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MG MGA - breather???

Hi to you all , just back from Le Man & a great trip , 1550 MGA miles & no problems , the Petronix system has transformed the car & i am now enjoying the drive !! Question < i have an after market rocker cover without a breather pipe, so the engine breathes through the tappit chest only , i seem to use or lose some oil , & still get some pinging could this be the cause as i seem to remember reading this at some point but could not understand why it should be .
colin daly

Pinking (or predetonation) is caused by a number of factors:

1) Too High compression
2) Timing too far advanced
3) Poor quality fuel
4) Too lean a mixture

I'd try running on 98 instead of 95 first and see if that helps. If so, then try again on 95 with a slightly richer setting.

If the 98 makes no difference, retard the timing a smidgeon. and try again.

If the compression is too high, these will help a lot too.

dominic clancy

There have been several discussions about non-vented valve covers, and the consensus is that it is a bad thing to do. With an unvented cover you will want to at least get a vented oil filler cap.

Jeff Schultz

That article CV-102 is about installing a PCV Valve to generate a vacuum in the crankcase. For normal crankcase venting on the MGA, back up a page to see here:
The MGB vented cap used on GA-GH engines has a very small vent hole and only works with a vacuum in the crankcase.

Standard draft tube venting requires a LARGE breather in the valve cover. Original issue was a 1//2-inch hose connection to the front air filter. For a sealed valve cover you might use a vented filler cap, but it would need to be the large mushroom style cap with horsehair (or wire wool) filter inside and a circle of larger vent holes underneath.
Barney Gaylord

This thread was discussed on 28/07/2008

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