X/F oil Breather Plumbing

[virden]

 I intend to fit a  crankcase breather my 1700SS  as per Roger King's recommendations,  with a pipe from the filler cap to a catch tank.   The trouble is I have an old style flat heater fitted and cannot see where there is space to plumb the pipe into the side of the rocker box.   If  I  fit it at the very back below the filler cap is there a probability of excess oil blowing straight out into the tank?

Does anyone have a photo of  a successfully fitted breather set up? 

Thanks

[Andrew Gilbert]

I'll try and get a photograph of the layout on my RK1700SS however mine may differ as its a dry sump set up with no heater.

[elie boone]

from the cranck case you connect to the end of the valve cover, it may be possible you will have to drill for a connector.

Be carefull is you place a connection on the side of the valve cover, the rockers are rather close to the valve cover, there is some space bang in the middle of it but mearure carefully before drilling

[virden]

Hi Elie, The problem as I perceive it is one of space, there appears to be no way of routing the crankcase breather into the side of the rocker cover because the inlet manifold, distributor and heater take up the space.  I cannot route into the front of it  because the water "tower " is there.  I think it impractical to go into the side above the exhaust manifold(?),  so that leaves the rear.  This can be done but it would be directly below the filler cap which is where the pipe to the catch tank is connected, so the oil from the crankcase will simply blow straight out into it?   A more simple solution would seem to be to vent the crankcase directly into the catch tank, but i am under the impression that a heck of  alot of oil  get thrown out from it. Or am I mistaken in this assumption?

[elie boone]

You have the filler cap at the back ? then yes it wouldn'd make sence to plumb in at the back of the rocker cover. There is space to run a 16mm OD hose under the carbs and behind the dizzy cap, maybe you could weld a 90 degree piece at the front corner of the vlve cover ?

[Roger King]

The whole point of feeding into the rocker cover is to recover the oil thrown out from the breather. There is no problem feeding the hose from the breather between numbers 3 & 4 inlet manifold branches and into the side of the rocker cover - you just drill and tap a hole in the rocker cover to take a right angled union  that you fit pointing downwards.

[Duckpit]

Thats what I did Roger

 

N

[virden]

Thanks Roger , as succunt as ever..... I don't suppose you would care to write a book on  care of the Cross Flow, I think a few of here would buy it!

[virden]

Oops that should have read "Succinct"!

[OliverSedlacek]

There is a good view of the breathers at http://www.hangar111.com/lotus/wp_car_dealer/caterham-seven-supersprint/

[Roger King]

That's a dry sump installation which is different. I must admit that I made the assumption that Virden's car is wet sump.

There is no need for a block breather on a dry sump installation because the scavenge pump itself removes excess pressure from the crankcase. The car in the photo appears to have the block breather still connected which won't really do any harm, but just means carrying extra weight to no benefit.

Incidentally, just to be certain, on a wet sump engine, as well as connecting the block breather to the rocker cover it is essential that the rocker cover then has a hose taken from its rear face to a catch tank. You can also plug up the breather outlets that appear in most filler caps - degrease and use silicone sealant.

[andy couchman]

Just to check my understanding Roger...

I have a dry sumped crossflow, Can I just delete the block breather piping? My system just has a block breather through the standard pressed steel Ford item and runs a pipe into a catchtank. Never seems to be any oil in there...

If so, what's the best way to seal the outlet from the block?

Sorry if that's a dumb question!

Can I ask a  supplementary too? I'm getting a bit of smoke on start-up, which I assume is due to worn valve stem seals (the head runs dual valve springs). Is there a best option or do I just order standard units from somewhere like Burtons. A mate with a Mini (A series) suggested I should get brown seals as that's what they use on Minis and they're much better than thre standard black ones with little metal springs on. I'd never heard of those and don't know if they're avalable for crossflows anyway.

And finally, do you recommend any particular head gasket. I run 83.5mm Accralite forged pistons.

Thanks for all your input Roger - it's much appreciated by all of us still running the dear old crossflow!

Andy

[Roger King]

The correct plumbing for dry sump breathers is to plug the block breather (Burtons certainly used to sell a plug for this) and take a hose from the rear of the rocker cover to the top of the dry sump oil tank. Then, a second hose should come out from the top of the dry sump oil tank to a catch tank. If the engine is healthy and the oil level correct you should rarely see anything in the catch tank.

The standard Crossflow oil seals won't fit inside double springs (they're useless anyway - the seals I mean) and the Mini type won't attach properly because there is no groove in the valve guide for the lip on the seal to engage in. My bronze guides were made to accept Vauxhall XE stem seals and if the engine used the original cast-in guides I used to machine the tops of them to take those seals as well. Failing that you need to find a solution with currently available parts that I may not be familiar with.

I found that the Ajusa head gasket was better than all the others, Cosworth included, but it is thicker than most so machining of the block may be necessary if you want to retain your original compression ratio. Don't even think of using the old copper/asbestos (or whatever they use now) gaskets. They fail easily and usually leak water - things have moved on a lot since the 1950s.

[Gloucestershire AR]

Thanks Roger