Spark Plug Issues

Maintenance advice to keep your Spider in shape.
DelRocco
Posts: 1
Joined: Fri Jan 26, 2018 1:04 pm
Your car is a: 1980 Fiat Spider

Spark Plug Issues

Postby DelRocco » Thu Feb 08, 2018 7:58 am

Hello all,
I am new to the forum and a proud 1980 spider owner for all if 3 weeks!

Yesterday I ran into an issue I've never had before on any of my projects.

I had planned to replace my plugs, but after getting one out (with relative ease) I was in able to get the new plug, or old plug back into the head...

To me this seems serious, am I just a good and doing something wrong or is purchasing a new head in my near future?

Frog2Spider
Patron 2018
Patron 2018
Posts: 387
Joined: Thu Jun 19, 2014 6:48 pm
Your car is a: 1981 2000 Spider
Location: Vancouver, Washington

Re: Spark Plug Issues

Postby Frog2Spider » Thu Feb 08, 2018 11:21 am

The fact that the old plug screwed out 'with relative ease', suggested that you are not lining the new plug up properly with the hole.
Carefully clean around the plug hole. Use a small tool to remove the dirt WITH A VACUUM CLEANER to suck up any debris after loosing it with the tool. (tape a 3/4" to 1" piece of PCV pipe onto the vacuum hose) Then use a clean rage with some solvent type cleaner to clean the top threads. Vacuum the hole again. Using a flashlight, carefully examine the plug hole threads for any signs of damaged threads, due to cross threading. If the plug you removed had been cross threaded, it should be easy to see.
Spark plug threads are course, and cross threading a spark plug, while not common, is easier to do in an aluminum head, than a steel one. Note that the plugs holes appear to be 90 degrees to the head, but they are not. They have a slight angle towards the firewall.
If you see that the threads have been damaged, find a machinist who may be able to use a thread cutter to 'clean up' the threads. The head may have to be removed to do this. You need to talk to an engine builder or machinist.
Plugs should screw in easily, by hand, and a wrench used only to secure the finial threads and tighten.

Good luck!
Dave
Always looking for curves under blue skies!
Frog2Spider

'81 - 2000 Spider


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