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Date:         Mon, 11 May 1998 14:39:27 -0400
Reply-To:     Erik O <koesel@UAKRON.EDU>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Erik O <koesel@UAKRON.EDU>
Subject:      Re: Oil Drain Hole Stripped: 91 Westy: Solutions Needed
Comments: To: "Mark B. Magee" <condor2@FLASH.NET>,
          "Vanagon@VANAGON.COM" <Vanagon@VANAGON.COM>
Content-Type: text/plain; charset=us-ascii

Posted by Mark Keller several months ago ...

Since I'm writing this for archive, I'll include my options and how each one would have worked and cost. Before I do though I like to suggest that on your next trip to FLAPS you buy a "piloted drain plug.", (My 91 VW Van used a 14mm x 1.5mm pitch plug, but check yours with the new one, to make sure you don't have something else.) This drain plug has a 3/8" non-threaded nose on the oil pan end so that it self aligns the plug in the hole, and thus is much easer to start threading in correctly. I've noticed that for me it's much more difficult to start bolts while laying on my side and back and looking up and usually over to the hole. Couple that to the fact that the VW drain hole is just tapped in to the soft aluminuin magnisium alloy case, and damages with little force required by cross threading. A Piloted plug will greatly reduce this cross threading problem.

The drain plug repair had three options for my situation. A stripped out drain hole, from the original sized 14mmx 1.5mm pitch drain plug. All involve removing metal filings from the top of the hole, so do a thorough clean up. Since my ream was not spinning fast like a drill, and I coated it with grease to hold the filings, and I removed and cleaned it several times as I progressed up the hole. I then used a clean cloth and my little finger to gently get all of the filings within reach off from the top edge of the hole I then poured rubbing alcohol into the oil add tube and let is rinse out any remaining filings, which I didn't see any. (I just drove 2000 miles with this repair, so I guess I'm saying the chance is small at actually picking up a filinging into the oil pump, but there is a chance and it gave me great peace of mind to take an extra 10 minutes to really clean out the hole.) Plus you need to do this anyway to prepare the hole for the Loctite thread lock compound. The other thing is to park on level ground so that the engine case bottom is level and the all liquid will settle over the drain plug area. I actually allowed the oil to drain all night, and even then is was a bit of a race to get the insert into the hole before oily seepage contaminated my clean and dry threads.

A. Get a 1/2" Triple oversized drain plug at $6 (I recommend getting three, see below). and crank it in there.

B. Use a helicoil 1/2" x 13 threads per inch. "coarse thread pitch" repair insert: drill it and tap it, and screw in a insert. Cost about $30 for helicoil kit plus $10 for the Drill bit and $2 for the plug.

C. Use a "sparkplug" repair kit. this kit uses a combination "ream and tap", which I'll loan out, and an insert that is threaded 14mm x 1.25mm pitch, "fine thread pitch". $30 for the Kit and $2 for the plug.

I actually bought all of the above hardware to have on hand, and then returned the other two. I elected the "spark plug cylinder" repair route, because I wanted "metric" and liked the idea of having a "steel insert" with fine threads, more clamping power, the insert had a "shoulder" to seal against, and being able to use a piloted drain plug.

Option One and least favorable to me was to get three self tapping drain plugs and just start with a double oversized, labeled "DO" American threaded 1/2" drain plug, then go to a triple oversized "TO" plug and run that in the hole, finally take a new TO drain plug and use it for the final plug. These do not come in a "piloted" version that I'm aware of.

This method I feel is designed for a steel drain hole of most American cars, and would have "gradually cut new American threads in the engine casing and probably would have worked, since a 14mm is slightly larger than 1/2" but smaller that the DO and TO plugs. Note that techincally TO plug still isn't large enough to cut theads completely into the original 14mm hole, however the difference is just few thousandths, and coupled to the fact that the threads are fine pitched, it will work, but not be really as strong as the other two methods in my opinion. But if your on a budget it's that or the "hangy way down rubber pluggy thingy." The drawback as I saw it was that the engine casing is an alloy of aluminum and magnisuim, and is soft compared to a steel helicoil type repair and you easily redamage the threads. Since TO is the largest repair you can't get a bigger one next time.

Method two was to get a helicoil type repair. This involves drilling up into the hole, then useing the supplied tap, to tap the hole, then using the special handle to screw the insert in, which is secured by loctite thread lock adhesive.

There is another brand of insert which I bought that uses an innovative design to install and anchor the insert. It has four pins which are located on the outside diameter of the insert, and fit into machine grooves that run perpendicular to the threads. The pins extend into the grooves about 1/8" and hang out about 3/8". You use this overhang to hand thread the insert into the hole so that the insert is just up above the edge of the engine case. Then you take a punch and drive the pins up into the grooves completly. The pins then "lock" the insert into place. I'd still use thread sealer to insure that oil doesn't leak past the exterior thread and pin arrangement.

I like this method, because it's solid and you can use the piloted drain plug. I didn't like the idea of buying a tap and drill for one use since you must buy the tap and drill bit separatly.

Method Three

The cylinder head/ sparkplug repair kit uses a modified tap to do both the job of enlarging the hole, easy since the case is aluminum, and also tap it for the insert. You install the insert with a sparkplug of all things. The insert is threaded on to a lubricated sparkplug, and Loctite is applied to the exterior threads of the insert, yeah this a go slow point. and then torque the plug and insert into the hole, wait 20 minutes for the Loctite to set, and then remove the spark plug.

I like this repair, because the insert had a "shoulder" on it unlike the other two. The shoulder allows the insert to protrude from the case about 1/16" and then the new drain plug gasket seats on it. Plus the insert is made for aluminum to start with, meaning that the thread pitches are fine, which gives greater holding power to the insert and the plug.

Ok, now for some names.

The 14mm x 1.25mm fine pitch drain plug is supplied by Dorman Products, a common automotive fastener supplier. Make sure the threads are right by interleving the drain plug threads with 14mm spark plug threads, they should mesh perfectly. I bought a sacrficial Champion plug , since I don't think Champions are good for anything else!

The Tap and ream kit, if you don't want to borrow mine, is supplied by,Champ. You will need to get a insert from them, I used the 1/2" depth one. Part no. 117303.

Champ Tools, listed as a "Rethreader Kit" # 117300 for 14mm spark plugs in aluminum heads. Champ's address is Edwardsville, Kansas 66111.

The job is tedious, and really takes two days down time. Allow for slow going and nerve wreaking patience. But the results are worth every minute.

Sincerely Mark 91 Carat WE "Lazarus"


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