Crankcase vent has been deleted. What to do for Vac? Engine builders get in here!

[Kingtal0n]

S13 valvecovers will lose some oil to the T by design, so having a drain back to the oil pan is necessary... unless.. you want all that oil to wind up in the catch can.

Catch cans are more for old engine's with blow-by, or as a safety precaution for when your piston rings come apart and you start pushing quarts of oil out the valve cover. A high performance "Raceing engine" that is warmed up properly, has round cylinder (because deck plate) and the right piston-wall clearance (because mazworx) with the right grade oil should not produce significant amounts of blow-by.


I have seen a sloppy 1000RW horsepower 2.5L Engine that depends on nitrous for 30% of it's power and spooling its GT42r- Those I have seen fill catch cans no matter what you do, probably due to the excessive piston-wall clearance and enormous blow-by produced. Again, if ring seal is good, no need can.

// hello world

As for crankcase pressure, I recommend you either use the factory setup with the inlet fitting facing the compressor wheel (angle the fitting in the intake to point towards the inlet) and use small diameter plumbing to help create a vacuum source.

OR

If this is getting more serious as a race car, either a vacuum pump or dry sump. If it's a cheap race car I've seen people use EGR pumps from chevrolet engines on their small displacement four... just a thought for those with welding skills and extra time.

[jr_ss]

Originally Posted by Kingtal0n

Catch cans are more for old engine's with blow-by, or as a safety precaution for when your piston rings come apart and you start pushing quarts of oil out the valve cover. A high performance "Raceing engine" that is warmed up properly, has round cylinder (because deck plate) and the right piston-wall clearance (because mazworx) with the right grade oil should not produce significant amounts of blow-by.

I'm not sure where in your head you determined catch cans are strictly for old, poorly assembled or unhealthy engines. Either way that's your personal opinion and you're entitled to it.

If you pull a vacuum on your crank case, regardless of the quality of build you have, you are going to pull oil vapor out of it. If one doesn't want to have that oil vapor go back into their motor, lowering octane ratings and potentially damaging their motor, guess what? They add a catch can. Sure, it won't stop all, but it will prevent most from entering your engine.

[mechanicalmoron]

Originally Posted by jr_ss

I'm not sure where in your head you determined catch cans are strictly for old, poorly assembled or unhealthy engines. Either way that's your personal opinion and you're entitled to it.

If you pull a vacuum on your crank case, regardless of the quality of build you have, you are going to pull oil vapor out of it. If one doesn't want to have that oil vapor go back into their motor, lowering octane ratings and potentially damaging their motor, guess what? They add a catch can. Sure, it won't stop all, but it will prevent most from entering your engine.

I have nothing to say about most of what you're saying, but:

I'm pretty certain that motor oil is higher octane than gasoline. I don't know for sure or anything, but.... it's AKI should be higher than diesel, given that in order to run a diesel on oil, you need to mix it with gas.

Of course, you don't want it in your intake. But I'm pretty sure you pulled the octane bit out of your ass, or out of SOMEBODY'S ass.

[jr_ss]

Originally Posted by mechanicalmoron

I have nothing to say about most of what you're saying, but:

I'm pretty certain that motor oil is higher octane than gasoline. I don't know for sure or anything, but.... it's AKI should be higher than diesel, given that in order to run a diesel on oil, you need to mix it with gas.

Of course, you don't want it in your intake. But I'm pretty sure you pulled the octane bit out of your ass, or out of SOMEBODY'S ass.

Perhaps you should do some research, instead of ignorantly commenting on something you know nothing about.

[mechanicalmoron]

Originally Posted by jr_ss

Perhaps you should do some research, instead of ignorantly commenting on something you know nothing about.

Go light a puddle of motor oil, and light a puddle of gasoline.

The one that burns more slowly, can be assumed to have the higher octane rating.

Care to guess which one it will be?

[rc1honda]

Originally Posted by Kingtal0n

S13 valvecovers will lose some oil to the T by design, so having a drain back to the oil pan is necessary... unless.. you want all that oil to wind up in the catch can.

Catch cans are more for old engine's with blow-by, or as a safety precaution for when your piston rings come apart and you start pushing quarts of oil out the valve cover. A high performance "Raceing engine" that is warmed up properly, has round cylinder (because deck plate) and the right piston-wall clearance (because mazworx) with the right grade oil should not produce significant amounts of blow-by.


I have seen a sloppy 1000RW horsepower 2.5L Engine that depends on nitrous for 30% of it's power and spooling its GT42r- Those I have seen fill catch cans no matter what you do, probably due to the excessive piston-wall clearance and enormous blow-by produced. Again, if ring seal is good, no need can.

// hello world

As for crankcase pressure, I recommend you either use the factory setup with the inlet fitting facing the compressor wheel (angle the fitting in the intake to point towards the inlet) and use small diameter plumbing to help create a vacuum source.

OR

If this is getting more serious as a race car, either a vacuum pump or dry sump. If it's a cheap race car I've seen people use EGR pumps from chevrolet engines on their small displacement four... just a thought for those with welding skills and extra time.

It's a pretty serious build.
It stroker SR 91mm crank 90mm bore. And the drain delete is PRESSED into the block. Meaning there is no way to utilize the factory crank drain without a lot of serious work.

That's why I'm looking for 3 port catch can now. And though this SR is spec'd for over 1000hp I will only be making around 500. It not a sloppy build at all and so far no expense has been spared. I not so much worried about blow by as I am of possibly introducing positive pressure into the crank case. The motor was built professionally with nothing but the best.

As far vac pumps, and dry sumps just seem a little impractical.

Those some very pricey options when it still possible to produce adequate vac from the stock setup.