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MG TD TF 1500 - MG TD breather pipe from valve cover to air filter

Hi, wonder if anyone can advise - I fitted an aluminium rocker [valve] cover bought from Toulmins in Isleworth 40 odd years ago. I have only just got the TD on the road after a very very long rebuild. This rocker cover is ribbed on the top and has no breather pipe to connect with the rubber tube to the air filter.
Firstly, what negative consequences from not having the breather tube, and secondly, does anyone have any experience or advice to fit one, my local garage were reluctant to try to make a hole in the rocker cover...thanks, Doug


DRP Wallace

There should not be any issues without the tube, provided that the tappet cover has an opening to the atmosphere.

The oil fill cap on the new rocker cover may be vented or it may be sealed depending on the design.
MG LaVerne

Doug,
I agree with LaVerne,, maybe just plug the inlet,,,

BTW,, where do your carbie overflow pipes end,,seems close to the exhaust????

Steve
Steve Wincze

The carb overflow pipes are much more important being in the right place than crank case venting at this point. My car many moons ago caught fire in that area which we believe was caused by a stuck float in one of the carbs. This is what caused the driver to wreck the car, hitting a cable guard rail plus other things in a panic situation. The right engine cover and both sides of the bonnet were severely distorted from the heat! I believe this is why the car sat in a building for over 20 years. I had to replace all of these items plus a few other things to make the car right again. Needless to say, the pipes have been changed! $$$. PJ
Paul S Jennings

I always thought the Vent to the Carbs and the tappet chest vent to atmosphere was to help remove any Crank Case pressure that pushed oil out the front and rear seals.
As the engine wears and blow by starts to increase. These vents help control the amount of oil your MG will mark its territory with. Should work perfectly without them but will possibly make more of a mess.
ļ
Rod.
Rod782

Actually the rocker cover vent to the carb is metered and very small in diameter. It basically just relieved a minor amount of pressure but supposedly burns off any fumes under the cover. Most venting is done by the pushrod cover pipe.

Expressing the importance of changing the carb overflow pipes in my earlier post, here's what I did as a lot of other fellows who I copied from. PJ




Paul S Jennings

The rocker and tappet covers are both venting the crankcase and aren't sealed from each other. Any blow by will go out either as a relief. If the volume of blow by was huge, then it may force oil out of seals and if that were the case then a second opening in the rocker cover may prove useful. I'd have serious doubts that tappet cover could not handle all the possible blow by generated by the engine.

MG LaVerne

Thanks for the help, my carb overflow pipes are quite long and end way down past the exhaust manifold.
Paul, nice pic., difficult to figure out where your overflow pipes actually end?
Steve, by plug the inlet, do you mean the small inlet pipe that comes out of the side of the air filter casing?
Not sure if the oil filler cap on the aluminium rocker cover is vented or not as I am in Indonesia, on the way back to England. The SU carbs have just been fully rebuilt by Burlen Fuel Systems in Salisbury [expensive!]
So basically I understand that there is no real need to start making a hole in the rocker cover to connect with the air filter?
Thanks!
Doug
DRP Wallace

See http://www.ttalk.info/td_pipes.htm for an idea. Bud
Bud Krueger

DOUG,
Yes,, that is the plug place that I was referring to,,, but I am having second thoughts,, a plug probably not necesary at all.. anything that goes through ther will be caught by the mash and oil in the filter housing,,

Over flow pipes,,, yes, we can see that the pipes extend down past the manifold,,, but how close are they to you exhaust pipe??? That is also a very hot ignition source...

STEVE
Steve Wincze

Thanks Bud and Steve, I feel more comfortable now.
Cheers, Doug
DRP Wallace

My pipes end down below the front of the sump, favoring the left side. PJ
Paul S Jennings

This thread was discussed between 06/01/2015 and 08/01/2015

MG TD TF 1500 index

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