Jump to content
SAU Community

Recommended Posts

So i am having some trouble with my rb25 at the moment. The motor was rebuilt just over 1 yr ago and runs on e85 and at every oil change of course there is always a smell of fuel in the oil which i have been told and have learnt to expect from ethanol.

 

But recently i had stopped up from a coastal run to find oil leaking from the front bumper which was traced back to the pod filter as my catch can is plumbed back pre turbo. So clearly my can was overfilled so much it was being pulled into the intake thanks to the turbo and smoothering the pod filter in oil.

 

Now this was the weekend before racewars and as i had no issues beforehand and had done a fresh oil change decided there wasnt much i could do and to just give it a go at racewars. But after 2 runs of the 800m i had again overfilled my 1.8l catch can enough to see oil out the bumper. Now what has me really concerned is the fact that after 2 runs of 800m my catch can and oil both reak of fuel.

 

I have spoken to the engine builer and he isnt concerned with oil and fuel in the can as it isnt a great design and so since this i have read most of the oil control thread and am planning the new catch can system to drain and vent to sump as it should. But i am concerned that even after this i will still have this same issue as im concerned the rings are shagged is there any chance its not the rings?

 

Thank you

Running an oil cooler?  Might need to be hotter.
Any chance that it's simply a bit rich somewhere in the operating range and washing down?
Nah no oil cooler. It normally sits at a stable and decent temp so i think its getting hot enough. It could possibly be running rich but i have had a few people go over the afrs as i wasnt overly confident with my most recent tune and everyone seemed to be faily happy with them?

Put it back in and i reckon your overfilling the catch can will go away.

 

I run just a basic catch can setup, pcv remains fitted. Hose from rocker covers goes to can and then from can to intake. Works well and never fills even after whole track days.

 

The only time its filled the can is if ive overfilled the engine oil too much.

 

 

  • Like 2

Not an answer to your problem and not sure if this will be of help/interest to anyone

 

Since my last motor work the catch can is filling up faster after some runs than it did before and I thought I had an oil leak  as there was oil under the front of the motor. The overflow used to go to the back through a tube and leak out if I didn't empty it, not ideal. I guess the tube is not there or has been disconnected somehow. About to have it checked out.

Being on E85 I am not sure if I want the contents of the catch can going back into my sump ?

Now I just make sure to empty the catch can and of course the problem stopped. Top the oil up when needed and all good

Maybe some of you have this problem , my catch can is a pain to empty because the nut is pretty well flush with the catch can and when you undo the bolt it makes it hard to catch all the oil and it can be messy , so I just ordered a valve to make it easy as it sits out away from the catch can and I will be able to get a funnel under it, maybe I will be able to put a hose on it once I have a chance to see it.

 

1292224343_OilValveforcatchcan.jpg.54b78db103ec6176e14ccaf84edc6f83.jpg

Put it back in and i reckon your overfilling the catch can will go away.
 
I run just a basic catch can setup, pcv remains fitted. Hose from rocker covers goes to can and then from can to intake. Works well and never fills even after whole track days.
 
The only time its filled the can is if ive overfilled the engine oil too much.
 
 
Ok ill try putting it back in im just so confused as i went a yr without any issues and now im overfilling the catch can after 2 pulls
Or if you are worried do a compression test and if keen a leak down test.
Yeh i think i will do a compression test aswell and possibly a leak down if it turns out bad
  • Like 1
Not an answer to your problem and not sure if this will be of help/interest to anyone
 
Since my last motor work the catch can is filling up faster after some runs than it did before and I thought I had an oil leak  as there was oil under the front of the motor. The overflow used to go to the back through a tube and leak out if I didn't empty it, not ideal. I guess the tube is not there or has been disconnected somehow. About to have it checked out.
Being on E85 I am not sure if I want the contents of the catch can going back into my sump ?
Now I just make sure to empty the catch can and of course the problem stopped. Top the oil up when needed and all good
Maybe some of you have this problem , my catch can is a pain to empty because the nut is pretty well flush with the catch can and when you undo the bolt it makes it hard to catch all the oil and it can be messy , so I just ordered a valve to make it easy as it sits out away from the catch can and I will be able to get a funnel under it, maybe I will be able to put a hose on it once I have a chance to see it.
 
