<VV> Engine building - bearing clearance

Tony Underwood tony.underwood at cox.net
Fri Jan 22 10:34:15 EST 2010


At 09:18 AM 1/22/2010, corvair at mts.net wrote:
>I've HEARD of line honing a block. I've never heard of anyone that's 
>actually done it, how they did it, and what the results were like.
>
>Les
>----


Happens often with inline or V engine blocks all the time, not so 
much with aluminum boxer crankcases like a 'Vair or other boxer 
unless the engine is a bit of an exotic (Porsche Ferrari etc) that 
commands some economic respect.


I *have* heard of people who line honed a Corvair crankcase to fix 
loose cam bores but it was a labor of love and they had easy access 
to a machine shop...  otherwise it would be much simpler and cheaper 
to pick up a good used crankcase for dirt cheap.   It's more a matter 
of economics than anything else but yes you can line hone a crankcase...


...but not much.   A few thou is about all you can get away with 
before you start having bolt hole issues with accessory components 
like top covers and bellhousings and front housings etc.   However, 
even so in these times 40+ years after the fact it's still pretty 
easy to turn up an excellent used crankcase that needs 
nothing...  which lends notion to the point that line boring or even 
honing a Corvair crankcase is pretty much unnecessary and unwarranted 
because replacements are available for less than the cost of the 
machine work and you get to avoid the pitfalls of an abbreviated crankcase.

Let's not forget that you have to do it *twice*... once for the crank 
and once for the cam.   And, if you had to take too big a cut from 
the mating halves to clean up a discrepancy you could end up with 
assembly issues with accessories' bolt holes not lining up quite 
right.   Hone, maybe...  bore, avoid it.


Or ask around this list for somebody with a crankcase they wanna sell 
for a few bucks.   ;)




tony..





More information about the VirtualVairs mailing list