Setting Valve Clearances


Mar 7, 2005
What sized wrench fits the valve adjuster? The locknut is 3/16W but I don't have a wrench/spanner small enough for the top of the adjuster.

Before I go to the specialty tool shop I would like to know if there is an alternative.

I used to use a pair of pliers until I replaced them with socket headed ones that take a small allen key.
It makes it much easier.
I think I got mine from Mick Hemmings
valve clearances

The type of small wrench used to bleed radiators in a central heating system will work well -- supposing that central heating is needed where you live !!,also the key used to wind up old clockwork toys works well, does anyone out there remember clockwork toys?!!, I suddenly feel really old!. Ride safely. James
Unfortunately I can't remember. I have a set of ignition wrenches and one of them fits. 7/32 is in my mind, no guarantees. But I have also used, a 4" or 6" adjustable wrench.
Thanks guys ... I didn't want to use an adjustable wrench... I like the sound of the key for wind-up toys.... Finding one of those will be my next challenge.

I have a 5mm socket that I will try next...
You piqued my curiousity so I had to go and check. 7/32 is a little sloppy. 13/64 fits better but the jaws are a little small on this wrench.
12 pt. 6mm boxed end wrench fits nicely on the 4 pt. stem.

IIRC the original tool kit had a special wrench for this.

My wrench of choice, 4" adjustable. (Just call me shade tree)
Ha! I'm not the only one! I, too, use a small adjustable wrench. Couldn't find anything else that fit.

It's a Whitworth adjustable wrench of course :wink:

Mick Hemmings uses what appears to be a skate key in his video (you do remember roller skates that clamped on don't you?) supposedly for the drain on some British automobiles radiator. He said it's available from auto parts stores.