Date: Tue, 10 May 2011 20:37:00 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: 2.1 rebuild - new nuts for case halves-thoughts for all
bolted connections.
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still can not see why anyone would want a fastener of a dissimilar weaker
metal, when there is absolutely nothing wrong with the orignal fasteners.
do whatever you want ..
but it's introducing something you don't need that may not be as good.
..this stainless nut idea.
as for head gasket failures being a fastner failure..
one some yes.
on a typical waterboxer ..
it's not usually a fastener failure that I know of .
it's not like the studs stretch and fail, or the nuts get loose.
it's that the design is a joke,
and aluminum does not like the same old coolant in the engine for 15+ years.
there are two sealing surfaces ..on this head gasket design. That's a
mistake right there.
it's the only head design in the entire automotive world like this.
All other engines and manufactuers are smart enough to make both combustion
and coolant sealing on one flat surface !
one is the metal rings at the tops of the barrels.
the heads are held down onto these metal rings by the nuts on the studs.
the torque on the nuts is 37 foot lbs ( or very close to that ) ..not much
as cylinder head nuts go, not much at all.
It does however, seem to work well enough ...keeping combustion pressure
inside the combustion chamger, and coolant out of the combustion chamber,
those metal rings and the sealing there. It is directly related to the
previous air-cooled design of course. No other watercooled engine anywhere
uses the 'two step' joke sealing system that the waterboxer engine does..
The small green o-rings on the barrels just below the metal rings are there
to keep coolant away from those metal rings. The green o-rings get hard and
don't seal after a few years. Usually there are just hard little strings
stuck in their grooves. Not doing much after sevearl years in service.
so one surface or level is for combusion sealing ..
the other sealing is to keep coolant in the engine.
the cyinder head studs and nuts have nothing to do with how well the outer
rubber gasket is compressed.
the head bottoms out on the metal rings on top of the barrels, and the
rubber gasket 'gap' is supposed to be 'just right'.
Sometimes it is ...often it is. Sometimes..........the gap is too large and
the rubber gasket does not get compressed enough. More common, it's too
small, and the rubber gasket gets pinched and fails early.
that is a design issue.
there is no adjustment for that rubber gasket gap.
Other than ..machine work..
and most machine shops are set up to surface the flat bottom of normal
heads, and they reference off the top of the head..
which won't work on a wbxr head.
the reference point is inside the combution chambers..
not only is it the distance , what I call the 'step distance' between those
two levels or sufaces ..it is also that it's level across the head, ideally
both combustion chambers are dead parrallel, and the flat bottom of the head
is the exact correct distance from them, and parrelel.
And both barrels sit in the block just right.
Fastener weakness doesn't affect the outer water gasket at all.
Those rubber gaskets fail from age, and from corrosion of the aluminum
head..
in one extra bad case, a piece of the block was corroded away even on one
engine.
Nothing to do with fasteners.
it's design ..
and it's neglect.
sure ..on old bugs and busses..
the studs were forever pulling out of the case.
it used to be standard practice to bore out and tap the case for inserts,
that the cyl head studs screwed into.
not a problem on waterboxer engines though ..
very good studs. The only thing they suffer from is ..
corrosion.
in a bad situation they break right off at their base, and that's extremely
hard to repair ..
Corrosion is the main enemy really ..
it's not that many fasteners are inherantly weak..
it's that metal corrodes,
and people do not change fluids enough.
and rust happens from road salt and crud.
and people don't treat it and address it.
and they don't spray lubricant on things nearly often enough.
I 'suppose' stainless may resist corrosion better for a while..
that it is a disimilar metal bothers me ..and it's weaker too.
I would concentrate on a really solid head gasket job ..
becuase that is a distinct design weakness. The fasteners are just fine
though.
I'm surprised on one has made a silicone outer rubber gasket somewhere..
or a 'galvanonmeter' readout on the dash to tell you when the coolant is
loosing effectiveness.
btw..
as I have mentioned many, many times, I use a bit of water soluble oil in my
coolant mixtures ..
machinist's cutting oil..as a rust inhibutor and water pump lube, I swear by
that in coolant to prevent corrosion.
heck...here is how important chagning the coolant is, and using a good
mixture ..
we all know 'the head gasket' will go if the coolant is never changed,
right?
I have a cast iron block 1.9 AAZ VW turbo diesel engine here from europe
originally.
That engine uses a multi-layer steel head gasket..
really tough stuff , very unlikely to fail in small areas like regular
engine head gaskets can.
And the cooling system was pure rust. Most likely coolant was never changed
in 10 plus years.
I get it all apart and all cleaned up..
and instead of the head gakset being toast from corrosion ..the top of the
cast iron block is pitted....really bad corrosion there. If you want to
resurface that ..the whole engine should be stripped down and bare block go
to a mchine shop ..
then, since it's a diesel ....you have to pay careful attention to head
gasket thickness.
Machine shop says can take off about 4 thousandths, but not less.
that calculates out to the thickest head gasket will be all right ..
but ...if it needs to be rebuilt again ...and a thicker yet head gasket is
needed then..there may not be one..
Kind of a pickle ...the 'real repair' is a new block or good used one.
not a fastener failure either ..
Corrosion baby ..
that is the main enemy.
anyway ..it's all fun.
scott
www.turbovans.com
----- Original Message -----
From: "Tom Lambas" <twlambas@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, May 10, 2011 7:38 PM
Subject: Re: 2.1 rebuild - new nuts for case halves-thoughts for all bolted
connections.
> Oops, forget about the seat belts. I got them from Max Wellhouse.
