N42 cam tower problem

[Orgreeny]

Just looking to see if anyone has any ideas i have a n42 head that i have been running over the summer with no issues at all i have taken this head of and fully rebuilt the bottom end and have done a bit of light smoothing and porting of the head. I have just gone to put the new uprated cam in to check it over and it will not fit at all!! I tryed a few other cams i had liying around and they were exactly the same i can get the cam all the way in with it spinning free untill i try and get it in to the last cam tower and it will no were near go in
So i put a strait edge across the bottom of the head and it is strait as an arrow! Now i have NOT removed the cam towers since removing the head so they have not moved
I then removed the cam towers and put a strait edge over the top of the head and it seems to look likr the middle of the head is lower than the two ends!

I cant see how only the top of the head can be warped and the only thing i can see to do is to get the top of tge head skimed then shim the towers

Any thaughts? Thanks

 

[jonbills]

Have you had any welding on the head, or had it skimmed?
If it’s been skimmed, they may have taken the towers off and put them back in a different order.
If you put the strait edge through the towers instead of the cam, where are the gaps?

 

[Orgreeny]

No the head has literaly been taken of and the only things i have touched are the ports
But that is a good idea il try putting going throghe the towers thanks

 

[jonbills]

Another thing to think about would be whether the block deck is straight - maybe if you bolt the head down the cam towers will come into line.