It’s been a while but I pulled the head and chased the thread from the inside because the other, outside end of the thread had been cross-threaded so badly. Only downside was I had to make my own replacement gasket. I like “a” though. That’s what I’d try now, though it’s a bit tricky to use apparently.
I have one (a), mentioned twice.
Count them using, say, your eyes, closing one each time
Not that I’m much interested in MAXPOWER for this application, but in any case there is seldom 2 foot of clearance for a breaker bar inside an engine compartment, and if there was, alignment is kind of important here, and wouldn’t be achievable with this thing.
Size really isn’t always everything. You’ve been misinformed.
I didn’t even know about the bottom up tool, but reading a few reviews online, you have to be carful not to get a cheap one as if it brakes it can drop in the engine,
also depending on how bad the treading is you can still have difficulty lining up.
I would stick with the tried and tested and take my time.
Spark plugs don’t make good taps. They’re hollow in the middle and are prone to snapping.
If you’re tapping aluminy-yumyum then be careful not to drop chips into the cylinder, as they’re hard to get out.
I’d use a traditional tap in most circumstances, along with grease to try and trap the chips from dropping into the cylinder.
Of course, this is all assuming easy access to the plug hole.
Worse case then the head needs to come off.
A starting tap will be tapered, which will help, but it’s obviously important to keep it centered correctly when gingerly feeding it in. This does require some skill and experience definitely helps.
It’s definately the first step though. Worse case scenario the head has to come off anyway.
When tapping aluminum especially, then it is really important to work the tap back and forth in small increments as well as remove it every now and again, to clean off all the chips, as the chips will clog the tap and act as a binder, potentially ruining the job entirely. Iron/steel is much easier to tap as it’s far less “gummy”.
The story (which I find fairly plausible) is that taps are designed to cut new threads, and if you give them a chance, they will, especially in soft metal like aluminium.
I don’t want that.
It may be possible to avoid this with skill (which I have no reason to think I have) or luck (ditto, or I would’nt be in this situation).
The flipside of that is that some Taiwanese mechanics and tool shops might have heard of taps, so you can probably get them,(as your Shopee link confirms, thanks) but they probably won’t have heard of the other options, (or would care if they had) so you probably wont be able to get them.
Its not news to me that Taiwan Spectacularly Sucks for this sort of thing.
I dunno. I might just ship (a) in, though it will involve quite a delay and will be expensive for a tool I hope to never use again.