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I have an issue with the 13/16 socket not engaging into the spark plug. My engine is a dual Weber carb set up and the socket gets stuck on the side of the carb manifold on both sides. Do they make a thin wall socket that will work without hitting the side of the manifold? I was going to check the plugs since they have been in for awhile.

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What Stan said.

I think my heads are SCAT, and the size plugs they take are more commonly used on motorcycles. They're easily accessed and removed with a standard Craftsman 18 mm, 3/8" drive plug wrench, and have 12mm threads.

Carbs are Weber IDF40 on EMPI manifolds.

Another thought is that your plug wrench may be contacting the holes in the tins and not the heads themselves.

FYI, I replaced plugs after about five years. They were a little worn, but not too bad. and I hadn't noticed any engine missing. After another two years, I checked the new set, and they did need to be re-gapped a bit. It's now about eight years on this engine, and I should probably replace the plug wires on general principle.


I’m going to hook up my endoscope and look into the opening to confirm plug size. Good advice, I was thinking of grinding the upper end of a socket so it won’t hit the side of the manifold. Going to tackle that this morning and will let you know what I come up with. Just wanted to check the plugs, clean and gap them. Car is 8 years young with 1200 miles.

@Popee posted:

Car is 8 years young with 1200 miles.

Respectfully, that's irrelevant. The thing about a T1 VW is that at this point, almost all of them are built either partially or entirely aftermarket parts, which is why the numbers on the case don't mean anything, nor can anybody (but you) be sure of what size spark-plugs are in it.

You have to know what you have. You aren't going to be able to go to any SN decoder website to tell you that you've got an AS41 case with a DPR stroked crank, 5.4 I-beam rods, a Web 120 cam, Engle lifters, and CB044 oval-port heads. Posting pictures here would help us help yourself, but don't expect a miracle.

Build sheets are invaluable.

With that said, almost all aftermarket VW heads built in the last 20- 30 years are "12 mm long-reach" threads, which use an 18 mm socket. I think there are a few VW Mexico (aftermarket) heads that used 14 mm plugs, but CBs, etc. were almost universally 12 mm. If I were betting, I'd bet you need an 18 mm socket. You can get an endoscope, but you're going to be doing this blind anyhow. I'd just get the socket, and a short extension, and give it a try. If it fits - yay!

If not, then back to the drawing board you go.

Tip:  Just break the spark plug loose with the socket and unwind it just until finger tight.  Then wiggle the socket off the plug and out of the hole.  Then push an 8-9" long piece of rubber fuel line hose onto the plug, and finish unscrewing the plug with the hose.  When it is unscrewed, the plug comes out of the hole securely attached to the hose (so you don't have to fish the plug out of the hole).

Better yet, when you reinstall the plugs, reverse the process by pushing the hose over the plug and then inserting the plug into the hole.  It will be much easier to start the plug into the threads by using the hose than trying to do it with a socket (and possibly cross-threading the plug in the process).

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