Listers,
For those who care about such things, the later TR4s and the TR4As used
identical double spring sets on the intake and exhaust valves. But we all know
that. What doesn't seem to be widely published are the dimensions of those
springs. They are:
Outer Spring
3-1/2 working coils
Free length? 1.67"
Solid length max 1.052"
Inner Spring
ID .648"??+/- .005"
Free length? 1.63"
Solid length max 1.02"
The dimension of the machined recess around the base of the valve guides into
which the springs fit apparently remained the same as that of early cylinder
heads : considerably greater than?o.d. of the above outer spring.
So the cylinder head I have on hand has proven to be a TR4A head (confirmed by
Terri?Ann's web page and?Ted?Schumacher)?and the springs and collars I
purchased are correct, even though they did not appear to be so. On with the
rebuild!
Ed Woods
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