Lots of us have tired engines with fairly serious blowby. We don't like venting into the intake because of the mess and having to burn the oil etc. Catch cans vented to atmosphere can lead to all kinds of problems including blown pan gaskets and seals. It seems like you could get the same effect of the factory-style vent into the intake with the old hotrod trick of venting into the exhaust. I have searched the forums and found a couple of mentions of this, has anyone actually done it? I found a guy who did it on a Chrysler 2.2 turbo:

http://community-2.webtv.net/PAGEBUI...CASEEVACUATION

And a guy who did it on a Triumph:

http://www.teglerizer.com/triumphstu...scavenging.htm

Any firsthand reports, good or bad?

West

 

Blowby doesn't really strike me as the most worrisome design flaw of these engines - in fact, they're pretty robust in terms of sealing even for very high-mileage engines. Case in point, my 951. 192,000+ on the clock and the compression numbers exceed stock specs across the board. Engine has never been cracked open. This is not uncommon either.

If you're running a track car, I'd say just run a straight breather. For street use, the stock setup seems more than adequate and prone to few problems. . .

I'm sure someone has encountered problems with it somewhere along the line though, so this is an interesting idea. . . Just seems like a lot of work for very little gain.

 

So the guy with the triumph has a WB02 and a carb?...
That's uncommon.

Anyhoo, Just what is wrong with venting it to the intake again?
A little bit of oil in the pipes is all I know of. Doesn't sound like a big deal. All of the cars I own have CCV systems that vent to the intake, and I don't have any trouble with any of them.

 

<<<Catch cans vented to atmosphere can lead to all kinds of problems including blown pan gaskets and seals.>>>

Not if you drill the AOS opening...

 

what about a recirculating catch can. Keeps vacuum, but catches the oil. You may get a fume or two, but nothing substantial.

 

That is a VERY smart Triumph owner - That's the part that is uncommon.

 

Where is the logic in that? If you are relieving pressure from the system then that's less pressure on the seals. This place makes me laugh with all of the info that gets thrown around.

 

Weston, I'm going to try an evacuator...

http://951forums.com/forums/index.ph...indpost&p=3847


I also heard about it from the turbo dodge community...

http://www.turbododge.com/forums/showthread.php?t=57536

http://www.turbododge.com/forums/showthread.php?t=84611

http://www.turbododge.com/forums/sho...d.php?t=108486


And here's a link from cornercarvers talking about crank evac...

http://forums.corner-carvers.com/showthread.php?t=1378

 

DanG - thanks, keep us posted

Eyal - A recirculating can is probably what I will end up doing, but I was curious about the exhaust venting.

Kevin/Chris/Everyone else - I have a drilled AOS, an externally vented catch can, and a blown pan gasket. Probably due to 10% leakdown on one cylinder. I realize there is a lot of BS spread on this forum, but not by me.

West

 

Sorry West, no harm intended but that statement is BS and you are spreading it by posting it. Yes you may have a blown pan gasket and yes it may be caused by high crank pressure, but I doubt that either of those problems started after you added your catch can or why else would you add one in the first place? What weight and type of oil are you running?

 

I've run a catch can for two years. Pan gasket is fine. I replaced it about the time I installed the can. No problems. I have no oil leaks at all.

 

Kevin,

Search the forums for people who have blown pan gaskets or have dipsticks popping out with an external can. I'm not going to get in a pissing contest with you, but I have had a number of problems appear since going to the external can, which I did to reduce the oil in the intake. The pan gasket has since been replaced and blown out again. It doesn't make a lot of sense to me either. But there is a limit to how much can get out the vent (my smallest restriction is 3/8 inch). You don't have to believe me.

BTW - I run Mobil 1 15-50, like everyone else.

West

 

I assumed that's what you were running. Do your self a favor and do a search to see why everyone is switching from Mobil 1. Send Ski a PM he'll enlighten you. It's not what it used to be.

 

Where is the exhaust evacuator getting put in? Looks like it has to go down to near the cat converter...

Ill stick with my Accurate Machine Works catchcan

 

I can't explain it either, but I've run for two years on an external can w/no pan gasket problems, no popped dipsticks, or anything like that. I too wanted to get the oil out of the intake, but since installing the can I've never had one drop to drain. The inside is dirty, and the filter is dirty, but no bad collection of oil. I'm also glad to avoid inducing engine-temperature air directly into the mouth of the turbo.

I've run high speeds (145 legit - on a track), and higher boost than I'm willing to admit to here. So it hasn't been babied. I just think if your seals blow with an external can, you may really have other problems. Venting crankcase to atmosphere is nothing new.