URGENT: Another Mechanical Question?

[rabbitearbandicoot]

Mazda Eunos 1.8lt V6 - trying to undo the crank bolt - of course using ordinary socket it just spins the engine - can't get at the flywheel to wedge it - mechanic told me to use a rattle gun with the relivant shatter proof socket of course - 21mm. So bought a rattle gun and sockets.

Tried several times - it makes a noise but doesn't move the bolt.

Question: would this bolt be normal thread or reverse thread?

[softail-joanie]

I don't understand, but that's not unusual.  What will either the screwdriver trick or the nylon rope trick establish?

Wait a minute here, I'm the one who's not supposed to understand. Umm, your trying to stop the engine from turning right?, The pistions are connected to the rods connected to the crankshaft. The spark plug holes is the only way you can redally access the tops of the pistons without tearing down the engine or removing the head/s. If the piston can't come all the way up to the valves, the engine can't very well turn.

The rope sounds like a better idea, less likely to harm the pistons.

[this-one-time-at-bandcamp]

Or, if you really want excitement, fill one cylinder with water, creating a hydrostatic lock........

I once was working on a car, when an early Chevy Vega came in for gas.  After the attendant collected the money, the girl tried to start it.......even from inside the station, I could hear the whine of an engine with no compression, so I went out to address the situation (besides, the girl was a fox).  I carefully removed the radiator cap, noticing that there was no pressure.  I then had the girl crank it, watching it blow smoke rings out of the radiator.  I told her that she most likely had blown a head gasket or even cracked a head, and would she like me to run a compression test to determine which cylinders were involved, to which she answered in the affirmative.  I removed all four sparkplugs, (very carefully so as to not strip the threads in the head), then installed the compression gauge in #1 cylinder.  This is where I learned a very important lesson......don't remove all the plugs.  When I had her crank the engine once more, boiling water shot out of #s 2 and 3 cylinders, all over my face and front. Fortunately I was wearing glasses, and as the water ran down either side of my face, the skin came with it.  I slapped wheel bearing grease on the burns, and soldiered on......

I didn't get the job, but the next day, the girl brought me a plate of home-made cookies.-

[softail-joanie]

LOL, thinkin about that fox instead on focusing on what your doing. many a men though. I still can't hardly believe I let that Nova go to the junkyard instead of putting a new timing belt on. I just about had the old one ready to come off. I needed to get rid of it fast though after buying that other one.

[rabbitearbandicoot]

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@softail-joanie wrote:

I don't understand, but that's not unusual.  What will either the screwdriver trick or the nylon rope trick establish?

Wait a minute here, I'm the one who's not supposed to understand. Umm, your trying to stop the engine from turning right?, The pistions are connected to the rods connected to the crankshaft. The spark plug holes is the only way you can redally access the tops of the pistons without tearing down the engine or removing the head/s. If the piston can't come all the way up to the valves, the engine can't very well turn.

The rope sounds like a better idea, less likely to harm the pistons.

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I see. Sounds like a lot of pressure to put on one piston / rod / bearing?

We've had no power all day today - they are replacing poles along our street - so have done nothing to car.

[monman12]

OK,  you are unable to use engine inertia and shock load a socket (hammer), or "blip" using the starter motor method, and are considering stuffing rope into a cylinder (mid stroke  the optimum).  Take a moment to consider the term hydraulicking ( from  my flying days lectures)  Never used it myself,  but theory is applicable, and I love engineering theory/practice.

Consider filling a cylinder with oil  when it is  midway between TDC & BDC on its  4th stroke (expansion)   then replace spark plug and torque away at the crankshaft nut..

Afterwards remove the plug and rotate engine to remove oil.

Nearest I got to that was using oil to calculate exact compression ratio of an engine once.

A locked piston can exert considerable force under the wrong circumstances, so it should easily do the trick!

[rabbitearbandicoot]

"A locked piston can exert considerable force under the wrong circumstances, so it should easily do the trick!"

- bend the rod you mean?

[monman12]

"A locked piston can exert considerable force under the wrong circumstances, so it should easily do the trick!"

- bend the rod you mean?

NO no RB. I mean that there will be  more than enough safe resistance to  crankshaft rotation to enable you to loosen the crank nut.

The photograph is of a hydraulicked piston/rod assembly from a running engine  that was driven through a flood,  and was the result of water suddenly being ingested........bang!

[monman12]

"A locked piston can exert considerable force under the wrong circumstances, so it should easily do the trick!"

- bend the rod you mean?

NO no RB. I mean that there will be  more than enough safe resistance to  crankshaft rotation to enable you to loosen the crank nut.

The photograph is of a hydraulicked piston/rod assembly from a running engine  that was driven through a flood,  and was the result of water suddenly being ingested........bang!

[rabbitearbandicoot]

just had a go with a 1200nm gun - no good. I think the bugga is welded in there.

[rabbitearbandicoot]

"I have a 3/4 drive double electric motor rattle gun that punches out about 1500nm... to the non mechanics that means that I generally need two fat blokes holding onto either leg when I squeeze the trigger or I will turn into a helicopter,"

looks like I need you and your two fat blokes ...