2.0s barrell Markings?

[gilbert911]

We're in the process of stripping down and re-building a '68 2.0s engine which I recently acquired.
Four out of the six barrells have marks on the bore surface (see pics below)
Would anyone be able to help me out with what might have caused this?
Would there be any problems with re-using them for the rebuild in the present state, or is there a fix?

Thanks for all help / suggestions

[davep]

I guess that depends on the marks. If it is pitted then that would be bad. What does a light bit of honing do?
Has that engine been added to the build thread yet?
http://www.early911sregistry.org/for...ad.php?t=24913

[gilbert911]

Dave,
Yes, it's already on there - serial #4080430
Any other views pls?

[911quest]

They look like paper weights to me. The pits in the cly. on the right look to be deep. Are you going to be using 81mm pistons or stock? Core 2.0 clyinders can be had for little money if your going to have them bored out but most are out of spec for a stock rebuild.

[gilbert911]

Tony,
Thanks for your reply,
It's more deposits on the surface than 'pitting'
I'm interested in what might be going on to have caused it?

[Bobs 67S]

Gilbert,
This looks like long term storage with dirty oil or moisture - or both.

If that's deposits and not pitting, do as Tony suggested and do a hone.

Check with Bruce Anderson's Performance Handbook and Wayne Dempsey's 911 Engine book for how to check for size, roundness and taper. Also find the manufacturer and type of metal the cylinders are made of: 1968 cast iron, replacement Mahle Nikasil or Alusil, or Kolbenschmidt Alusil. Some can be honed and some can not.