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I have always used S blocks on my race mini.....this time I decided to try the solid chest block....so, question for those who are using these blocks in competition .
What is the best way to relieve the crankcase pressure.
Think is a picture of a Forum member's car....if it is...hope the owner doesn't mind me using it as an example.
I have been studying the system that is installed...looking at the way the pipes are connected has me wondering if this is a very efficient setup....
Like to hear from those who have a really good breather system for these engines.

Looks a bit strange to me ... I assume it is what I'm seeing ..

Pressure is being generated in the crankcase due to compression leaking past the rings. The only way this gas can escape is up the pushrod holes (and maybe some cars have extra drain holes not occupied by pushrods??)

I would think it more efficient if the gas coming through the transfer case were to vent directly rather than join the stuff coming up the pushrod holes and then out though the rocker cover vent.

I currently have this vent capped as I have other vents; rocker cover , (S) back plate and cam drive case. I can always bring it into use if required..

Cheers, Ian

If it needs that much venting, then I think they should be looking elsewhere !

That's the race set up the likes of Swiftune and MED that goes to a catch tank.

I'm running the factory open breather on the transfer case as used by Austin 1300's in the late 60's and a couple of home made open breathers with wire mesh inside on the rocker cover and MED timing cover. Seems to work ok.

As that's my car pictured I should probably chip in!

As already mentioned, in competition, you can't have open breathers; they must feed into a catch tank.
There are many ways of doing this but one of the neatest/most reliable ways is the Swiftune/MED type arrangement pictured.
It's available to buy as a package without doing your own fabrication and it's easy to fit and remove.

Generally, I'm happy to go along with whatever Swiftune are using as they are testing it day after day in the dyno booth and out on the track.
Hard to argue with their results.

Andy

Lakeland997 wrote: ↑Tue Jan 26, 2021 12:27 pm As that's my car pictured I should probably chip in!

As already mentioned, in competition, you can't have open breathers; they must feed into a catch tank.
There are many ways of doing this but one of the neatest/most reliable ways is the Swiftune/MED type arrangement pictured.
It's available to buy as a package without doing your own fabrication and it's easy to fit and remove.

Generally, I'm happy to go along with whatever Swiftune are using as they are testing it day after day in the dyno booth and out on the track.
Hard to argue with their results.

Andy

Hi Andy
Good to hear it is from your car....was wondering who owned it!
Yes, do agree...hard to fix something that isn't broke.
I might just buy the set-up from Swiftune.....looks like a very professional design.
From my experience....the 1300 blocks do need a lot of well designed venting...
Chhers
D

Just a shame they don't put the effort in to make/source a nice hose with a 90 degree bend in it and get rid of the joiner and jubilees. Or T it into the other hose and get rid if one piece of fabrication on the rocker cover.

With the Swiftune / MED setup, would the rocker cover act as a bit of a catchment area for any oil that was carried up from the transfer case.

GraemeC wrote: ↑Tue Jan 26, 2021 1:10 pm Just a shame they don't put the effort in to make/source a nice hose with a 90 degree bend in it and get rid of the joiner and jubilees. Or T it into the other hose and get rid if one piece of fabrication on the rocker cover.

That looks like MED set up.
Swiftune do as you suggest, hose from rocker cover, hose from flywheel housing, both into a t-piece then into a catch tank.

Swiftune same as MED.

Minisprinter wrote: ↑Tue Jan 26, 2021 8:33 pm

Lakeland997 wrote: ↑Tue Jan 26, 2021 3:03 pm Swiftune same as MED.
a2940a7a472bcba7550000ddb9fea5b2.jpg

I wish people wouldn't use that pikey lawn mower fuel hose looking stuff, but perhaps there is a reason for it.

MS

This hose is also usen on many Aston Martins.

The good thing is, you see directly if there is something wrong with the engine with this hoses...

We use this type on the new Astons

This is my set up, I made the rocker cover myself... I also didn't like the joiner Idea so angled my crank case breather backwards a little, allowing a nice swoop on the hose. There is also a breather from the timing case in the other end of the cover. And then it vents to a catch tank in the inner wing.

Best photo I have of that side.

A few things. The setup in the first post is a breather design that we used in Miglia racing in the 80’s, it’s not a Swiftune design, it was just something that evolved, Longman, KWR, Slark and others all used it. The reason for the two separate pipes (rather than the T) is that one pipe equalises the pressure between the crankcase and the rocker box, the other pipe vents the excess to the catch tank. Clear pipe is used so that you can see any fluid present.

Where does the tapper cover one connect in? Can’t see it in the pic

Minisprinter wrote: ↑Tue Jan 26, 2021 8:33 pm

Lakeland997 wrote: ↑Tue Jan 26, 2021 3:03 pm Swiftune same as MED.
a2940a7a472bcba7550000ddb9fea5b2.jpg

I wish people wouldn't use that pikey lawn mower fuel hose looking stuff, but perhaps there is a reason for it.

MS

johnv wrote: ↑Wed Jan 27, 2021 8:32 am Where does the tapper cover one connect in? Can’t see it in the pic

Catch tank attached to the RH inner wing.

Whilst not quite the same bore I used a homemade setup with catchtank under the NS wing, seems to work well enough