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MG MGA - Valve cover

I have a 1957 MGA and am interested in replacing the beat up valve cover with one of the nice cast aluminum covers. I notice that the Moss model is not vented.
Is this a problem? Does it need to be vented?
Thanks,
Bill Chandler
Ann Arbor, Michigan
W Chandler

I have a modern alloy cover on my 3 bearing MGB engine which also has no vent in it.

It seems to run really well without a vent and the only sign of any pressure build up in the cover is a mist of oil on the top of the cover after a run. I presume this is blowing out of the small vent hole in the oil filler cap.

I have thought of fitting a vent pipe to the cover but my carbs have ram pipes fitted with individual sock type air filters and so there is no air filter housing to run a vent pipe to.

The engine has only done about 5000miles from being totally rebuilt and so probably there isnt too much gas blowing past the pistons yet to put excess pressure into the crankcase. But I suppose that this will not always be the case as the engine wears.

I have heard that you can fit a vent hose which ends in a small K & N type crankcase filter but I havent seen one of those yet.

But if your car already has a vented crankcase cover and runs ok, I would probably would recommend that you stay with the same type.

I recall seeing pictures of an alloy cover modified to fit a vent hose. (probably on this forum )

Colyn


Colyn Firth

Yes, crankcase ventilation is important. Do install the valve cover vent for MGA, as it works well with the draft tube. After mid 1964 the MGB had a PCV valve to draw a vacuum on the crankcase, and a small restrictor vent and air filter in the oil filler cap. In 1970 it got fuel vapor recovery, a carbon canister, and the restricted vent changed to the back end of the valve cover with a sealed oil filler cap, the PCV valve was deleted, and vacuum source changed to carburetor venturi.

In all cases there is always a source of fresh air ventilation through the crankcase. This is important to purge the naturally occurring presence of water vapor and other contaminants that are byproducts of combustion. If you don't have crankcase ventilation, then you need to change the oil more often to get rid of the contaminants.
Barney Gaylord

Fitted this alloy cover about 3 years ago and followed Barneys advice. The unit came without a vent so drilled and tapped and fitted hose to filter as shown. I did not fit an internal baffle and have had no problems...but ventilation through engine guts is important so vent should be fitted.


Neil Ferguson

I bought a Vented aluminum valve cover with a vent tube for my MGA from Moss Motors when I was in the UK back in 1997. Don't know if they still offer them

Cheers. David
David Honness

I had the non-vented alloy cover. I suffered the same oil puddling that Colyn mentioned. Actually, he only mentioned misting. After a few years of wiping the cover after every run, I added a vent very similar to Neil's. I never had an oily cover again. I'd highly recommend adding one.
Chuck Schaefer

It looks like I will have to fit a vented valve cover then.
I have looked in the Moss MGA catalogue but have so far have only been able to find the non-vented alloy covers so far.
Does anyone know where I might buy a vented one?

Or can anyone tell me how to fit a vent tube to my alloy cover ie. can I buy the parts to make the vent or do I have to fabricate these myself?

Colyn
Colyn Firth

Colyn,
Have you called Moss? When I bought mine they were not in the catalogue but they had them on the shelf.

Good luck...Cheers, David......
David Honness

Simply drill a hole in the cover and tap it to the appropriate pipe thread. Use a brass tubing nipple and fit the stock rubber hose to the filter canister. I can't remember the size but it is easily purchased at your local big box store.
Chuck Schaefer

Colyn, an alternative might be a vented filler cap. There is a type of plastic filler cap that has a built-in mesh filter, the part No. is GFE 6003.
Lindsay Sampford

.....in fact that is what Moss supply for their alloy MGA rocker covers! http://tinyurl.com/74u7eh5
Lindsay Sampford

Hi Bill,


Before you order the valve cover from Moss, please e-mail me. I can get you a discount on the valve cover.

My e-mail is bscr@bscr.com.


Thanks,


Ken
KL Ken

This thread was discussed between 13/01/2012 and 24/01/2012

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