Date: Thu, 28 Nov 2013 09:09:02 -0600
Reply-To: Jim Felder <jim.felder@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jim Felder <jim.felder@GMAIL.COM>
Subject: Re: off with her heads
In-Reply-To: <BAY406-EAS5121D6895931877DAE4550A0E30@phx.gbl>
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I have to question this advice, or at least advise looking into it further.
I think that honing cylinders is standard practice when fitting new rings.
While there may be exceptions (Porsche 911 silicon-impregnated cylinders,
cylinders that still have enough roughness to seat rings and especially
soft or otherwise compliant rings come to mind). Honing is at most going to
remove a few tenths of a thousandth. You would have to be at it all day to
hone out what ordinary tools could even measure if you are doing it right.
To not hone a cylinder that is receiving new rings is to take an
unnecessary risk.
Jim
On Fri, Nov 22, 2013 at 11:36 PM, Dennis Haynes <d23haynes57@hotmail.com>wrote:
> See below!
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Tom Carchrae
> Sent: Friday, November 22, 2013 4:50 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: off with her heads
>
> Hi All,
>
> I got the bolts fixed and the heads vacuum tested by the machine shop (if
> you are in Vancouver, Alec's
> https://plus.google.com/103170149757334342065/about?hl=en - they were
> helpful and seemed pretty fair). All good, and my 1984 NLA
> thermostat/water-pump housing is saved from the snapped bolts... for now.
>
> How important is it to hone a used cylinder. The internet seemed full of
> opinion on it. I remember Dennis saying to carefully remove the carbon on
> the top, but honing to help the "piston rings seat' (I am replacing the
> rings) did not yield any clear answer on the great internet.
>
> I really don't believe in honing the cylinders much. You need to measure
> carefully. It is easy to remove a few thousandths quickly and you will end
> up with an engine with piston slap noises. I am even seeing (hearing) this
> with engine rebuilt with the new knock off cylinder kits.
>
> I had also asked them if they could clean up/smooth the surface area under
> the compression gasket (where the head mates with the cylinder) and they
> said they were not sure how to do that properly, but they had called around
> to some other shops to ask and suggested I take it there (which I totally
> respect them for admitting that). I am considering doing this myself -
> there is no major damage. The worst is a small scratch from the (first and
> only) use of a screwdriver to remove the compression gasket - the rest of
> it
> is just carbon crap.
>
> Machining the tops of the barrels requires a lathe and someone who knows
> what they are doing. The lathe and the chuck needs to accurate. I have
> probably replaced more cylinder sets due to top damage or bad pistons than
> cylinder wear or bore damage. You can try cleaning the tops using a very
> flat surface and a fine grit emery. If you can see or feel the scratch I
> wouldn't use the cylinder. Not only does the top of the cylinder have to e
> near perfect, the two of them side by side have to be perfect together.
> Hylomar is a good sealant to use on this gasket and the O-ring.
>
>
> I am considering removing the engine to check the clutch, although I don't
> have a floor jack and the engine is really high up from the ground (van is
> up on blocks). I might try the winch method, or just leave it. Common
> sense tells me I should check the clutch while I am in this deep (how deep
> is the rabbit hole...). And I'm sure I'll my sanity will thank me when I
> put the piston rings on (without removing the pistons).
>
> If you're going to work on your van at some point a good floor jack is a
> must. Get it over with and get one. Look for one with a large saddle.
> Preferably a removable saddle so that tranny adapters and stuff can be
> fitted.
>
> Tom
>
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