Printable V8 motor

by sirmakesalot, published

Printable V8 motor by sirmakesalot Aug 17, 2011

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Here is a motor with a v8 configuration. It is two halves mounted ninety degrees from each other with the same crank shaft, connectors and pistons as the four cylinder just more of them. It is worth noting that they can be alternatively mounted flat or opposing piston configuration. I opted for the muscle of the V8!

I have added the crank shaft parts layout and the source file as separate files so if any parts brake, you don't have to print the whole thing again!

UPDATE: I have uploaded the fixed STL files, no more errors from Skeinforge! Thank you all for your valuable input as I am still learning too.

I have added a larger piston file but it requires good printer settings.


Use the file marked v8 layout fixed and V8 body #2 at the bottom of the file list for plate printing. One of the piston blocks wasn't on the build surface so now it is fixxed! Thanks to Thingiverse user JohnA for pointing that out!!
A little tricky to get together and a couple of approaches work so its up to you but here is how I did it. Look at the picture for some reference, the crank shaft is symmetrical and the same one as my 4 cylinder motor and the pistons have room on each mounting rod for two.
The pistons mount to the connectors with 3mm filament.
It helps to put the crank shaft together without the ends that it pivots on first, don't forget to put the pistons on as you go.
Then I put the piston and crank assembly in the cylinders then glued the blocks together. I used Krazy glue but what ever works for you, acetone, hot glue, etc. The cylinder blocks mount on each others end but note their is a rounded corner, I did this for a nice feel in your hand when holding the motor.
Finally I put in the two small rods that the whole thing rotates on and the crank handle.
Your done!

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What's the difference between v8 body 2 and v8 body fixed?

How did u guys connect your pistons to the rest of the motor?

Oh wait never mind...

How do you put it together?

Oct 20, 2014 - Modified Oct 20, 2014

I'm a new user, and i tried printing your V8 as the first challenging build. Boy, turns out, its quite challenging. I use a 1.75 mm filament, and I suspect that is the problem. My crankshaft parts can't readily assemble to each other.

The mating link has a hole smaller than the shaft of the link. I had to use a 6 mm hand reamer to ream the hole big enough to fit, making the wall thickness a lot flimsy. Also, the engine blocks could have small locating pins and holes for perfect location before glueing them together.


Is there a ratio to an actual motor on any of your designs?

Is there any way I can make this without 3mm filament? I use 1.75mm filament.

this thing is a lifesaver

Piston wrist pin for W16 engine
by sboerup

Design pins in sketchup.

I printed mine out and it didn't run! WTF...and yes i put gas in!

I have tried to print this on my replicator, but it keeps freezing at ~ line 172888 (over an hour in) for some reason. The printer just stops, for no reason I can determine. the print looks good tp that point, and ReplicatorG still thinks everything is fine, and just waits for the replicator to come back.

I can end the print and print a different thing with no issues.

Any ideas?

That, I am afraid, is beyond my expertise. It could be something with your profile. Perhaps try moving it on the build platform in repG then save and re slice?

I personally haven't had any issues. Most curious.

The v8body fixed file has a tiny, tiny issue. One of the 4 cylinder banks sits .25mm lower than the other....

Hi John,

Here you go! Use the one marked v8 lay out fixed at the bottom of the list. I moved the block onto the build surface. Thanks for pointing that out! :-D

Opps! I'll fix that and reload them today by noon, sorry about that!

would love to have a starmotor variant of this :)

I recently uploaded this...


Perhaps this is what you are looking for.

Radial or Hula Motor

That is strange. Did you move anything around before printing? Is your build platform level? Sounds like the back set prints fine and the front is in the air? This is the first I have heard of this issue regarding the v8 motor. I have recently printed off this in black and green on my TOM and it worked fine. I must admit I am unfamiliar with the Ultimaker so not sure what to suggest.

Ok, I finally have my MK6 built and working (required jumping through hoops with firmware re-compiling because I'm still on Gen3 electronics). Anyone print this with a MK6 on a TOM or Cupcake and use any special settings? Thinking I might want to up my cool time from 10s min/layer.....

Is it just me or are the tolerances between the piston and the engine block unnecessarily large?

I don't have the MK6 extruder yet so I was happy about the little larger tolerances :)

Still some sticking when turning the crank but I'm sure acetone treatment takes care of that..

Yeah they are a bit. I wanted to make sure that there was enough room. At the time I designed this my machine wasn't as dialed as it is now. I think it could be reduced too however some people have had problems so it might be best to just leave it. It would be worth a try if you like I have posted the source file below.

Hmm, i'm not sure opens cad works with 3dm files :(

Perhaps, you could upload different versions? What is the spacing now between them anyway? It looks to be r_inner +=1 or 1.5

I have uploaded a larger piston. The original space I left was 1mm between the wall and the piston so I made the larger pistons 0.5mm bigger. That should take up the space,

Let me know how it turns out!

