What I have been told about reaming and hone bronze guides is 1. It is very
possible to get a slight bend in the guide during the pressing in operation.
The reamers are slightly flexible and will follow the bent centerline of the
guide during the reaming process, hence the guide will not end up as
straight as it should be. Some of my experiences in the past seem to bear
this theory out. 2. The cross hatch pattern produced during the honing
process is said to be a better surface to hold some oil and improve the
lubrication of the valve stem to guide interface. The people who do my
honing for me have never had a problem with "bell mouthing" the guides. They
always come back very straight and true. The hones that they use are
designed to do guides and the setup is on the same principle as the hone for
doing pin bushes. So the sizing is also aways very good and acurate. On a TR
with an iron head, manganese bronze guides and stainless valves with chromed
stems, I ask for .0015"-.002" clearance on the inlets and .002-.0025" on the
exhausts. Tighter than is we have had valve sticking problems as the guide
expands from heat and closes down the clearance. It can not get larger
because it is captured by the iron head which is for all intents and
purposes not going to get larger as it gets hotter.
Regards,
Greg Solow
----- Original Message -----
From: "Bill Babcock" <BillB@bnj.com>
To: <MJSUKEY@cs.com>; <fot@autox.team.net>
Sent: Friday, September 19, 2003 10:08 AM
Subject: RE: Bronze Valve Guides
> I'd like to hear the explanation too--I've never honed guides. Maybe I'm
> missing something. I'm always a little nervous about hones creating an
> hourglass cross section when they stroke out of the top and bottom of the
> work.
>
> -----Original Message-----
> From: MJSUKEY@cs.com [mailto:MJSUKEY@cs.com]
> Sent: Friday, September 19, 2003 10:00 AM
> To: fot@autox.team.net
> Subject: Bronze Valve Guides
>
>
> Hmmm, it was mentioned here that bonze valve guides should be honed, not
> reamed. I'm thinking size is size, no mater what the method. You can
> change the size in smaller increments honing but if you have the right
> size reamer you can do the job, no? Am I missing something here? Somebody
> straighten me out please.
>
> Marty Sukey
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