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Bruce Johnson
 Post subject: crankshaft timing gear
PostPosted: Fri Jul 26, 2002 6:09 pm 
I feel stupid asking this question, but here goes...I'm rebuilding a 78 slant six to install in my 70 Duster. The crankshaft timing gear absolutely will not come off, even with heating, beating and the big puller that gets the rear drums off my 62 Dart. Is there something I'm missing , or will I have to get it pressed off at a machine shop. How bad would it be to use the old gear with a new timing set? Can a forged crank be used in this motor if I install the rods to match? Thanks everyone!


starship@bwave.com
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Bruce Johnson
PostPosted: Fri Jul 26, 2002 10:53 pm 
Couldn't resist, allthough I hear Wong is still the most common name in the world, as are slant six's with cast cranks I gave my 78 engine away even though the numbers matched my body It costs allot to build a engine and there is still allot out there with forged cranks, which is what a 1970 car would have.My advice, Save the head and the rest, ditch the block and crank.good luck Bruce
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Bruce Johnson
PostPosted: Sat Jul 27, 2002 3:54 am 
Don't get me Wong; I do appweciate the virtues of a forged cwank. Sorry Bruce. It is hard to resist. Seriously, the crank is perfect except for the damn gear which refuses to budge. All the journals are round and show only .0002 wear so I would like to use it. Any advice on gear removal or using a new chain with the old gear? Thanks again. Bwuce.

starship@bwave.com
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bud L.
PostPosted: Sat Jul 27, 2002 10:38 am 
Quote:
: Don't get me Wong; I do appweciate the virtues
: of a forged cwank. Sorry Bruce. It is hard
: to resist. Seriously, the crank is perfect
: except for the damn gear which refuses to
: budge. All the journals are round and show
: only .0002 wear so I would like to use it.
: Any advice on gear removal or using a new
: chain with the old gear? Thanks again.
: Bwuce.


I am not sure a drum puller is the right tool for the job. The puller you need is a two piece affair that is bolted together and is thin enough to split apart and slip behind the gear and then you tighten the bolts as far as you can till its up against the sides of the crank snout. I've heard some people call it a 'clam shell' puller, but I don't know that that aptly describes it. Anyway, you then screw in a stud on each side of the 'clamshell' and slip on a slotted bar with a solid center for threads for the jacking screw that centers on a crank/pulley bolt. It helps to chuck the crank bolt in a lathe and center drill it, first. Crank it in real good. If it isn't going to move, then you'll have to use some heat. Use a large enough torch, with a small enough tip so that you can put a large amount of heat in a small area in a short amount of time. Concentrate the flame in one(or maybe two spots opposite each other). You want to heat up the gear without heating up the crank snout. Otherwise the crank will grow at the same rate as the gear and you won't gain any clearance(or more correctly, you won't reduce the interference that is holding the gear on the crank). Keep plenty of tension on it, while you're heating it. Be advised if it's stuck on there that good, it might let go in a hurry. If it doesn't come the first time, be patient. Keep the tension on the puller, and let it cooldown. You can try using Mopar brand rust penetrant to kind of quench it. Repeat as necessary.
As a last resort, I would try weakening the gear by grinding part way through it with a little crazy wheel on a die grinder. But be VERY careful, you're grinding very close to the crank that you want to save.

fglmopar@aol.com
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Doctor Dodge (Doug Dutra)
PostPosted: Sat Jul 27, 2002 11:48 am 
Quote:
: I am not sure a drum puller is the right tool
: for the job. The puller you need is a two
: piece affair that is bolted together and is
: thin enough to split apart and slip behind
: the gear and then you tighten the bolts as
: far as you can till its up against the sides
: of the crank snout. I've heard some people
: call it a 'clam shell' puller, but I don't
: know that that aptly describes it. Anyway,
: you then screw in a stud on each side of the
: 'clamshell' and slip on a slotted bar with a
: solid center for threads for the jacking
: screw that centers on a crank/pulley bolt.
: It helps to chuck the crank bolt in a lathe
: and center drill it, first. Crank it in real
: good. If it isn't going to move, then you'll
: have to use some heat. Use a large enough
: torch, with a small enough tip so that you
: can put a large amount of heat in a small
: area in a short amount of time. Concentrate
: the flame in one(or maybe two spots opposite
: each other). You want to heat up the gear
: without heating up the crank snout.
: Otherwise the crank will grow at the same
: rate as the gear and you won't gain any
: clearance(or more correctly, you won't
: reduce the interference that is holding the
: gear on the crank). Keep plenty of tension
: on it, while you're heating it. Be advised
: if it's stuck on there that good, it might
: let go in a hurry. If it doesn't come the
: first time, be patient. Keep the tension on
: the puller, and let it cooldown. You can try
: using Mopar brand rust penetrant to kind of
: quench it. Repeat as necessary.
: As a last resort, I would try weakening the
: gear by grinding part way through it with a
: little crazy wheel on a die grinder. But be
: VERY careful, you're grinding very close to
: the crank that you want to save.


Great advice Bud, if it does come down to cutting the gear off, grind your slice right over the keyway slot. (If you go to deep and hit the key, no big deal)
Often you can grind 3/4 through over the key slot then get the old gear to split / crack right along the keyway with a well placed hit from a stout / sharp cold chisal.
DD
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Bruce Johnson
PostPosted: Sun Jul 28, 2002 5:29 am 
Thank you everyone for the advice. I'll try cutting the gear. On a related subject, can the cast crank block be fitted with a forged crank? I have a surplus of these cranks but fewer non forged crank blocks.


starship@bwave.com
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Doctor Dodge (Doug Dutra)
PostPosted: Sun Jul 28, 2002 8:22 am 
Quote:
: ...On a related subject, can
: the cast crank block be fitted with a forged
: crank? I have a surplus of these cranks but
: fewer non forged crank blocks.


I have never personally done this swap but I have *heard* of it being done. (in a race engine no less)
The cast crakn block uses thinner main bearings so my guess is that some shimming for the # 3 thrust main sides would be needed.
Get in there and check things out.
DD
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