To hone or not to hone Nikasil

If you dont hone them the rings will not seat. You can see the cross hatching but it wont be rough enough to cut the rings and "wear" them in so you will have problems unless the engine only has 1000kms on it from new. The problem with honing a nikasil liner is the removal of the nickel-ceramic coating. How thick is it? I dont know. The next step would not work for you but I would bore the liners and forget about the coating and go with oversize pistons, etc....probably not what you had in mind. Its a tough call, one that I wouldnt want to make on my own car due to the level of work involved only to do it again a 2nd time.

 

I have bottle brush honed countless nikasil liners in this manner, with an air drill and flushing with solvent, and have never had any problems. I have never seen any factory recommendations to do this but what I do know is it will clean all the imbedded particals from the surface. You will be able to see scratches in the surface not evedent before as well as having a fresh 'hone pattern'. I have always felt that the real benifit of doing this is for cleaning the liner surface. The coating is so hard you will never hurt it with just a ball hone.

 

Thats interesting because Ive heard of issues with the coating flaking off causing problems of course. Guess nothing is carved in stone. I wouldnt want to do it but something has to be done because simply installing new rings is a mistake without a fresh surface.

 

You just want to deglaze the cylinder and nothing more. Do a search on Porsche 911 forums.

http://www.babcox.com/editorial/ar/eb110242.htm
Goodson’s Jensen says PERs have had success honing Nikasil treated cylinders with diamond. But for smaller shops that have only portable honing equipment, you can’t exert enough pressure with diamond to hone Nikasil. The best advice here is to use #220 silicone carbine and just do a couple of strokes to deglaze the cylinder. If a cylinder has to be bored to oversize, cut it out with a boring bar and then hone in the usual manner to achieve the desired dimensions and finish.


http://forums.pelicanparts.com/printthread.php?threadid=73286
The Nikasil cylinders can indeed be honed and reused. They typically have a ‘MAHLE’ stamp on the lower side of the cylinder. The nickel-carbide surface needs to be lightly honed with a special silica impregnated tool, or what is commonly known as a grape or flex hone. The surface properties are too hard for normal tool steel honing machines. The Nikasil coating will be ever so slightly magnetic when you place a magnet next to it. The honing process is performed using special tools – either a specific tool designed to hone the cylinders, or a grape hone. Either way, you should only have an expert familiar with the Nikasil cylinders perform the honing process.

 

Bring it to your local machine shop and have them take care of it for you. Did you tell the piston company that you have nikasil cylinders so they don’t give you chrome rings?

 

I wouldnt remove the liners to hone them and if you send the block to get steam cleaned after, that will be all you need to have it ready to reassemble.