Morris Minor Owners Club

No harm in trying, however I don’t think it would help. I’d be more inclined to check what you’ve done, just in case there is a valve not fully closing, after the adjustment. If all ok, yes look elsewhere.

Hi All,
Thank you for all your advice. I have no idea about any history of the engine. I will work through the checks that you have suggested. I adjusted the tappets as per the Haynes manual description, no. 8 valve fully open and adjust no.1 tappet and so on.
Will let you know how I get on.

Elsewhere, Phil has just told us that the thread on the tappet adjuster is 26 threads per inch (tpi) which is a pity ‘cos if he’d said 25 tpi then one turn of the adjuster would be exactly 40 thou movement, and so a quarter turn, or 90 degrees, would be exactly 10 thou, and of course, half a quarter turn would be 5 thou, and so on. Life would be simpler, tappets would be easy to adjust and you could throw all those clickerty SPQR gadgets away. But instead the thread is 26tpi and full turn of the adjuster is 38.46 thou! A lost opportunity, I think. I blame Phil, but nevertheless, I feel a little tool made up of a protractor and pointer is coming on.
Of course, you might think that there’s no such thing as 25 tpi but the interweb tells me that the screws that hold the trigger guard on the 1903 Springfield bolt action rifle are ¼ inch x 25tpi. But not a lot of people know that.
MikeN.
PS Of course, the O BA thread is 25.4 tpi. Near enough surely . . . .

You are forgetting about including the rocker ratio in your calculation

My original spqr kit works perfectly and is very quick and easy to use.