Building an Entire Engine from scratch isn't that hard

Added: 2026-05-26

[00:00:00]Hey guys, welcome back to the channel.

[00:00:01]And if you're new here, I'm Logan and I'm trying to build a 150 cc four-stroke race engine for my motorcycle. Now, frankly, I set down this path because it's something I've always dreamed of doing and I didn't think it would be this hard, but we're in too deep now and I ain't giving up. So, I have a cylinder that I have cast and machined and is ready for nickel silicone carbide plating. And we're going to go see my mate Dino at NZ Cylinders and get to it.

[00:00:47]Bob pushing the button.

[00:01:11]Can you make it do that again?

[00:01:24]Now, this plating process is highly protected. So, courtesy of Bonnie the Cat, here are some out takes. I'm in too deep now. Oh, hey, Bon. Don't put your ass in the camera.

[00:01:37]No, no, no, no, no, no.

[00:01:41]Postplating process.

[00:01:54]I'm back in the garage, but I have left the cylinder with Dino at NZ cylinders as he needs to do some finish measurements at a very controlled temperature. And what we're up to next is we're about to upgrade the lathe with a coolant system as that was a major limiting factor when I was machining the dummy crankshaft.

[00:02:08]First up, we need to give the lathe a damn good clean because, as you can see, it is not oil or watertight. Then, I need to seal up all the gaps between the bed and the tray.

[00:02:19]Then, it's on to designing some fittings in Fusion. And then, while these are 3D printing, I'm going to case harden the exhaust cam shaft.

[00:02:57]Now I'm going to leave the cams to temper in the kil for a couple hours and that should hopefully stop them from snapping. And this is just in time for the 3D printer to finish. So let's get back onto the cooling system.

[00:03:53]It has gotten to the point where it is ridiculous how many of my knobs are loose and fall off. So, I'm going to lock tight them all while I'm at it.

[00:04:05]Jeez, there's still some warmth on that.

[00:04:11]And that is both cams case hardened and tempered and ready to drop back to Peter at Canali Cam. So, I'm going to go see them now.

[00:04:21]And then back to the cooling system.

[00:04:23]Here is our fish tank pump. And as you can see, these fittings it came with are nowhere close to fitting. So, I have a steel one and some smaller line. I'm going to weld them together.

[00:04:43]That should do the trick.

[00:04:59]All right, that's close.

[00:05:12]And one half of this.

[00:05:18]Jeez, that's getting close to the top.

[00:05:20]The feed side of the coolant system is ready for testing. I have everything connected and plumbed up. We've got the system filled and yeah, I'm going to see how much comes out of here. Hopefully, it is not too much cuz I do have the pump set on the minimum setting. Here goes nothing. Plugging it in.

[00:05:37]That looks right.

[00:05:41]Let's unplug that. Turn that one off.

[00:05:46]Turn this one on.

[00:05:48]Looks like a good amount of coolant.

[00:05:52]Now to build the return side. All right.

[00:05:54]This is the cleanest my layer. is ever going to look. Uh, but let's, uh, see if we can find a low spot with a little bit of coolant for where we're going to put the drain.

[00:06:05]All right. So, pretty typical. It is pulling not where I want it. I really wanted it here. So, I can actually push it down and then that's the low spot and it starts to pull towards there. So, I think that's what I'm going to do.

[00:06:25]With our low point established, I'm going to cut up an oil jug and use that as the catch tray. And then I just need to design an adapter, print it off, and of course, it is exactly 180° out, so I had to make another one.

[00:07:01]Hey.

[00:07:12]Hey. Hey.

[00:07:25]And with that, the lathe is ready to make some chips. So, we're going to start machining the actual crankshaft, which is made from 4140 versus our dummy crankshaft here, which is made from mild steel. So, first things first, I'm going to double check a few of my measurements off the original crank and the dummy crank to make sure I don't make any mistakes on the actual crank. And of course update the design in Fusion.

[00:08:00]All right.

[00:08:06]Looks good to me.

[00:08:35]And there we are. That is the first test run of the coolant system. I removed about 10 mil off this side, 5 mil off this side, and it is still stone cold to the touch and surface finish is way better. So, very happy with how the cooling system is working so far. Cuz frankly, when I machined up my practice crankshaft, um this thing would be getting bloody hot and then I would have to give it a couple hours to cool down before I did any measurements and then continue machining. So, the only downside I see so far is it is a little bit messier. I have had to turn the speed of the machine down, so it's flinging off less of the coolant because a bit of it's going on the wall and the floor. Now, I'm not too worried about the floor, but uh the wall is probably not waterproof and it's running down the back a little bit. So, I might have to make a splash shield that catches that uh in the near future. So, yeah, I'm going to get back to doing some more machine.

[00:09:46]And I think my wooden shelf's going to have to go as well cuz it is absorbing an awful lot of coolant.

[00:10:02]All right. So, this needs a bit of balancing cuz that is way off.

[00:10:26]It's closer.

[00:10:31]All right, that is pretty close. And by the time I add the weight of the bolt, it should be pretty well balanced.

[00:10:59]Right, let's despite how crazy that looks, feels nice and balanced.

[00:11:19]Let's do some highly interrupted cuts.

[00:11:31]Well, this is one of the trippiest looking time lapses I think I've filmed so far. And this looks nice and peaceful, but in reality, this is what I was listening to for hours on end.

[00:11:52]I had no idea how much flex this tool actually had till I watched the slow-mo.

[00:11:56]So, please, please don't send me to machinist jail.

[00:12:02]Just to be on the safe side, every couple of hours I would check over everything, make sure everything is still nice and tight because lathes are incredibly dangerous.

[00:12:12]All right. 32.5. So, we got 75 of a mil left. All right. I think it's time to change tools.

[00:12:57]This sounded terrible, so I've turned it down to 5%. And the audio didn't even work on this one. Probably sounds like jumping in a swimming pool or something.

[00:13:15]As I am getting quite close to final dimension, I need to double check the rod clearance and the diameter so I don't overshoot my mark.

[00:13:55]And there we are. After a day and a half, this is starting to look like crankshaft, which is pretty cool. So, I got the outside's bang on the money. The inside's exactly where it needs to be. I have this slightly oversized so we can tidy up that crappy surface finish. And then once everything else has been machined, it is going to be nitrided and then finished ground. But that's going to have to wait until another video because yeah, the lathe at the moment with chucking coolant over me and the wall is a pain in the ass and I really need to get that sorted before I do any more machining. Uh, so yeah, I'm going to make up some guards and stuff and that will get that sorted. And I'm still waiting on the cams. So, they'll be back soon hopefully and then I can finish machining them. Uh crankshafts coming along nicely. The barrel, the Nixel plating's been done. I'm just waiting for it back. It needs to have the final measurement done, which is done at a very precise temperature. It's all very accurate. And yeah, I think that's probably about it from me. This has been Logan from the Motorcycle Forge. I hope you enjoyed and I'll catch you next