Type 1 pushrod tube seals - getting it right

Bob Hoover wrote:
> On Nov 20, 4:49 pm, Leopold Stotch > wrote:
>
>> What do you advocate using for the sealant? RTV?
>
> -----------------------------------------------------------------------------------------------------
>
> Most VW sealing chores are handled perfectly well with Permatex. I'm
> not sure what they call it nowadays; 3H or something like that. Usta
> be "Aviation-grade" Permatex. Comes in a little can with an
> applicator brush made into the lid.
>
> RTV -- Room Temperature Vulcanizing -- is primarily used to form a
> compliant (ie, flexible) GASKET rather than being used as a sealant.
> In so far as I know Volkswagen has only recommended RTV once on its
> engines -- as a replacement for the paper gaskets used between the
> crankcase and the cylinder barrels. They may have specified it for
> use on the T4 or on some accessories but I've not run into it.
>
> Volkswagen was one of the first companies to use gasket-less sealing,
> in that the parts were machined so well that they needed only a THIN
> coating of sealant to provide a leak-free fit. But in doing so they
> had to re-educate mechanics to convince them that a thin coat of
> sealant was all that was required; that room temperature torque values
> had to be quite small, and so forth.
>
> -Bob Hoover
>
> -
>

Bob,

Thanks for the information. I particularly appreciate your clarifying
the difference between sealants and form in place gasket compounds.

Another question for you. I've used HondaBond II in place of Permatex
3H for case sealing with good results. Haven't done enough engines to
say that is it better, though others who have claim some improvement.
Have you any experience with Hondabond II and if so do you think it
would be appropriate for sealing pushrod tubes? It is my understanding
that Hondabond II was developed to seal aircooled engines (Honda
Motorcycle and ATV engines specifically) case halves. Certainly would
seem appropriate for ACVW engine applications (at least sealing case
halves).

Thanks,

P.J.Berg wrote:
> On Fri, 21 Nov 2008 01:49:29 +0100, Leopold Stotch
> > wrote:
>
>> Bob Hoover wrote:
>>
>>> I don't think I can point you toward a reference saying these parts
>>> must receive sealant but the general rule is that ANY part subject to
>>> oil MUST receive sealant. Otherwise, it's going to leak. Such leaks
>>> are most evident when the engine is cold. As the engine heats up the
>>> heads will expand. That expansion will cause the washer to form a
>>> leak-free fit with the head... assuming the interface has been given a
>>> coating of sealant.
>>> -Bob Hoover
>>
>> Bob,
>>
>> What do you advocate using for the sealant? RTV?
>>
>
> Loctite 510, 515 or 518:
>
> http://www.henkel.com.au/cps/rde/xch...=1000000 9R4K
>
> http://www.henkel.com.au/cps/rde/xch...=1000000 9R5A
>
> http://www.henkel.com.au/cps/rde/xch...=1000000 9R65
>
>
> Nice short links, eh? #:-]
>
> J.
>
>


RTV has very little use in a VW engine. MAYBE between the cylinder and
the case. I don't use it anywhere.

I have had pretty good results with Mahle cylinder sealant. White
"toothpaste" tube, red print.

They make RTV type stuff without that vinegar smell that doesn't eat
metal. Lots of brands, most call themselves "gasket maker" or something
similar. I sometimes use that to seal engine tin to the case to
eliminate all air gaps. (You know how poorly the aftermarket tin fits,
and it gets worse when the engine dimensions change in a high
performance build)

Jan

Dear Leopold,

I have never used "Hondabond II" so I can't offer an opinion. But as
a point of interest, that applies to an untold number of other
sealants in that, never having used them, I know nothing about them.
Yet at the same time it raises an interesting point: The reason I've
not tried any of the many other sealants is because Permatex works
well enough that I've never felt the need to try other sealants. By
the same token, if I HAD to find another sealant, I would first use it
on a Test Engine, probably something that never left the test-stand --
possibly a 2-stroker, hoping to accumulate more data in less time than
with a 4-stroke.

A second point with regard to "Hondabond II" is that most of Honda's
efforts now involve WATER-COOLED engines. If I had to find a new
sealant I would look for something that was SPECIFIC for air-cooled
engines.

Please understand my position here is not meant to be contentious. I
was shown how to assemble Volkswagen engines in a certain way. Oil
leaks were never a problem and never a point of discussion. There are
a number of difference between what I was taught and the methods &
procedures shown in various popular manuals. People who use those
'popular' methods often complain of oil leaks, causing oil leaks to
become a frequent topic on Groups such as this, where people advocate
different sealants, torque values and so on. I've mentioned the
methods I use but only in the sense of saying: "I do it like this."
There is no need for argument since the engine(s) speak well enough
for themselves. Nor is there any reason for me to experiment with
other sealants since the ones I use don't leak.

In the past I HAVE pointed out that other sealants are available but
that was mostly for non-stock applications, or applications for which
the Factory Service Manuals offered no information. Or for the
notorious 'cardboard' sump-plate gaskets.

-------------------------------------------------------

Some years ago I was invited to attend the assembly of an engine,
partly because the fellow needed help installing the cam gear on the
crankshaft but also for the purpose of my catching any errors the
assembler might make. This was not a comfortable occasion for me but
one I could not gracefully get out of. In fact, I didn't see any
glaring errors but neither did I see anything worth copying. What I
DID see was -- over a period of about four hours -- the assembler
talking on the telephone, talking to friends who dropped by (some of
whom stayed), drinking a couple of beers, searching for tools and so
on.

