Page 1 of 1

Rounded off spark plug

Posted: Mon Sep 08, 2014 8:01 pm
by capri_rob
Any tips on how to get this out ? Managed to round off number 3 tonight.

Worth trying with the engine warm ?
Any other tips ?
Need a better quality plug spanner :roll:

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 1:37 am
by driftwood
A better spark plug socket would be the 1st thing to try, maybe after 10 mins of soaking with penetrating oil. Maybe not on a hot engine though. If not, knocking a slightly smaller sized long reach socket onto the spark plug or using a multi-size socket might work. Tapping it undone with a hammer and chisel sometimes works. If not it's cylinder head off time and down to an engineering shop to have it drilled out.

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 9:45 am
by German-Whips
A high quality spark plug socket is probably the first thing I'd try too!

Had the same issue where the socket was slipping, not getting a good grip and starting to round off the spark plug.

Went back to Halfords, returned the cheap £5 spark plug socket and bought the £25 Halfords Professional spark plug socket set and give it another try and I could easily undo the spark plug.

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 12:17 pm
by HairyScreech
A 6 sided socket rather than a 12/18 point one will shift that.

Also warm engine will help.

DO NOT TRY TO HAMMER ANYTHING ON THE END OF IT!
(unless you like dropping bits of ceramic into the engine.)

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 6:38 pm
by capri_rob
Took it up to a mate today who has a decent quality 6 sided plug spanner and couldn't shift it.

Have bought penetrating oil and put some down it today

Went to motor factors who showed me a standard plug in a standard plug spanner and it is not a good fit ! Loads of play no wonder they slip.
Plus because of the slightly recessed design of the sockets they don't actually grip that much of the plug before the socket touches the head it doesn't actually grip all of the plug just the top bit.
To get round this I may grind the top couple of mm off a 6 sided plug socket flat so it grips all the way down

Also ordered a deep 20mm socket as a last resort to try and tap on and grip it :roll:

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 6:55 pm
by DanThe
Feel free to have a drive up to my place Rob, got loads of equip :D

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 7:12 pm
by capri_rob
Might take you up on that mate problem is if I bust it somewhere other than home I've then got to limp it back :(

Anything else you can suggest other than the above mate ?

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 7:15 pm
by DanThe
Ive got a tow rope but im sure it wont come to that!

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 7:16 pm
by capri_rob
Finish at 5 tomorrow if I pop down to the unit or up to your house ?

Just need it loosening I've ordered a replacement plug

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 7:21 pm
by DanThe
I will still be working at that time mate

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 7:49 pm
by capri_rob
You at the unit ? If so will see you just after 5 tomorrow

Re: Rounded off spark plug

Posted: Tue Sep 09, 2014 11:15 pm
by DanThe
Yep

Re: Rounded off spark plug

Posted: Wed Sep 10, 2014 6:32 pm
by capri_rob
Quick update put 3 lots of penetrating oil down the plug well and Dan managed to undo it tonight. Thanks again mate. :D