Are new Cyl/head valves straight Fit or Not ?

[nosey-bonk]

I have to replace the 4 inlet valves on partners 1.2 8v Clio, as they have been bent due to the cam belt snapping.

I'm amazed after stripping cylinder head, how lucky they are with such little engine damage. The only other damage seams to be slight scuff to top of pistons, that am sure will easily rub out with appropriate metal paper.

So can anyone tell me if new valve fitting is a straight replacement or do i need to do some specific task first to re-seat them.

If so any pointers on how to do it or get info on it would be appreciated.

 

[Matteh]

if there's no damage to the head, then they'll just need 'lapping'

 

[nosey-bonk]

can you expand on lapping for me.
What is that, whats involved ?

 

[jackfm]

can you expand on lapping for me.
What is that, whats involved ?

google?

 

[Jay Payne]

Dont try rubbing the piston marks out with metal paper.


Lapping in valves: You will need grinding paste and a lapping stick. Involves grinding the seat of the valve and head to get a good seal

 

[Alastair.]

i lapped my mrs valves on her 106 with the stick attched to my cordless drill, so lazy.

 

[nosey-bonk]

Cool thanks

found this and it doesn't seam such a big task. Sounds good to do.

http://www.dazecoop.co.uk/10-02-2007/how-to-valve-lapping-on-mini-head

what do you recommend then for rubbing out the edges of the valve marks on pistons?

surely a bit fine grade wet and dry metal sand paper will be ok.. Theres not a big edge to the scuff, just ever so slightly, but an edge never the less ...