MGB Register Forum

Overhauling the head on my 1970 MGB roadster, I notice the collets are held in by a spring clip placed in a groove in the collets. I also noted that the valve stem seals are used on these collets in the form of an O ring. I have purchased a later type of valve seal which fits over the valve guide. Having lost the last collet (which will probably turn up in a years time from some hidden corner of the workshop) I have bought another pair of this type of collet but wonder if it is necessary to fit the O ring types as well as the others to help secure these type of collets. Also, are the securing springs really necessary as the later type of collet never used the securing springs. Your guidance will be appreciated.
Thanks, Mike

Hi Mike, I can give you my opinions but they may not be what everyone else thinks. I have rebuilt many B series, A series, and Triumph TR engines but have no engineering qualifications as such!
# oil stem seals- the later type (a cap rather than an O ring) are undoubtedly more effective. I usually find the O ring type fracture easily and end up in the oil under the rocker cover. Take your pick which you install. I didn't bother fitting them sometimes, especially on exhaust valves, - pressure tends to not draw oil down those guides.
# spring clips - optional again I think. I wouldn't bother with them. I suppose they may have some function if valve bounce occurs at high revs?

Ian F

When stripping the head on my MGB last year, it had the O ring seals. They were clearly original and whilst intact, were as hard as steel, so serving no useful purpose.

New O rings came with the head gasket set, but I replaced them with the modern cap type.