I'm running a high compression 0.5 overbored motor.
I've been losing about 2 litres of oil in 1-2 months time.
The spark plugs are burning fine. Compression is fine. There are no leaks anywhere on the block.

What can cause the problem?


**Revised info from thread below:**
- the dipstick seems low on oil
- Defi oil pressure gauge reads 5-6 kgf/cm2 at 3000-4000 RPM and 2-2.5 kgf/cm2 at idle (I believe this is normal, can someone confirm?)
- using HKS oil cooler, so oil capacity should increase slightly more (plus 0.1-0.2L)
- NGK copper 7 spark plugs burn fine (golden brown)
- compression # is within 5%
- using Greddy oil catch can (non-baffled)
- no black smoke at high RPM unless I downshift hard and then there's a small puff, but I think that's normal
- noticed that the catch can is 1/4 full. (haha)
- using Motul 8100 0W40
- using Mugen baffled oil pan
- no visible oil leaks underhood, undercar, nor on ground

Oil pressure seems normal. I'm using Defi Link. It is electrical and it is one of the best and accurate ones out there.

I realized that some of the oil has probably entered into the Greddy oil catch can, so maybe the oil loss isn't as significant as I thought.

When is the best time to check the oil?
Can the dipstick be a problem?
Can the Motul 8100 0W40 oil be too thin, thus easily to burn?
Would a baffled oil pan interferes with the dipstick reading?

What other possibilities?




Modified by Project X at 11:04 AM 3/25/2004

 

what kind of pistons?

 

if you didn't seat the rings well it might be burning oil.. especially if you dont see it leaking anywhere... are you blowing black smoke, more noticable when you shift gears at high rpm or when vtec engages..

 

A bit more info:

- the dipstick seems low on oil
- oil pressure gauge reads 5-6 kgf/cm2 at 3000-4000 RPM and 2.5 at idle (Is this normal?)
- using aftermarket oil cooler, so oil capacity should increase slightly more
- NGK copper 7 spark plugs burn fine
- compression # is within 5%
- using oil catch can
- no black smoke at high RPM unless I downshift hard and then there's a small puff, but I think that's normal
- noticed that the catch can is 1/4 full. (haha)

 

Rings fO shO

 

its kinda normal. compression might show up good but bad oil contol rings wont show up on a compression test.

if you had my engine you would be cursing......

 

How did you break the motor in? Did you do the ring seating properly? You are not suppose to baby the engine right after you put it together.. if the rings didn't seat right you are burning oil and now need new rings to fix the problem...

When you downshift you should not be getting oil smoke (thick black/blue) out of the exhaust.. what you see might be just excess fuel if your car is running rich.. if its oil then theres more proof that the rings are shot...

 

How can I tell whether my rings are shot or not without disassemble it.
Will a leak-down test work?

 

are you checking the oil after the car has sat for a while and is on level ground? is that the only way you're checking it? drain your oil and measure it before you add any.

if it is rings, he would have seen smoke and he would have noticed it on the plugs. he said the plugs were fine and all he saw was some black smoke(running too rich).

 

Revising the above info:
- the dipstick seems low on oil
- Defi oil pressure gauge reads 5-6 kgf/cm2 at 3000-4000 RPM and 2-2.5 kgf/cm2 at idle (I believe this is normal, can someone confirm?)
- using HKS oil cooler, so oil capacity should increase slightly more (plus 0.1-0.2L)
- NGK copper 7 spark plugs burn fine (golden brown)
- compression # is within 5%
- using Greddy oil catch can (non-baffled)
- no black smoke at high RPM unless I downshift hard and then there's a small puff, but I think that's normal
- noticed that the catch can is 1/4 full. (haha)
- using Motul 8100 0W40
- using Mugen baffled oil pan
- no visible oil leaks underhood, undercar, nor on ground

Oil pressure seems normal. I'm using Defi Link. It is electrical and it is one of the best and accurate ones out there.

I realized that some of the oil has probably entered into the Greddy oil catch can, so maybe the oil loss isn't as significant as I thought.

When is the best time to check the oil?
Can the dipstick be a problem?
Can the Motul 8100 0W40 oil be too thin, thus easily to burn?
Would a baffled oil pan interferes with the dipstick reading?

What other possibilities?



Modified by Project X at 11:03 AM 3/25/2004

 

0W40? So it pours like water eh? Last time I checked, oil is supposed to have some viscocity. I must be a newb to oil, never heard of 0W..

 

That explains it. B series engines are notorious for burning certain types of oils (including every 0w40 I've tried as well as all forms of Mobil 1). I've got it twice as bad by running Mobil 1 0w40. It performs quite nicely though. I burn a good quart or more of oil between each change (every 2500 or so miles).

 

Hmm...if that's the case being the oil too thin, then I'll switch back to 10W40 or even 15W40. Thanks.

 

honda recommends a 5w-30 oil for B-series. since my engine is getting a little older, i've been using a 10w-30...burns less.

0w oils are very common for newer motors using synthetic oil. mercedes, porsche, bmw and some new hondas use a 0w oil. i think you need to read more about oil. the #w is for the weight of the oil, not viscosity, the second number is for the temperature range. i don't really think a 40 is neccessary. but, to each his own.

 

So when is the best time to check the oil?
When the engine's cold, warmed up or after a hard run?

 

COLD

 

cold and on level ground.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Project X &raquo;</TD></TR><TR><TD CLASS="quote">I'm running a high compression 0.5 overbored motor.
I've been losing about 2 litres of oil in 1-2 months time.
The spark plugs are burning fine. Compression is fine. There are no leaks anywhere on the block.

What can cause the problem?

</TD></TR></TABLE>


If your car spends a lot of time in Vtec that can burn oil..

 

***UPDATE***

I was reading some archives here on PCV valve.
My car is about 100,000km and I have not changed the PCV valve.
Could the burning oil be the cause if the PCV valve is not working right?

 

[QUOTE=hadehatch You are not suppose to baby the engine right after you put it together.. [/QUOTE]


what do you mean ?"?????? explain please


Modified by jason bouchard at 3:41 PM 3/25/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jason bouchard &raquo;</TD></TR><TR><TD CLASS="quote">what do you mean ?"?????? explain please </TD></TR></TABLE>


http://www.mototuneusa.com/break_in_secrets.htm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Primo. &raquo;</TD></TR><TR><TD CLASS="quote">


http://www.mototuneusa.com/break_in_secrets.htm </TD></TR></TABLE>


wow , ok then

 

Update...
I recently replaced the PCV valve. Apparently, upon shaking the old one it still rattles, but the brand new one rattles more. So, my guess is that the old one is dying out.

As well, after recently changed my NGK copper to some Denso Iridiums and the PCV valve, I've noticed that I've gain 100kms of gas per tank.

I'm not sure whether the worn out NGK plugs and the fucked up PCV valve cause my huge mileage drop, but I'm glad it's good now.

As for the oil loss problem, I'll have to wait few weeks to find out. I checked it few days ago when the engine is cold and the dipstick shows the oil level normal (in the middle between min and max).