I have two interrellated issues with my cylinder head.. what is the recommendation of people in the know?
12G 940 head with 36/31mm valves from factory.
New MS bronce valve guides
New MS double valve springs
1.5 non-roller rocker assy
Engine is a 1310 for pretty fast road operation
I advised my macine shop to press the guides in as per manual, i.e. 0.54" (or 13.72mm) from spring seat to top of valve guide.
So far so good, that's what he did.
- Only now that I got the head back I noticed that the valve spring seat depths (from rocker cover gasket face as datum point) differ by up 1.2mm (that is the number 2 cylinders difference between inlet and exhaust, which is the worst). Hence the guides are all pressed in to varius depths.
I understand that the best solution would be machining the spring seats to equal depth . But how is it done?
Would shimming be an option? Suppose yes, but needs plenty of different thickness shims I aint have.
I reckon shimming might be okay as the valve seats had to be cut quite a bit back to get the required seat width, hence the stems stick out a bit further (a few tenths of a mil) as a result. - Secondly, the cones on the end of the exhaust valve guides hardly protrude from the casting - towards the valve that is. I.e. most of the guide cone is within the bore of the head. Is this normal?
1st photo is of centre exhaust port with hardly protruding guides
2nd photo shows depths of spring seats.
