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MG TD TF 1500 - Oil Fill Cap Venting

My TF has a non-standard valve cover. The cover is ribbed with the oil fill cap at the rear of the cover. The cap has holes for venting. I am getting some oil expelled through these vent holes. The oil that comes out is very minor but I am curious why the cap has such vent holes. The valve cover has the normal vent tube on the right side that vents through the forward air filter. Are the vent holes on the cap really needed or can they be plugged.
Please see the attached photo.

Thanks--

Larry


LD Kanaster

My valve cover cap is an MG T rad cap....no possible vents... I would say if you have a vent to the cover, that you could seal these in the cap.....
gblawson(gordon- TD27667)

Ditto Gordon.

Mine lacks the side vent, so I have a breather style cap... Think a tall cap stuffed w/ Brillo...

Warmly,
Dave
Dave Braun

Is the vent to front carb "baffled"?
If not ...blocking the venting on your cap could cause a real mess in the filter! (and bonnet)
David Sheward

Dave-- Can you describe the 'baffle' you refer to re the vent? I do not remember seeing a baffle inside the valve cover (doesn't mean it isn't there) but the vent hose just goes from the tube on the side of cover to the forward air filter. I have often wondered why such a system doesn't eventually show lots of oil dripping from the filter but so far I have not had any indication of oil coming out of the air filter. Am I correct in my thinking that if the vent to the filter is working, i.e. no blockage or anything, then I should not really need the holes in the oil fill cap and perhaps I could plug them? Maybe just to be safe I could do as Dave B. says and use gauze material--it works pretty good on the side vent for the tappets.

Larry
LD Kanaster

Larry,
My aftermarket cover simply has a "tube" running out the side to hook up to the air cleaner. Cap is "sealed". The stock cover has a baffle as shown below that keeps direct flow from the vent pipe.
At high RPM my front air cleaner was soaked from the sucking action of the carb. To the point it was dripping out the bonnet lovers.

I tried a few things ...and put a baby food jar "in line" on the vent tube to monitor what was working, (and what was not).
What finialy worked for me was one of the vent plugs Moss sells for the "outside" of the cover when you are running aftermarket air cleaners with no provision for venting. I cut it down and installed it "inside" the cover with some brass wadding.




David Sheward

This is the "baby food jar" setup I used to monitor how my "baffle design" was working. Looks stupid ...but better than cleaning up the mess each time!

Thought I had a picture of "final baffle" but can't seem to find it.
I can get you a pix next time I have the cover off if that will help.


David Sheward

Dave-- Regarding the baffle, I really don't think I have such a thing on the inside and definitely not on the outside. Your cover looks pretty much like mine except that on mine the oil fill cap is on the rear (or the cover is mounted backwards to yours). Since I am not getting any oil coming out through the filter, which is good, I wonder if the pressure is being relieved thorugh the holes in the cap and thus the oil in that area. If this is correct I would just as soon stay with the holes in the cap--much easier to clean the small amount of oil that comes out.

Larry
LD Kanaster

Larry,
Normally can't mount them backwards as holes are "offset" and groved for head bolts.
Mine is a strange one ...most I have seen like it have filler in rear...wish mine did!

Went in the house and found the pix on pc in there.
I ran S&H air cleaners for years so this was on the "outside" of the valve cover.

This year I "made" some K&N filters for the Vokes and am running them now. Much improvement in preformance.
The baby food jar is highly advisable to monitor how much oil is being sucked up by the front carb. It was a nasty mess in the front air cleaner.

All is good now with this little mod to the inside for a baffle. (trird a few that didn't work very well.

I'm afraid if you block the venting from the cap you may end up with the same mess I had!


David Sheward

This thread was discussed between 29/08/2012 and 03/09/2012

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