Author Topic: S6 crankcase pressure venting  (Read 580 times)

0 Members and 1 Guest are viewing this topic.

Offline Kalle

  • Full Member
  • **
  • Join Date: Aug 2015
  • Posts: 30
  • Location: Gothenborg
S6 crankcase pressure venting
« on: 23 Jul 2019 at 13:56 »

Hello
I have a S6 from the 1930s with high oil and crankcase ventilation to the transmission chain. Have read an article on the forum (Subject: S6 crankcase ventilation June 1, 2015). My barrels have been drilled to 0.40 ". The connecting rods have new rollers. I think previous owners have changed the cam gear and the ventilation disc. Sending photos to my ventilation disc and photo from the forum Is there anyone who knows if it is possible to manufacture a new disc with the right dimensions and use the spring and cam gear I have for the drive. Eddie writes that the correct drive should be with 4 small springs but then the cam drive must also be replaced.
Br Kalle

Offline douglas1947

  • Senior Member
  • ***
  • Join Date: Feb 2014
  • Posts: 314
  • Location: Germany
Re: S6 crankcase pressure venting
« Reply #1 on: 28 Jul 2019 at 16:30 »
Hello Kalle,

I had also trouble with crankcase breathing on my S6, when I bought it a few years ago, always a leaking timing case.
I had checked the breather several times. In the end the mistake was the "missing" hole in the gasket on drive side crankcase to let the brather air free to the chaincase!
I send a photo of a 4 spring breather disc.
But, may be you can use your breather parts, if they will work?

Michael

Sorry, the attachment of the photo to send do not work.

Offline Kalle

  • Full Member
  • **
  • Join Date: Aug 2015
  • Posts: 30
  • Location: Gothenborg
Re: S6 crankcase pressure venting
« Reply #2 on: 01 Aug 2019 at 10:02 »
Hi Michael
Thanks for the tip
The ventilation and strainer in the cover is ok and it is in the channel for the chain lubrication that all oil and ventilation come.
Have lowered the oil level in the engine sump without results.
When I have driven about 50 km and stop, the rear frame parts, rear wheel rim and chaincase is soaked and for a while it runs out about 1-2 food spoon oil on the floor.
One thought is to reduce the size of the tracks of the breather disc
Br Kalle

Offline eddie

  • Master Member
  • ****
  • Join Date: Mar 2006
  • Posts: 1423
  • Location: Hampshire, UK
Re: S6 crankcase pressure venting
« Reply #3 on: 01 Aug 2019 at 11:51 »
Kalle,
          The breather disc runs against the inside of the outrigger plate. Now, there should be a seal between the outside of the outrigger plate and the inside of the timing cover (originally it was a cork washer with a ring of steel tube around it to prevent it spreading out). If that seal is defective, gas will be able to bypass the timed breather causing excess oil to be carried over to the primary chain.

 Regards,
                Eddie.

Offline Kalle

  • Full Member
  • **
  • Join Date: Aug 2015
  • Posts: 30
  • Location: Gothenborg
Re: S6 crankcase pressure venting
« Reply #4 on: 12 Aug 2019 at 17:18 »

Hi Eddie,
Thanks for your tip, I have carefully measured the height dimension (5.6 mm) for the tube and added an O-ring and sealing ring as a replacement for the cork ring. Has also put as a test a hose in the plug hole next to oil is pressed located to reduce the crankcase pressure. Unfortunately, that didn't help. Think of reducing the recesses in the ventilation disc if it is the right disc
Regards
Kalle

Offline eddie

  • Master Member
  • ****
  • Join Date: Mar 2006
  • Posts: 1423
  • Location: Hampshire, UK
Re: S6 crankcase pressure venting
« Reply #5 on: 12 Aug 2019 at 20:02 »
Kalle,
          Firstly, the extra breather that you have fitted to the top of the timing chest will defeat the action of the timed breather.

          Secondly, the breather disc that you have is not the original fitment for the S6, so may need to be modified to get the correct breather timing. Your breather disc looks to be smaller in diameter than the original. The original was a round disc with a deep groove around the diameter that connected to the 2 breather holes in the face that runs against the outrigger plate. The deep groove has a brass gauze covering it (to help prevent the passage of oil). The back face of the breather disc has 2 lugs to take the drive from the inlet cam, and there are 4 pockets to take the springs that keep the disc pressed against the outrigger plate.

  Regards,
                  Eddie.

Offline Kalle

  • Full Member
  • **
  • Join Date: Aug 2015
  • Posts: 30
  • Location: Gothenborg
Re: S6 crankcase pressure venting
« Reply #6 on: 13 Aug 2019 at 13:06 »
Eddie
Thanks for your reply.
They are probably so the ventilation disc and the outrigger plate have been replaced by previous owners. See in the spare parts list that there is a fault in my engine.
My idea is to try to find out what the area should be on the right disc and reduce the recesses (2pec) with weld in the one I have. The brass mesh is important as you type so that the oil cannot penetrate the disc and out through the outrigger plate.
Winter work in the workshop !!!

 Regards
 Kalle