1965 356C Vented Valve Covers or Not?

356 Porsche-related discussions and questions.
Message
Author
User avatar
Greg Carter
356 Fan
Posts: 115
Joined: Fri Apr 09, 2010 8:33 pm

1965 356C Vented Valve Covers or Not?

#1 Post by Greg Carter » Sat Nov 03, 2018 4:49 pm

Are 1965 356C cars supposed to have vented valve covers? My car does not but that doesn't mean somebody swapped out the original valve covers for non-vented types.

I've been sorting through issues with a top end rebuild that generally included blowing oil everywhere. See below:

viewtopic.php?f=1&t=47091

After disassembly and inspection we've basically came to the conclusion the rings didn't seat due to using Brad Penn 20W-50 synthetic oil which caused over pressurization of the case. At this point, we've ordered new rings and cleaned everything up to put it back together. This time we'll use break in oil with Total Seal rings in an effort to avoid the same problem this go round.

The engine as rebuilt now runs 9.2:1 compression and an SC cam effectively making it pretty close to "SC specs." I want to avoid any other issues and wanted to know if I should also have vented valve covers to help with the pressure in the crankcase.

Thanks in advance.

Greg

User avatar
Wes Bender
356 Fan
Posts: 2296
Joined: Wed Aug 27, 2008 10:54 am
Location: Alpine AZ, Green Valley AZ

Re: 1965 356C Vented Valve Covers or Not?

#2 Post by Wes Bender » Sat Nov 03, 2018 4:56 pm

Not vented.
Some days it just isn’t worth the hassle of chewing through the restraints......

User avatar
Greg Carter
356 Fan
Posts: 115
Joined: Fri Apr 09, 2010 8:33 pm

Re: 1965 356C Vented Valve Covers or Not?

#3 Post by Greg Carter » Sat Nov 03, 2018 5:41 pm

Mr. Bender,

Did Euro cars have vented covers?

I ask because we have an original '65C engine in Euro Heater trim at the shop and that engine does have vented valve covers. We're pretty sure it's all original so I was curious if US and Euro cars were different.

Greg

User avatar
Wes Bender
356 Fan
Posts: 2296
Joined: Wed Aug 27, 2008 10:54 am
Location: Alpine AZ, Green Valley AZ

Re: 1965 356C Vented Valve Covers or Not?

#4 Post by Wes Bender » Sat Nov 03, 2018 5:58 pm

I'm not familiar enough with the Euro spec cars to give you a definitive answer. I'm sure somebody will chime in though. U.S. spec Cs definitely didn't have vented covers. That's not to say that somebody couldn't add them, but I don't know why they would.
Some days it just isn’t worth the hassle of chewing through the restraints......

User avatar
Ron LaDow
356 Fan
Posts: 6255
Joined: Wed Mar 26, 2008 11:45 am
Location: San Francisco

Re: 1965 356C Vented Valve Covers or Not?

#5 Post by Ron LaDow » Sat Nov 03, 2018 7:28 pm

Ron LaDow wrote:
Greg Carter wrote:Are 1965 356C cars supposed to have vented valve covers? My car does not but that doesn't mean somebody swapped out the original valve covers for non-vented types. [...]Greg
The non-vented rocker boxes were introduced along with the case venting into the right-hand carb; an early attempt to reduce emissions. Vented rocker boxes will drip oil from any engine, since all engines have some blow-by. The oil comes out as a vapor, condenses on the relatively cooler outside surface and then drips.
Do not know regarding the Euro-spec engines
Ron LaDow
www.precisionmatters.biz

User avatar
jim nelson
356 Fan
Posts: 2018
Joined: Wed Mar 26, 2008 2:18 pm
Location: SoCal
Contact:

Re: 1965 356C Vented Valve Covers or Not?

#6 Post by jim nelson » Sat Nov 03, 2018 7:51 pm

My Euro S90 has vented covers, and I think I’ve about had it with cleaning up that mess.

User avatar
Greg Bryan
356Talk Moderator
Posts: 2234
Joined: Sat Oct 04, 2008 1:05 pm
Tag: Be Nice!
Location: San Pedro, CA 90732

Re: 1965 356C Vented Valve Covers or Not?

#7 Post by Greg Bryan » Sat Nov 03, 2018 9:48 pm

My Euro-spec SC had vented covers when I got it about 10 years ago. It no longer has vented covers ...
Greg Bryan
356Talk Moderator

User avatar
David Jones
356 Fan
Posts: 3463
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Harrodsburg, Kentucky

Re: 1965 356C Vented Valve Covers or Not?

#8 Post by David Jones » Sat Nov 03, 2018 11:00 pm

The parts book is very confusing as it only lists 2 different part #'s for valve covers.
597 104 305 00 and 616 104 043 01
The part # for the 912 valve cover is also listed as being 597 104 305 00 Here is a link to the Porsche classic parts list. I give up as it is too confusing for my little brain.
https://www.porsche.com/usa/accessories ... catalogue/
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

User avatar
Ron LaDow
356 Fan
Posts: 6255
Joined: Wed Mar 26, 2008 11:45 am
Location: San Francisco

Re: 1965 356C Vented Valve Covers or Not?

