From Prototype to Production: A Look at the HOWIN L6 210 Straight 6 Engine | Stirlingkit

From Prototype to Production: A Look at the HOWIN L6 210 Straight 6 Engine | Stirlingkit

From Prototype to Production: A Look at the HOWIN L6 210 Straight 6 Engine | Stirlingkit


Here is the comparison chart between the Prototype sample engine and the production version of the HOWIN L6-210 21cc Straight-six Four-Stroke Gasoline Engine Model Building Kits Water-cooled 13500 rpm based on the information provided in Dennis’s video.
For more details, please check the following blog or the video.


Prototype sample engine

Production version

Head color

Different blue

Not specified

Head size

Smaller head

Not specified

Valve cover size


Not specified

Valve cover lock


Has a lip that locks

Plug type

Small plugs

Not specified

O-ring type


Rubber O-rings

Rocker arm shaft


Studs with adjustment nuts

Push rod guides

Not specified

Nice bronzed bushed

Cylinder chamber

Not specified


Side cover


Bolt on with lifters set inside


No bearing

Has a bearing and journal



Numbered for the Rings fit back into the cylinder bore

Engine name

Not specified

HOWIN engine printed on the side

Distributor case


All together different with updated distributor

Hall sensor

Not specified

Closer to the outside and has a small hole

Distributor timing adjustment

From the inside

Adjustable from the outside

Main support


Well proven bronze


Note:Some information was not provided in the text and is marked as "Not specified" in the chart.



Today's video is a comparison of the Prototype sample engine and the production version of the HOWIN engine Straight-six Four-Stroke Gasoline Engine Model Building Kits. I got sent this howin engine as a test engine to do a video and give my thoughts. I want to show the test prototype and the final production version to everyone to see what engineering goes behind an idea from sample to testing to the final production engine. I'd like a test engine because it gives you that kind of an Open Door in your mind for creativity, and when I saw the final product, it was pretty stunning. So, who would have thought that we would have something like this now?

There are many changes that they made, so let's start from the top of the block. First, you'll notice that the production Stone head is a different blue color, and the valve cover is taller, but the head is smaller. When you compare apples to oranges, it's still the same height, but the head is a little shorter and the valve cover is a little taller. Another improvement is that the valve cover now has a lip that locks in, making it more secure than the old design that just sat on top. This also helps prevent grease and oil from seeping out the sides and making a mess.



This new HOWIN RC L6 FORD L6 300 engine uses small plugs and rubber O-rings for the intake and exhaust manifolds. The old engine had a gasket that went through the side, but the rubber O-rings on the new engine provide a better seal for the intake. Another improvement is that the fixed rocker arm shafts on the old engine were not adjustable, but on the new engine, you can adjust them by backing the screw off a little bit.



Now the new production engine actually has studs with adjustment nuts on the thing so that way you can adjust each and every rocker arm in there, and inside where the close up here inside you'll see the nice bronzed bushed push rod guides in there, and you'll see the cylinder combustion chamber is a lot cleaner on this final version of HOWIN L6 engine model. The overall appearance is really nice. That's one of the changes I've seen there on the top. Now as far as we go down, you're going to see there's no side cover on here, and it has two square blocks that screw in here with hooks because the camshaft did not have a bearing.



This camshaft has a bearing here and a journal, which sets inside the block tightly and turns to keep it from flexing up and down, bending in the middle from the stress. So the side cover actually bolts on to the side just like a real engine, just like that that bolts on, and you can take it off, and your lifters set inside these bronze tubes. I numbered my block because I numbered them for the Rings fit back into that cylinder bore. It does have the HOWIN engine printed on the side underneath.



I did notice there's tiny little holes inside the journals here you see a little angle in there each one has a hole that looked like they did not open it up does it look like they were going to have an oil Gallery come in here and lubricate these. But they're closed off, so I think they're working on the splash technique of the oil inside to lubricate the push rods the lifters and the camshaft.

So there is a little provision on the side cover at the right back here for a nipple, so it's probably up to you what you'd like to do. Running an oil Gallery in here ain't gonna really do no good unless you want to open up those little machine holes that they started to let it drip down but for some reason they eliminated that, so that's unneeded.



Now the front distributor case is all together different on this thing and they have an updated distributor here. You can see HOWIN totally updated, it has a small little hole in the side here right is there for your hall sensor to go in, and I did notice inside the distributor they moved the hall sensor closer which is cool and this one came with complete wires and everything.

And you'll see here it is adjustable, they have slots where you can adjust your distributor timing from the outside this one here did not have any of that. You had to do it from the inside, you see the slots were on the inner case so you had to take everything back off to adjust your distributor timing, so that that's pretty cool to see that I wanted to show you.