1292224343_OilValveforcatchcan.jpg.54b78db103ec6176e14ccaf84edc6f83.jpg
Hmmm sounds interesting maybe the ring gap is abit looser on this motor and so more blowby? I may have to try something similar as although apparently lots of people do it im not sure i want to return the e85 contaminated oil back to the sump?

I personally do not see the sense of taking a chance that a contaminant from the catch can going back in my oil to save a couple of $s

Before the build the sludge that came from the catch can was brown ish gunk  , E85 has a water content I think and mixing with the oil could change the colour . This is what first made me think I had an oil leak as the oil on the garage floor looked like oil and when I emptied the catch can this time , it looked like oil but probably had a small amount of water mixed with it as I am sure some water came out first.

Probable be some condensation in the mix as well , but ?

11 hours ago, pogman said:
16 hours ago, Nismo 3.2ish said:
Not an answer to your problem and not sure if this will be of help/interest to anyone
 
Since my last motor work the catch can is filling up faster after some runs than it did before and I thought I had an oil leak  as there was oil under the front of the motor. The overflow used to go to the back through a tube and leak out if I didn't empty it, not ideal. I guess the tube is not there or has been disconnected somehow. About to have it checked out.
Being on E85 I am not sure if I want the contents of the catch can going back into my sump ?
Now I just make sure to empty the catch can and of course the problem stopped. Top the oil up when needed and all good
Maybe some of you have this problem , my catch can is a pain to empty because the nut is pretty well flush with the catch can and when you undo the bolt it makes it hard to catch all the oil and it can be messy , so I just ordered a valve to make it easy as it sits out away from the catch can and I will be able to get a funnel under it, maybe I will be able to put a hose on it once I have a chance to see it.
 
1292224343_OilValveforcatchcan.jpg.54b78db103ec6176e14ccaf84edc6f83.jpg

Hmmm sounds interesting maybe the ring gap is abit looser on this motor and so more blowby? I may have to try something similar as although apparently lots of people do it im not sure i want to return the e85 contaminated oil back to the sump?

Why not? That's where it came from. How far can you afford to let your oil level drop?

Don't know about you Bob, I have 10.5 Lt sump , it is a street car and I do not do long races where I would think this is a major problem waiting to empty the catch can and maybe running it back to the sump may be the best option for your car's motor internals , I don't know. Then totally change the oil after the race, but I doubt if you use E85 you would leave the contaminated oil  in the car and race again and again , oil is cheaper than a rebuild, but I do not know?

I do have flex tune but use E85 100% atm

I can only go on my limited experience , I emptied the catch can and drove the car 330klm to Sydney to have some work done on it .

Had the head ported, cams modified and the CR up from 8.1:1 to 9.8:1 , the car was tuned and I am sure there were lots of 7500 ish rpm runs on the Dyno before it was done, drove it home 330klms and loading it up as I went, did another 300klm through the hills , then a mate came up and gave it heaps for 120Klms and it used up about 1.2Lts plus some water in the mix. So I had 9.3 Lts of uncontaminated oil left in the sump and for me, I will take a loss of 1.2Lts of crap that is not going back into my sump , than having it returned.

Maybe I am being too careful Bob , but I have spent a shatload on my motor and think I am doing the right thing , but ???

[emoji87][emoji3166][emoji856]

I thought e85 draws in condenensation and can easily be contaminated.

If it is in the can it can draw condensation through the airways. Same with your conaminated oil in the sump but will more than likely evaporate quickly in the engine and show as condensation on the inside of the oil cap. Saying this hopefully the can is saving the sump oil by being the only atmospheric inlet mildue can get in.

When on petrol the temps are higher and the fuel and moisture evaporate away from the oil easier and qucker.... e85 more fuel and less evap and more drawn in condensation fr9m e85... messure what you tip out compared to what you need!

More blow by will add more.

Does the engine have a breather?
May help if pvc return dont.
I used to use 1 on the top of the can so not all vacum was applied to the motor.
Also the can will be the moisture catcher still.

