
After breaking the motor in (JG Breaking Oil) and tuning the ECM we headed to the track. The second session we notice lower oil pressures but were not overly concerned at idle as the engine\oil temp. was 230\240. (Idle\230-240\20psi)... And upon feeding the throttle the pressure will jump to 45/50psi (hot). HOWEVER, suddenly when returning to the track, we lost pressure and the warning message was displayed "Low Oil Pressure". The gauge dropped to approx. 5psi. and the pressure would NOT climb even when feeding throttle! After cooling down a little and letting the car seat for 1hr. or so...the pressures returned.... when back on the track and after the 3 turn, complete pressure loss and "Low Oil Pressure". After 1/2 hr. of seating...Pressures returned!

Question: What would cause the pressure gauge to loose\drop reading randomly considering there was never a lack of oil volume?

Thank You.

EVRose

Faulty/failing oil pressure sending unit?

c5racr1

What did the motor sound like when the pressure drop was indicated?

zo6style

There were no issues with sound, rev., power, or overheating. All was normal but the Oil Pressure. Upon waiting overnight to completely cool oil pressure was at 120 deg. = 40psi @ idle and 50psi @ 3000-3500

KB9GKC

zo6style

I was afraid so.. As I understand its located at the back of the engine behind the air intake hence, its a task to get to.
1 - It there an after market unit which may be better?
2 - Is there a way to read the oil pressure from the bottom of the motor as well? if so, how and where?

Thank You

1Hotrodz

Check where the oil cooler lines exit the block. I believe there is a 1/8" NPT pressure tap located on the oil cooler line mounting block.

zo6style

So I decided to replace the Oil Pressure Sending Unit....the easy way...approx. 45min. to remove (complete breakdown from top to removal of sensor). See pics.
Ps. I plan on relocating the sensor with a guage. I will update with pics upon completion.

zo6style

Replaced the Oil Pressure Sending Unit and added an analog gauge as backup.....STILL LOOSING PRESSURE!
At idle and 195-200deg. Pressure is fine BUT when loading the engine at 3500-5500 rpm the pressure is lost... all of it! If I shut the engine off and wait 5-10min. I get my pressure back at idle.... totally crazy!!

vertC6

Get an UOA, you could have a bearing issue

zo6style

What is an UOA?

vertC6

Used oil analysis from Blackstone lavatories. You could have a serious issue with your main bearings. The oil analysis report will show it.

Do you have issues with a hard start when is hot?

zo6style

NO issues with starting and oil is new 5/30

BUT!
I was told to add some oil and watch the level in the oil tank. WELL..WELL... When it drops pressure I noticed that there is no oil in the oil tank...Could it be a bad oil pump? Dipstick was dry (after waiting a couple of minutes)!!!! Where did the oil go?

zo6style

After replacing ...still issues.


I was told to add some oil and watch the level in the oil tank. WELL..WELL... When it drops pressure I noticed that there is no oil in the tank...Could it be a bad oil pump? Dipstick was dry (after waiting a couple of minutes)!!!! Where did the oil go?

0Pete@ChampionMotors

How much oil are you running? Are you only losing pressure at high rpm? We have done lots of testing with the stock dry sump setup and found above 6k rpm oil is being aerated so bad pressure dropped 10psi from 6-7rpm

zo6style

Well...its lost at higher temp ... 195-210 in which upon feeding throttle above 2500-3000 rpm causes the pressure to be lost. The strange part is that after over filling the oil so it can be easily monitored.... the oil from oil tank seems to vanish at time when pressure is lost. I think oil is not returning to oil tank properly.... hence oil tank drys out after a while...but only at full temp and higher rpm.

Strange but true!

0Pete@ChampionMotors

I would cut open your oil filter and have a good look inside, or send some oil to the lab.

zo6style

That is an option. I wondering if there is a constriction in the oil return line (oil return to oil tank). Is there a check-valve or ??? could be sticking?
Why after the oil tank dries up ..... I wait a couple of hours or so and the oil returns to the oil tank.... Where does it disappear to? or return from?

CRAZY!

zo6style

View of inside filter and oil tank. ENGINE IS A NEW BUILT WITH ONLY BREAK-IN, HEAT CYCLE AND DYNO....

0Pete@ChampionMotors

What is all that debris in there?