

| Subject: | Re: off with her heads |
| From: | Jim Felder |
| Date: | Thu, 28 Nov 2013 09:09:02 -0600 |
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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