Clamping cam gear to tighten

M

matchlessman

Junior Member
I've just changed my crank and cam gear (went to the aluminum gear) with the engine in the car. A bit of a piano but it's done. I'm reading the preferrd method to hold the cam gear to tighten the nut is by clamping the gear with a "C" clamp. How is that done? I can't understand how the gear can be clamped with a "C" clamp such that it would hold the gear while the nut was tightened to 100 ft. lbs.

Ken
Eastern Ontario
 
DO NOT CLAMP THE GEAR!
I use two short slats of wood and two "C" clamps. Place a slat of wood on each side of the timing gear. Clamp them to the gear using one clamp above the pan and the other below the block. The slats below the block will hit the block when tightening and hold the gear from turning. You can now torque the nut. Just be sure to really tighten the clamps.
 
Here is what I did to tighten my cam gear nut. I put the car in high gear and the overdrive in over drive and put on the parking brake and blocked the wheels. Tightening the cam gear nut will try to move the car backwards. Loosening it will try to move the car forward. If you have the type of overdrive that can be damaged when the car is in reverse, then keep the overdrive in direct drive. I have the aluminum cam gear. I don't know if the fiber gear will take the torque.
 
There is absolutely no need to torque the cam gear nut to 100 ft-lbs. It's unfortunate that this continues to be passed along as gospel. Not sure where it comes from or came from but half that much torque is more than sufficient to hold the cam gear in place.


On edit, it is extremely poor practice to use the gear teeth to prevent cam rotation when tightening the cam gear nut. Best practice is to always clamp the gear rim as above to react the tightening torque against the side of the block. There are only 3-4 teeth in contact at a given time and it is possible to slightly deform the gear tooth surface if using them to prevent rotation.
 
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The torque figure of 100 ft lbs is out of Andrew's book. I thought it seemed a bit extrme. What torque is sufficient?

Ken
Eastern Ontario
 
What I've done to tighten the cam gear nut is to place a handfull of rag at the intersection of both gears and the tighten the cam nut. To remove the rag use the crank nut.
 
I am with AL in NY I use a thick piece of towel jammed where the teeth meet . On tightening the towel feeds in and jams the rotation . Reverse the turn and pull the towel clear . Nothing gets bent ,trust me !!!

John in New Year Suffolk County England
 
GPierce said:
Seems to me with the teeth jammed you still have the load from torquing on the teeth.
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You are right. After torquing with the teeth jammed, no matter how they are jammed, you can put the gear back in the gear cutting machine and it will take metal off where the teeth were jammed. That means the teeth are bent.
It might wear in and run for many moons but you will always have that worn off metal going through the bearings.
Eventually you wil be helping some tow truck driver buy a new yacht.
 
Pete said:
You are right. After torquing with the teeth jammed, no matter how they are jammed, you can put the gear back in the gear cutting machine and it will take metal off where the teeth were jammed. That means the teeth are bent.
It might wear in and run for many moons but you will always have that worn off metal going through the bearings.
Eventually you wil be helping some tow truck driver buy a new yacht.
Click to expand...

I never seen the slightest suggestion of this.
 
Tightening the camshaft nut to 100 lb-ft is not necessary, and is not specified in any Ford literature.

In the Model A era, fastener torque was controlled by using special tools during assembly and 5-Z-XXXX dealer tools afterwards.

The wrench for the camshaft nut, 5-Z-1832, has a 9 1/2 inch length between the center of the nut and where the wrench is gripped by the mechanic.

If the mechanic exerts 50 lbs at 9 1/2 inches, the resulting torque is about 40 lb-ft.

If the engineers at Ford wanted the camshaft nut to be tighter, the 5-Z-1832 wrench would have been longer.

Although the threads on the crankshaft ratchet nut are much smaller than the threads on the camshaft nut, the engineers at Ford wanted the crankshaft ratchet nut to be tighter.

The wrench for the crankshaft ratchet nut, 5-Z-1900 has a 17 inch length between the center of the nut and where the wrench is gripped by the mechanic.

If the mechanic exerts 50 lbs at 17 inches, the resulting torque is about 71 lb-ft.
 
What Terry said X2... I have often said that the vast majority of "A's " over the course of the last 90 years have never crossed path with a torque wrench.

Joe B
 
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