valve guides - engine rebuild

[djc]

Hi

I'm rebuilding my 1982 Esprit S3 engine. I've removed the worn valve guides but was surprised to see that several of the old guides had been knurled along part of their length prior to installation. I measured the o.d of the guides to be 11.90mm, whereas the workshop manual states that standard guides should be 11.94-11.95mm for intereference fit into the 11.915-11.925mm bore in the head. So it appears that the guides were undersize and had been knurled to ensure that they stayed in the head!

The problem is that the two sets of new guides that I've seen (one in steel, another in colsibro) are also undersize at about 11.90mm. Has anyone come across this problem?

Rather technical for my first post, but I hope someone has some information!