Safest way to lock engine to remove bottom pulley.

[stecad]

Been reading through the forum and there seems to be lots of debate about this.
I have the engine out and need to change the water pump and cambelt.
I can see that getting the bolt loose on the bottom pulley will be a tough one and have a very long bar.
What's the safest and easiest way to lock the engine?

[mr2magic]

I found it best to jam a pry bar/ tire iron into the teeth of the flywheel and rest it against the shaft of a screw threaded deep into one of the bolt holes for the gearbox bolts. Something like this....

[alanmr2turbo]

Invest in or find someone who has a good impact driver.

I wouldn't recommend the above photo for trying to undo bottom pullet bolt.

[mr2magic]

Impact driver?? On a crank shaft? You do realise there are conrods attached to the crank and that these have journal bearings... the bearing surface doesnt take kindly to repetative radial force of the kind caused by impact guns.

The above method is used (with minor alterations and special tools) by almost all manufacturers.

[Dale_V]

I made a toothed tool that locks the flywheel completely, it bolts to the top 2 bolt holes in the block and interlocks with around 5cm worth of the flywheels teeth..

[yokomomr4bx]

Taken off hundreds of crank pulleys for cam belts with impact guns, always used impact gun for tightening back up again aswell. Never had any problems.

[SonicSW20]

Heat up the flange on the bolt if it's the earlier one piece design to give you a fighting chance. the later washer type ones come off much easier.

[Draven]

When i did it, i used a long screwdriver to jam the flywheel..

FYI, I wouldn't do it like that if I did it again.

A decent impact wrench is much better.

[ashley]

Heat up the flange on the bolt if it's the earlier one piece design to give you a fighting chance. the later washer type ones come off much easier.

Except the crank pulley is made of two pieces of steel sandwiched together with rubber which really doesn't like heat

[SonicSW20]

Except the crank pulley is made of two pieces of steel sandwiched together with rubber which really doesn't like heat

The one on my Gen3 3SGTE would not budge with a breaker bar + extension, or a 450NM 1/2inch impact gun even after soaking with good penetrating fluid. Wouldn't have come off any other way

[ashley]

I hear you- I've wrecked a couple pulleys having to resort to heat in the past as well mate

[abovetherim]

Similar to the fist method suggested you can use a chain from flywheel or clutch cover to engine block. Have the engine well and truly wedged somewhere and very long bar

[tiff_lee]

Impact driver?? On a crank shaft? You do realise there are conrods attached to the crank and that these have journal bearings... the bearing surface doesnt take kindly to repetative radial force of the kind caused by impact guns.

The above method is used (with minor alterations and special tools) by almost all manufacturers.

Can you expand on that at all? The crankshaft would barely be turning (if at all) using an impact drive so what radial force is there on the journal bearings?

[mrdb]

Breaker bar with one end on floor. Pull coil lead. Flick starter it will break it free and then just remove with ratchet.

[SonicSW20]

Breaker bar with one end on floor. Pull coil lead. Flick starter it will break it free and then just remove with ratchet.

Wouldn't recommend that with the engine already out of the car

[tiff_lee]

Ah engine out... not that i've done it on a 3SGTE before but if you're happy to remove the sump then place block of wood between the block and crankshaft counter weight (or whatever you want to call it) then use breaker bar + scaffy bar if required....

[MartinF]

Make up a tool and use the two bolt holes in the crank pulley that Toyota provided for you.

[stecad]

Thanks for the suggestion. There are no holes in the pulley. There are a couple of small recesses on the rim but these are timing marks.
The sump will be coming off shortly so will check out the earlier suggestion.

[mr2magic]

Impact driver?? On a crank shaft? You do realise there are conrods attached to the crank and that these have journal bearings... the bearing surface doesnt take kindly to repetative radial force of the kind caused by impact guns.

The above method is used (with minor alterations and special tools) by almost all manufacturers.

Can you expand on that at all? The crankshaft would barely be turning (if at all) using an impact drive so what radial force is there on the journal bearings?

Think about how an impact tool works for a minute. If running freely with no load it rotates without an impact. Only because the driven object (here the crank bolt) provides a counterforce does the hammer mechanism come into play. Now in our case the crank isn't in any way fixed, its able to rotate along its axis provided there is sufficient force, but it also presents enough force to the impact driver, to cause the hammer mechanism to engage. This becomes more apparent when holding the crank pulley while using an impact gun - you feel the pulley turning in your hand even though the bolt is being loosened.

The fact the crank turns isn't in and of itself bad. The problem arises in conjunction with the connecting rods and their bearings.The connecting rod bearings have play - yes it is a very small amount, but it is play. During normal operation oil pressure is sufficient such that the small lubricated area between bearing surfaces takes up the load imparted by the combustion without shearing or without being displaced. When we remove the oil pressure the remaining film is a) a lot less than during operation and b) able, through force, to be displaced even more. While hammering on the crank bolt with an impact gun we have no oil pressure so all force is acting on the remaining unstable and displaceable oil film.

As i wrote before the crank will (want to) turn during impact gun use and the amount it wants to turn is much greater than the oil clearance in the connecting rod bearings so basically the crank journal pushes up against one side of the connecting rod bearing half shell. Now even then it's not a big problem as long as the force remains constant or increases constantly. The problem arises because of the hammer effect. The force is being applied/removed/applied/removed.....and so on hundreds of times a minute all with the effect of ramming the crank bearing surface up against the half shell again and again. This causes flat spots and crushes the bearing layers together altering their composition.

The whole process is kind of akin to detonation during combustion which is known to cause bearing failure, just taht the force isn't being applied from the connecting rod to the crank bearing but from the crank bearing to the connecting rod.

That being said...using an impact gun doesn't automatically mean your bearings and /or engine is going to grenade on you. What it does mean is the application of unneccessery stress for the components of the engine - this may cause failure at some point.

I hope that clears my stance on the practice up a bit.

[SonicSW20]

I would be surprised if your average home gamer 240V impact wrench will be powerful enough to cause that kind of damage. If you were hammering away with a mega 1000NM+ air impact wrench then maybe.