Welding Aluminum Cylinder Heads Options

[Alfred]

When I bought my '73 2.0 a few years ago, the car ran like cr@p so I took the motor out and disassembled the top end and found that one of the spark plug holes was completely stripped and a couple of the others were on their way to being completely stripped. I took the cylinder heads to my local VW dealer and they installed helicoils in all the spark plug holes. From what I've read, this method of repair is ok and can sometimes be even "stronger" than the original threaded holes. Part of me, though, would prefer to have the spark plug holes welded up with aluminum and then have the holes re-machined. Has anyone else had their spark plug holes stripped, and, if so, how did you repair them?

Thanks,
Alfred

[EdwardBlume]

I had this very problem where I was checking the plugs on my 2.0. I only had 2K on the motor at the time, and the plug wasn't coming out easily. I kept working it carefully and ended up with the whole helicoil on the plug out in my hands!

I thought the same thing about welding it back.

Instead, I took it into a guy at a local shop who told me that it can happen from time to time and he reinstalled another helicoil without welding. It's running fine without any problems (and I drive the hell out of it).

If you are really concerned about the condition of the head and its an older head, you may want to consider other options. On my car, the heads were fine otherwise. Th repair was so easy, I wouldn't go through the trouble of welding unless there were some other reason.

Good luck.

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[Brad Roberts]

Time sert. Heli Coils can and will come out sooner or later. Time Serts (I feel) work much better. You can "stake" them into the head so they dont come out.

Head shops can and will weld them up for you (requires them being OFF the car)

We do this all the time, when repairing the typical cracks around the spark plug holes on 2.0 heads. We drill into the crack until we dont see any more crack and back fill with weld. Then we drill the spark plug hole and tap it to the correct size. Doesnt take long to do it correctly.. but tearing the engine down sucks.

B

[Alfred]

Time sert. Heli Coils can and will come out sooner or later. Time Serts (I feel) work much better. You can "stake" them into the head so they dont come out.

Head shops can and will weld them up for you (requires them being OFF the car)

We do this all the time, when repairing the typical cracks around the spark plug holes on 2.0 heads. We drill into the crack until we dont see any more crack and back fill with weld. Then we drill the spark plug hole and tap it to the correct size. Doesnt take long to do it correctly.. but tearing the engine down sucks.

B

Thanks for the information Brad.

A few years ago I phoned around (Vancouver) to see if anyone could weld up my cylinder heads but very few shops had the skills to weld aluminum. At about the same time our then socialist B.C. government spent billions of Canadian dollars to build a couple aluminum hulled fast ferries that turned out to be total cr@p and had to be sold for scrap. (You might be able to pick one up cheap - the Diesel engines are German). Anyway, the end result is that there are now some trades people up here who can weld with aluminum but it was a very expensive training program.

Alfred