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914World.com _ 914World Garage _ Vented Heads / Breather Box

Posted by: d7n7master Dec 7 2004, 03:25 PM

Hi All,
I tried a "search" but came up with nothin'...

I have a 2.0 that needs a rebuild. I have a fresh longblock ready for me to transfer all the accessories now that their re-painted.

As I was fitting the engine tin I noticed that my (old) engine has the heads vented. The vent hoses were attached to the air cleaner.

The (new) engine has NO VENT PIPES!!!
Now what? Should I just add a breather to the oil filler??? Or...? unsure.gif
Thanks, Gary

Posted by: URY914 Dec 7 2004, 03:36 PM

On some engines the valve covers were vented instead of the heads.

Posted by: Dave_Darling Dec 7 2004, 03:39 PM

Actually, all of the vented valve covers in 914s that I've seen have been add-ons.

The earliest 914s did not, I believe, have vents in the heads. Nor did the 75-76es; or possibly just those of the latter years that had EGR and/or a smog pump.

It's probably a good idea to have the rocker box vented...

--DD

Posted by: URY914 Dec 7 2004, 03:43 PM

I have a engine from a teener that has vented v/c but it may have been done by a previous owner. confused24.gif

Who knows?

Paul

Posted by: d7n7master Dec 7 2004, 05:27 PM

Thanks alot everyone.
I've seen some interesting looking breather boxes venting @ the oil filler. From what I've read here on the board - that's not enough unless you can mount the breather box way-up-high. Guess I'll look for vented valve covers as well.

Posted by: SLITS Dec 7 2004, 06:05 PM

Drill and tap the boss that is on the heads and run the fitting of your choice. You can do it off the engine or on the engine.

IPB Image

Posted by: bperry Dec 7 2004, 10:04 PM

Any suggestions on fittings?
Can you just tap the hole and use a threaded brass fitting directly?

--- bill

Posted by: SLITS Dec 7 2004, 10:20 PM

QUOTE(bperry @ Dec 7 2004, 09:04 PM)
Any suggestions on fittings?
Can you just tap the hole and use a threaded brass fitting directly?

--- bill

Standard pipe thread hose barb....I would think about 3/8" i.d. (guessing). I would try to match the factory i.d.

If doing this while the head is on the engine, I would use a shop vac to suck up the metal as you drill and tap. You can also use heavy grease on the tap to trap the cuttings to avoid metal intrusion into the engine.

Posted by: SirAndy Dec 7 2004, 10:34 PM

yupp, early engines didn't have the head-vents.
in fact, my '74 1.8L engine didn't have them.

BUT, those engines didn't have a PCV valve either, they were venting the crankcase through the oil-filler neck hose to the air cleaner without a valve.

if you mix & match parts make sure the breather system is working properly.

wink.gif Andy

Posted by: synthesisdv Dec 8 2004, 07:03 AM

my head, one of them at least biggrin.gif


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Posted by: URY914 Dec 8 2004, 08:43 AM

QUOTE(SLITS @ Dec 7 2004, 08:20 PM)
QUOTE(bperry @ Dec 7 2004, 09:04 PM)
Any suggestions on fittings?
Can you just tap the hole and use a threaded brass fitting directly?

--- bill

Standard pipe thread hose barb....I would think about 3/8" i.d. (guessing). I would try to match the factory i.d.

If doing this while the head is on the engine, I would use a shop vac to suck up the metal as you drill and tap. You can also use heavy grease on the tap to trap the cuttings to avoid metal intrusion into the engine.

Also take the v/c off and use the shop vac inside to suck the cutting out from the inside.

I drilled a hole and epoxied (JB Weld) a barb onto my v/c. No leaks and simple. but be careful of the location in relation to the bale wire. Mine are on the ends toward the top.

P

Posted by: d7n7master Dec 8 2004, 09:31 AM

biggrin.gif
That's where the p.o. - or someone installed the vent pipes on my (old) engine. Right @ the boss.
Looks like I'm off to Harbor Freight - again.
beer.gif

Posted by: Dave_Darling Dec 8 2004, 05:49 PM

BTW, a setup like that makes it a bit tough to replace the vent hoses. Space is very tight... Especially if you're trying to undo a hose clamp right there!

--DD

Posted by: bperry Dec 8 2004, 05:59 PM

Space is tight, but to me it really doesn't seem any different than
the factory vent tubes. And if you size the fitting properly won't you
be able to get away without having clamps just like the factory
vent tubes?


--- bill

Posted by: d7n7master Dec 10 2004, 11:47 AM

I never had clamps on the hoses (on the old engine). I used a 'lil bit of permatex (black) on the inside of the hose ends, shoved them onto the vent tubes & let it dry overnight. No leaks.

But now that I'm thinkin' about it - the oil level in the v/c's wouldn't ever fill to that level anyway - would it??? blink.gif
Thanks, Gary

Posted by: Porsche Rescue Dec 10 2004, 01:36 PM

I don't know about how "full" the valve covers get but I lost a hose at the head during a recent autocross. From the amount of oil puddling under my car and splashed around the engine tin I thought I had serious problem. Re-attached the hose and all is well (after cleaning oil off rear shock, control arm, spring, inside of wheel, etc).

Posted by: synthesisdv Dec 10 2004, 01:48 PM

QUOTE(Porsche Rescue @ Dec 10 2004, 02:36 PM)
I don't know about how "full" the valve covers get

This is how full they get. It's a type I but you get the idea.


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