This one uses the well-proven bronze main support for your crankshaft. I noticed a lot of engines are using these now because they work. And of course, we got our main caps that go inside here upside down here to hold those bronze bushings in and support the crankshaft.



The timing gears for the camshaft and crank now have marks see there's three one two three and there's actually one up here oh that's just a piece of post so it has where you set your timing compared to your crankshaft has one too where you set your timing.



From what I gather from what I've seen between the two engines, this little dot here on the bottom of your crankshaft here goes in between women those like that to create a three-position notch there that's what I'm seeing um because mine I had to kind of turn my camshaft by hand until I figured out the cam timing in it which took quite a while.



Other than that it still has the the one-way bearing starter on the thing with the gear not a belt which is good. A lot of the other stuff has been really machined well, so it fits together real nice. This one here I had to hand fit almost everything and I had to tap some holes because it was a sample prototype engine so.

Now the crankshaft I noticed on the back this is just some of the stuff I noticed off the bat. I'm gonna put this whole thing together this weekend and get it running. I'm still waiting for the ignition kit to come, which is Three-way Nozzle, Radiator Support Holder Kit, Water Tank Water Pipe Kit, CDI Ignition Compartment and Inch Thread 3/16-40 Spark Plug, they're supposedly on the way. The shafts coming out of the back of the the crank on the Prototype is four millimeter the crankshaft coming out on the back of the production version is five millimeter that's a good thing because if you want to hook this directly up to a universal joint or something like that or a drive shaft five millimeter is usually the standard, so that's cool I really like that and the quality of this crankshaft is really good.



Now, I checked each journal on here, and they all come up to be 599, because it's supposed to be a six-millimeter journal, so that 599 gives it just a little bit of room to keep oil inside it without running dry. Other than that, it came with a full complete gasket kit, head gaskets, belts, oil pan. These are the Teflon style gaskets, and this for your timing cover in the front has a paper one, but the Teflon ones are really cool because you can reuse them over and over again.

One other thing I did notice that I was really excited about when you put your timing all together, you have to grease it, but here's what I noticed on the front cover. You'll see a little Notch at the very bottom down here or that goes into the block, and there's a rubber o-ring on the outside here that seals it. That's going to let oil get splashed up in oil are timing gears; that'll be nice that way we won't have to tear it apart you know after so many hours and re-grease everything because this here it's a lot of work to take all this off just to re-grease your timing set. So they've already taken care of that and looked ahead that's cool good thing there. And basically, the rest of the engine is pretty much the same as far as the twin carbs, the brackets, the starter Motors well, they're all the same with the gear on it. That works well for the TOYAN V8 Nitro Engine FS-V800 RC Engine Model Building Kits 28cc, so there's a lot of things. I see that a lot of other companies, like TOYAN engine, CISON engine and ENJOMOR engine, are doing to these as far as your main journals, making those nice and beefy and solid, the starter motors with the gear not the belts, seeing what's working now and this is the whole part of the early transition of when they're building an engine model.



It's a larva stage. so you think about this what six years ago the Italian 100 came out, those are still pretty good engines you know they had a debacle with the TOYAN FS-L400 14cc Inline 4 Cylinder 4 Stroke Water-cooled Assembly Engine Model For RC Model Car Ship Airplane, but now  through changes and changing bearings and all that stuff, they're working it out. So these I don't know what the longevity of these engines are, because some of them are more Nitro and the Nitro ones were really expensive to run, because nitro is about 50 a gallon and now these are all going to be gasoline so with oil in them and it's just like that engine there it's gasoline with oil, that's cool. When the Starter Kit for HOWIN  21cc Inline 6 Gas Engine DIY Model Kits comes, then we'll be able to fire it up. So excited I love hearing a new baby cry when you first fire an engine up you get the you get the feel of how it's going to be how it's going to run you get to tune it and then then you get to put it in something.


Episode 2 of rise and shine it’s engine time!


Other related blogs of howin engine you may wanna read.

HOWIN Inline Six Engine L6-210 Full Reviews by Customer | Stirlingkit

After-sale Service on Howin Inline Six Engine | Stirlingkit

Is it Hard to Make A Scale Model of An Inline Six Engine? | Stirlingkit

Everything You Need to Know about Howin Inline-six Engine Model | Stirlingkit

 HOWIN Designs & Makes Inline 6 Cylinder Engine L6 Now




1 comment

  • Vince: January 28, 2024

    Haven’t noticed if you had this running yet I’m interested in buying one will yours be for sale when you get done with the videos thank you

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