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> Head gasket, Is this the VW bulletin?
DavidSweden
post Nov 19 2014, 01:51 PM
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I am currently rebuilding engine. In order not to tire everyone with a lot of newbie questions I have been searching the forum (thanks for the tip CapĀ“n).

There has been a lot of debate about using or not using head gaskets. Is this the VW tech bulletin which has been referred to in some of the post recommending not to use the head gaskets? VW Tech bulletin head gasket

David
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r_towle
post Nov 19 2014, 02:03 PM
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that is the basic explaination.

I would suggest you assemble the motor dry and measure your deck height (top of piston to top of cylinder) to determine your compression ratio first.

then you can use a combination of a head gasket (if you chose) and a cylinder base shim to set your CR properly.

Those measurements stated in the bulletin may not even be close to what you really need.
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Elliot Cannon
post Nov 19 2014, 07:20 PM
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FAT Performance uses head gaskets. European Motorworks uses head gaskets. As it turns out, so do I. (IMG:style_emoticons/default/biggrin.gif)
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r_towle
post Nov 19 2014, 07:56 PM
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QUOTE(Elliot Cannon @ Nov 19 2014, 08:20 PM) *

FAT Performance uses head gaskets. European Motorworks uses head gaskets. As it turns out, so do I. (IMG:style_emoticons/default/biggrin.gif)

You use lots of things that maybe only you would use (IMG:style_emoticons/default/biggrin.gif)

A three letter acronym of a certain substance that smears all over the place.....
Things like that ....
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ThePaintedMan
post Nov 19 2014, 08:45 PM
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(IMG:style_emoticons/default/stromberg.gif)
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Mark Henry
post Nov 19 2014, 09:57 PM
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I don't use them, new AMC heads have a big red warning tag telling you not to use them.

But I do check CR and use cylinder shims.
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Cap'n Krusty
post Nov 19 2014, 10:10 PM
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That's it. Applies ONLY to certain VW Bus engines, NOT 914s.

The Cap'n
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Jake Raby
post Nov 20 2014, 12:23 AM
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I haven't built a single engine with head gaskets since 1997. I've never had an engine come back to me with a head leak, either.

The key to keeping the heads sealed off is controlling expansion, and the key to controlling expansion, is directly related to thermal control.

To me, the part thats not there, can't fail... I'd pull them out even if I never saw the VW bulletin.
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DBCooper
post Nov 20 2014, 01:39 AM
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QUOTE(Cap'n Krusty @ Nov 19 2014, 08:10 PM) *

That's it. Applies ONLY to certain VW Bus engines, NOT 914s.

The Cap'n

Do something for me, Cap'n. Look at the date on that bulletin. Manufacturers are required to support their products for ten years, meaning Volkswagen had an obligation to issue that bulletin while Porsche, who had stopped selling cars with those engines more than ten years previously, had no obligation. But they're the same engine if installed in a Volkswagen or a Porsche, aren't they? So why would VW's advice be any different if their engines were installed in Porsche cars or VW's?

The problem VW was addressing was the tendency of their head gaskets to fail and burn through the gaskets, usually but not always on high mileage engines. Aircooled engines run hot and the VW design sandwiches an iron cylinder between an aluminum case and an aluminum head, where the heat cycles from normal use repeatedly compress the head gasket, eventually consuming all its flexibility and ability to seal. Combustion will eventually erode through a head gasket, and usually take the head with it. You may have never had the problem, I don't know, but Volkswagen did, and they had it a lot. They didn't issue that bulletin frivolously, defective products are a very hard and expensive thing for any car company to admit. It's not an imagined problem, there was a good reason.

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ClayPerrine
post Nov 20 2014, 05:46 AM
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QUOTE(Cap'n Krusty @ Nov 19 2014, 10:10 PM) *

That's it. Applies ONLY to certain VW Bus engines, NOT 914s.

The Cap'n



(IMG:style_emoticons/default/agree.gif)

Nothing in that bulletin addresses the 914.
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Mark Henry
post Nov 20 2014, 08:15 AM
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I haven't built a engine with head gaskets in at least 15 years, I've only ever had one engine failure and it was the last head gasket I used. Blow torched right through it.