>
> On Tue, May 10, 2011 at 9:23 PM, Tom Lambas <twlambas@gmail.com> wrote:
>
>> Thanks Dennis,
>>
>> I have all my old case nuts, washers, and through-bolts soaking in
>> naptha,
>> I ordered a bag of type 1 case assembly hardware also. At the very least,
>> I'll be able to use the 4 nice sealing nuts for the oil pump, and
>> hopefully
>> end up using mostly new hardware.
>>
>> BTW, I used almost all of your seat belt stuff. I was surprised at how
>> worn
>> all the seat belts were in my van.
>>
>> Cheers,
>>
>> Tom in Minneapolis
>>
>>
>> On Mon, May 9, 2011 at 10:41 PM, Dennis Haynes
>> <d23haynes57@hotmail.com>wrote:
>>
>>> Here are two links that give some good information. One is how a clamped
>>> or
>>> bolted connection works and is indicative of case main bearing bolts and
>>> rod
>>> bolts. The other is the relative strengths of various grades of
>>> fasteners.
>>> Note the difference in strength of the A2 or A4 stainless as compared to
>>> property class 10.9. This class is the most common class used on the
>>> Vanagon. The real important stuff can be 12.9. In order for these bolted
>>> connections to work the nut and if used washers need to be matched. The
>>> nut
>>> has to be strong enough to stretch the bolt and get it under tension.
>>> The
>>> washer has to carry that load. If the washer distorts then the
>>> connection
>>> becomes loose.
>>>
>>> In addition to the strength of the material, finish, (zinc, black oxide,
>>> chrome, cadmium, organics) and lubrication, (oil, anti-seize, sealants,
>>> Loctite) will affect the torque required to reach a given clamp load.
>>> Black
>>> oxide, organics, and cadmium are often used on high strength fasteners
>>> as
>>> they provide more consistent torque tensioning. Zinc is sometimes an
>>> issue
>>> as it may cause hydrogen embrittlement. Some lubricants or wax coatings
>>> can
>>> reduce required torque by 40% or more. Consider that when thinking of
>>> never
>>> seize on your lug bolts.
>>>
>>> Many engine problems or failures come down to fluid problems or fastener
>>> failures. Internal head leaks, (gasses in coolant or coolant in
>>> cylinder)
>>> if not due to an actual cracked head are really a fastener failure. A
>>> problem is that engines will often be repaired or rebuilt without
>>> addressing
>>> the failed part.
>>>
>>> Dennis
>>>
>>>
>>> http://www.unified-eng.com/scitech/bolt/clamping.html
>>>
>>> http://www.tessco.com/yts/customerservice/techsupport/whitepapers/pdf/bolt_g
>>> rade.pdf
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
>>> Of
>>> Daniel Rotblatt
>>> Sent: Thursday, May 05, 2011 12:05 PM
>>> To: vanagon@GERRY.VANAGON.COM
>>> Subject: Re: 2.1 rebuild - new nuts for case halves
>>>
>>> There have been several discussions on other forums about this.
>>> Essentially, if it's a torqued nut then the torque setting is defined by
>>> the
>>> type of nut and stud - stainless (or different grade nuts for that
>>> matter)
>>> require different to torque settings. Saying "stainless is not as
>>> strong"
>>> is incorrect - like different grades of nuts, it depends on the alloy of
>>> the
>>> stainless. I imagine that standard stainless nuts may be "less strong"
>>> then
>>> standard non-stainless nuts, but that is still a generalization. The
>>> alloys
>>> used in stainlesss (and there are many many alloys) give the metal
>>> different
>>> properties then carbon steel. There is even a problem changing the
>>> strength
>>> class (using grade 8 nuts/bolts when grade 5 are specified) - some
>>> nuts/bolts are specified because they are supposed to fail at a certain
>>> stress to prevent further damage to the engine - and of course there's
>>> that
>>> torque issue again.
>>>
>>> The upshot, is that if it's a torqued nut, use the manufacturer
>>> specified
>>> if
>>> possible. If you replace with stainless when not specified, you take a
>>> chance that the nut will fail. Doesn't mean it will, just that it may
>>> or
>>> may not be within proper specifications (thus Franks observation that he
>>> uses stainless hardware and does not have failure).
>>>
>>> Dan
>>> Los Angeles, CA
>>> '85 Westy Weekender
>>>
>>> On May 5, 2011, at 2:33 AM, Frank Condelli wrote:
>>>
>>> > I beg to disagree. All engines I have rebuilt here get
>>> > stainless hardware everywhere possible. Never seen any problems
>>> > related to the use of stainless hardware on the engine cases or
>>> > elsewhere. See here > http://www.frankcondelli.com/21engpcs.htm
>>> >
>>> >
>>> > On 2011-05-05, at 12:00 AM, Automatic digest processor wrote:
>>> >
>>> >> I sure would not be putting any stainless fasteners on it.
>>> >> they are not as strong ..
>>> >> stainless is not titanium or 'fautless' like people want to think it
>>> >> is.
>>> >
>>> >
>>> >
>>> > Cheers,
>>> >
>>> > Frank Condelli
>>> > Almonte, Ontario, Canada
>>> > '87 Westy & Lionel Trains (Collection for sale) Frank Condelli &
>>> > Associates - Vanagon/Vanagon Westfalia Service in the Ottawa Valley
>>> > Vanagon Stainless Steel Exhaust Systems BusFusion a VW Camper camping
>>> > event, Almonte, ON, June 09 ~ 12, 2011
>>>
>>
>>
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