Ok, just printed it, it actually runs smoother then my other one, as theres little space for 'racking' to occur between the pistons and the engine block.

Great work!

A suggestion though, instead of having to glue the two engine blocks together, you might be able to use a dovetail join, which should make it more friendly to assemble.

Having keys in the cam parts will also make the camshaft stay straight all the time, which means you don't really h
ave to use glue.

Yeah I actually had an issue with my cupcake not being dialed in well enough to print this. Also not having a stepping extruder (was waiting on parts) made cleanup a nightmare. Almost done building the extruder now so I'll reprint and see how the tolerances look.

Cool! looking forward to seeing the results.

Another video. Not as nice as the others, but still shows what clear PLA can do to the model. http://www.youtube.com/watch?v=hMjt-ByAs_chttp://www.youtube.com/watch?v...

Oh man, I love the clear touch of the PLA. Must be cool to put LED lights inside stuff made from it. Have you ever seen clear colours or used a marker to tint it as you print?

Nice, I was using this print as my first PLA print and am having troubles with the inner face of the cylinders not adhering properly and causing massive stringies when when cleaned up afterwards cause grooves in the cylinder that the piston catches on. I think I need to do more testing... :(

Fix this by rotating the cylinders 90
° around the Z-axis. I had that problem until I tried this...revelation!

All files have been fixed. No more skeinforge errors!

Perfect, the new files and a slightly higher build temperature for PLA and it's printing like a champion.

Earlier axtheb suggested netfabb to repair an stl file. I am running these through and will post the repaired files later today.

AWESSOOOOOME! Im now thinking about experimenting with clear PLA. When the time comes may I pick your brain?

Can you provide parts for the cylinders and piston heads separately? I want to try clear cylinders without printing repeat parts.

I have uploaded the pistons and cylinder bodies bellow. Hope it works out, I would love to see a clear one!

Cheers, should be all printed in a few hours.

This is great!

Skeinforge 41 really doesn't like this model though. Some of the cylinders end up with these ridges inside that make the bore too small, and there are weird gaps in between the cylinders and where the cylinder mounts are. Maybe it has something to do with the way Rhino handles STL export.

, this is a very cool model.

I fixed all the STL files if you want to try again.

Might be your settings in Skeinforge. I had the same problem but not as bad as what you are experiencing. I had what appeared to be some cylinders overlapping but only by a small amount. I sanded them off. Try a layer thickness of .3 mm and turn on the reverse option with about 75-78ms and infill to 100%.

I know rhino could be the issue.

Awesome work sirmakesalot! Got a question... RepG is putting out a lot of errors when slicing layout2 that look like:

[22:33:38] Warning, the triangle mesh slice intersects itself in getLoopsFromCorrectMesh in trianglemesh.
[22:33:38] Something will still be printed, but there is no guarantee that it will be the correct shape.
[22:33:38] Once the gcode is saved, you should check over the layer with a z of:
:38] 2.62499775513

Any ideas what could be causing that? I'm trying to print on a Cupcake if that helps at all?

Thanks very much!

I have been getting the same error message with this and some of my other prints from Skeinforge 40 but It still prints out ok for me and with other prints just fine as well.

As best I can tell it may have something to do with the program I am using to draw this with and it isn't translating well, (I am using Rhino if you are familiar with it, I put the source file below) I am still fairly new to this stuff so I am not too sure and as for the cupcake thing I would think it doesn't matter should print just the same.

Have you checked the Skeinforge wiki? Might be something there and what happens when you print?

Let me know how it turns out!

You can easily repair STL files with netfabb cloud service

Wow! What a difference! Thanks again for the tip I have run all my files through and cleaned them up, all future files too!

Nice tip!

Ran it through netfabb and resliced; no errors from repg/skeinforge! Thanks for the tip. Time to start printing!

My wife, Nanci Ezzo, is the driver ;-)

P.S. This was one of the funnest "things" I've made with my TOM to date!

Awesome job! very nice print. I loved making mine too, I am so glad you like it and getting such enjoyment from it!

Stay tuned, more to come in the future!

Great job !! What are you using to draw these? Would be nice to get the sources so we can play with it ... Thanks for sharing!

I have added the source file for you, have fun!

Thanks! I use Rhinoceros 4.0 NURBS modeling for windows. I will upload the source file for all my motor models for people to play with this eve!

When are you going to get serious and print one that fires? LOL. Awesome work!

Or one that runs off of air...

next step is a v12? thanks

relet - in reply to Ben

No, next step is a parametric motor in arbitrary configurations and angles.

Another great upload! I've just started the print for your 4 cylinder! Did you print it with an ABS raft? :-D

I printed this raft-less with ABS.

Great stuff. Can you make a fully printable sterling motor? Thanks for the cool designs and inspiration to make more things.

Thanks for the compliment. I am working on a hula motor now, it's turning out to be way more challenging to make it printable.