An Improved Crank Ratchet??

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Model T Ford Forum: Forum 2012: An Improved Crank Ratchet??
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Sunday, July 22, 2012 - 12:36 am:

Assuming that the best way to hand crank start a Model T is the pull up on the crank handle starting about 7:00 to 8:00 and finishing about noon or 1:00 then a question comes to mind. Why does the crank ratchet have four notches as opposed to just two? If you’re a crank spinner, then this discussion will be of no interest to you. However is you hand start by pulling up on the crank handle, no matter which hand you use, then maybe this would be if interest.

With the standard crank ratchet, top dead center of the engine will be at 11:00 or 5:00 crank handle position when on one set of the ratchet notches or at 2:00 or 8:00 in the other ratchet notches. With the ratchet is engaged in the TDC 2:00 or 8:00 notches, attempting to start is fruitless. You would be starting the pull very near TDC and ending the pull before the next TDC. This is totally counter productive and the pull will kind of go - whoosh.

So, my solution was to eliminate two of the crank ratchet notches. This guarantees that each pull of the crank handle will be past TDC (11:00 crank handle position) and eliminates any wasted effort in cranking in the wrong notches or just wasted time in figuring out what notch the crank handle needs to be engaged in.

I brazed two pieces of metal in the useless ratchet notches and it seems to work well. Hand crank starting is now more straight forward with no wasted effort or time.

Jim








Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Sunday, July 22, 2012 - 06:14 am:

Let us know how it goes. I suspect that there will be occasions when you would want the other position, as the engine will occasionally stop at odd positions, but those instances are few and far between. The other instance I can think of is when you are setting timing. I'm almost positive I use both positions as I'm trying to slowly turn the engine around. For normal starting, I think you will be just fine.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Sunday, July 22, 2012 - 08:01 am:

When I asked on this Forum many years ago where the crank should be at TDC, nobody replied. I had bought a really long crank which I had cut down to just clear the Windsplitter radiator, and didn't have an original for pattern. I drilled it for TDC at 9 o'lock, figuring that's where my arm would have the most leverage.

Turns out the standard crank I bought later for the ol' brass picup also has TDC at 9.

rdr
Coburg B&B


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Sunday, July 22, 2012 - 08:25 am:

When I am shimming rods I need the other set of notches to pull the crank into proper position. It is easy to lay there on a creeper, reach up in front of the car and move the crank.

Without that set of notches you would have to be in front of the car. Then you would not be able to see where the rods were.


Top of pagePrevious messageNext messageBottom of page Link to this message  By A. Gustaf Bryngelson on Sunday, July 22, 2012 - 10:33 am:

It is interesting that the crank for the Ford GPW only has two notches, but it is a crap shoot as to where they will be in respect to the pistons as any variation in the thickness of the crank pulley will change the position of the hand crank.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Haynes on Sunday, July 22, 2012 - 11:48 am:

I think I must not understand what advantage is provided by the modification. There are lots of times when I have needed to engage the crank in what is a convenient orientation, but is not the optimal position for crank starting (the "unused" notches). To me, they are not "unused", they are less-often used, but still useful when needed. Maybe Jim can describe the benefits?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Sunday, July 22, 2012 - 12:23 pm:

It really depends on what you use the hand crank for. If it is just used as a backup plan when the electric starting system goes south or if it is just used when working on the car, then this modification would be of no value. However, if it is the only method of starting, then it may be useful. I do have an original ratchet and if really needed it can be changed in a minute or two.

The bottom line is that the unused notches are worthless in actual starting but may be occasionally useful (but not required) when positioning the engine for some maintenance.

Here is a photo with the crank pin horizontal (TDC):


And the useless notch at TDC:


And the angle of the hole in the crank handle:


Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Haynes on Sunday, July 22, 2012 - 02:35 pm:

But what is the actual, tangible benefit by filling in the notches that "...may be occasionally useful..."? I don't understand the goal. The "useful" notches were there already, right? Or did you move them to a better spot?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Sunday, July 22, 2012 - 03:40 pm:

Dan,
Yes the useful notches were there and were not changed. The benefit now is that if the crank is engaged and is near the 7:00 to 8:00 position you are guaranteed that the crank is placed in the correct position for starting. With the original ratchet the crank can be engaged in a notch with the handle positioned near the 7:00 to 8:00 position and you will not know if it is positioned correctly or not till you pull on it. If it is on the wrong notch and pull to start, your effort is wasted, it will not start because you are not turning the engine over TDC.

With many hand crank engines I can see an advantage of four notches because the relation of the crank handle to the engine position is not fixed. Unlike a Model T, many crank ratchets are on a nut on the end of the crankshaft with the position changing from engine to engine. On a Model T engine the crank engages the pin on the crankshaft and the relationship to the engine is fixed.

My Hercules engine has a four notch crank nut that screws on the the crankshaft. Four notches on it makes sense.



Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Sunday, July 22, 2012 - 08:59 pm:

Jim

Your methodology is nice, there is a benefit in getting the crank at the right spot for easy starting. The topic reminded me of this 'tip' published in Fordowner, 1919.

Changing the angle of the crank handle to get the proper position, the tip does read that 'heat and twist the handle several times to get it right'....a bit of trial and error :-)


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