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johnnyspencer

crank case ventilation breather

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I am rebuilding a mk1 fiesta with the mk1 xr2 crossflow engine. The crankcase vent pipe at the back of my engine has been blanked off, It has an oil filler cap with gauze and holes in the underside of the mushroom part, as far as I can see that all there is for crank case ventilation. I am wondering if it will be ok like this or will it do any harm? should I be taking the blank off and fitting an external breather? or is this something that people do? the haynes manual shows a number of breather pipes coming from a different type of filler cap. The engine has obviously been running like this at some time, I bought it partially stripped for inspection with a box full of parts and just put it back together. I suspect the engine has been in a kit car or mk1/2 escort as it had escort oil pump etc. any info would be appreciated thanks.

 

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You need a Crankcase breather to stop pressure building up in the lower part of your engine. 

Sometimes a blocked breather can cause oil to leak past the sump gasket or even crank oil seal if it's excessive. 

You'll see a lot of cars that have removed the PCV valve then run them with a pipe to a catch tank. 

Worst one I've seen was on a diesel forklift that has the 1.9VW engine in. This would spray oil out of its dipstick. Granted it also had  low compression, so some gases were passing from the top of the pistons, past the rings and into the sump. 

You can get a replacement elbow to run from the breather hole to a catch tank. Although mine is a Pinto engine, look at the ally elbow just behind the oil filter in the pic. 

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I wouldn't run with it blocked off personally, can cause more problems as Dale as stated. The very least I would run a pipe into a catch tank or pending air filter fitted you could run a pipe into that then any fumes the engine produces will go through the carb and out the exhaust. Other alternative is to fit a proper breather box and run a vac pipe from inlet manifold, any 1300/1600 crossflow one should fit.

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Ford supplied them blocked off, as the fiesta suffers from oil surge on right hand corners with a breather fitted so it will be ok to run like it is.

 

 

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7 hours ago, bert said:

Ford supplied them blocked off, as the fiesta suffers from oil surge on right hand corners with a breather fitted so it will be ok to run like it is.

 

 

I dunno about that, if they were supplied blocked off why doesn't it state that in the haynes? This might sound stupid so please correct me if i'm talking sh*te but wont it breath through the pushrod gaps into the head then out of the breather filler cap?

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Thinking of getting something like this. There are 2 outlets on it, (or one outlet one inlet) would one go to breather hole above fuel pump and one to vac intake on manifold?

 

catch tank.jpg

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because its the Haynes manual!

I have dealt with many xr2 engines and only the early ones had breathers, once ford realised the surge issue they blanked it off. The 1300 block doesn't have one and they are ok.

 

unless you are building a screamer then leave it as is.

 

 

 

 

 

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9 minutes ago, bert said:

because its the Haynes manual!

I have dealt with many xr2 engines and only the early ones had breathers, once ford realised the surge issue they blanked it off. The 1300 block doesn't have one and they are ok.

 

unless you are building a screamer then leave it as is.

 

 

 

 

 

ok that's good enough for me. thanks

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I know its a different subject but to what degree before tdc should the xr2 crossflow be timed to? haynes manual says check engine decal? fat load of use that is! I have static timed it to 6 degrees before tdc and it starts and runs ok. I should also mention that I have done away with the stupid  breakerless ignition and module and fitted an 1100 dizzy with points.

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8 hours ago, johnnyspencer said:

Thinking of getting something like this. There are 2 outlets on it, (or one outlet one inlet) would one go to breather hole above fuel pump and one to vac intake on manifold?

 

catch tank.jpg

That catch tank has 2 inputs and a filter breather.

tank should be fitted with filter higher than rocker cover but of course your limited by bonnet.

1 inlet from crankcase the other from a sealed filler cap with takeoff

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I think 6 degrees may be to little advance, I’d go for 8 first and if no pinking you can try a bit more as it’s an XR2 engine.

i don’t know if the cam has a bit more duration and lift from standard but suspect it’s no more than a twin choke carb and a 4 branch exhaust which was Fords standard way of doing a GT engine for years.

Edited by Snapper
Reduce waffle

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4 hours ago, Snapper said:

I think 6 degrees may be to little advance, I’d go for 8 first and if no pinking you can try a bit more as it’s an XR2 engine.

i don’t know if the cam has a bit more duration and lift from standard but suspect it’s no more than a twin choke carb and a 4 branch exhaust which was Fords standard way of doing a GT engine for years.

Thanks, I'm not sure but I think they are slightly different cams I'v seen them described as gt cams If that means anything

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