The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Drew Back on 13.04. 2015 02:28

Title: Broken Spark plugs in head
Post by: Drew Back on 13.04. 2015 02:28
I have this A10 head I was stripping down and I seem to have broken both plugs off in the head they are rusted solid..I tried drilling them out and wont budge at all..I dont want to damage the threads any other ideas???I tried busting them out with a punch but again im to close to the threads..
Title: Re: Broken Spark plugs in head
Post by: duTch on 13.04. 2015 03:29

 Just had a look for it but can't find- a few months ago, I think it was Olev posted suggesting a 50/50 mix of acetone and ATF, to which I keep meaning to add my mixed (....the odds be 50/50) results . Try that and see, but stock up on cold drinks cos it takes a while. ..I have a 2" pipe cutter that had a seized citing wheel.
 I'd tried all the obvious things to no avail, but as soon as I read the post I did it, and after a few weeks, the wheel was free. .. trouble is the acetone evaporates fairly quickly when the air is warm, and as someone else noted the two don't mix readily- may depend on the brand of ATF...! That's about the best I can do.
Title: Re: Broken Spark plugs in head
Post by: WozzA on 13.04. 2015 08:23
You could try heating the head ( in oven or BBQ ) as you would to remove valve guides & a easy out..
Title: Re: Broken Spark plugs in head
Post by: bsa-bill on 13.04. 2015 08:39
As WozzA says heat the head, and if you've made a hole in the plug body squirt in some of that plumbers Freeze spray into the plug, might help shrink the plug a little.
never used this spray myself so don't know if it spits or misbehaves in any way soead the can maybe
Title: Re: Broken Spark plugs in head
Post by: stu.andrews on 13.04. 2015 11:45
Have heard that Coke (the drink, not the other kind) can do it but have never had to try it.
Has anyone else tried it?
Title: Re: Broken Spark plugs in head
Post by: Drew Back on 13.04. 2015 15:03
Well I got them..I step drilled up to 15/32 then pounded a large bolt though to take out what was left and used a thread chaser looks good as new..What a relief!!!!!!!!!Now off to the welder to fix the broken fins I now have when the head flew off the bench when drilling.....Make sure when drilling a head you have it completely fastened down..Lesson learned......
Title: Re: Broken Spark plugs in head
Post by: RichardL on 13.04. 2015 15:17
Glad you were successful. Sorry about the fins.

Richard L.
Title: Re: Broken Spark plugs in head
Post by: muskrat on 13.04. 2015 20:34
Bugga.
A pair of sliding clamps are the most used tool on my bench.
Cheers