Pelican Parts Forums - Bore refinishing & Piston to bore clearance

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Bore refinishing & Piston to bore clearance

I am working on a project and am researching bore refinishing and piston to bore clearances. What can the assembled experience here tell me about this topic?

I have found a business in Wisconsin called Millennium that replates bores with a NiSiC (like Nikasil) and hones the bores to match your pistons. Some of my questions:

Anyone have experience with this replate process?

What piston to bore clearance is speced by Porsche with Nikasil bores?

Can Alusil bores be replated with Nikasil? (I haven't asked Millennium this as yet).

What other experience/suggestions/knowledge can shed light on this issue.

Thanks

I have used Millenium several times to bore and replate both Nikasil and Alusil cylinders. I specify the bore to achieve the piston to cylinder clearance I want based on the piston diameters. I have been happy with their quality and turn around times. Piston to cylinder clearance will depend on the type of Pistons and cylinders you are using.

Here is a more detailed discussion of piston to cylinder clearances:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/890612-je-pistons-cast-iron-barrels.html

Thanks. That was a very useful thread.

What tolerance do you specify when redoing a Nikasil set up? (I am guessing about 0.002")??

Mahle pistons in Mahle Aluminun cylinders...Most people specify 0.0015-0.0020" for the clearance.

Quote:

Originally Posted by motogman (Post 8941237)

I had my Nickie cylinders replated by them a few years ago and they did a great job and were very nice to deal with. They answered all my questions and turn around time was excellent. it sure as hell beat buying new jugs and paying Charles at LN a set up fee for an order under 6 ----WTF!
Call the piston manufacturer (in my case J&E) for recommended piston to bore clearance. It depends upon the piston material used and they can provide the best info. Milennium will know the proper clearances if you tell them the pistons you are using.
Good luck, and you should be able to plate alusil liners as long as you go over on the bore size enuff to get past the alusil coating and provide clean material for the Nicosil process.

Fred