Even Porsche eliminated head gaskets on the 3.2, but I guess that's OK because the factory did it. (IMG:style_emoticons/default/rolleyes.gif)
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r_towle
post Nov 20 2014, 09:23 AM
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QUOTE(Mark Henry @ Nov 20 2014, 09:15 AM) *

I haven't built a engine with head gaskets in at least 15 years, I've only ever had one engine failure and it was the last head gasket I used. Blow torched right through it.

Even Porsche eliminated head gaskets on the 3.2, but I guess that's OK because the factory did it. (IMG:style_emoticons/default/rolleyes.gif)

worked well on the 3.6....which they ended up putting the head gasket back in under a TSB after a few years of problems.

On a type 4, I do not run them.
I also dont plan to see 100k miles on any of my type 4 motors before I die...
I am far to ADHD to wait that long, so I change the motor around anyways every once in a while.
My latest rebuild lasted (in my head) about 1 hour...now I MUST change the camshaft not due to any breakage, I just chose the wrong camshaft for my goals.

I would not use one, Like Jake said, its one less variable that you have to worry about.

Rich
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Highland
post Nov 20 2014, 09:56 AM
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When I worked on my motor I searched all the threads on head gasket usage and noticed people only talk about head gasket failure.

For those of you in favor of using the head gasket, what's the failure when no head gasket is used? Has anyone experienced a head seal or overheat issue because of no head gasket?
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DBCooper
post Nov 20 2014, 10:19 AM
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The Porsche six cylinder engines aren't really comparable. First because they have individual heads, so get more uniform clamping, and they have aluminum cylinders between aluminum heads and case, all similar metals. The cast iron cylinders in the VW T4 motors are the real problem because they react differently in the heat expansion/contraction cycles than the aluminum heads and case.

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Jake Raby
post Nov 20 2014, 10:25 AM
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QUOTE(DBCooper @ Nov 20 2014, 08:19 AM) *

The Porsche six cylinder engines aren't really comparable. First because they have individual heads, so get more uniform clamping, and they have aluminum cylinders between aluminum heads and case, all similar metals. The cast iron cylinders in the VW T4 motors are the real problem because they react differently in the heat expansion/contraction cycles than the aluminum heads and case.

The 911T had iron cylinders.
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DBCooper
post Nov 20 2014, 10:29 AM
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QUOTE(Jake Raby @ Nov 20 2014, 08:25 AM) *

QUOTE(DBCooper @ Nov 20 2014, 08:19 AM) *

The Porsche six cylinder engines aren't really comparable. First because they have individual heads, so get more uniform clamping, and they have aluminum cylinders between aluminum heads and case, all similar metals. The cast iron cylinders in the VW T4 motors are the real problem because they react differently in the heat expansion/contraction cycles than the aluminum heads and case.

The 911T had iron cylinders.

Sorry. So Porsche sixes "generally" use aluminum cylinders, but point's the same, they aren't a good comparison.

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stugray
post Nov 20 2014, 10:30 AM
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QUOTE(Mark Henry @ Nov 20 2014, 07:15 AM) *

I haven't built a engine with head gaskets in at least 15 years, I've only ever had one engine failure and it was the last head gasket I used. Blow torched right through it.


The "blowtorch effect" is made worse with the headgaskets because it creates a sandwich of dissimilar materials. Once a leak occurs with the gasket, the heads are usually toast. I think the copper in the gasket makes it worse.
If a leak occurs without a gasket, there is a greater chance of saving the head.

I have not used the gaskets since my first type IV rebuild in ~89.
Since that was almost before the internet, I have no idea where I even learned to NOT use them.

Never had a blowout either. (IMG:style_emoticons/default/cheer.gif)
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Cap'n Krusty
post Nov 20 2014, 10:31 AM
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QUOTE(DBCooper @ Nov 19 2014, 11:39 PM) *

QUOTE(Cap'n Krusty @ Nov 19 2014, 08:10 PM) *

That's it. Applies ONLY to certain VW Bus engines, NOT 914s.

