360 3D Printed Crankshaft Spacer for Timing Belt Service

I found turning the engine over using the crankshaft pulley bolt was cumbersome and required two hands due to the large socket, heavy ratchet and short head on the bolt. I came up with a different idea.
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This is more than a spacer. It's a socket insert that allows turning over the engine without replacing the crankshaft pulley bolt. It fits neatly onto a 1-1/2" Craftsman 12 point socket so that the bolt isn't required.

Here's the insert (aka spacer) with the socket.
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Here's the spacer on the crankshaft.
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Here's the socket and ratchet hanging off the spacer ready to be used.
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I wrote a longer and more boring version of this post here: https://www.ferrari360.org/2023/08/ferrari-360-crankshaft-spacer.html

The .stl for this tool can be downloaded here:
https://www.printables.com/model/554745-ferrari-360-crankshaft-spacer

The 1-1/2" Craftsman 12 point socket can be purchased on Amazon.
https://www.amazon.com/CRAFTSMAN-Shallow-Socket-12-Point-CMMT47518/dp/B07QKWQLQ4/ref=sr_1_1

 

I haven't tried it myself, but perhaps because the bolt would go down into the crankshaft too far, and that might be a problem because?

I think my method is superior because it allows the full depth of the socket to be used and that makes it easier to handle. For experts, probably nonsense but for amateurs and hobbyists, a little easier is always nicer. Besides, I love to design things.

 

A degree wheel isn't required to do a belt service. As far as keeping the tool, it costs about $0.62 to make so just chuck it in the trash when the belt service is complete and print another one next time. I didn't have a large 6 point socket, the biggest one in my tool kit is the 1-1/2" 12 pointer.

The pulley gets in the way of the timing belts. Adding the pulley and inserting the bolt is an extra step. Besides, the primary reason for me designing this part is that I don't like the way the head of the bolt sits in the socket. To me, it's difficult to use and slips off easily. Having the socket firmly sitting on the tool allows me to do it one handed and not have to worry about the ratchet dropping off the bolt. Additionally, the socket sits closer to the engine block which has less interference with the plumbing. As I said earlier, for an expert, this is probably inconsequential but for me, it's painful enough to spent an hour designing a part that solves the problem. At least for me.

 

It's great that you have so much experience to know exactly what to do. I am an engineer who probably overthinks everything and am careful to a fault. When going into something a first time, it really doesn't hurt to have both belt and suspenders checked and rechecked.

As for your recommendations, I'll be dead by the time that time so no worries! Besides, from the quality of work I've seen on my car, and by Ferrari mechanics, I can honestly say I do a far better job. So you may be the ultimate cheeseblock when it comes to mechanics, but the quality in the average tech is rather low. I'd say DIY can be a plus if it's well documented and done by a caring owner.

There's a guy here in town with your exact same attitude. He claims he has lots of experience and has serviced many Ferraris here. One of those he serviced jumped a tooth on the cambelt and has had the engine in rebuilt for about a year. It pays to be careful, even if you're so cocky to know you don't need to be.

 

And if I worked for the government, I'd charge $500 for licensing the tool instead of just posting it for free.

 

That would work great if it was printing in metal but since this is plastic, the forces would likely overcome the plastic and strip out the 1/2 drive opening. With the way I constructed the insert, most of the forces are in compression, which is ideal for plastic. I tested the setup with a lot of torque and it held without even marring the plastic.

It would probably work with a 3/4" drive though. That might be enough to keep it from stripping out.

 

Let me see what I can do.

 

The longer I own a 3D printer, the more I find myself using it. When combined with a reliable design program like Fusion 360 (though there are many free options available), it becomes a powerful tool.

Over the past two years of owning this device, I've created hundreds of designs. I now simply print many of the items I once used to carve out on the CNC. One major advantage of 3D printing is the elimination of waste material and often the removal of finishing steps. Unlike when using the CNC, which requires several steps post-extraction, objects from the 3D printer usually emerge ready to use.

My introduction to 3D printing was different from the norm. While many start with a cheap, sometimes self-assembled printer, I chose a different path. Many beginners get frustrated with low-quality machines and end up upgrading after a year of struggles. But I began my journey with a top-tier model: the Prusa MK3S+. I purchased it assembled because my goal was to print without delving deep into the mechanics of the device.

The very first design I printed was a preset that came with the Prusa, and it printed flawlessly. It was only around my 200th print that I encountered a problem, which was a result of my own doing. This required me to learn more about the machine's operation. By that time, I was already familiar with the potential and quality of the device. Now, I not only know how to operate the printer but also produce consistently high-quality prints.

For DIY enthusiasts who want to craft their own designs, I highly recommend getting a 3D printer and a design program. These tools are relatively intuitive, and for every design software, there are countless instructional videos available. It's a powerful experience to be able to design and print intricate mechanisms or even directly download and print items from online repositories.

 

@360+Volt=Prius - I created a test article with a 1/2" opening and was full length of the rachet, about 1/2" to similar specs as the spacer/insert. The barrel section is sized for a 1-1/16" socket, which is one I grabbed out of the drawer. The socket emulates the crankshaft.

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Mounted it in the vice.

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Hit it with the torque wrench. I started at 10 ft. lbs. and moved up by 5 each time. At 20, it felt a bit rubbery. At 25, I could see the plastic was moving. Here's the overhead view at 30 ft. lbs.. Plastic is permanently deforming but not giving yet. It's likely a few tugs at 30 would have rounded it out since it was breaking.

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Before 35, it rounded out.
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I checked my car and at 30, the crankshaft wouldn't budge. So as I suspected, the plastic isn't strong enough to resist the torsional force of such a small rotor. That's why I used the socket. Plastic is great in compression and the socket keeps everything under compressive forces, so it's likely the plastic with the socket would hold until the key started cutting into it. I suspect that would be around 100 ft. lbs. or maybe more. Plenty for my purposes.

 

The tool worked great when working from underneath but seemed a bit loose and prone to slip off the socket when used from above. I made a couple of modifications to address that shortcoming.
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I added some "ribs" so it fits snuggly in the socket, increased the length of the base and also added some material above where the crankshaft ends to make the thing stiffer. Works great.

Next will be the cam pulley lock.