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X/Flow oil catch tank problem SOLVED - at last - I hope


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I know that by now there wont be too many X/flows out there, but I still thought I'd share this fix in case it helps anyone who still has one, as the bits on here helped me.


After my first track session at a recent Castle Combe track day, I went to check under the bonnet AAARGHH - catch tank full, plus a bit. Oil all over the place. I've had this before and have always thought it was blow-by past the rings forcing the oil out - I've  had my 1700 supercharged X/Flow for nearly 30 years......... and rebuilt the engine numerous times.


I returned the oil to the sump and went a little less vigorously next sessions and it wasn't as bad but it still there. The 90 mile journey home all went OK, no issues.

After checking on 'tinternet a few days later and seeing the various suggestions to rectify this problem, I realized that I had not plumbed the breather in the optimum way for all this time, having a breather pipe out from the Ford tin block breather connected to another breather pipe from the rocker cover and then into my catch tank. Not only that but I also saw a post from one of you guys showing the (Burton) fuel pump blanking plate with an oil deflector that I felt sure I hadn't fitted all those years ago. I hadn't.


When you have the blanking plate off, if you feel into the block and upwards, you can feel the hole into the block breather directly above the center of the plate. In fact it is this positioning that causes the oil to be forced up into the breather as the original fuel pump cam lobe whizzes around on a track day.


I then decided to re-route the pipework from the block breather to the front of the rocker cover, reasoning that even if the same amount of oil was to be forced up the pipe to the rocker, it has 8 x 20mm. push-rod holes for the hot oil the drop through back into the sump. A new breather pipe from the back of the rocker cover alone fed into a newly purchased catch tank. I also made a deflector plate and fitted it to the existing fuel pump blanking plate.


I've only done a couple of journeys since but absolutely no oil has appeared in any of the pipes, let alone the catch tank. A track session is another thing I know but I'm very confident that this is the solution that works.


I hope that these few words might help someone out there. I know that if I'd had the gumption to look into this problem on my car, it would have save me from at least three rebuilds and a several hundred pounds.... derrrrrr!







Burton Blanking and Deflector Plate.jpg

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I'm still running a mighty X-Flow and already have that little blanking plate installed (actually it's undergoing a rebuild at the moment) 😄 I only replaced the mechanical fuel pump a couple of years ago, and fitted that plate at the same time!

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Seems obvious if you think about it? Not obvious enough for me - obviously!

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So you've basically got the oil that would have gone to the catch tank, now going up into the rocker cover?

The problem with the lower breather hose, is if you use a transparent hose you can see it just gets filled with oil, and then the blowby gases force it upwards.
I think the plate with the deflector actually does very little, because if you look into that area you can see that the cam passes very close to the block and rotates upwards preventing oil from exiting the area.
On the original xflow engines, there was a PCV system and a small reservoir, which allowed oil up into it, but had enough space to allow gases to pass through without forcing oil up the next hose, from images I can find, it also appears that short tube from the breather to that reservoir was a tube within a tube, perhaps to allow oil to drain back down into the crankcase?

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As far as I can tell, the OP still has that small tank still directly connected to the block. I certainly still have it on mine. The outlet of that is attached to the breather / rocker rather than routed to the inlet manifold.

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