crossflow blowing out oil on trackdays

[groutledge]

Here's a good one that I'm sure somebody must know the answer to.

 

I have a live axle crossflow that i use for trackdays etc. At moment it has an oil breather coming from the gallery to the catch tank and also a breather pipe from the rocker cover filler cap to the same tank. I have an Accusump to help with oil surge.

 

Problem is after every session the catch tank has about a pint of oil in it. ( It as always done this even without the accusump so it's not that ). Obviously I would preffer it if it was in the engine rather than the catch tank.

 

Question is can I modify the oil system so that oil blown out from the gallery goes into the rocker cover rather than the catch tank obviously I would have to keep the rocker cover breather as well.

 

 

Or does any body have any better suggestions bearing in mind I don't wnat to go dry sumped.

 

Graham

[robmar]

I used to suffer from this im last car which had a xflow, what I did (after advice) was to drill a small hole int he plaqstic oil filler cap and these seemed to cure most of the problems, and no it didn't blow oil out of the new hole

 

not sure if it would help but it is a quick easy mpd that is easy and cheap to fix (buy another plastic cap) iof it doesn't work...

 

rob

[Roger King]

This is a very commmon problem with wet sump Crossflows on the track. Assuming that the engine is in basically sound condition and therefore the rings are not allowing excessive blow-by, then what you are experiencing is the oil being mechanically thrown out.

 

The breather is directly above the eccentric lobe on the cam that drives the fuel pump. With the higher revs and greater oil surge that you get on the track, this lobe literally shoves the oil out of the breather. Some engines are worse than others for no apparent reason.

 

The ultimate solution is to dry sump the engine because you can then plug the block breather.

 

Assuming that you do not wish to take this step, you can machine the rocker cover so that the block breather hose feeds directly into it via an elbow. BUT, while this makes sure that the oil is returned to the engine, it also removes 50% of the breathers; it is essential therefore that an extra outlet is machined into the rocker cover and fed to the original catch tank. This allows the block to breathe into the catch tank via the rocker cover.

[Graham Sewell]

What is all this about breathers.... My 1995 (year) x-flow doesn't have one. The hole has been plugged and I get a 'gentle mist' coming through the filler cap - most noticeable when idling at traffic lights.

 

I don't object to this too much as it means that I don't have to waxoyl the engine bay smile.gif.

 

Cheers,

 

Graham

[sparkey]

I have the same problem, which I thought would be cured by rebuilding the engine, re-locating the catch tank, and various other expensive and pointless jobs, but it still chucks half a pint out after every track session. I think that's just what crossflows do ! Burton Power advised that I should weld an elbow onto the sump and attach a pipe from the bottom of the catch tank to the sump so that it just drains back into the sump. i haven't tried this - it's easier just to empty the catch tank between sessions and top up the oil when required.

 

I also find that if I keep the oil level just above the minimum mark on the dipstick, the problem is reduced considerably, and it doesn't seem to suffer from any oil surge, or loss of oil pressure on track

[Roger King]

Graham,

 

The later Crossflows came through from Ford without the breather. This is what you have and was presumably done because most of the engines of that era were going to be used in FF1600 which were always dry-sump; it would also cut costs (just can't keep the cynic in me down!).

 

In my opinion, this plug should have been removed and replaced with a breather by Caterham.

 

As you have noticed, this leads to a permanent mist around your filler cap which is now the only breather on the engine. This breather is not only not big enough, but crankcase pressure now has to find it's way to the top of the engine via the pushrod holes which at the same time are trying to pass oil downwards.

[Roger King]

Graham,

 

The later Crossflows came through from Ford without the breather. This is what you have and was presumably done because most of the engines of that era were going to be used in FF1600 which were always dry-sump; it would also cut costs (just can't keep the cynic in me down!).

 

In my opinion, this plug should have been removed and replaced with a breather by Caterham.

 

As you have noticed, this leads to a permanent mist around your filler cap which is now the only breather on the engine. This breather is not only not big enough, but crankcase pressure now has to find it's way to the top of the engine via the pushrod holes which at the same time are trying to pass oil downwards.