?It may be to much vacum in the motor pulling the fuel past the rings if they are gaped more? Very queationable! [emoji89]

[emoji51]

3 hours ago, Slap said:

I thought e85 draws in condenensation and can easily be contaminated.

No, E85 makes condensation.  Because of the much higher hydrogen:carbon ratio of ethanol compared to 7-9 chain length hydrocarbons, it simply make a higher % of water vapour in the exhaust gases and therefore you get more of that condensing in the oil.

Oil/sump temperature will be about the same regardless of 98/E85 fuel in use.  It's the upper end of the engine that runs cooler.  The bearings still make a lot of the heat that turns up in the oil, probably more on E85 if it's got more timing/boost/power.  But the water is continuously being made.

It should be safe to return it all to the sump, because the water should boil off again, but by the same token, if there's enough in there it will sink to the bottom of the sump, get priority pickup by the oil pump and f**k the bearings in short order.  So, a large catch can and a very decent breather system that can pull off water vapour before it condenses and send it to be burnt are probably the wisest idea.

  • Like 3
4 hours ago, Nismo 3.2ish said:

Don't know about you Bob, I have 10.5 Lt sump , it is a street car and I do not do long races where I would think this is a major problem waiting to empty the catch can and maybe running it back to the sump may be the best option for your car's motor internals , I don't know. Then totally change the oil after the race, but I doubt if you use E85 you would leave the contaminated oil  in the car and race again and again , oil is cheaper than a rebuild, but I do not know?

I do have flex tune but use E85 100% atm

I can only go on my limited experience , I emptied the catch can and drove the car 330klm to Sydney to have some work done on it .

Had the head ported, cams modified and the CR up from 8.1:1 to 9.8:1 , the car was tuned and I am sure there were lots of 7500 ish rpm runs on the Dyno before it was done, drove it home 330klms and loading it up as I went, did another 300klm through the hills , then a mate came up and gave it heaps for 120Klms and it used up about 1.2Lts plus some water in the mix. So I had 9.3 Lts of uncontaminated oil left in the sump and for me, I will take a loss of 1.2Lts of crap that is not going back into my sump , than having it returned.

Maybe I am being too careful Bob , but I have spent a shatload on my motor and think I am doing the right thing , but ???

Its really only on the track that you do a lot of running at WOT where you could potentially starve the pump of oil. Most people change the oil after each day at the track and yes oil is cheaper than engine rebuilds!

So quick update as i put a filter on the catch can rather then having it return to the intake and went out last night to test it out and gave her some shit and barely any oil came out of the can. Still havent done a compression test as esspecially after that im hoping i dont need one now as it seems to have fixed it for now but its definitely due for an update as im still not a fan of the way the can looks.

  • Like 2

You should be able to run a breather on the can and still have a vacum from the can to the intlet pre turbo post maf. That way it still sucks the fumes away but now wont over apply vacum to cam covers.

So quick update as i put a filter on the catch can rather then having it return to the intake and went out last night to test it out and gave her some shit and barely any oil came out of the can. Still havent done a compression test as esspecially after that im hoping i dont need one now as it seems to have fixed it for now but its definitely due for an update as im still not a fan of the way the can looks.

It will change what the maf sees so do a reset if your on the stock ecu.(4 other readers) This will also extend maf res [emoji3166][emoji1782] by causing an air leak post maf pre turbo. Can be dangerous if over size. Can increase fuelcut limit of boost. A wee bit.

 

