valve question.

[R.White]

Could someone  please tell me if the lower valve spring cup and keeper should be fixed or should the middle part rotate? 

 

I seem to remember being told that valves need to be able to rotate to allow for even wear however where on some of these keepers the middle section where the pin sits rotates -  on others it is fixed.  I think they would normally be fixed and have come loose with use but I simply don't know.

 

Does this mean that the worn keepers need replacing or won't it matter either way?

 

Ray.

Edited October 27, 2016 by R.White (see edit history)

[robert b]

Ray on the 128 engine the valve , keeper, and follower  is the same as  yours , the valve rises the cam follower rotates in turn turning the valve as it lifts from the seat and in turn rotates as it seats again . The valve does not rotate in a circle but rather a quarter turn . This rotation is done by the follower running of center to the cam lobe . More info if needed. Bob

[R.White]

Hi Bob. Thank you for your reply but I am not sure you have quite answered my question. I am aware that the valve should rotate but if the middle of the keeper (where the pin sits) is unable to rotate in the cup then the pressure of the spring against the pin will force the whole cup itself to rotate against the spring. In some of the keepers the middle is loose and would allow the valve to rotate more easily. In others it seems to be fixed.  I wanted to establish which is correct. 

 

It looks like the keeper is made in two parts but I can't establish whether they should move independently - or if they were intended to operate as one piece - in which case, I am having difficulty in seeing how the valve could rotate especially as the pin tends to embed itself in the inner part.

 

Ray.

[robert b]

Ray the rotation is only about 10 degrees and the spring rotates an returns back to the seat . The amount of rotation is only enough to disturb the seat face to dislodge any carbon .   The valve does not rotate  in a circle  , just a oscilation .The keeper is solid and the pin wear is normal , have seen 1/8 pins worn to about half their size.

[R.White]

OK, So the keepers should be solid.  Presumably, this means that the ones I mentioned in which the middle part (where the pin sits)  are loose have got this way due to wear and tear.  I can't see it will make any difference so I will put them back in.  I have new springs and pins and have new inlet valves on order.  The inlets seem fine as one might expect and have lapped in nicely.

 

Thanks Bob.

 

Ray. 

Edited October 28, 2016 by R.White (see edit history)