Tightening Crankshaft Pulley bolt

[Alpine 1789]

There was a discussion here a few months ago on the importance of making certain the bolt that holds the crankshaft pulley was tight. I know I tightened it to spec when I rebuilt the engine, but I can't remember if I used Loctite or not. Just to be safe, I want to double check it as part of my Spring check-up. What is the best way to be sure the engine doesn't turn while I am doing this? I certainly don't want to do any damage in the process.

 

[Bill Blue]

Jim, if the engine is in the car, I don't think there is any reasonable way you can be sure the engine does not turn over. About the best you can do is put the car in top gear and apply the parking brake as tightly as possible.

Bill

 

[agmason54]

Tightening the crank pulley

Here's a sure-fire trick I use-

Pull #1 plug

Turn engine by hand and stick the dip stick down the hole to feel the top of the piston and make sure it is down.

Take some clothes line or soft rope and put it down in#1 hole and turn the engine over by hand and the rope will lock up the motor.

Tighten the crank bolt and then back up the engine by hand.I grab the fan.

Take out the line .

Put back the plug.

Easy old school trick works evey time.

Don't forget to put the dipstick back.
Agm

 

[RootesRacer]

Here's a sure-fire trick I use-

Pull #1 plug

Turn engine by hand and stick the dip stick down the hole to feel the top of the piston and make sure it is down.

Take some clothes line or soft rope and put it down in#1 hole and turn the engine over by hand and the rope will lock up the motor.

Tighten the crank bolt and then back up the engine by hand.I grab the fan.

Take out the line .

Put back the plug.

Easy old school trick works evey time.

Don't forget to put the dipstick back.
Agm

This would be a great way to bend a rod and damage a rod bearing.

Seriously, dont do it this way.

 

[tony perrett]

Tightening crankshaft pulley bolt.

The Workshop Manual advises using a Churchill "hammer-tight" spanner (RG290) for this job. I would have thought that the inertia of the internals would have make the locking of the engine unnecessary, if not positively dangerous.

 

[agmason54]

tightening the crankshaft bolt..

I've done the old rope trick a least 100 times.I think a little piece of rope will give and the bolt would be sufficiently tight before a rod bends or a bearing goes.I doubt that a gorilla with a ten foot bar on the crank bolt could bend a rod or even phase a bearing no matter how may bananas you offered him.
On the same note I have also broken frozen engines loose by making a custom fitting to duplicate the spark plug threads and attach that to a heavy duty grease gun. Just pull the rockers so the valves are all up and install the fitting in a spark plug hole and pump the grease gun.The engine will free up and I bet there must be TONS of pressure from the gease.Now thats asking for it but all that ever happened was the motor broke free.No bent rods or damaged bearings.After the engine is free then thin out the gease with some fuel,put the rockers back on and wind the motor to blow the grease out the plug hole.Caution: the grease will shoot 20 feet.
It worked for me-but what do I know? I've only owned 30 Alpines.You can ask my gorilla.He's old school also.
Cheers,
Slick Al TLP

 

[V_Mad]

I dont see the problem. If you apply a torque to the crank (via the pulley bolt) of, say 100 ft lb, using a spanner, the load on the conrod and bearing is no greater than when the engine is running, and the piston/conrod combination is applying a similar force onto the crank. Or is that too simplistic?

 

[jumpinjan]

Not really. You guys need to take a long look at the geometry of the crank/rod/piston combination. Tell me the position of the crankpin that exerts the greatest pressure on Al's rope, for a given amount of torque on the crank bolt?
Jan

 

[Tom H]

The greatest pressure on the rope (and rod) occurs if the piston gets near TDC (or near the bottom). But if you put in enough rope to keep the piston near mid stroke that would minimize the stress n the rod.

Tom

 

[jumpinjan]

Tom,
That's correct. But I expect that Al's rope is about flattened to about 1/4" and that very close to TDC, and that puts a termenduous amount of force on all the components. In normal operation, there is no where near that amount of force exerted on the crank/rod/piston combination at TDC. So, the result is don't do it.
Jan

 

[V_Mad]

OK, I agree that the 'don't do it' choice is the safest bet.