The Cap'n

Do something for me, Cap'n. Look at the date on that bulletin. Manufacturers are required to support their products for ten years, meaning Volkswagen had an obligation to issue that bulletin while Porsche, who had stopped selling cars with those engines more than ten years previously, had no obligation. But they're the same engine if installed in a Volkswagen or a Porsche, aren't they? So why would VW's advice be any different if their engines were installed in Porsche cars or VW's?

The problem VW was addressing was the tendency of their head gaskets to fail and burn through the gaskets, usually but not always on high mileage engines. Aircooled engines run hot and the VW design sandwiches an iron cylinder between an aluminum case and an aluminum head, where the heat cycles from normal use repeatedly compress the head gasket, eventually consuming all its flexibility and ability to seal. Combustion will eventually erode through a head gasket, and usually take the head with it. You may have never had the problem, I don't know, but Volkswagen did, and they had it a lot. They didn't issue that bulletin frivolously, defective products are a very hard and expensive thing for any car company to admit. It's not an imagined problem, there was a good reason.


"But they're the same engine if installed in a Volkswagen or a Porsche, aren't they? " No, they're not. The head design on the 2.0 914 is substantially different from that of the Bus. "Supporting" the engines means supplying parts, NOT fixing them or addressing problems beyond the written warranty period. You see Porsche supplying a "fix" for the smogged up 2.7 ten years down the road? Or, beyond defective valve guide replacement, even during the warranty period? I think not. You'll note the changes under discussion affect only certain original and factory remanufactured engines, hence the statement: "These changes effect Engine codes: GD, GE, CV." Note the elimination of head gaskets goes along with piston lubrication, increased piston to cylinder clearances, and replacement of the paper base gaskets.

I know Jake doesn't use head gaskets, and we've had discussions to that effect. He does a lot more engines than I, and he doesn't just "rebuild" them. EVERY case is selected and remanufactured according to strict guidelines he has established for his work. Few, if any, are what you would call "routine rebuilds". Most, in fact, are what you could call "modified for performance purposes". Some cost a lot more than the cars they're going into.

If you're willing to put the kind of basic prep work into your engine that Jake does, the absence of head gaskets is probably not going to be a bad thing. How many folks here have the cases checked for warpage, and corrected both at the bore AND the deck? People on this forum complain about the cost of a rebuild, and they don't even do a proper "remanufacture". Most just do the minimum and forget it until something fails prematurely. Not so Jake, and not so me.

The Cap'n
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DBCooper
post Nov 20 2014, 11:09 AM
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The 2.0 heads have a different combustion chamber, sure, but how, exactly, are the sealing surfaces any different? Again, the engine codes cited were the only ones sold by VW in that ten year period, meaning those were they only engines that VW was obligated to address. And the sealing of the heads in those particular engines are no different than any other T4 engine that came before. Only difference is falling within that 1980-1990 period or not.

Those were VW's instructions to re-manufacturers of VW products, so why exactly would it make a difference whether it's a production rebuilder, a local shop, or a home mechanic? VW's only obligation is to detail best practice recommendations, and that's what they did. At this point both Porsche AND VW are out of the picture. You know their best-practice recommendations, whether or not you follow them is your choice.



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Elliot Cannon
post Nov 20 2014, 12:38 PM
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QUOTE(r_towle @ Nov 19 2014, 05:56 PM) *

QUOTE(Elliot Cannon @ Nov 19 2014, 08:20 PM) *

FAT Performance uses head gaskets. European Motorworks uses head gaskets. As it turns out, so do I. (IMG:style_emoticons/default/biggrin.gif)

You use lots of things that maybe only you would use (IMG:style_emoticons/default/biggrin.gif)

A three letter acronym of a certain substance that smears all over the place.....
Things like that ....

RTV is NOT an acronym. (IMG:style_emoticons/default/poke.gif) FAT Performance uses it, European Motorworks uses it and as it turns out, so do I. (IMG:style_emoticons/default/av-943.gif)
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