stripped #1 spark plug thread

Haven't been around for a while, but need the collective wisdom of the good folks here.

Long story short, we managed to get the #1 spark plug thread stripped. Oh joy! Don't ask :(

I remember reading somewhere about something like a case saver or heli coil where you can rheam out the current hole, install the saver and hey presto, you're good to go. Checked on CIP1 but can't find anything. Does anyone know where I can find such a beast? Does anyone recommend using these or have any other recommendations short of chopping off the hands of the person responsible so he never does it again?

Cheers,
Dom

Yeah, I have done that too. I was recommended KD Tools products by a long-time VW mechanic, and it works great. http://www.sjdiscounttools.com/kd2125.html

I bought the kit which includes a reamer and several inserts in varying sizes. I did the repair with the motor still in the car with no problem.

I recommend grease on the threads when using the reamer, and I also used a special adapter to let me shop vac suck out most other debris... of course any other aluminum bits will blow out the exhaust.

I tore down the motor many miles later (for a different reason) and the thread repair was still holding.

best luck

Thanks Dan, sounds just the ticket. I will give it a go and report back. So you did the reaming with the head still on the engine? I would be concerned of any metal shavings getting in the engine and causing problems, but it sound like it worked out AOK for you.

Many thanks.

I've made this repair on many customer vehicles over the years. Very little aluminum falls into the cylinder when you tap for the insert. NEVER had an ill consequence from the metal shavings

Dom,

When the long-time VW mechanic told me about this process, I had the same concern as you about the aluminum shavings potentially wreaking havoc inside the cylinder.

He assured me that this process was very common and in his experience (which is vast) he has never seen a problem caused by any errant aluminum bits... further, that any leftover bits inside the cylinder were blown out the exhaust as soon as the engine turned over (or just were simply burned up immediately).

The grease on the threads of the reamer (I removed the reamer several times in the process to wipe the threads clean & re-applied grease) seems to catch 99% of any aluminum bits anyway.

I can now recommend it personally as well!

-dan

I use anti-seize compound on the spark plugs; I've heard pro and con comments about those. In any case, if you service your spark plugs (clean & re-gap) every 6,000 miles you shouldn't have a problem regardless if you use anti-seize or not. Just make sure you start the spark plugs in delicately and don't overtighten.

Only install plugs when the heads are cold, should help avoid problems. I use a little never-sieze on the threads too.

And make sure the piston is at bottom of stroke when you run the tapper in or you risk damaging top of piston and your newly cut threads! It can be done with engine in the car but is a pain. Might actually be easier in a Speedie than in a T1 though.

Thanks everyone - as usual, lots of good advice. I have ordered the kit mentioned above and it should arrive later this week hopefully. If all goes well, my speedie should be up and running again next week.

Thanks,
Dom

Dom:

Like Larry, I've used Heli-coils on a LOT of older VW engines, always with good success. Follow all the advice on here and you'll be fine. The problem is caused by mounting steel plugs in an aluminum head which causes electrolytic corrosion which corrodes the plug to the head. When you ty to remove it, it takes head thread metal with the plug and ends up like yours. Really common.

I also use Anti-Seize on the plug threads as Ricardo mentioned, but I'm running Platinum-tipped plugs (Kelly Frazer now has one in his car after Carlisle - my spare!) and, since they last 75-100 thousand miles and don't need re-gapping, I don't plan on pulling them out in my lifetime. ;>)

gn

Gordon, you're correct about the plug corroding but another common problem is cross threading.

I always start new plugs with my fingers or, a small piece of rubber hose over the tip of the plug, then slowly twist the rubber hose.

NEVER, NEVER put the plug in the plug wrench to screw the plug into the cylinder head, you can't feel if it's cross threading.

Well, when we replaced a suspect plug in Kelly Frazer's car at Carlisle we didn't have any hose kicking around in the Ramada parking lot so Chris spun it in with his fingers on the socket - went right in - Bingo.

THEN the fun started....we couldn't get the damn socket off of the plug!!!! That little rubber doofus inside held on for dear life.

Pulled everything back out and scrounged the cars/trucks in the lot for another plug socket til we ended up with a fluted Snap-On version which worked better.

Whew! You can't beat taking half of the tols in your shop to events (although it's a crap shoot as to which half you'll need!!!!!)

gn

P.S.: I usually put a film of Dielectric grease on the porcelain of the plug to make it slip easier on the plug wire boot. Makes it come off easier in the future, too.

Once agin, thanks to everyone who responded with advice and suggestions. Speedy is back up and running again after a week off the road, and the new platinum plugs are great - a noticeable difference from the old copper core plugs.

After drilling and reaming the case to full flow it and now this, I'm starting to get used to attacking my engine with almost reckless abandon. Thankfully no problems to date (not just knocking, but violently pounding on wood).

Thanks everyone,
Dom

Dom:

I have to tell you....it you had the guts to drill and tap your case for full flow, especially if the engine was still in the car, you can tackle anything on these cars!!

Just taking that leap of faith of drilling into a perfectly good engine is all it takes to give you pride in your work.

My hat's off to ya!

Gordon