Type 1 pushrod tube seals - getting it right

All,

First the alternator takes a dump. Have the thing towed home, pull
engine, replace alternator.
Then the alternator pulley splits in two. Tow home a 2nd time, replace
pulley.
Now..it leaks oil. In late 2002 I pulled the engine and resealed the
top-end and it has remained dry until now. So I pulled the engine
again, and starting on the passenger side I removed the head and
cylinders. My intent is to apply a new bead of RTV to the base of the
cylinders, and replace the pushrod tube seals. Said pushrods are now
sporting a fresh coat of FlatBlack.

What I am trying to figure out is the talk of the 'lip' on late model
head castings that can create a problem for the pushrod tube seals.
Bob Hoover posted a description about the 'lip' several years ago,
which I re-read today, but honestly I haven't been able to figure it
out. So, I picture myself being a pushrod tube, looking into the head.
I see a tapered hole. The bottom of the hole on the head I pulled
tonight has a vertical 'wall' at the BOTTOM of the pushrod tube hole.

Anyway, I took a picture. Is this the 'lip' that I should dremel down
into a nice radius and then clean and reinstall the head? The engine
was dry until I pulled it to change the alternator. The leak I think
is a result of two pushrod tube seals that were brittle and me pushing
and pulling on things during the engine removal that pushed the
marginal seals over the edge. All this despite the fact that the seals
I used in 2002 were the preferred 'white' style. Bummer. I have 16 new
ones to install along with new tarboard. And the new transaxle mounts
are in, thanks. ;-)

Since pulling my engine isn't something I like doing I'd prefer to
seal this up right NOW and not have to mess with it again until the
engine is at TBO.

http://digitalpics00.no-ip.org/~halatos/****edOffVW

Yeah, the first picture is of my garage floor covered with engine.
It's an unholy mess in there right now and I need to fix it
RealSoonNow. Company showing up next week, any advice would be
appreciated....

Chris

Dear Chris,

I see no evidence of leakage at the push-rod tube gaskets. The
sealing surface is nice & clean and the lip that caused the trouble I
wrote about some years ago is not evident in your pictures. And no,
the edge you're pointing to in the second picture does NOT need to be
Dremeled; it should seal just fine.

However... the four stays (or 'studs,' if you prefer) that are
secured inside the valve gallery do not show any evidence of sealant.
The holes -- and the washers that go into them -- should receive a
light coating of sealant since the washer must provide an oil-tight
seal. I've found it works best to apply the sealant to the eight
washers and eight holes some time BEFORE installing the heads. This
gives the sealant a chance to partially cure and prevents it from
being squeezed out when the stays are torqued-up.

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.

But as for leaky push-rod tubes, I saw no evidence of that in the
pictures you've provided.

-Bob Hoover

Hi Bob,

> I see no evidence of leakage at the push-rod tube gaskets. *The
> sealing surface is nice & clean and the lip that caused the trouble I
> wrote about some years ago is not evident in your pictures. *And no,

The reason there is no visible evidence is I already removed it I
had already cleaned out the sealer from the lower head stays and the
residue from the bottom of the head casting.

The 'leak' was from the passenger side of the block, that entire
portion of the casting would be wet after a drive. I could clean it
all off, go for a short drive, pull in the garage, take a look..no
leak. Come back an hour later..I see oil. Then the oil would collect
onto the area where the sled- tin screws normally go into the block
and from there drip off onto the floor. When I removed the head and
was able to finally see the top of the pushrod tubes, two of them were
covered in a mix of dirt and oil. In addition, two of the seals were
hardened.

> the edge you're pointing to in the second picture does NOT need to be
> Dremeled; it should seal just fine.

Okay good thank you.

> However... *the four stays (or 'studs,' if you prefer) that are
> secured inside the valve gallery do not show any evidence of sealant.

Yeah, I cleaned that out. Last time I put this together I used the
orange high-temp RTV, the stuff that smells like...vinegar. I won't be
using that again having read that it can attack the metals, this time
I'm going to try the blue 'sensor safe' RTV for sealing the cylinders
to the block and the lower head-stay washers to the head.

> 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

Case in point..when I did this job last time, as I've described..I put
everything back in, drove for a few days and went to take a look to
see if I had caught everything. I saw a small bit of fresh oil coming
out from the rocker arm studs on the inboard side of the head. I
didn't have any O-rings handy when I assembled the engine, and I
figured..there's just no way any oil can get between the head and the
rocker shaft attachment points. Wrong. So I took the rocker shafts
back off, shot a bit of RTV into the 'hole' where the O-ring would
normally go..and it has remained dry.