#9 Post by Ron LaDow » Sat Nov 03, 2018 11:04 pm

"My Euro S90 has vented covers, and I think I’ve about had it with cleaning up that mess." - Jim
"My Euro-spec SC had vented covers when I got it about 10 years ago. It no longer has vented covers ..." - Greg.

First, Greg: Did your Euro-heater car vent the case to the right hand carb? Inquiring minds...
And then, Cliff is absolutely correct that the only reason to vent to the carb is a preference for 'originality', which is silly on an engine with a compound distributor, but I reserve the right to be silly now and then. And wonder if I could run higher than 10:1 in a twin plug if I vented it overboard...?
Oil has a really crummy octane rating, as is obvious in that folks get it to pressure-ignite in diesels.
Ron LaDow
www.precisionmatters.biz

User avatar
David Jones
356 Fan
Posts: 3463
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Harrodsburg, Kentucky

Re: 1965 356C Vented Valve Covers or Not?

#10 Post by David Jones » Sat Nov 03, 2018 11:19 pm

Ok Ron I agree with you on the octane of oil but explain why modern F1 engines deliberately burn oil to get more power.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

User avatar
Ron LaDow
356 Fan
Posts: 6255
Joined: Wed Mar 26, 2008 11:45 am
Location: San Francisco

Re: 1965 356C Vented Valve Covers or Not?

#11 Post by Ron LaDow » Sun Nov 04, 2018 12:05 am

David Jones wrote:Ok Ron I agree with you on the octane of oil but explain why modern F1 engines deliberately burn oil to get more power.
When I was keeping the Cozzy in shape, there were some few bits of tech which would transfer to 616 engines. In the early '00s, I got an intro to a guy who worked at a commercial supplier of V-10s to several F1 teams. By then the intersection of F1/616 engines was pretty much zero. Our discussions had to to with the length of the V-10s (and the regs) requiring pipes from the front cylinders too long for proper extraction and how they were altering the cam timing on the front cylinders to compensate.
By now, I have no idea how F1 engines make use of any of the fuel they are allowed to use.
Ron LaDow
www.precisionmatters.biz

User avatar
JERRY LANDES
356 Fan
Posts: 227
Joined: Sun May 11, 2008 2:31 pm

Re: 1965 356C Vented Valve Covers or Not?

#12 Post by JERRY LANDES » Sun Nov 04, 2018 11:37 am

I installed vented valve covers on my 912 engine when I used the earlier set up (356A) that doesn't vent to the carberator. It's messy. Can I just put the non vented valve covers on and hope that it will somehow vent through the earlier oil filler?

User avatar
Wes Bender
356 Fan
Posts: 2296
Joined: Wed Aug 27, 2008 10:54 am
Location: Alpine AZ, Green Valley AZ

Re: 1965 356C Vented Valve Covers or Not?

#13 Post by Wes Bender » Sun Nov 04, 2018 1:59 pm

If your oil filler can is vented, you should be able to switch to non-vented valve covers.

After searching through all of my reference materials, the only info I can find is that later S-90 engines had vented covers (Harry Pellow). The PET for the USA spec cars shows vented valve covers for the S-90. The parts listed immediately after the cover are for a screen, ball and cotter pin, which would indicate to me that the cover was vented. The PET also seems to indicate that 1600 Supers could also have had them, but my early 1600 Super did not.

I see no reason why a car with a European heater would need vented valve covers and it wouldn't have been likely that the factory would install them (unless it was a S-90 engined car).
Some days it just isn’t worth the hassle of chewing through the restraints......

User avatar
JERRY LANDES
356 Fan
Posts: 227
Joined: Sun May 11, 2008 2:31 pm

Re: 1965 356C Vented Valve Covers or Not?

#14 Post by JERRY LANDES » Sun Nov 04, 2018 6:03 pm

So Wes, Are you talking about the pipe that goes down through the sheet metal to about the bottom of the engine? That's considered the vent?

User avatar
Wes Bender
356 Fan
Posts: 2296
Joined: Wed Aug 27, 2008 10:54 am
Location: Alpine AZ, Green Valley AZ

Re: 1965 356C Vented Valve Covers or Not?

#15 Post by Wes Bender » Sun Nov 04, 2018 6:27 pm

Yes. On later cars the filler can vent was routed to the right hand air cleaner.

On a recent thread, there is a car in Mexico that has a small, highly restrictive filter mounted on the oil filler can instead of the tube to the right air cleaner or a tube down through the engine tin. A few of us think that the small filter is a potential cause for excessive oil spray and the dipstick being blown out of it's tube. We haven't seen anything to dispel those opinions.....
Some days it just isn’t worth the hassle of chewing through the restraints......

Post Reply