General Miata Chat A place to talk about anything Miata

Losing Engine Oil

Thread Tools
 
Search this Thread
 
Old 04-03-2007, 09:46 AM
  #1  
Junior Member
Thread Starter
 
qes78's Avatar
 
Join Date: Mar 2007
Location: Singapore
Posts: 130
Total Cats: 0
Default Losing Engine Oil

Hi Guys,

Yet another question:

Some time ago, I overhauled my engine and took the opportunity to skim my valves, pistons and block.

Ever since then, I've noticed that my Oil catch tank seems to fill up pretty fast. My Oil catch tank is connected to both the crank case vacuum as well as to where the PCV valve is.

Before the overhaul, I used to not need to top up any engine oil between intervals, but nowadays, I need to top up every month or so. I change my oil and filter around every 6000km. My car is not spewing out any white fumes either

I'm using Shell Helix Ultra 5w40 and have been doing so since I got the car till now. I'm also using Denso Iridium Ik20L and I rev the car pretty hard. Change is normal above 4K and i redline the car pretty often. I reside in Singapore where Humidity is high and temperature is usually around 32 deg celcius. I also have the timing set at 16 Deg and running a K&N cone filter together with JR cables. Other than that, the power plant is stock.

My question is:
What can be causing me to lose Oil unlike last time?
Likely to be from PCV or crank?
qes78 is offline  
Old 04-03-2007, 10:51 AM
  #2  
Senior Member
iTrader: (1)
 
Mimime's Avatar
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

Hello,

In anycase, I am running in Hong Kong and would have the same bazzard weather as you would in Singapore.

I am also using SHELL Helix ( 15W-50) I would use something more thick for engine oil as to 5w40 in our turbo cars.
Mimime is offline  
Old 04-03-2007, 10:57 AM
  #3  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,493
Total Cats: 4,080
Default

post a pic. I'm having a hard time picturing the setup.

I'm picturing that you have both the breather line and pcv line connected to the same catch can, which then vents to the atmosphere...correct?

if so, remove the pcv line and plumb that back to normal and report back.
Braineack is offline  
Old 04-03-2007, 11:19 AM
  #4  
Junior Member
Thread Starter
 
qes78's Avatar
 
Join Date: Mar 2007
Location: Singapore
Posts: 130
Total Cats: 0
Default

Braineack..

Tt's correct. is piping both the pcv and crank case via a T joint to the oil catch can with the other outlet going to atmosphere a bad thing?
qes78 is offline  
Old 04-03-2007, 11:39 AM
  #5  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,493
Total Cats: 4,080
Default

you've removed the major vacuum source from the crankcase, so whatever compression your rings may be losing is causing oil to be pumped out of the lines.

i suggest you remove the line from the pcv side and return it to oem. See if that doesn't cure it.
Braineack is offline  
Old 04-03-2007, 11:50 AM
  #6  
Junior Member
Thread Starter
 
qes78's Avatar
 
Join Date: Mar 2007
Location: Singapore
Posts: 130
Total Cats: 0
Default

braineack.
Thanks for the reply.
I've done a compression check and the cylinders seem to all be ok...
I'm not sure i follow your chain of logic
Can I trouble you to elaborate to me please?
qes78 is offline  
Old 04-03-2007, 11:58 AM
  #7  
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,091
Total Cats: 7
Default

The PCV vacuum source from the crankcase on the intake side of the motor pulls vacuum on the crankcase removing pressure when under vacuum situations. This allows your rings to stay seated. If you install the PCV line back into the intake manifold like it was from the factory with a good working PCV valve it could solve your problem. Check your PCV valve though, you should only be able to blow through it one way. If not, you'll introduce positive pressure to the crankcase under boost.
My version. I'm sure brain can explain it more simply.

Last edited by cjernigan; 04-03-2007 at 12:09 PM.
cjernigan is offline  
Old 06-26-2007, 10:38 AM
  #8  
Junior Member
Thread Starter
 
qes78's Avatar
 
Join Date: Mar 2007
Location: Singapore
Posts: 130
Total Cats: 0
Default

Sorry for the late reply.

The Oil was spewing out even faster with forced induction and my Carbing Oil catch can quickly filled up and start to exit from the exit pipe. Strangely, after that, i had a whole load of WHITE smoke spewing from the exhaust only at idle and after the car had warmed up. Smoke cleared when I drove off.

I did as suggested, basically to pipe the PCV line back into the intake manifold, and i emptied the oil catch can. The WHITE smoke problem seems to have disappeared. I cant figure out the rationale though.
qes78 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Full_Tilt_Boogie
Build Threads
84
04-12-2021 04:21 PM
stoves
Suspension, Brakes, Drivetrain
5
04-21-2016 03:00 PM
tazswing
Race Prep
20
10-03-2015 11:04 AM
Aroundcorner
Miata parts for sale/trade
2
10-01-2015 03:20 PM
Trent
WTB
2
10-01-2015 12:15 PM



Quick Reply: Losing Engine Oil



All times are GMT -4. The time now is 06:06 PM.