I came away with the impression that assembling the engine was
something SECONDARY, a matter of less importance than talking on the
phone, chatting with friends, drinking beer and so forth.

I think the point here is that the fellow doing the assembly created a
number of opportunities where errors COULD occur. I can't say if they
did or not, although once assembled he seemed to always be pulling the
engine for one reason or another.

I don't assemble engines in that manner but I don't see any benefit in
advocating my method over his. Clearly, the assembly of the engine
was a matter of lesser importance than other factors to which he
devoted considerable time. I don't know if he had any sealing
problems but I saw several opportunities for such problems to occur.

I've a hunch that people who experience oil leaks or sealing problems
are liable to blame the sealant rather than their assembly methods,
leading to a never-ending search for a 'better' sealant when in fact a
low-cost, commonly available sealant such as Permatex seems to be more
than adequate... so long as it properly applied and the engine is
properly assembled.

-Bob Hoover

On Sun, 23 Nov 2008 06:38:20 +0100, Bob Hoover > wrote:

> Dear Leopold,
>
> I have never used "Hondabond II" so I can't offer an opinion. But as
> a point of interest, that applies to an untold number of other
> sealants in that, never having used them, I know nothing about them.
> Yet at the same time it raises an interesting point: The reason I've
> not tried any of the many other sealants is because Permatex works
> well enough that I've never felt the need to try other sealants. By
> the same token, if I HAD to find another sealant, I would first use it
> on a Test Engine, probably something that never left the test-stand --
> possibly a 2-stroker, hoping to accumulate more data in less time than
> with a 4-stroke.
>
> A second point with regard to "Hondabond II" is that most of Honda's
> efforts now involve WATER-COOLED engines. If I had to find a new
> sealant I would look for something that was SPECIFIC for air-cooled
> engines.
>
> Please understand my position here is not meant to be contentious. I
> was shown how to assemble Volkswagen engines in a certain way. Oil
> leaks were never a problem and never a point of discussion. There are
> a number of difference between what I was taught and the methods &
> procedures shown in various popular manuals. People who use those
> 'popular' methods often complain of oil leaks, causing oil leaks to
> become a frequent topic on Groups such as this, where people advocate
> different sealants, torque values and so on. I've mentioned the
> methods I use but only in the sense of saying: "I do it like this."
> There is no need for argument since the engine(s) speak well enough
> for themselves. Nor is there any reason for me to experiment with
> other sealants since the ones I use don't leak.
>
> In the past I HAVE pointed out that other sealants are available but
> that was mostly for non-stock applications, or applications for which
> the Factory Service Manuals offered no information. Or for the
> notorious 'cardboard' sump-plate gaskets.
>
> -------------------------------------------------------
>
> Some years ago I was invited to attend the assembly of an engine,
> partly because the fellow needed help installing the cam gear on the
> crankshaft but also for the purpose of my catching any errors the
> assembler might make. This was not a comfortable occasion for me but
> one I could not gracefully get out of. In fact, I didn't see any
> glaring errors but neither did I see anything worth copying. What I
> DID see was -- over a period of about four hours -- the assembler
> talking on the telephone, talking to friends who dropped by (some of
> whom stayed), drinking a couple of beers, searching for tools and so
> on.
>
> I came away with the impression that assembling the engine was
> something SECONDARY, a matter of less importance than talking on the
> phone, chatting with friends, drinking beer and so forth.
>
> I think the point here is that the fellow doing the assembly created a
> number of opportunities where errors COULD occur. I can't say if they
> did or not, although once assembled he seemed to always be pulling the
> engine for one reason or another.
>
> I don't assemble engines in that manner but I don't see any benefit in
> advocating my method over his. Clearly, the assembly of the engine
> was a matter of lesser importance than other factors to which he
> devoted considerable time. I don't know if he had any sealing
> problems but I saw several opportunities for such problems to occur.
>
> I've a hunch that people who experience oil leaks or sealing problems
> are liable to blame the sealant rather than their assembly methods,
> leading to a never-ending search for a 'better' sealant when in fact a
> low-cost, commonly available sealant such as Permatex seems to be more
> than adequate... so long as it properly applied and the engine is
> properly assembled.
>
> -Bob Hoover

Have you written something on the topic of proper assembly ?
I have the Sermons, but must admit it is quite some time since I read all
of it. How is the Blue Bentley manual on this topic ?

J.



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Thanks for the answer Bob.

Just to clarify an issue you brought up in your response. Hondabond II
is what Honda recommends for sealing cases of their *aircooled* engines.
I for one also tend to think of Honda as a maker of watercooled auto
engines, but in fact they have a good reputation and do a good business
in making well regarded aircooled engines for motorcycles and ATVs (and
perhaps even snowmobiles if memory serves). Hondabond II is what Honda
recommends for sealing cases on their motorcycle and ATV engines. It is
supposed to seal a little better than Permatex (but as you point out,
once you reach the point of "good enough" (i.e. performs the task at
hand) there is little incentive for improvement). I have heard of guys
that could not get a good seal with Permatex that subsequently got their
case halves to seal up with Hondabond II. Most likely, they were
dealing with mating services that were no longer true and flat or had
been abused by attempting to break them apart with a screwdriver or
other prying tool. The other thing the Hondabond II advocates claim is
that if you ever have to split the case halves apart in the future this
material is easier to remove and clean up as compared to Permatex.

As always, I value your clear thinking and years of experience. Thanks,