[Vwdiesel] Should I Re-Ring?

Sat Jan 25 09:52:06 PST 2014

dSo far we're having the mildest winter in 4 years, but February can change all that!

Below is an attempt to clarify what and why I did to avoid a rebore on my 1983ish engine. Have a look at the ring gaps on my engine on the link below, and consider 
that this engine had only given starting issues for a couple of months prior!

As an engine builds up the mileage, it wears in the bore. It is mostly confined to the last 1/2 " or so of the travel of the top compression ring. Thus over time a ridge forms 
at the point where the top ring finishes it's travel each stroke. It's actually a groove, but feels like a ridge. 

As the top ring wears radially, the ring gap enlarges, lowering the effective compression. At the same, time the ring being in a hard carrier actually gets thinner, and 
becomes a looser fit in it's groove. The significance of this is that on the up stroke the ring gradually stops lower in the bore creating a sloping upper 'ridge'.

Naturally reboring removes all this, but may then involve oversized rings being needed, and also oversized pistons to maintain that close fit of piston to the bore. If you 
were to merely replace the old rings with new, say expensive chrome rings, there is a near certainty of top ring breakage. 

Some ring designs including the currently heavily discounted Grant rings have a convenient notch out of the uppermost edge, which despite the new ring being back to 
full thickness, actually avoids this tapered ramp at the top of the bore. As the new ring wears it will gradually meet up with the ramp and wear a new profile.

I believe I have found that, depending on the severity of the bore wear in the first place, [just prior to reringing], this will determine just how much knocking occurs as the 
new rings wear. This is why I have determined that effectively shifting the ridge up the bore by a couple of mm, by blending the ramp with a small Dremmel type grinder 
wheel, removes, or at least reduces this issue. 

By only touching up the ridge, and not grinding away the bore between where the top ring stops and the top of the block, original pistons, [if not damaged] will fit as 
snuggly as when first fitted. 

The link below is how bad my rings were back in 2010. Top ring had a gap of 6mm! 
http://imagizer.imageshack.us/v2/800x600q90/809/imgp9942.jpg

Mark
======================================== 
Message Received: Jan 25 2014, 12:43 PM
From: "Bryan Belman" 
To: "Mark Shepherd" 
Cc: 
Subject: Re: [Vwdiesel] Should I Re-Ring?

Hi Mark, happy new year from FREEZING New Jersey.

that thinks on the idiot that backed up into you.
I am having trouble picturing what you are saying here, can you try and explain a different way?

"Be sure that the top groove 
is eased 
out with a grind wheel if significant. Grant rings have that convenient notch 
out that helps prevent."
tks

Bryan Belman, Pt. Pleasant, NJ
04 Jetta Wagon TDI PD BEW, 100hp, 5sp -- running :<)
04 Golf TDI PD BEW, 100hp, 5sp Tiptronic Auto -- running :<)
82 Diesel Westy 1.9NA 1Y -- running :<)
70 Type 1 Beetle -- Under Restoration forever:-)

On Friday, January 24, 2014 9:07 AM, Mark Shepherd  wrote:

Hi,
There are a few Ex-Quantum drivers here. Parts are getting scarce over here too; especially as some of the cars are going for 10 x £ they used to due to those born in 
the 1990's wanting to make them 'rat' look messingwith the paintwork and chopping the springs... Duh... I've just recently raised the rear by about 5". I must have the only 
'Countryman Quantum LOL.
I have a stock of spares, including 2 rust free complete QTDs, that I may put back on the road if this one dies. I have about 3 sets of spare doors. What will get me, is if 
some idiot smashes another headlight. Nearly all the spare lights on Ebay are LHD. 
So easy to work on in the engine bay, compared to the Golf mk2...
I only have to open the hood of the Golf mk2 GTD, to appreciate this! The body work steel is of sufficient quality for most damage to be hammered back out.:o)

Although I like the wagons, with the #1 roof rack ever made by Audi/VW, and the luggage space;I do have 1 TD Quantum fastback:

This is so close to being a 4 door Scirocco, and is a true factory TD and has all it's extra insulation, and all the under car soundproofing intact. I was going to put the a/c 
in 
there that I imported from the USA many years ago... 

The Syncro site on Yahoo might be a good source of parts as well as the D.O.G.S site.

Welcome to the Quantum clan....
Mark

========================================
Message Received: Jan 23 2014, 11:06 PM
From: ctpops32 at aol.com
To: mark at shepher.fsnet.co.uk
Cc: 
Subject: Re: [Vwdiesel] Should I Re-Ring?

Beginning to think I may have been the only Quantum diesel on the list. Picked up an 84 the middle of December. Most of it in good shape. Some small stuff to fiddle with 
tho. Good to know there is at least one other around. Just noticed the UK on your address. How is availability of Quantum parts there? Very scarce here.

Dick McBride
Cypress, TX

-----Original Message-----
From: Mark Shepherd 
To: vwdiesel 
Sent: Thu, Jan 23, 2014 3:54 pm
Subject: Re: [Vwdiesel] Should I Re-Ring?

