Crankcase Breathing

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Bruce.m
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Crankcase Breathing

Post by Bruce.m » Sat Oct 10, 2015 4:45 pm

Or when condensed water in the sump is evaporated by the hot oil but then hits a cold "separator" which causes the water to re-condense & mix with oil to form a "mayo" emulsion. If the oil separator is hot, only the oil droplets will be caught and returned.

At least that's how I interpreted it but....

dscott
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Re: Crankcase Breathing

Post by dscott » Sat Oct 10, 2015 9:53 pm

I'm trying to find a hot air/oil separator but not sure where to find one. I fixed my oil filler baffle and reinstalled with SS pot scrubbers. I notice filing oil is slower now, but I assume that's normal and to be expected considering the idea is to prevent oil from spraying out. What type of gasket is everyone using for the valve cover? Cork I assume. Are there any tricks to help seal the Valve covers better to prevent leaks so I have a better chance creating vacuum using the check valves?

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Piledriver
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Re: Crankcase Breathing

Post by Piledriver » Sat Oct 10, 2015 10:08 pm

FJCamper got it right, but i strongly suspect the base of the alt stand where the woven scrubbers would live gets plenty of heat, at least if you drive it more than a few miles.

Vaseline==petroleum jelly==emulsified oil and water==the goo under your oil filler cap in cold weather.

I suspect actual "Vaseline" is made from purified mineral oil and distilled water, but it's the same stuff for descriptive purposes.

You can get permanent glue-in silicone valve cover gaskets, i'm still using cork held in with fel-pro high-tack gasket adhesive. (basically contact cement in a tiny toothpaste tube)

I have finally run out my pile of of cork gaskets so I need to find where to buy the silicone ones again... in about 30K miles..
Addendum to Newtons first law:
The longer a vehicle rests on jackstands,the more likely it is to remain that way...

dscott
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Re: Crankcase Breathing

Post by dscott » Sun Oct 11, 2015 12:32 am

I found this place for silicone gaskets.
http://www.realgaskets.com/files/automobile.htm

I use yellow whether strip tac to attach cork gasket to cover and it allows me to take off the cover without damaging the cork. I was wondering if there was anything I can do to seal it better because after hours of driving hard I had some oil that came out of the top of the cover. I thought about trying some form a gasket between the cork and cylinder head when reinstalling.

Willstang
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Re: Crankcase Breathing

Post by Willstang » Thu Sep 08, 2016 9:30 pm

Maybe someone can inform me if this would work. Instead of routing the breathers from the valve overs to a box or tower on the alt/gen stand wouldn't venting into the base of the stand work? One on each side to return the oil to the case ,should it get that high, and with the stainless steel pads inside (great idea) should keep misting to a minimum and use a vent from the oil filler either aftermarket or stock to an air filter should solve most pressure issues in the valve covers for engines except the really high revving race engines. Am I way off my rocker with this idea? Is there a compelling reason to have the valve covers vented higher than that that I am missing?


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Marc
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Re: Crankcase Breathing

Post by Marc » Thu Sep 08, 2016 9:36 pm

dscott wrote:...I was wondering if there was anything I can do to seal it better because after hours of driving hard I had some oil that came out of the top of the cover...
Marc wrote:...You can add tension to the bales by slightly exaggerating the bends (easy in a vise).
I used to seal the valvecovers on racecars so well that on a couple occasions when a bale popped in a collision the cover stayed on and didn't leak. It took a while to figure out the best way; I tried silicon seal first (dismal failure), brazed-on tabs around the inside of the covers, even laminating two gaskets together. What worked best was to stretch the gasket slightly so that it fits snugly in the cover, then use Gask-a-Cinch to bond them together at the face and outer edge. Apply to both surfaces and let dry before joining. After installing the cover I'd center it on the head and then work silicon seal into the small gap between the edge of the cover and the head all the way around. On cars where access to the top of the cover was limited I'd dab the silicon seal along the inside edge at the top half of the cover (NOT on the gasket face) before putting it on, then pull the cover as far down as it could go on the head before filling in the gap along the bottom half.

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Piledriver
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Re: Crankcase Breathing

Post by Piledriver » Fri Sep 09, 2016 2:16 am

Has anyone tried the reinforced silicone valve cover seals?
(I forget who makes them, but there's a place that makes them for a lot of cars, T1s and T4s included)

I guess I could break down and buy the CSP covers with a real oring.

Venting the 3/4 side rocker box has been argued both ways..
I don't, I feed purge air in that side via a check valve and vacuum break, and run some case vacuum pulling on the case bbreather. I'm not racing, but the speed limit here is 75mph, so shes turning over pretty fast at cruise for extended periods. 1/2 side is vented to the air cleaner via another large GM AIR system check valve (out only), and the line pretty much stays dry, as if there are no positive pressure pulses it stays closed.
My setup is almost certainly different than yours, YMMV.
Addendum to Newtons first law:
The longer a vehicle rests on jackstands,the more likely it is to remain that way...

Jkolb
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Re: Crankcase Breathing

Post by Jkolb » Sat Dec 03, 2016 9:10 pm

Newby member. Very interesting thread. Can anyone with 356/912 experience translate the content into recommendations for the 912? I have vent capability directly from each head. Late 356's and 912's have the large steel oil filler can off of the generator stand which typically serves as a condenser for moisture in the crankcase and creating a mayonnaise like substance that is an emulsion of oil and water. The oil filler can also vents directly into the air cleaner for 1-2, carrying enough oil vapor to quickly alter the performance of the carburetor, proceeding also to coating that side of the engine in a film of oil. I've looked at air-oil separators for Subarus, but the are heated by engine coolant to keep the oil vapor hot enough so it does not emulsify. Thanks in advance for any suggestions. I am just now building a new engine and would like to fix this issue before start up.

slowandlow
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Re: Crankcase Breathing

Post by slowandlow » Fri Jul 12, 2019 2:04 pm

does anyone knows ET performance is still in business? their website is our of business. Have found Hayden enterprises who is making krank vent plus. around 100 dollars each... do you really need 2 or would 1 do the trick as well?

andy198712
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Re: Crankcase Breathing

Post by andy198712 » Sat Jul 13, 2019 11:54 am

there must be an OEM equivalent that's cheaper surely?

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ps2375
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Re: Crankcase Breathing

Post by ps2375 » Sat Jul 13, 2019 12:28 pm

I use a couple of these on my crankcase vent system.
http://www.siliconeintakes.com/liquid-a ... -9583.html

I wish they had larger than 12mm available, but they seem to work fine.

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Piledriver
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Re: Crankcase Breathing

Post by Piledriver » Sun Jul 14, 2019 3:24 am

and for smaller, even cheaper ones for many uses, these get used a lot by the turbo'd watercooled vw folk.
https://www.usplastic.com/catalog/item. ... d=redirect
Addendum to Newtons first law:
The longer a vehicle rests on jackstands,the more likely it is to remain that way...

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