I am sure that this questions has been asked a million times, but I am not finding the answer that I need at the moment, so I feel like asking.

Issue: I have been running a simple and small catch can on my turbo setup. I have the stock vent from the valve cover running to it, and I replaced the two dead plugs in the block with prelude oil lines. The oil that goes into the can gets drained right back into the motor...

"This is bad because unused fuel sits in the oil and can destroy the piston rings" - is this a correct statement?

I have been running the setup this was for a while, but since I don't drive the car often and literally have changed the oil about every 50-100 miles, I have never had any issues.

This oil change i have probably driven 100 miles on. I took my vehicle out Sunday and I got on it pretty good for a little while (10-15 minutes), came home, let the timer do its thing, and went to bed. Today, I went in my shop and I swore up and down that I was smelling fuel. I couldn't smell it around any of the fuel lines (i.e. a leak) but I slightly smelled it above the motor. When I pulled the oil cap off and took a whiff.... my oil is contaminated with fuel.

What is the solution? I am thinking i just need a bigger catch can and stop returning into the crankcase. The can I have now will literally fill up on a good long highway pull. It will not suffice....


SUGGESTIONS? COMMENTS? INPUT?

 

Ditch the fittings on back of the block vent front from of valve cover and it won't really get much if any oil in the can and it won't be draining back into the motor

 

Blowby contains a lot of contaminants from combustion byproducts to fuel to water. None of which are good things to be draining back into the oil inside the crankcase.

Ditch the return line

 

So basically I need to get -10 AN fittings welded to my VC.... DAMNET. Tig welder is out or gas....

Why have i seen the crankcase vent so often in the past?

Return line has already been ditched. IMMEDIATELY!

I am looking for a way to solve this without having to do much major modifications to my set up.

 

Those two galleys are some of the main conduits for oil to drain back down from the head..
That's why it fills the bottle so quickly when they are used.
The Endyne system uses extended nipples (always a good thing ) to try and catch gasses above the layer of liquid oil flowing down and the Prelude fittings lack this feature iirc.

 

The problem with the prelude fittings is the small diameter of the inlet side of the fitting (block side) plus the design of the fitting ensures that any oil that gets on the portion of the fitting between the inlet and the end of the threaded portion of the fitting gets sucked up

Also. Extending the inlet is a crapshoot because if you make the piece of pipe too long all you'll suck up is oil

 

My buddy is welding bungs to my VC Thursday night, so problem solved.

Should I just loop the two prelude oil fittings in the back of the block?

 

why does the t1 catch can return back to the motor??

I'm sure that guy knew what he was doing.
Is condensation really not making its way into the motor already without a drain back?

 

For the most part, no

 

i have done both and yes it does contaminate the system but nothing drastic, didnt see anything when doing a oil change and that was 30k on a built and stroked single cam b4 i sold it

 

Id say your gonna have a healthier longer lasting motor overall if you do not drain back. My car does not drain back and the oil smells heavy of E85 when I change it. Everyone I talked to said no no no since I was going E85.

Im sure regular gas gets into your oil too but doesnt have the same obvious smell to it, nor is it as corrosive the oils lubricity. I wouldnt be too worried about condensation, because that will evaporate as the engine warms up.

 

The endyne fittings are supposed to be any syphon but they don't work oil still pushes into the can pretty bad.

 

I'm tapped into the back of block with 2 10an fittings, my can stays pretty empty if I don't get on it a lot. But after a few races it fills up pretty quick.


I'm on go-autoworks kit without drain back.

 

You won't see anything in the oil when you drain it. The contaminants will cause damage to things like the oil pump rotors. Bearing/crank surfaces, the cam journals... and if you check the screen on the vtec solenoid it would probably be full of random ****

 

considering I drive as little as I do, I do not think that I will see much anything anywhere, but the smell of gasoline was just SO overwhelming that it scared me. I am doing the vent from the VC and an oil change and taking the car out this weekend to play.

What suggestion do you guys have to do with my prelude oil fittings in my block?

I have deleted the black PCV box with a freeze plug also.

 

Ditch the prelude plugs. They cause oil to be siphoned out of the motor into your catchcan

Get two 10an fittings to replace them. Goautoworks makes a kit with two 10an fittings that thread into those two ports as well as an o-ringed billet block off for the black box plug. I believe B&R fittings makes something similar. This will eliminate any chance of the crankcase pressure leaving the block sucking up oil with it.

 

Alright, so here are my thoughts..... I am having my VC welded tonight to have -10 AN fittings on it. I am going to keep the prelude oil **** for now, and just loop the two together until I purchase and receive the -10 replacements that you speak of. Either that or I will have a set of those made from stock fittings.... not sure yet... either way I will be using those. Will I still have the fuel smell in my oil if I run four hoses (two from thecrank case, and two from the VC to the catch can? And if I loop the prelude lines for the mean time WHILE RUNNING THE VC VENTS, I wont blow the hose off, WILL I??

I REALLY NEED confirmation on that last question. Thanks guys!!!

 

You should be fine looping the fittings until you get the 10an fittings to replace the prelude fittings

As to the gas in the oil smell... how rich is your tune? Excess fueling can actually wash the cylinder walls and you'll loose ring sealing in a cylinder and that will allow raw fuel to enter the crankcase and the oil.

You might want to do a compression and leak down test just to make sure the motor is still healthy and that the cylinders don't have ring issues. Because it's hard to get fuel into the oil if everything is in optimal condition

 

Definitely a rich tune, and only tuned for full throttle. So I may be impinged lee than I need at cruising speeds. I will speak with my tuner a little bit more when I get a chance and I will also do a compression test when I get my valve cover back on. Either tonight or tomorrow. I will post the results. As for a leak down test, I lost faith in the last tešter I had, so I can't do one at the moment and won't ever buy another from harbor freight lol.