Reringing will improve things if the current rings are worn. Use the Grant ones. 
They will last for years. Over honing merely adds to the enlargement of the 
bore, as the 
mountains you have created wear down to plateaux. Deglazing, followed by correct 
fluctuating loading of the rings will bed them in. Be sure that the top groove 
is eased 
out with a grind wheel if significant. Grant rings have that convenient notch 
out that helps prevent.
Do not grind anything from the cylinder above the ring line to the top of the 
block, [unless reboring for oversized pistons], and you will maintain good 
compression. 
Look up some of my posts re my engine. I live and breathe what I say... 

If rings haven't worn [do Loren's check], then check that ring gaps aren't 
aligned. 

Today I'm sitting in my Quantum outside a furniture shop. I bend down to pick up 
a battery from my camera that my daughter dropped under the passenger seat, and 
I feel 
a small but significant thump. When I get back upright I see a BMW crawling 
away, thinking my car was empty when he'd reversed into it! That is the 5th time 
that that 
corner of my car has been hit. Weather good, sunny and almost no traffic around. 
I'm really thinking that my car may be invisible....

Mark

========================================
Message Received: Jan 23 2014, 08:46 PM
From: "ralph meyermann" 
To: "Will Taygan" 

Cc: vwdiesel at vwfans.com
Subject: Re: [Vwdiesel] Should I Re-Ring?

Excessive temps can cause the piston/cylinder wall clearance to tighten up
and possibly seize, if they are tight tolerances to begin with. The 1.6 na
in a Westy is very sluggish at best, many of the rolling hills here in Iowa
I was needing to run in third gear to make it up. The best thing I've done
was swapping in the 1.9AAZ turbo diesel, WOW what a difference and keeping
the same fuel economy and possibly gaining a touch while eliminating the
smoke too! I suggest saving up some $ and doing that swap.

Velma 82 1.9L AAZ td westy
On Jan 23, 2014 1:28 PM, "Will Taygan" 
wrote:

> I have factory install rings on Kobenschmidt pistons. What would
> measuring the end gap tell me other than whether the bore is shot? Will
> it tell me if the rings are worn-out?
>
> Factory rings in +1mm would set me back over $400, Hastings about $100
> and Grant $25. I was leaning towards the Hastings, but really have no
> idea..
>
> Is there a downside to honing and installing new rings? Will they only
> help or could it hurt? Not looking for long-longevity, not burning any
> oil, cold start is acceptable, but I am looking to increase power..
>
> I'm pushing a Westy with the 1.6NA, and can really notice the power drop
> as compression has gone from 450+ down to ~400.
>
> I don't have any piston tools, so I'm shying away from re-ringing,
> unless it'll help with power and not damage what's in there.
>
> Would the coolant loss and oil pressure loss burn out the rings, or
> mostly just hit the bearings (or valves??)
>
> Thanks,
>
> Will in Alaska.
>
>
> On Wed, 2014-01-22 at 11:23 -0500, lbaird119 at aol.com wrote:
> > Since you'll have the head and pan off, I'd pull a piston and measure
> the end gap. (pull top ring, put it in the cylinder then flip the piston,
> push down until second ring stops it, remove and measure the gap.) I only
> say this because I had a rebuild where the rings wore excessively due to
> the shop not honing the bore coarse enough. Otherwise I'd say you have no
> indications to need to look.
> >
> > Looks like you're leaking between #2 and #3 mostly with #2 possibly
> leaking a little into the water jacket but not enough to blow coolant.
> >
> > Never use oil on a hot compression test, especially on a diesel. I
> had a 302 Ford fire on me and peg my gauge, a diesel certainly could.
> > Loren
> >
> >
> >
> > -----Original Message-----
> > From: Will Taygan 

> > To: vwdiesel 
> > Sent: Tue, Jan 21, 2014 6:51 pm
> > Subject: [Vwdiesel] Should I Re-Ring?
> >
> >
> > (Crossposting from the Diesel-Vanagon group:)
> > Background: 82 Stock-ish 1.6NA - 2yrs+35k on bored +1mm rebuild. Lost
> > oolant at 10k, lost oil pressure at 34k. Still running. Was running
> > ot on hills under load, replaced thermostat and radiator, helped (like
> > erfect) for a couple weeks, now running hot and cold every couple
> > iles. Oil in coolant, replaced oil cooler, coolant tank stays full.
> > Plans: replace head gasket, swap oil pan for a turbo pan (a delayed
> > roject) and install new Peloquin trans coming this week from
> > ATransaxle.
> > ** Compression 400,345,370,400 (HOT), 450,390,440,450 with a spoonful of
> > -cycle oil. Is a +50psi with oil sealing like this expected on normal
> > ings, or would there be a benefit (or disadvantage) to putting new
> > ings in?
> > Probably should have replaced the headgasket a long time ago, but my
> > ompression tester was broken, and it HAS been driving daily (though
> > ust on local roads, not the highway).
> > SHOULD I RE-RING? I'll have head and pan off anyway, but it would be
> > n-rack with crank in. I have another engine to rebuild when this one
> > ies, but I would really like to get this one in shape for summer.
> > Thanks for you opinions! I have disassembled a bunch of parts engines,
> > ut have never done rings or put pistons back in.
> > Will in Alaska.
> >
> > ______________________________________________
> > wdiesel mailing list
> > wdiesel at vwfans.com
> > ttp://www.audifans.com/mailman/listinfo/vwdiesel
> >
> > _______________________________________________
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>
>
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