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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Thu Feb 11, 2016 8:35 pm Post subject: Pre-A vs 36HP breathers |
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Is a Pre-A breather any better than the standard 36HP breather?
http://www.thesamba.com/vw/classifieds/detail.php?id=1404629
Cheers,
Paul _________________ "I would rather have questions that can't be answered than answers that can't be questioned."
Richard Feynman |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Jacks Samba Member
Joined: July 15, 2006 Posts: 2347 Location: San Clemente, Ca.
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Posted: Sat Feb 13, 2016 9:35 pm Post subject: Re: Pre-A vs 36HP breathers |
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The 356 super can have breather issuses due to several factors. One factor is that larger "Super" bore on some earlier engines moves more air in to the crankcase as the pistons return to the lowest position. Another factor is that higher compression can allow more gasses past the rings, particulary when worn, increasing crankcase pressure. Gasses escaping past valve guides/stems add even more pressure. As of this is not bad enough, the waste gate of the oil pressure relief valve on two piece 356 engines, as well as associated VW cases, dumps excess oil in to the timing gear area, which has limited drain back to the sump resulting in potential overfilling of the timing gear chamber. Slinging of oil off the timing gears exacerbate the problem. The higher rpm redline of the super adds to the overfilling of the gear chamber with oil due to higher oil pump speeds. This excess oil, combined with crank case pressure, can blow oil far up into the generator tower and out the road draft tube of the filler. Porsche added a larger chamber to the filler which allows excess oil to accumulate in the chamber briefly during high rpm's which will drain back to the engine (hopefully) after shifting or otherwise lowering rpm.
I have had good results using this part (a copy of a factory part, IIRC):
https://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=111115450
In my experience, this part does not install in minutes as claimed, due to irregularities of the casting in the tower area. Significant trimming, and multiple attempts of installation may be required.
I do NOT recommend opening up the tiny square hole at the bottom of the cases between chambers to allow oil to flow back to the sump. This modification may allow even more oil into the timing chamber during long uphill climbs when full throttle applications are needed.
Does this help? _________________ Jack Staggs
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Tue Feb 07, 2017 7:16 pm Post subject: Re: Pre-A vs 36HP breathers |
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Can the WW oil baffle be installed on a built engine (ie in the car) is can it only be installed when the case is split?
Thanks
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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txoval Samba Member
Joined: January 23, 2004 Posts: 3552 Location: The Woodlands, TX
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Posted: Tue Feb 07, 2017 7:28 pm Post subject: Re: Pre-A vs 36HP breathers |
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Can be installed on built engine. It simply slides into the space beneath the generator. So remove the fan shroud/generator, remove the gasket, insert piece, install new gasket, install generator/shroud
Since I added other vents/breather I didn't install one, even though I have it.
Too bad you don't live in the states, I'd give it to you.
It also comes flat...you have to bend it into shape |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Tue Feb 07, 2017 8:17 pm Post subject: Re: Pre-A vs 36HP breathers |
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Thanks for the useful info; the 36hp dumped a patch of oil out of the standard breather tube after about 1.5hrs of relatively hard running the other day, despite having fitted the vented valve covers. I'm therefore thinking the baffle may be worthwhile. At least if they are sent flat the shipping may be less!
I was also considering whether to fit a filler/breather box; such as a Berg breather. Does anyone know whether these can be easily adapted to fit 36hp?
Thanks
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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txoval Samba Member
Joined: January 23, 2004 Posts: 3552 Location: The Woodlands, TX
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Posted: Tue Feb 07, 2017 8:50 pm Post subject: Re: Pre-A vs 36HP breathers |
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I took a later model 36hp breather/oil cap and welded a cover and breather port on it, to make it similar to late model 1600's.
Let me know if want a better picture of mine |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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txoval Samba Member
Joined: January 23, 2004 Posts: 3552 Location: The Woodlands, TX
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Posted: Wed Feb 08, 2017 6:46 pm Post subject: Re: Pre-A vs 36HP breathers |
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Yes
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