What is the size?

[spareparts]

14 mm thread, 26.5 reach. If youve got the more popular compression tester, its the biggest adapter thats also the longest

[steplift20]

Thanks Destroyer and spareparts. I am just surprised it's a metric size , I will post what the compression is when I get it. I hope it's not very bad news but I will see.
Just curious. Are all spark plug threads metric?

[spareparts]

yes, most are metric, including domestic vehicles

[steplift20]

Hey spare , how do I check for spark? I'm going to do a compression test on Sunday but was wondering I also want to see if all the plugs are firing, there are no wires only coils.

[spareparts]

you have to use a test stand specifically for checking coils. You could probably rig something up with a spark carb and a ground wire. If its missing from spark , you should be able to tell by the way its idling.

[steplift20]

Thanks spare, but honestly I have no idea what you mean.
But can I pull out the coil,attach the spark plug and turn over the engine and see if it's got a spark? I would stand by the plug while my son cranks the engine
What do you think?
I just what to make sure he is getting spark to all the cylinders, but I have a feeling the compression test is not going to have a good out come.