Good morning all. I've been doing some work on the cylinder heads of my Navigator. I see that the "inner pillars" that support the rocker spindles have top hat shaped bushes pressed in to place, see photos.
Any ideas on the purpose of these bushes?
Only a guess - but as that end is only splash lubricated, it was decided to have a replaceable bush there in case anything went wrong - better then scrapping the head. In reality, i've never seen any issues there in any engine i pulled apart.
I cannot see the need for lubrication here.
I wonder if "fretting" may have been a problem, the clamping of the spindles isn't that positive. I have six heads here, all are a reasonable fit on the spindle, so probably not fretting.
Another thought that it was a way of rescuing a manufacturing mistake, the bush is in the parts list, so, again probably not.