> But as for leaky push-rod tubes, I saw no evidence of that in the
> pictures you've provided.
>
What I noted after removal of all of the sheet metal is that the
alternator tower looked like it was leaking a bit from the back side,
so I took it off and gave it a coat of paint and will re-seal it
tonight. The top of the block, aside for the part directly behind the
alternator stand, was dry. The oil cooler was dry. The drivers side of
the engine is dry. Hopefully a properly sealed alternator stand,
cylinders and new pushrod tube seals will chase the drips away.

Thank you...

Chris

Did you measure the length of the pushrod tubes?
And stretch them as needed?
I think normally it should be 7.5". I forgot if that is total length or
seal seat to seal seat on the tube.

I like the black RTV and I think that some RTVs don't handle the oil or heat
as well as others. ;-)
Not sure you really need the high temp stuff.
AND for the pushrod tube seals I prefer the liquid sealant.

I like that you are searching out and repairing the leaks! 8^)

good luck with it!
One out of many daves


> wrote in message
...
Hi Bob,

> I see no evidence of leakage at the push-rod tube gaskets. The
> sealing surface is nice & clean and the lip that caused the trouble I
> wrote about some years ago is not evident in your pictures. And no,

The reason there is no visible evidence is I already removed it I
had already cleaned out the sealer from the lower head stays and the
residue from the bottom of the head casting.

The 'leak' was from the passenger side of the block, that entire
portion of the casting would be wet after a drive. I could clean it
all off, go for a short drive, pull in the garage, take a look..no
leak. Come back an hour later..I see oil. Then the oil would collect
onto the area where the sled- tin screws normally go into the block
and from there drip off onto the floor. When I removed the head and
was able to finally see the top of the pushrod tubes, two of them were
covered in a mix of dirt and oil. In addition, two of the seals were
hardened.

> the edge you're pointing to in the second picture does NOT need to be
> Dremeled; it should seal just fine.

Okay good thank you.

> However... the four stays (or 'studs,' if you prefer) that are
> secured inside the valve gallery do not show any evidence of sealant.

Yeah, I cleaned that out. Last time I put this together I used the
orange high-temp RTV, the stuff that smells like...vinegar. I won't be
using that again having read that it can attack the metals, this time
I'm going to try the blue 'sensor safe' RTV for sealing the cylinders
to the block and the lower head-stay washers to the head.

> 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

Case in point..when I did this job last time, as I've described..I put
everything back in, drove for a few days and went to take a look to
see if I had caught everything. I saw a small bit of fresh oil coming
out from the rocker arm studs on the inboard side of the head. I
didn't have any O-rings handy when I assembled the engine, and I
figured..there's just no way any oil can get between the head and the
rocker shaft attachment points. Wrong. So I took the rocker shafts
back off, shot a bit of RTV into the 'hole' where the O-ring would
normally go..and it has remained dry.

> But as for leaky push-rod tubes, I saw no evidence of that in the
> pictures you've provided.
>
What I noted after removal of all of the sheet metal is that the
alternator tower looked like it was leaking a bit from the back side,
so I took it off and gave it a coat of paint and will re-seal it
tonight. The top of the block, aside for the part directly behind the
alternator stand, was dry. The oil cooler was dry. The drivers side of
the engine is dry. Hopefully a properly sealed alternator stand,
cylinders and new pushrod tube seals will chase the drips away.

Thank you...

Chris

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?

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.


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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

-

On Nov 21, 5:44*am, Jan > wrote:

> 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)
---------------------------------------------------------------------------------------------

I'll second that. RTV is lovely stuff for ensuring your tin-ware fits
properly... which it seldom does. Those 'unimportant' little gaps
here & there rob the engine of a surprising amount of cooling air. You
could spend 40 or more man-hours making a set of tin-ware that really
fits. Looked quite neat but it was impossible to justify the cost.
By getting the tin-ware close rather than perfect, RTV was then used
to seal any gaps.

-Bob Hoover

On Fri, 21 Nov 2008 14:44:12 +0100, Jan > wrote:

> 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

The ones I linked to are not RTV but Anaerobic, used by OEM companies like
Piaggio, Mercedes etc.(Even Raby uses the stuff, and he can be a tad
picky).

J.

>



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Jan wrote:
> 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

Yes, I did hesitate to suggest RTV as I see it used on so many hack
jobs. Of course, the Henkel products you suggest are excellent
sealants. Thanks for the tip.

Oh, the RTV you mention that cures without the classic "vinegar smell"
is GE Silicone II (sold I'm sure under several trade names). Unlike
tradition RTV Silicones (which evolve acetic acid as they cure - i.e.
vinegar) GE Silicone II evolves Methanol during it's curing process.
This is generally more favorable since methanol has a neutral PH factor
(less concern about invoking corrosion on metal substrates). I suppose
there might be some plastics that might have some problems with the
methanol, but generally all but the cheapest plastics are fairly alcohol
resistant.

Thanks again for the suggestion.