[Thomas]

Hello Brett,

very good that the text helps. I am not sure about the valve measures because they somewhat differ for different machines. Attached is the drawing from GS Valves for my motor. My head diameter matches with your size but they are slightly longer by 3.6mm. The latter is not a very big problem because you can alter the pushrod lengths or you use the small freedom with the valve clearance adjustment by the rocker arms. I do not believe that the rocker box is a weak point. I rather believe that one of the previous owners did not take care for the shims on the head bolts that carry the box. That are four bolts and they need to have the correct lengths. If one is slightly too long or short one can use shims. Otherwise one can easily break the box when fastening it. The attached text helps you understanding and solving your issues. And I attach a text about my valve guide disaster.

Cheers, Thomas

[Bert44]

Hi Thomas,
I've used your engine overhaul on rebuilding my bottom end. It was very helpful. Great job. I found that my 60. Thou. end play was due to the unshouldered bearing being on the timing side, amongst other serious issues.
I'm starting on the head and have very sloppy valve guides. The valves are 43 mm head diameter and over 4 inches long (nothing like what is offered by the club). I'm not sure what the Series 2 valve sizes were originally. My rocker box has also been cracked and re welded. Maybe it was a weak design point.

[Thomas]

Hi Brett! Congratulations for the new machine! In 1937 Sunbeam was sold to AMC. The new owner took the Sunbeam parts from the works in Wolverhampton and assembled them in their factory in London and called them Series 2 (there is no Series 1). There is no basic difference between the former models (e.g., 1936 and 1935) except some modifications like the new valve covers and oil feeding design. In the club website technical part you'll find "1937 Sunbeam Model 9 Engine Overhaul" which I have written together with a fellow motor afficionado for supporting the club fellows. It might help to understand what is going on in the motor black box. Cheers, Thomas

[Bert44]

Hi everyone,
I recently purchased a 1937 Model 9 Series 2 and am having difficulty finding what differences there are between the last of the Model 9 Series 1 and Series 2.

Brett
Australia