I've been procrastinating away the winter, but it's time to address a few items before spring.

Oil leaks - Ok, this is my biggest problem and is the reason for this post. I'm getting a lot of crankcase pressure since I added the turbo. Off boost I've got no oil leaks. On-boost I've got leaks from the valve covers and pushrod tubes (both new and in good condition). I've got the rocker-box vents plumbed up to the spark-arestor where they are joined by the oil-filler vent hose and this three-into-one arangement then goes via single 5/8" hose to a home-made catch can. Do you think running these as three individual lines (rather than plumbing them down to a single 5/8" hose) would cure the problem, or do I need something more agressive in the way of venting/scavenging?

-Ben M.

Add a puke box to the venting system. Are the rings fresh? it could be extra blow by.

What about going from the catch-can to an oil separator (may be redundant, but it'll keep the air clean), and from there to the vacuum side of your intake using a PCV valve?

For the push rod tubes did you use the locktite pipe sealant with Teflon? Jake’s trick works real good. You can reuse your old seals as long as they are not cut. Clean every trace of oil before you reinstall them.

Where does your breather end up? Do you run a hose to the air cleaner, before the turbo? I do this on N/A’s but I don’t know if the oil mist would hurt a turbo.

I’d ask over on the STF forced induction forum here

QUOTE (airsix @ Feb 2 2005, 11:52 PM)

three-into-one arangement then goes via single 5/8" hose to a home-made catch can

there is your problem!

while the oil-filler neck always has positive pressure, the head-vents will have positive pressure at and above idle but will turn to *negative* pressure (sucky sucky) on higer rpms.
for the catch can to be most effective, you'll need to route each to the can individually.

Andy

QUOTE (SirAndy @ Feb 3 2005, 09:20 AM)

QUOTE (airsix @ Feb 2 2005, 11:52 PM) three-into-one arangement then goes via single 5/8" hose to a home-made catch can there is your problem! while the oil-filler neck always has positive pressure, the head-vents will have positive pressure at and above idle but will turn to *negative* pressure (sucky sucky) on higer rpms. for the catch can to be most effective, you'll need to route each to the can individually. Andy

So what's causing this "negative" pressure at the higher rpms? Just curious.

Still curious.

If it's just fine off boost, but leaks on boost (duh....forced induction), there's nothing I can think of but the intake manifold (vacuum side) that could draw pressure off the heads/case. Wouldn't everywhere else be under a (positive) pressure due to the turbo?

QUOTE (Special_K @ Feb 3 2005, 03:22 PM)

Still curious. If it's just fine off boost, but leaks on boost (duh....forced induction), there's nothing I can think of but the intake manifold (vacuum side) that could draw pressure off the heads/case. Wouldn't everywhere else be under a (positive) pressure due to the turbo?

Right. I think the best option is to find a way to vent to atmosphere more effectively. I've seen crankcase pressure scavenging systems before (for drag motors) but I'm going for the keep-it-simple solution.

-Ben M.

K.I.S.S. is always preferred, but with forced induction (can't recall what boost your running) it may be tricky relieving the crankcase/head pressure.....On the other hand, you turbo'd a TypeIV. And everyone knows that can't be done...

Keep us posted on your solution!

Andy,
Would a setup like yours be good for a turbo engine, or would something else be needed?

Andy,
Tell us about that CB puke box JmuRiz just posted a pic of. I see three lines going in... but where does it vent too? Does it have a breather element running around the sides (like a webber airbox) and we're looking down on the top of the lid?

-Ben M.

QUOTE (airsix @ Feb 4 2005, 09:38 AM)

but where does it vent too?

it has a wire mesh (that i added), then a spunge/filter and it vents out around the top cover.
there is a gap under the cover, it doesn't seal. so the vapors go in the box, through the filter and out into the engine bay.
any oil gets collected on the bottom of the box and will eventually run back to the heads.
the 2 lines on the sides go to the heads. the one in the center comes from the oil-filler neck.

it works like a charme, but i can't say for sure it would work well on a turbo ...

unless someone wants to lend me his turbo setup for "testing"
Andy

I copied Racer Chris's design for his race car...here is a pic of his



I have one of those CB ones like andy has right now and it isn't adequate for my 2056, so I doubt it will adequate for a turbo motor. After one good autox run I have oil coming out of it and dripping down onto the tin.

On the new on I will be running -10 lines, mostly cause I had some left over from when I put in my oil cooler...I will snap some pics once I get it installed.

Tony

QUOTE (cha914 @ Feb 4 2005, 12:28 PM)

I have one of those CB ones like andy has right now and it isn't adequate for my 2056, so I doubt it will adequate for a turbo motor. After one good autox run I have oil coming out of it and dripping down onto the tin.

interesting!
how did you route the hoses? heads/filler?

i have a 2056 as well and i haven't had any problems with overspill yet ...
Andy

Yep,

One to each head, and one to the filler cap vent...its even mounted almost exactly where yours is mounted. After a good spirited run where the revs are over 4K for any kind of period, or a few autox passes the element on the inside of the box will be fairly saturated and there will be drips under the box on top of the engine. I have also had some problems with oil seeping from different areas on the engine and I think its because the crank case can't breath well enough...and thats also what Jake suggested, so gonna follow the builders advice and put a bigger breather on it...I built a box almost exactly like Chris's shown above...

Tony

I like Chris' unit but I'd have a drain back.....I hate the CB unit, cheap POS that leaks crap down your firewall.

Sorry, but thats my opinion of them and I've seen, installed, modified and tossed in the trash 100's of them. On a turbo it will just blow the crap all over the bay.

Chris's does have a drain back, as well as mine...you just can't see it in that pic because the drain back is at the bottom and on the other side, so it requires a hole in the trunk wall. As long as my welds are all tight any oil that makes it into the can will drain back into the case after the engine cools down...we shall see...

I agree, the CB unit is a pice of crap...

Tony

Here is the pic from the engine bay looking at the trunk wall on chris's car...