Date: Tue, 5 Apr 2005 18:57:23 -0500
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: Heads off, piston ring broken
In-Reply-To: <002301c53a2f$4264bfa0$6e01a8c0@GOOSE2>
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Brian Keese wrote:
>Well, now I've gone and done it. I'm working on resealing the heads on The
>Ark (84 Westy, 1.9). I tried to get the heads off without bringing the
>cylinders with them to no avail. In fact, I'm glad I didn't spend too much
>time trying because it took major tapping (more like banging), prying,
>heating, and cursing to get the cylinder sleeves off, even with the heads
>out of the van. And so in hopes of finding a way to finish the job without
>dropping the whole engine I searched the archives. I found a couple of
>members who succeeded in using a wrench-type ring compressor to get the
>cylinders back on the pistons without removing them and I thought, 'Aha!
>That's good news. I'll give that a try.' Well, I tried and on the first one
>(out of three to do) I ended up breaking one of the rings - the fat one with
>the spring inside. Now, I'm not sure how I should proceed and so I am
>availing myself of the wisdom of the list.
>
>
>
>Is it OK to just replace one of the rings in one of the cylinders? Should I
>replace all the rings on that cylinder? Should I replace all the rings on
>all the cylinders? Are different size rings available? How do I know which
>to get?
>
>
>
>Many thanks,
>
>Brian Keese
>
>84 Westy Wolfsburg 'The Ark'
>
>81 Isuzu P'up Diesel 4x4
>
>Bloomington, Indiana
>
>
>
>
Brian,
This is just my opinion, based on my own experience with cylinder
barrels and rings......you need to do a ring job, period. Why, one would
ask? Well, for one thing, when you pulled a piston out of the barrel you
have upset the seating of those rings to the barrel and you will never
get the rings back as they were. To ever get a good ring seating, you
need now -- at the least -- to hone the barrels with a hone to
re-establish the cross-hatching that aids in creating the ring seal. To
match this new cross-hatching you should put in new rings. The old rings
will be work-hardened and worn on the ring face that seats against the
cylinder barrel, and there will be wear on the part of the rings that
fits into the lands of the piston. There will also be wear in the piston
lands. If you install new rings now - provided there aren't to many
miles on the engine to begin with - new rings will bring the clearance
between the land and ring back closer to spec, and you will have a new
ring face that is not wear-hardened to match the new cylinder barrel
cross-hatching. This will increase the prospects of getting a good ring
seal wear-in so the oil consumption will be low and compression high.
I will tell you that much of my experience with this comes from being an
aircraft mechanic, and old rings going back in to an engine after the
rings have been unseat is anathema to most aircraft mechanics I know.
Oh, yes, it is done, and I have done it myself, but I had to really
rationalize the circumstances. For myself, I hate having to do a job
twice, and while re-using old rings might work for a while, just keep in
mind what you are going to have to deal with in the future. Ask yourself
this. If the engine repair is giving you fits at this stage of the
game, are you sure you want to go through it all over again in the
future, before the engine life is reached. I know I wouldn't. I would
rather get it right the first time, even if it took some extra
one-legging crow hopping.
The WBX has a strong lower end, and I think in some ways the 1.9L is
stronger than the 2.1L. It is often said that if you rebuild the top
end, the increased compression will result in wearing out the bottom end
faster becasue they are mismatched interms of wear. For me, so be it. I
would go for it, and deal with the lower end overhaul if and when it
needs it.
When I sold it, my 85 GL had 205,000 big ones on it and was never
rebuilt, ever, in any way. No interim valve job, no head replacements,
no ring job....nada. I just drove it. Kept it up good, but just drove
it. I should have kept it. The 88 GL I got in its place turned out to be
a maintenance lemon. It's fine now, but I had to invest a lot in it to
get it right. Now I have no intention of ever disposing of it. I'll just
drive it. It is very reliable.
Like I said before, it's all IMHO!
Good Luck,
Regards,
John Rodgers
88 GL Driver
Chelsea, AL
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