Damaged Spark Plug Hole Thread Chaser

Swarf was yesterdays word. We have moved on, though maybe the swarf remains.

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While I very much dislike installing fastners dry, I’m not confident enough of this "“translation” procedure (on a first go, anyway) to use the derived torque-and-angle spec.on the lubricated fastners

I would have to repeat it, hopefully with more consistency, and I don’t think it is worth the additional wear on the dry components, so I’ll just live with the dry-torqued situation for now.

Perhaps some other time…

That’s the technically correct answer anyway. The problem with having any kind of lube is that engines go through quite a bit of expansion and contraction every time they’re used, so you really want that tight seating w/no lube to minimize the chance of things coming loose.

However, if you really, really want “something”, Loctite does have a product specifically for heads. (I’ve never used it nor met anyone who has, YMMV, IANAAE etc.)

Depends. From reading, (I’ve only done one other head and I can’t remember if it was lubed or not) engine oil is commonly recommended, and aftermarket head bolt makers (ARP?) spec their own lubes (which I THINK tend to have molybdenum in them) so lubricated headbolts are not exactly heretical weirdness.

Manufacturers that spec dry probably do so to reduce the variables. Any lubricant will increase the bolt tension at the same torque setting, but the “rules of thumb” on reducing the torque setting vary a lot.

Repeated head bolt installations long after any warranty has expired are not likely to be a focus of manufacturer concern.

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Or not.

Looking like my only chance of getting the crankshaft pulley bolt off may be to use the starter, which would have been fairly safe with the head off, but is likely to clout valves in the current configuration.

Should have anticipated that.

Much messing about under de hot sun, rigging a brake holder-downer and jacking/ Spanish Windlassing the engine about so the crank bolt is back in line with the port in the wheel arch, (engine mountings are off) but the transmission slips.

Might be possible to jam the starter ring gear or pack rope into the cylinders via the plughole, but if that doesnt work I will likely have to either take the head off again (reluctant) or reinstate the old belt.

But why? :thinking:

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Was wondering about that one too!

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Now I think I may have a name for a fictional character I haven’t visited in over thirty years. He works in a shop that does metal fabricating work, and he’s yesterday’s character, so I guess it’s appropriate.

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You have to take the crankshaft pulley bolt off to remove the pulley.

You have to remove the pulley to remove the lower timing cover.

You have to remove the lower timing cover to…oh fuck it…remove some other stuff, so you can replace the timing belt.

You have to replace the timing belt because, on a standard autodestructing rubber band engine, if it busts your pistons clout the valves and the engine is no more…

You have to do this, IOW, due to inadequate consumer resistance to shite design.

Thats why.

Ah, so not related to the sparkplug problem, this just an add-on that might as well get done while you’ve got the engine out anyway.

But you can’t easily stop the crankshaft from rotating when you bear down on the bolt because you’ve got the engine out.

Normal answer (e.g. engine fully assembled/installed) would be to use the starter. Getting the starter engaged at this juncture may be a bit of a pain but that is almost certainly still going to be the easiest route. (Or if you can leverage against the flywheel in a similar manner w/a prybar or something.)

I dont have the engine out.

If I had the engine out I couldnt have made ineffective attempts to stop it rotating with the brakes and gears, but I would have much better access to that end of the engine.

Took the head off (large variation in breakout torque seemed consistent with the angle data implication that bolt tension isnt very well controlled) and packed the cylinders with rope, then put the head back on with the bolts finger tight.

That stopped the crank moving, but still couldnt shift that pulley bolt. Just bent my cheater tubes. Thats what comes of dry torque specs, I’m thinking.

(I’m assuming here it isn’t reverse threaded. THAT would be a military grade gotcha, and I don’t know how I’d check. but the manual doesn’t mention it if it is)

Tempted to break out the charcoal again, but i suppose a scaffolding pole is a marginally safer option, or I might just put the new belt on the “sometime” shelf and try and reinstate the old (12 years) one.

Quite possible it is, just depends on the direction of rotation when the engine is running. Should be easy to look that up online though.

As I said, saw nothing in the manual.
I don’t think it does depend on the direction of engine rotation.
It depends on whether they chose to reverse thread it or not.
Doesn’t seem to be usual.

I suppose it might make sense for the bolt to be reverse threaded to resist loosening, but I THINK they just massively overtorque it dry, and, to quote Saturday Night Fever, Screw The Future”

I did wonder if “remove crank bolt” meant “simply remove crank bolt” or “by some miracle remove crank bolt”.

Now I know.

These rubber band autodestructing engines are even worse than I thought, and I thought they were bad enough to have studiously avoided them up to now. In this instance the crank bolt is rather hard to get to which doesnt help.

The rope trick does stop the engine rotating, but Im not sure it would be completely safe if massive scaffolding pole stylee forces have to be applied.

To use the starter trick I now realise Id have to put it all back together otherwise the loose timing belt might get jammed up, plus securing a spanner in place looks difficult/impossible.

If i put it back together im likely to leave it like that, Saturday Night Fever stylee.

Its a car of its time

Stayin ali-iii-iii-iii-ive?

It should be fine, and a quick image search online for Daihatsu crankshaft bolts shows them all to be standard thread. So just get a longer/stronger cheater bar and have at it! :sunglasses:

Logically it would oppose the direction of the engine rotation, such that the engine does not rattle it loose.

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276 posts in and nearly three months long and still there’s no end in sight for this cross-threading saga. I’m thinking it would make a great cross-cultural documentary. Call it Cross Threaded.

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Sub-titled: The Spark(Plug) That Lead to a (Engine) Revolution

If anyone wonders how cars end up sitting for years on end, it’s examples like in this thread, and the Friday Bin thread :smiley: