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914World.com _ 914World Garage _ Blow-By

Posted by: 914ghost Dec 1 2004, 12:22 PM

So...My car runs great, abosolutely perfect usually.
Starts and warms up in the 24' deg weather here, good heat, great power, fun slides!!
But why the HECK do I have so much blow-by?
I have a good Cb performance breather set-up.
From oil filler, and each head to the breather, and I put a little K&N filter poking out of the breather top to vent it.
But MAN alot of oil fumes come out of that thing- enough to leave a little puddle and have some drips of oil running off the breather- on a 40 mile drive....Compresion is great, 145'ish on all 4 and I get hardly any smoke- just a puff when I rev it up and shift- I guess thats valve guides..?
But what are some guesses as to why I have so much case pressure?
cheeeeers!
Bob O

Posted by: Root_Werks Dec 1 2004, 12:30 PM

Undo each line and blow into it. Yep, you heard me. Not with the engine running of course. But each line at each head, blow into it to make sure they are not plugged up. Even the one at the filler. If all are free, not sure what to tell you other than keep things "up". i.e. put a breather box 6" above the engine and have your lines go up to it. It allows oil to drain back before filling up the box and dripping out. Worked for me anyway. <_<

Posted by: Jake Raby Dec 1 2004, 12:44 PM

Remove the element from the CB breather and that will help. also shim the cover up a bit to relieve more to the atmosphere..

The blowby is being generated by worn guides and maybe warped heads and worn rings. Maybe someone rebuilt it with Grant rings or some suck ass China ring set- they last 2K miles before they are toast if you ever get them to seal.

FYI engines that are running too hot over expand and puke alot more

BTW, your engine is telling you that it has a problem in a nice way. I highly suggest that you find the issue now before it finds you...

Posted by: airsix Dec 1 2004, 01:16 PM

Don't feel bad. You should see MY blow-by. In California my car would fail emissions - AT THE BREATHER.

-Ben M. (old motor + turbo)

Posted by: 914ghost Dec 1 2004, 05:14 PM

I aint too worried about it actually.
The engine was rebuilt 9 years ago- 14,000 miles., by the shop I worked at.
I actually remember pulling the engine out and tearing it down...I HATED 914's!! Though less than all the other Type 4's (busses, 411's..)
try hearing this all day: "Bob- go pull that alternator on the 914, pull the head of that 76' Bus, do the fan/pulley seal on that 72' bus". I thought Type 4 engine were the biggest shitholes. Don't worry, I'm converted.
Anyway, the p/c's are Mahle- and were new. And I actually had to seal the breather top to the body because I got sick of the oil dribbling out the side. And I drilled the top and put a K&N filter on there to vent it. I don't know what the deal is, dont really care, it runs great and if it blows up I'll rebuild it.
Maybe it'll last until I get a real job and can afford some real parts ...maybe even from that J-aby guy what's always got some fancy idear how to get mo' power....
Bob O

TO ME!!!

Posted by: jwalters Dec 2 2004, 08:05 AM

Man, you want to talk about blowby------let me just say that I have sooo much I had to cut the lines going to the breather and leave the holes open where they are. I even took a hacksaw to my filler neck, whacked of the threads for the oil cap, and clamped a Mr. Gasket shorty carb filter and base to it. After each drive I wipe down the front left corner of my fwd firewall from splooge, then my rear right corner of the aft firewall. I cannot stand it!!! Compession is 135-141-138-145---its gotta be the guides, and rings, and warped cylinders, and.......60W motor oil is a god send when it is needed!!!

But the turbo rebuild has begun, yesterday the heads were sent to Len for his black magic-----

Good luck in diagnosing your delimma,,or you can just do like me, say screw it, I am going to rebuild it anyway, and drink some red stripe...

Posted by: JmuRiz Dec 2 2004, 10:25 AM

Sounds like my motor, puffs some smoke when it's revved up under load. It was told to me by a local 914 buddy that it's probably the valve guides. So a head re-do is in the works sometime soon. I'm just waiting on what's instore from RAT. I just got a CB style breater and will install that to help reduce the posibility of this happening later on after the heads get done. Best of luck.

Posted by: Jake Raby Dec 2 2004, 11:16 AM

Smart Man

Posted by: Sammy Dec 2 2004, 11:47 AM

The hot setup for aftermarket breathers IMO is to use the bug type breather box with atomizer element (foam type thingy) and mount it as high as possible, and then run a catch can from the bottom of it and a higher breather element from the top. You would have to seal the box where it usually vents but a little rtv would take care of that. That give the element a chance to seperate the oil from the gasses.
It would prolly be even better to run two different breathers, one for each head.

Posted by: d7n7master Dec 2 2004, 02:16 PM

Not to hi-jack but, I have two (2) 2.0's in my garage. One has vented heads & one doesn't. The one that doesn't is a fresh rebuild. The one that does needs a rebuild.
Should I add vents???

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