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Date:         Fri, 16 Jan 2004 08:01:11 EST
Reply-To:     THX0001@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         George Goff <THX0001@AOL.COM>
Subject:      Re: Exhausting Exaust
Content-Type: text/plain; charset="US-ASCII"

In a message dated 1/15/04 6:01:06 AM, RAlanen@AOL.COM writes:

<< . . . No way you can go there with a drill to drill out the broken studs & bolts. . . .

. . . If the nuts and bolts break off the best way is drop the engine. . . .

. . . Then drill out the broken bolts & studs, fit helicoil thread repair inserts to all eight locations then use stainless steel bolts of the proper length at ALL locations.

. . . Clean up the exhaust port gasket surface before putting the engine back. Good clean surface here is IMPORTANT to having the gaskets seal well. ALSO, use Loctite Ultra Copper High Temp Silicon Sealant on both sides of the gaskets. . . .

. . . To make all this expensive work worthwhile and to not have to visit this scene again sometime in the future think about fitting a stainless steel exhaust system. See my _STEBRO/Vanagon Stainless Steel Exhaust System. . . Cheers,

Frank Condelli >>

While I agree with some points here, I disagree with others.

It is possible to drill out a broken stud and install a HeliCoil with the engine in place. To be done with certainty, the work requires a close quarters right angle drill motor, aircraft drills (or shortened jobber's drills) and an accurately made drill plate to keep the drill perpendicular. Dropping the engine certainly makes the work much easier, but for one hole it is hard to justify the hassle.

I prefer key locking inserts to HeliCoils because they will never back out with the fastener as has known to happen with HeliCoils. Also, the inserts use standard sized taps instead of the dedicated taps required by HeliCoils.

One dodge for someone stuck in the middle of the night with no access to a proper repair insert is to tap the hole to a 3/8-16 thread. A stripped 8mm tapping is already very near the tap drill diameter (5/16") of a 3/8-16 thread anyway. If the 3/8-16 tapping gets bitched, there is still enough material remaining to drill the hole for a HeliCoil or some other type of repair insert.

I also use stainless steel fasteners to secure the header pipes, but I prefer to use studs instead of capscrews (aka, bolts). I adjust the head pipes so that they are an easy fit over the studs instead of fighting and prying the pipes into place only to strip a thread by running in a cocked capscrew. The first van I bought had the material of the head beside one of the studs broken out. I was puzzled about how that could happen until the first time I renewed an exhaust system. Then, I imagined the wrestling match that must have occurred until the stud broke free of its hole.

The use of Loctite Ultra is dubious at best. There are various exhaust sealants, Loctite Ultra is not one of them. A properly prepared gasketed flange joint does not require it and, like smearing RTV on an O-ring, it might cause more harm then good.

I tried aftermarket exhaust parts more than once before I returned to using the real deal, i.e., VW-OE-bought-from-the-dealer. My experience with aftermarket exhaust parts echoed the sage advice I received many years ago from Gordi of 4ever4 in New Hampshire whenever I asked if he sold stainless exhaust parts. He said that an OE system is a proven quantity which lasts for 100K, so, what more could you ask for?

While I have never used the Stebro system, what I have seen of it does not impress me. From the first time I realized that the things of my world did not drop out of the sky, but were made by man, I have been taught to use the fewest connections possible in any fabrication be it electrical, piping or mechanical in nature. It is the hallmark of a craftsman to do such work. Yet, the photo's posted of the Stebro muffler show what appears to be a clumsy assemblage of patch pieces stuck together with sloppy welds. Someone far wittier than myself has called it a "Spam can" muffler.

Also, the mounting brackets (?) attached to the Stebro appear to have been designed more as an expediency to allow a wide latitude in the fit of the muffler than to hold it fast.

Perhaps, above all else, it is made of Type 409 SS which, although it is filling the racks of every muffler shop in the Free World, is only recommended for use in mildly corrosive conditions. The material of choice for corrosion resistance at elevated temperatures is Type 321 SS and for the cost of the Stebro system nothing less should be used.

George


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