Changing Timing and Crank Gear

Ed Northrop

Senior Member
I am installing a new aluminum timing gear and have the matching crank gear. Due to the difficulty involved in removing the crank gear I am wondering if it would be ok to leave the old crank gear. I have attached pictures of my existing gear. There is rust pitting in the teeth.
Thanks Ed
 

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That gear looks pretty rough and would probably eat up an aluminum gear. They can be hard to get off, heat and a big puller are usually needed. I'd recommend replacing it.

When installing the new gear, don't pound/hammer it on. Push it on. I use a squared up piece of pipe with a cap welded to the end and threaded for a crank bolt. Then use another bolt to press/push the new gear on. Heating the gear helps, just don't use as mush as you did to get the old one off.
 
I just did this a couple weeks ago on a Model T crank = same principle. I heated the new crank gear in our kitchen's oven @ 500 degrees for about 15 minutes. Using vise grips to carry the gear when heated, I rushed it down to the garage where the crankshaft was sitting in cold winter temperatures. Aligning the gear's slot with the woodruff key in the crankshaft, I slipped the gear over the end of the crank and pushed it home. It slid easily all the way down until it bottomed out. Easy as pie! A couple minutes later and the gear was unmovable. The combination of the heated gear (expanded metal) and the cold crankshaft (contracted metal) worked perfectly. Leave your garage unheated overnight before performing this procedure the next day so that the little extra bit that the cold crankshaft contracts will be just that much more helpful.
Marshall
 
By the way, make sure you install the new steel crankshaft timing gear with the marked tooth for mating with the camshaft's timing gear indent/dimple facing OUT.
Marshall
 
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I have another question about removing the crank gear it looks like I would be able to use a bigger puller if I was to remove the hunk of steel that the hand crank goes through. When I remove the U-bolts will I have to be cautious of the axle moving out of placement.
 
Ed
If you need to you can remove the upper hand frank bearing that the u bolts go over by removing the 4 NRA below he spring plate and removing the upper plate.
With the car on the ground it will sit there . Be careful if you are lifting the engine or using a jack underneath. I might suggest removing one of the engine mount bolts in the Rear to allow the rear to pivot without bind
I have done many of these
Larry Shepard
 
Larry thanks for the information I have removed one bolt from each side and have loosen the other engine mount bolt. The engine pivots easy. I have read several times that model a ford springs you need to treat with respect.
 
Hey Ed, the front spring is pretty safe.
It's the rear spring that can cause grief if the centre bolt breaks while disassembly. Good luck with your repair. Jeff
 
Also, the snout of the crank is buggered up from using a pipe wrench on it. Dress the high spots down before pulling the gear or you might get stuck even tighter.
 
Also, the snout of the crank is buggered up from using a pipe wrench on it. Dress the high spots down before pulling the gear or you might get stuck even tighter.

GOOD advice ..this !

BTW..who the heck uses the pipe wrench on a crank nose to turn a crank :( !
 
Also, the snout of the crank is buggered up from using a pipe wrench on it. Dress the high spots down before pulling the gear or you might get stuck even tighter.

Looks like the gear ID is larger than the snout where the pulley goes.

Bob
 
Simple way to heat the gear. Lay the gear by the hole on the top of a 100 watt light bulb till it gets hot. It should go on easily with a little help from a hammer. Be aware, the key sticks out of the gear so, you will need a pipe with a notch or a piece of an old pulley to get it on for the last 3/16" or so. You can hammer the gear some if, you don't use an 8# sledge or hit it like you are breaking concrete.
 
Picture showing how I pushed the crank gear onto the crankshaft. I heated the gear up with a Bernz O Matic torch using map gas. I held onto the gear with channel locks. The gear slid on quite ways with just hand pushing it. I used part of a 2 piece pulley and the old crank gear. I finished tighten it up with the impact gun. I have read about tighten down the timing gear nut from 60 to 100 foot pounds. It seems like a 100 would be way overkill as 60 sounds better. I was thinking just snugging it up with a impact gun on low setting. Would that be a bad idea. Thanks for all the input.
 

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A little more information I think the marks on the crank shaft is not from some one turning the engine over. With a closer inspection it looks maybe marks from a sharp chisel trying to raise some metal to tighten up a loose pulley.
 
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Good job! Just did this last week. Crank gear was as bad. Pulled both bolts on each side, had to replace the rubber any way. As it was the motor mounts, one had crack and the other cracks and a piece missing.
 
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