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MG MGB Technical - alloy valve cover

I would like to minimize the valve noise by utilizing an alloy valve cover on the 73B. I cannot seem to find one that has a breather tube. Do they exist? Tom
Tom in beautiful upstate NY

Some - but not all - alloy covers have a small, thick, boss molded
somewhere inside the valve cover (along the top, or sides).

Shop carefully.

This boss provides a place to drill and tap for installing a hose
barb.

Be aware that some MGB's (including your '73) will require some sort of air restrictor inside the hose barb.
Daniel Wong

Tom,

You can also drill and tap one of the plastic oil caps. I did it for mine. Then I brazed a small brass threaded/barbed fitting closed and drilled it out to the size of the restrictor hole in the original valve cover. I put a tube on the fitting and ran that to a small fuel filter and left one end of the fuel filter open.

I think you can make it out in the attached pic. I would have use a 90 degree fitting, but I was doing it about 2:00 AM and had to use what I had on hand.

Charley

C R Huff

Contrary to common belief an alloy valve cover does not reduce tappet noise in fact if anything it accentuates it.
Iain MacKintosh

If you intend to do away with the canister at the same time as fitting an alloy rocker cover then surely the sensible option is to use a vented (they are also filtered) oil filler cap to maintain engine breathing, rather than mounting a filter on a non-vented cap. If you add a port to the new cover then the restriction is about 1/32".
Paul Hunt

OK guys, thanks for the venting advice but, if the alloy cover does not quiet things down, why bother? Is there another way(s) to minimize the valve clatter in the cockpit? Thanks, Tom
Tom in springy upstate NY

Tom-
Fitting a new rocker shaft and rocker arm bushings is the surest way to quiten the assembly.
Steve S.

Ear plugs or a louder stereo, it is always a noisy engine.

How are your valve clearances? If the rocker pads are worn with grooves you will get over-large gaps if you set them with flat strip-type feeler gauges. My engine may be unique but I've found the back few valves aren't at their biggest gaps when using the usual adjustment method i.e. rule of nine. Since I started checking the gaps at the largest point, which can be one side or the other of the rule point, they are a bit quieter. But still much noisier than the V8.
Paul Hunt

This thread was discussed between 20/03/2009 and 23/03/2009

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