Spark plug threads
 

Hi guys,

One of the spark plugs on my Rover 75 V8 almost popped out today damaging the threads in the hole.

Anyone any experience of how to repair this and in particular the Sav-a-Thread spark plug hole thread repair insert. Appreciate any assistance.

Martin

cannot remember the size now but maybe someone else will. i bought a retap sparkplug tool for the size on ebay. it has two sizes on it (the most common i suppose) i bet if you go to a factors or auto spares shop they will have one. you could take a plug with you.

they are deep fine threads so unless you have done a lot of damage and stripped the thread completely you should get away with it. new copper washer if poss and it should hold. going down the helicoil or thread insert road wont be that simple unless its off the car.

This is common on the V8 (Ask me how I know) I think I still have a sav a thread in the spares box somewhere.

Send me a PM and ill dig it out and get it in the post for you.

Thought I still had one…

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I was once driving a TR7 I owned across a major bridge when the engine started running terribly. I made it across and into a parking lot and found one of the spark plugs hanging by it's wire. The threads in the head were totally stripped. (Note: The threads on a TR7 are much shorter than the plug threads on a modern car). I got a ride home to get some tools and stopped by the auto parts store on the way back and bought a Heli-coil kit for the spark plugs. I tapped the thread out in the parking lot, screwed the plug back in and was on my way. I didn't worry about the shavings from tapping the alloy head getting into the cylinder as the alloy is softer than the working bits in there (I did retrieve as much as possible) When I got home I Heli-coiled the rest of the plugs and never had another issue with them,