I think if theory assumes there is an ideal crank angle its OK but, in practice, as you said the rope will compress considerably, and then if the angle is anywhere near TDC (or BDC) the pressures would become multiplied several times or more. I can't be bothered to work out the trig but I think its a Tan (theta) function that is infinity at TDC, and that will definitely break something.

 

[agmason54]

tightening the crankshaft bolt..

If you do the rope trick right it will work everytime.First of all the piston has to be down or you can not even feed the line into the combustion chamber. Feed as much line as you can and then turn the motor with the crank bolt.The line will stop the piston.Now tighten your bolt,back up the engine and you are done.Simple one man job.Surely someone else who has turned a wrench has done this.I did not invent this method.It was taught to me somewhere done the line. I knew I would hear from the best of the best.I'm not telling anyone what to do.I'm just telling everyone I did it and it worked everytime.
I'm waiting for some reponse on the grease gun trick for freeing up frozen engines....I choose grease over gunpower.
With the grease trick the piston should be UP.That's all the geometry you need to Know.
Comments?.......
Respectfully yours,
Al Mason

 

[am99ey]

Thought about this too. But was never really confonted with it (yet).

What about a chain wrench tool like this.
I use one with a soft belt for removing the oil filters.
Any experience ou there?

Andy

 

[jumpinjan]

A strap wrench will not damage the pulley, it you can get it in there.
http://www.ridgid.com/Tools/Strap-Wrench

 

[skywords]

I personally have used the rope trick with no ill results on auto and aircraft engines. If that is a no no then please share with us what is the better way.

 

[skywords]

In conjuction with my starter post. I was at the bus yard late Friday night when the starter finally shot craps and had to push start the car alone. I was wishing I had the crank. I know Jan you hate that pulley nut but I would have given another kind of nut to have it Friday.

 

[Jim E]

I just use an impact wrench

 

[RootesRich]

I personally have used the rope trick with no ill results on auto and aircraft engines. If that is a no no then please share with us what is the better way.

The key to the rope trick boils down to the level of experience of the mechanic. The Forum is comprised of all mechanical abilities and this is not a tip for the inexperienced as one can easily damage an engine if not done properly and the piston is not "locked" in the correct position to minimize stress.

That said, I've perfomed the rope trick on a couple of m/c engines with success, but I pulled the radiator and used a strap wrench on my Holbay engine.

 

[RootesRacer]

If you do the rope trick right it will work everytime.First of all the piston has to be down or you can not even feed the line into the combustion chamber. Feed as much line as you can and then turn the motor with the crank bolt.The line will stop the piston.Now tighten your bolt,back up the engine and you are done.Simple one man job.Surely someone else who has turned a wrench has done this.I did not invent this method.It was taught to me somewhere done the line. I knew I would hear from the best of the best.I'm not telling anyone what to do.I'm just telling everyone I did it and it worked everytime.
I'm waiting for some reponse on the grease gun trick for freeing up frozen engines....I choose grease over gunpower.
With the grease trick the piston should be UP.That's all the geometry you need to Know.
Comments?.......
Respectfully yours,
Al Mason

Al,

You are not getting it.


The force on the rod is related to the vertical vector, which is dependant on the crank angle of the rod when the piston locks.

Even with the crank throws at 90 degrees, your 100 lb/ft of torque is greater at the piston since the rods are NOT infinitely long. As the rod to piston angle (theta) approaches zero degrees, the force approaches infinity (tangent of theta).

 

[Dr.NO 007]

Master Mechanic

The simplicity, the logic, the beauty of it all !! After listening to Rick Barter & Rich Vose I feel ready to nominate Al Mason as "Master Mechanic of the month". Each month another experienced Alpine mech. or maybe Al again can teach, share something "top-gun" for all of us beginners / apprentices on the forum and win the award "Master Mechanic".

As for the frozen engine trick (the piston should be UP) - if the engine is frozen it will not turn, so I guess by powers of deduction you would have to check / feel in each of the four cylinders for the piston near the top and select that one and put the spark plugs back into the other three ? I tried the gun powder method and over loaded the cylinder "combustion" chamber !!
Everything loosened up - BAMM all over -- new poster "Series II parts car available" just kidding!