Crank Pulley

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Model T Ford Forum: Forum 2012: Crank Pulley
Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Steven Robbins on Monday, September 03, 2012 - 01:31 am:

Whats the best, safe method to remove the crank pulley?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Steven Robbins on Monday, September 03, 2012 - 09:28 am:

Guess I should explain better. I'm a long time reader, first time poster. What I want to know is how to remove the pin in the crankshaft pulley without causing any damage to the bearing or anything else in the process. I am having a hard time keeping the belt on the pulley. my old leather belt stayed on until it broke, and my new one just won't stay. Thanks for any help. Steve


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Monday, September 03, 2012 - 11:12 am:

It would be easier if you remove the radiator so you can see what you are doing. There are two holes in the outer rim of the pulley and a cotter pin in the pin at the end where the larger hole is. You need to remove that cotter pin first. Then turn the pulley till the small hole is on top and the pin is lined up with the drain hole in the nose of the pan. Then using a drift you should be able to drive the pin out. Some times they are tight some times they just slide out. When you put it back together don't for get the cotter pin.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Steven Robbins on Monday, September 03, 2012 - 12:08 pm:

Thanks Mark, I am going to get started now, while it's only 90 out. supposed to be 103 today. Steve


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Steven Robbins on Monday, September 03, 2012 - 01:21 pm:

O.K. Went out and pulled the radiator, got the cotter key out and the pin out. The pulley is stuck to the crank. I have tried prying while tapping on the pulley but it is still stuck firm. I'm afraid if I pry too much it will mess something up as it is pulling the crank forward. Not enough room for a puller. Any ideas?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gene Carrothers Huntington Beach on Monday, September 03, 2012 - 01:28 pm:

Put a little heat on just the inside to free if from the shaft. You don't want to be binding it if your only prying on one side either. Many of the pulleys are sort of too loose.

If your seal is leaking any oil at the crankshaft while you have the pulley off make sure to install a new modern seal to the outside of the cover now.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Steven Robbins on Monday, September 03, 2012 - 01:32 pm:

Thanks Gene, Heading out to try it now. Will try to pry evenly on both sides. Steve


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Steven Robbins on Monday, September 03, 2012 - 02:48 pm:

Couldn't get the pulley to budge, so I cut it off with a grinder and CAREFULLY cut the sleeve with a chisel an finally got it off. Question; I have 5 thousanths between the pulley I am going to use and the crank diameter, is this enough? Should I not try to use another old pulley and bite the bullet and buy a new style pulley. The pulley I am going to use shows no wear and may be nos. What's the odds of this one keeping the belt on better than the one I took off? Thanks to all who respond! Steve


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, September 03, 2012 - 03:42 pm:

If the unworn pulley you have has a crowned outer surface it should work. The belt tends to wander to the largest diameter if the fan pulley and crank pulley are lined up and parallell.

Has someone tried to file back the crown on a bad pulley while the engine is running? Not sure if it's a good idea or even if there's enough space.. Might work and be round enough, though?
Idling for some time without a fan belt calls for the use of a portable electric fan blowing through the radiator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Monday, September 03, 2012 - 03:44 pm:

You didn't mention why the belt is slipping off the pulley. In my experience slippage is due either to using a water pump or oil on the belt, typically from where the crankshaft enters the pan and timing gear cover. Since I run water pumps, I opt for purchasing the repro pulleys with the lips on the sides. If you go that route, grind down the pin that comes with the pulley or use an original style pin. The one that comes with the pulley is too big and you have to hammer the heck out of it to get it in the hole. Otherwise, you run a very real risk of opening up the babbitt in the front main cap.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Verne Shirk on Monday, September 03, 2012 - 08:26 pm:

Steve,
I am guessing you are talking about there being 5 thou difference between the diameter of the crankshaft and the ID of the pulley. That sounds rather excessive. You don't want the pulley to flop around on the crank. A nice press fit is best...something you need to "tap on" to install.

The pin on my early T's (smaller OD on the crankshaft pulley) goes into one side of the pulley, not the other. That way, the pin can be held on by one cotter pin. There isn't much clearance on an early T (small diameter pulley) and the starting crank ratchet. The cotter pin that holds it in keeps it from coming out of the pulley...the other end has the small hole. If the pin is a little loose, lay it on an anvil and smack it a good one to expand it out, or you might even put a slight bend in it. You don't want it coming out while you are driving! (That happened to me once when I was a youngster in high school.)

As Mr. Karlsson said, the pulleys work best if they have a crown to them...both the fan and crank pulleys. The fan pulleys that are dished (instead of crowned) are much more common. They are...how do you say it...worn out! You might be able to file them to a crown but I kind of doubt it. The crown is what keeps the belt on the pulleys. If it wants to go one way or another, the one side of the belt doesn't want to expand and go over the crown.

I might comment on the leather belt. I've used them in the past. Leather tends to stretch. The isn't good for the theory of how the belt stays on the crowned pulleys. They sell one that has stitching on it. I believe those might be a little better as I believe the stitching is supposed to keep if from stretching.

It is kind of hard to get everything lined up with the radiator on. As Mr. Gregush said, removing the radiator to remove the pulley will make it a lot easier. It will make the re-installation a lot easier too. That way you can really get a good look at how things are lining up.

You may have to bend the arm that holds the fan (I am assuming you have the arm instead of the 1926-27 style fan pulley holder that fits on the cylinder head.) If you need to bend the arm, bolt it up tight to the timing gear cover, remove the fan pulley, and take a Cresent wrench and "adjust" it. You should be able to bent it around a little "cold" unless it is really bent. I usually have to adjust a few times in order it get it just right. The 1926-27 model may be able to be aligned with some washers to space it out, if needed. A wouldn't think a bent one of those is as common due to the fact they are fairly substantial.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Richard Bennett on Monday, September 03, 2012 - 08:43 pm:

Robert, Verne was on the right track when he mentioned bending the fan arm to get the belt to stay on. However, I would caution against bending it in-situ. I am currently re-building a motor which has had to be repaired because the fan mounting boss was broken off.

If the fan arm is bent down, and many are over the years, the belt will run off the front of the crank pulley. Judicious bending of the fan arm will get the fan shaft back into parallel with the crankshaft and then the belt will stay in place.

Hope this helps.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, September 03, 2012 - 09:33 pm:

I have found that if the belt is too tight, it will run off, but it should be as loose as you can get it and still turn the fan. Check after driving it for a while. It might stretch a little and then need some tightening. As for the pulley, I have had success by using some shim stock half the size of the clearance and putting equal pieces on each side of the pulley, and then tap it into place. The pin should also be snug in the crankshaft. Sometimes it can be tightened by putting a small bend in the center.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Steven Robbins on Monday, September 03, 2012 - 10:05 pm:

Thanks to all the great help. Turns out I had a extra pulley that was in as new condition. Put it on and drove this evening and it didn't come off once. I am using the leather belt with stitching. I'm sure that oil was part of the problem as about half of my pan bolts were loose. Tightened them all up and surprise no more belt slipoff. I probably need to bend the arm a little bit as the belt still wants to run to the front half of the crank pulley. Again, a big thanks to all who responded. Steve


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