VW Vortex - Volkswagen Forum banner

21 - 22 of 22 Posts

·
Registered
Joined
·
898 Posts
Re: Cylinder honing: DIY, or better left for professionals? (Bora Lab)

I think we have it down to semantics at this point...
If the cylinder is within spec...the cleaning and honing can be done at home. This implies a ball hone or a 3-stone finishing hone. The ball hone is an easy way for a home mechanic to plateau the rough surface left by a boring process...or, to clean a glaze and plateau the surface of a dirty, but useable block.
If there are dimensional problems, then something other than a finishing hone must be used...whether we call it a honing machine, boring machine, or whatever.
The problem with using a honing machine (Sunnen, etc) is the finished product. Sure...an out of round cylinder can be made round again...but, the only choice is to widen the whole hole (heh heh
) to (or slightly larger than) the widest area. How will your pistons fit then? What about the ring gaps? These are not trivial matters and are precisely why there have been oversized pistons available for decades. That is, when it's time to remove material, it must be done to match the oversized pistons and rings...not just until a round bore is (re)achieved.
Traditionally, you bore to an oversize...and, hone to prep the surface. Whatever you want to call it, though, the concepts are the same...a good cylinder just requires surface prep...a bad cylinder must have material removed (to restore the straightness and roundness of the bore) and then a surface prep. Simply prepping a bad hole...still leaves you with a bad hole.
 

·
Registered
Joined
·
1,170 Posts
Discussion Starter · #22 ·
Re: Cylinder honing: DIY, or better left for professionals? (The Quinner)

Well, I decided to go the safe route and just have my cylinders bored and fit larger pistons. I went from 82.5mm pistons to 83.5mm, and they should be in today. My machinist is going to measure them and then bore the cylinders appropriately. I'm happy now because I know that my cylinders are going to be perfect, and the pistons will fit just right. And I'm getting an extra 50cc's out of it.
Thanks for all the advice,.. this thread really turned into a good informational tek. Hopefully other people will be able to use it in the future.
-Nick
 
21 - 22 of 22 Posts
Top