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Discussion Starter #1
Hey guys,

Just had something that i was worried about so i thought id ask about it here. :)


I normally clean my engine bay out twice a week myself and normally, while cleaning, i take a look around and make sure nothing's loose etc.

This time, i noticed my oil catch can was half full.

The last time i cleaned the engine bay, it was empty. The thing is, i had a race last night which wasnt really gruelling and was only about 3 - 5 minutes long.. I didnt rev beyond 7000rpms as well.

Anyhow, today, i noticed the oil catch can is half full and it made me abit worried.

With regards to my blowby, the left side of my engine has one pipe thats coming from the right side and the other one into the engine.

On the right side, one outlet is of course, that said pipe going to the left side and the other one to my oil catch can.

The other hole on my oil catch can has a hose pointed towards the floor connected to nothing.

Is that supposed to be correct?

How come so much oil collected in my oil catch can overnight?


I was also told my turbo oil seals weren't in good shape cause everytime i hoist up the car, the blow-off valve seems to have abit of oil there and look like it spurted out oil when driving..

Whats the actual problem? Anyone faced anything like this before?

Thanks a bunch for the responses in advance!
 

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Rapid filling of catch can, can be a sign of high blow-by.....worn bores / cracked ring-lands / cracked rings.

Has it got noticably worse recently? The RB26 does `breath` quite heavily with nothing broken.....
 

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Discussion Starter #3
ExScoobyT: Not to say that it has gotten worst recently.

In fact, it doesnt occur at all. Normally my oil catch can is empty. Its just after last night when i drove the car quite hard during a race and today when i cleaned out the engine bay i noticed the oil. It wasnt there before but it just came after last night when i drove the car hard.

Is there anything to worry about?

Thanks for the response bro
 

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The other hole on my oil catch can has a hose pointed towards the floor connected to nothing.

Is that supposed to be correct?

Thats the overflow in case the tank fills completely. I had this problem at Spa last year amongst other things and it was my head gasket, so a compression test would be a good idea.
 

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i would attend to that hose to nowhere. if the catch can fills completely and overflows to the road onto your tires it many end in a horrbile crash and bill to your wallet.

It does happen even on some of the big drag cars..
 

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I vent the bottom of the catch can to the sump, via a -10 flapper valve, to stop crankcase pressure that *MAY* be higher in the sump than the cam boxes, forcing oil back up. I vent the catch can top to another breather can, in turn vented to atmo. This has resulted in zero oil loss to the second catch can even with a tired engine and many many circuit laps. My next engine is having external drains from the head to the sump, as the RB* engines have poor oil return paths from head to sump via the castings internal drains. Engines like the Toyota 2JX-GTE don't suffer with this, as their internal drainage passages are MUCH larger.
 

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Chris - Still not sure about the flapper valve. If you leave it out, you effectively vent both cam covers and crankcase to atmos. This eliminates any internal pressure differential between crankcase and camcase.
 

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Chris - Still not sure about the flapper valve. If you leave it out, you effectively vent both cam covers and crankcase to atmos. This eliminates any internal pressure differential between crankcase and camcase.
Ah, but not when the head to sump drains are full of oil due to the cam boxes and head not draining as fast as oil is being pumped past the tappet buckets and cam bearing journals, then, and this is exactly why oil vents from the cam boxes, because they can't drain fast enough, a pressure differential can and does (I measured it) exist between cam boxes and crankcase. The flapper valve stops this differential pumping oil up the oil catch tank drain hose to exacerbate things.
 

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...but looking at that situation:

You are on full throttle. Head is `full` of oil. Flapper valve is closed. Crankcase has no vent other than internal oilway. Crankcase pressure builds due to blow-by. Therefore the oil in the cam covers can`t drain back due to the pressure in the crankcase?

No flapper valve, same senario as above. Crankcase pressure cannot build-up as it is vented to atmos. Cam also vented to atmos. There can`t be a pressure differential between head and crankcase. Oil drain back is reliant purely on hole diameter etc but there is no pressure at the bottom of the engine stopping the return.

I take the point about the flapper valve stopping oil being pumped into the catch can from the sump, but ironically the flapper valve makes this situation more likely as you are allowing crankcase pressure to build in the first place.....????
 

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I have given this some thought and have to agree with you, but it's the same set up Gibson Motorsport used on the Group A Bathurst cars. That's not to say they didn't add the flapper needlessly! If I feel brave I'll make a hose sans flapper valve and see if it makes any difference. Good point well made, thanks.
 

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Discussion Starter #12
Wow.. Thats alot of feedback. hehe


So i managed to get some feedback from some workshops..

1. If the piston rings are busted, the car wont drive smoothly or make power/hold boost.

BUT.. the car is running fine and smoothly and making the same power it makes.

2. NO more oil enters the oil catch can. Even when i gas it abit harder. Its just that same bit that flew in when i had that race. No other time did oil enter.

3. The workshop however said that there was white smoke coming out of my blow-by. That means that the piston rings are gone but if the piston rings are gone, it shdnt be so smooth or making power.

So im still kinda lost.

Im not in any pain though not being able to drive my car cause my registration tags expired and im getting em renewed over the next couple of days. Hehe..

Anyone had this happen to them before?

JUst one big burst of oil into the oil catch can and never again on subsequent drives.

And to top it off, the car drives fine and power is fine and is still holding and making boost like before.

Thanks alot for the responses guys!
 
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