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Spark Plugs!!!

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mharrelll311

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I recently came into possession (after years of waiting for the right time) of my grandfather 1966 Spitfire MK2. I am going completely through the car with my trusty original manual, but after going to auto zone to pick up some new plugs, i found that the original equipment on the car called for 3/4 inch throw instead of the 1/2 inch I pulled out of the motor. The motor is rebuilt but it is a mk2 era engine. So what I am wondering is should I go with the 3/4 throw or the 1/2 throw? Any real difference? Thanks for the response. Marc

P.S. Anyone know of a decent Triumph/MG/British mechanic near Savannah, ga? Any help would definitely be appreciated. Thanks
 
I would stick with the stock 3/4" If your head is completely stock, it will need that length to get the electrode exposed to the combustion chamber. Otherwise, your electrode will be 1/4" up into the hole and won't allow for the best combustion.
If the combustion chamber has been altered in a way the you have exposed spark plug threads, then you will need a shorter plug.
BTW, welcome to the Forum!
 
Boy, do you have options!

Spits bits Spit Bits link

Spitfire & GT6 Magazine Link

Links to clubs and information

Now, about spark plugs. If you do decide to go with the longer plugs, be sure to buy a "spark plug Thread Chaser". The threads at the bottom of the hole will have all kinds of deposits on the and you need to remove those before putting in the new longer spark plugs.

217hN65VHjL._SL500_AA300_.jpg


Gramps probably couldn't find the right ones so put in the shorts ones. Sometimes if the engine is burning oil, putting in short ones will keep the plugs from fouling so fast.
 
Most all of the 1147 engines used 1/2" reach plugs. It's confusing, because some of the earlier 948s used 3/4" reach plugs, and the 1296 and 1493 engines (as well as the sixes) use 3/4" reach plugs. If it's an FC serial number on the engine, it's 1147 and takes 1/2" reach plugs!

I remember going through the opposite situation many years ago while working on a friend's Mk2. It was a bit tricky removing the plugs, which turned out to be 3/4" reach plugs. Tough getting them out since nearly the last 1/4" of threads stuck well into the combustion chamber!
 
mharrel-welcome to the club.
My daughter is going to SCAD but can't help you with your problem of a mechanic
 
Thanks a lot for the responses. I'm going to grab a chaser and run that through first. I wish the spark plugs were the hardest question I will be asking, but I'm going to be running through the entire car and trying to bring it back to life, so many more questions to come. Thanks again!
 
Don, SCAD is great school I'm sure your very proud she's going there, they have really made Savannah a better place. And if she know's how to turn a wrench on a Spit, just let me know! I'm going to need a lot of help.
 
You can stick a small screwdriver bent at the end or an equivalent tool and reach down into the hole to measure the length of the thread.
 
mharrelll311 said:
Don, SCAD is great school I'm sure your very proud she's going there, they have really made Savannah a better place. And if she know's how to turn a wrench on a Spit, just let me know! I'm going to need a lot of help.
Click to expand...

More a lotus fan ,Pretty much hates both my TR's

IMG_2755.jpg
 
mharrelll311 said:
I'm going to grab a chaser and run that through first.
Click to expand...

Good practice IMO, even if you aren't changing plug reach. Also a good idea to smear some grease in the flutes, to try and catch some of the gunk from the threads, rather than letting it fall into the cylinder where it just might get caught and scratch a wall.

I like to also use a dab of copper-based anti-seize on the plug threads.
 
Roger that, sounds like a plan. Thanks for all the help. Anyone know what to do about re-dipping a tank? There was fuel in it for twenty years and I just got it out of the trunk, and I'm debating cleaning it out or just buying a new tank. Any thoughts?
Don-She's got good taste in cars!
 
Haha yea, well it's the best of the best. Plus you can't beat the weather here. That's why I'm trying to get this Spitfire running! St. Patty's day and spring is coming! Let me know if you need anything here, or if she needs anything, take it easy.
 
mharrelll311 said:
Anyone know what to do about re-dipping a tank? There was fuel in it for twenty years and I just got it out of the trunk, and I'm debating cleaning it out or just buying a new tank. Any thoughts?
Click to expand...

Something like this, perhaps:
https://gastankrenu.com/
 
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