Lemons into Lemonade

I have new spark plugs for the Ferrari but I can’t find my old spark plug socket and my new spark plug socket does not fit down the hole in the 308’s cam cover.


Older sockets tend to have thinner walls because the steel was stronger. Modern sockets may be cheap but they are are made from lower quality steel so need thicker walls thereby increasing the overall diameter of the socket. This is why my modern spark plug socket does not fit. Ebay to the rescue with a search to find a second hand, US-made Craftsman 13/16 spark plug socket since I know those fit 308 cam covers.

Found. Ordered. Delivered… No damn sparkplug insert! More lemons!

Missing spark plug insert

The sellers says it is my fault for not requesting a spark plug socket with an insert! Like I am supposed to know the one he was going to send me did not have an insert. Isn’t a spark plug socket without a spark plug insert just a socket?!?!? Jerk. Lemons^2

So how to make an insert to turn my new ‘spark plug socket that cannot hold a spark plug socket’ into a ‘spark plug socket that can hold a spark plug’? And my lemons into lemonade.

What I needed was thin closed foam cylinder with an outside diameter the size of the socket and an inside diameter the same size as the ceramic neck of the spark plug. The friction would be just enough to hold the spark plug centered in the socket. What I really needed was a little pool noodle (for my international readers this is a pool noodle).

Then, it came to me… one of the newer-style foam wine corks might be about the correct size. The outside diameter was very close so I just needed to drill a hole the correct size through the middle.

Drilling out center for the spark plug

Access to the spark plugs on the front bank of the 308’s V8 engine is notoriously difficult so any spark plug socket needs to grab the plug securely enough that its not going to fall out while fumbling around blindly down the front side of the engine. It also has to be able to release easily the plug easily when done so it can be retrieved on the end of a wobble extension. I milled the inside of the cork to give the perfect level of grip and stuck it into the socket with 3m foam tape.

Completed spark plug insert

Behold my lemonade… the perfect 308-specific, vintage Craftsman spark plug socket (and one fouled plug):

Spark plug socket and fouled plug

Disclaimer: 308restoration.com describes the restoration work I perform on my car and only my car. I am not a professional mechanic. The website content is presented for entertainment purposes only and should not by seen as any kind of advice, information, instruction or guidance for working on any other car. The opinions stated here are my own and no-one else’s.

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