Rocker Cover Breather

[Guest Fred2b]

Can anybody answer this one for me?

My car has the 2.0lt EFI Pinto with a 75mm dia pipe from the air vane box to the throttle body. On that big pipe I have managed to fix a pipe to the rocker cover oil filler cap similar to the way it was on the Sierra. If I take that off and have a simple pipe to the throttle body i.e. without the takeoff to the filler, the engine runs better.

Is it ok to do this or will the oil fumes clog up the engine eventually and what effect will it have on emissions test at MOT time?

Regards

Fred

[Guest Phil Slater]

Fred,

 

I'm not sure if this fully answers your question but my understanding is that it is the oil in the off-take from the filler cap that ultimately causes tickover problems by gunging up the throttle control valve. So I've actually removed smaller pipe from the 75mm rubber hose and blocked the hole. But, and again this is my understanding , the engine still needs venting, I could just vent to air but you end up with oil kind of condensing in the engine bay so I think I'm going to have to fit some kind of collector box to vent the fumes into and collect the oil.

 

 

With regards to your engine running better - if what you are saying is that the pipe that originally came from the oil filler cap to the throttle body hose is now just open to the atmospere but feeding into the 75mm pipe at the other end??? Well, I would have thought you were kind of bypassing the sensors in the air vane and the throttle contol valve toa certain extent. Whilst it may seem better , I suspect it may cause the ECU problems getting the mixture setting right - but maybe somebody knowledgable in that area could give more accurate advice.

 

 

Hope that's of some help

 

Phil Slater

[Guest Ant]

The oil filler cap definitely needs venting. The EFi cap is tall, contains a strainer to trap oil, and has the pipe outlet. The non-EFi cap is much lower profile (so it fits under the bonnet better) and it still contains a strainer, but vents directly to the engine bay. I have the low profile type on my engine. There's a bit of soot on the rocker cover around it, but its not a big problem to wipe it whenever I put oil in. My inlet pipe goes straight from the MAF sensor to the throttle body.

 

The gas in the rocker cover comes up from the cylinders around the valve seals. Without a vent you will burst an oil seal and spurt engine oil everywhere. Definitely vent it to somewhere. the idea in the EFi setup is that the vapours are actually combustion gas, so routing them into the air stream burns them all over again rather than venting them to atmosphere.

 

Ant

[Guest Steve Allen]

Ant

This may help. attached is a pic of a mod I ahve just done to help breathing, the better the engine breaths the better it will run.

Just to explain the mods. here is what i have done.

Rocker cover has been modified to breath out through the side(note the pipe is dead centre were the cam housing is, this restricts the flying oil inside.

(If you have a 205 block) there is a plug you can tap into. so the rocker breathes straight to a tank with a filler breather cap on. any oil that builds upin this than drains straight back into the sump. (both head and sump breath well and no compression build up(also helps on the oil leak problems)

Then, this will not apply to you if you are injection (I'm running 45's) the block breather goes straight into another expansion tank. so all the sections of the engine are breathing without restriction.

(IF you have a Burton brochure have a look at the second page) this is how they run stock cars using Pinto's

Steve

[Guest Ant]

That's a very neat solution. Here's the cheaper solution for those who don't want to fabricate a catch tank:

[Guest Ant]

Second pic. Anyone would think I'd got a new toy to take photos with

[Guest Guy]

My EFI is set up similar to Ants', the pipe from the air flow metre to the throttle body is sealed and the oil filler cap vents to the engine bay, I had no problems with SVA.

[Guest Fred2b]

Steve

That looks really neat but alot of special tanks to be made up.

I don't see a filler cap on the rocker cover, how do you put oil in?

Fred

[Guest Steve Allen]

The pipe from the rocker now goes to a tank that has the original breather cap on. so you fill into the tank and it goes straight to the sump.Benefit is: it now breaths to atomsphere (as before) but has chance to turn back to liquid and drain back to the sump, As it is running on 45's with a fast cam the rev's area lot higher and it blows oil allover the rocker.(well used too) also it helps take the pressure out of the sump. (this being smaller in capacity as well now (as most are when moded)

Redline of brighouse recommended the mod and it is also highlted in the Burton catolouge.

steve

[Guest Mark Cosh]

i have a catch tank and have had a problem lately with oil being blow out of filler cap.........should the filler cap be a blocked seal with no venting for the catch to work?

[speedtripledan]

i have a catch tank and have had a problem lately with oil being blow out of filler cap.........should the filler cap be a blocked seal with no venting for the catch to work?

you have jumped on a 9yr old thread here, in answer to your question no mine was a vented cap with the crankcase vented into a catch tank DO NOT vent the rocker cover into it as well or you will end up with problems

[Guest mower man]

Why ? pcv valves are ok in a system designed for them but with the mods we put on you will get either probs with oil vapour messing fueling up or oil being pushed out every where or even both , my pinto has c/case and cam cover breathers and a sealed cap before this mod it eaven maneged to blow a cam seal out of its housing mick the catch tank needs to breath through a fiter to atmos