 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Yeah, thumbsup from me. The distant shot of the bay just looks same-same as before.
    • Dad had a court case drag out with them from 1998 to 2004. He was in a not at fault accident, NRMA were the ones who covered the other person. They tried to blame his neck injuries on the fact he'd had an injury in 1981 on his extreme lower back where he slipped a single disc right near the bottom. Had been all cleared from that injury for years. This accident destroyed his shoulder, and f**ked a heap of discs in his neck, and he still has major problems with it to this day. Sarah's sister while on her L plates had a small Suzuki Alto, she had stopped to give way to an ambulance, and someone changed lanes behind her because there lane was also slowing, and rear ended her at 80km/h. (She had been stopped for a few seconds already too!). Car was completely f**kED. NRMA sent the vehicle around to 3 different workshops as they kept claiming "We believe it can be repaired, and not written off, we just need to find the correct workshop". It took 3 months, and a lot of arguing before they'd concede and wrote it and paid out. About two years later her sister had a Lancer, someone pulled out of a stop sign without stopping (in an 80 zone). Her sister swerved, hit the front of the other persons car (Instead of dead t-boning the drivers door), which ramped her Lancer, and made it roll multiple times down the road. It hit every panel on the way through. Her sister had slid her self out of the car, and remembers the ambos walking to the accident (They'd been sitting at a set of lights just down the road and witnessed it) and they were saying "Well, this ones going to be a fatality, no way you can walk away from that". Well, she did. And then NRMA sent two assessors out to look at the car, both of which wrote it off. They tried to send another assessor out, except a HUGE uproar was raised, and they FINALLY paid it out. That was on a car, that had damage to EVERY panel, you could see from 100m away the whole car was also twisted, roof bowed etc. Nah, we'll try get out of needing to payout on a $10,000 car... Her sister ended up with major shoulder reconstructive surgery being required, and was permanently limited in her ability to do her job as a nurse after that, as she can't (And was told before surgery too this would be guaranteed to happen) regain full strength in that shoulder. However, there was no choice to not have it, as she could barely use her arm, which was her dominant one, and was in near constant major pain. (And she's the type of person that would try and walk off a broken leg!) NRMA did the biggest run around on the personal injury side too for about 18 months, even to the point of trying to put 100% blame of the accident on Sarah's sister, even though the other driver admitted she didn't look, and didn't stop, and was charged by the police. Sarah used to have a Barina insured with them. It was a policy setup, paid all 12 months in advance. At the end of the 12 months, Sarah was living with me, I reviewed the renewal, it clearly stated "If you do nothing, your policy will cease on XYZ date". We did nothing, as we moved her insurance in with all of mine and I was with Shannons. We find out 10 months later, NRMA decided, because he DAD had a car insurance policy at the same address as what Sarah's mailing address was (Garaged address had been changed), that they'd put Sarah's (What should have been non existent policy) onto her Dad's month to month charges on his credit card. We had to jump through hoops, to get a refund. They didn't care that we actually found the letter that said "If you do nothing, your policy will cease" they made us prove we had NON COMPULSORY insurance else where before they'd issue the refund, and after they agreed to the refund, it still took another 6 weeks and 3 more phone calls for them to actually process it. They also had two insurance claims from storm damage, and they were an absolute cluster to get resolved as well (one vehicle, one house). Some how, up until about 3 years ago, her parents were still loyal to NRMA too, and we were like "How the hell are you so loyal to staying with them, when other places are so much cheaper, and they've f**ked you over every time you've ever had to make a claim?"
    • I got the four AN10 fitting welded up to the cam covers and started up making the head to sump breather/drain lines. The front passenger side cover I used a 45 up top and a 90 at the bottom into the stock VCT head drain spot (3/4" BPST to AN10 adapter) thats unused on the RB25DET NEO with some speedflow flame shield to protect it from the manifolds heat.   back passenger side was a 90 up top with some flame shield and 45 at the sump end. The rear drivers is 45 at both ends   the front drivers fitting is capped off for now but ready to go if i want to try moving the breathers around. I was told by the fabricator to leave all the welds raw for now to make sure there are no pin hole leaks. A lot of cleaning up, re bundling looms and degreasing to go as well as final assembly on the cam cover baffles. The first real test will be 28th March at a Circuit event. added complexity and more spots for leaks but overall looks relatively neat imo
    • Yeah i think the dash needs to come out. To get the loom or maybe just climate control and radio cluster. My mirrors are done i think the motors don’t work so well after flood haha i need the ac fan, you said you wanted to keep it for your 31 and interior loom not including boot. The wiper motor. I’m not sure how good the window surrounds are on the exterior on the pintara.  I will message you to get your bank details shortly 
    • Just another barrier put up to stop cars being modified. When we're all driving Chinese sewing machines, you won't want to modify it anyway, and you'll likely already have slashed your wrists and be locked up in a padded room for your own protection.
×
×
  • Create New...