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Chinese Vertical Hit and Miss

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Cogsy

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After a few months of being curious, I got myself one of the Chinese Vertical Hit and Miss engines and thought I'd share my experience of it so far.

Straight out of the box it and first impression was that it was a very nicely machined and finished engine. I like the 'blasted-look' finish on the crankcase and cylinder and there's no machining marks to be seen anywhere.
1.JPG


There are some obvious solder joints on the fuel tank and the piping of the cooling system but they're pretty neat as well - probably a better standard than I could achieve so I can't complain.

2.JPG


There's a decent amount of brass used and it looks to me like the head and rocker assembly is made from bronze. The flywheels are steel outer rims and I think the centres are anodized aluminium. In my opinion they suit the engine quite nicely.

3.JPG
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As you can see from the picture above, there's a starting pulley on the left side of the engine and it was supplied with a starting handle and a short piece of starting cord. In practice I didn't need to use the starting handle but it might be handy if you have hand issues like arthritis or something, although in that case you might want to change the starting pulley for some sort of spigot to use an electric drill for less starting effort.

So I was pretty impressed with how it looks and the apparent build quality at first glance. This post is getting long so I'll start another one.
 
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Cogsy

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So, what do you do as soon as you get your hands on a new model engine? Of course you turn it over to see how much compression it has right? So I turned it over and it had none! A couple of seconds of confusion and I found the rocker arm was 'sticky' and was holding the exhaust valve open. I shut it manually and the next spin showed a decent amount of compression. The sticky rocker recurred the next time the valve opened though, so it had no chance of running in that condition.

The rocker seemed like it was only 'just' sticking and I thought a little light oil might solve the issue so I administered a few drops and worked it back and forth for a while. That didn't seem to make any difference at all so I figured I needed to remove the rocker arm and just polish the edges a tiny bit with some wet and dry to fix the problem.

The pivot pin for the rocker is a ~2.5mm pin and is retained by a tiny circlip. Somehow even with my fat fingers I managed to remove the circlip without flinging it off into oblivion and having to source a replacement. It wasn't fun though.

6.JPG


Once the circlip was removed I was expecting the pivot pin to slip right out but it was reluctant to move at all. I got a small screwdriver under the head of the pin and got it to move a few millimetres before it refused to budge any further. Reluctantly, I removed the entire rocker pivot from the head (and the head bolts were super tight) so I could work on extracting the pin.

Rocker pivot 1.JPG


I had to resort to making a small drift punch and drove the pin out of the rocker without too much trouble in the end, but it would have been a difficult job to do with it mounted to the engine.

With the pin removed the rocker was still reluctant to come out of the pivot so I assumed there was a bit of a burr on one of the parts causing the sticking issue. Once I got them apart a few seconds with a piece of 600 grit wet and dry cleaned up the rocker and it moved very freely in the pivot and I thought the problem was solved.

When I went to check the fit of the pivot pin to see if it was tight in the rocker or the pivot itself, I found the actual cause of the binding. The pivot pit was intended to be a close fit in the pivot and rocker, but (I assume due to slight misalignment on assembly) the pin had been bent and was binding in the pivot and the rocker itself, as you can see in the picture below. A few minutes of gentle adjustments had the pin straightened out well enough to be reinstalled and the assembly then operated very freely.

Rocker Pivot 2.JPG


Wow this is turning into a saga. Next up will be getting it running.
 
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Cogsy

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There weren't any detailed instructions on running the engine, which is what I expected to be fair, so I simply dribbled a bit of light 3-in-1 oil on the moving parts that I thought needed it. Based on the radial play in the crankshaft, I assume the main bearings are ball bearings, but I don't know if they are sealed or require lubrication through the crankcase so I thought it best to squirt some in there to be safe through the bung in the back (with the engine inverted for good measure). Then I gave it all a few spins and called that good enough for a start.

4.JPG


I also installed the 3 AA batteries for the ignition in the holder in the wooden base. I initially had an issue with the middle battery refusing to stay seated in the holder until I found a thin black elastic band was around the holder and I had trapped it between the batteries. I think this band is intended to keep the batteries in place but you have to install it correctly for it to have a hope of working.

As this engine is water cooled, with a nice brass radiator and is fitted with a water pump, I wanted to run it with water in the system and see if it worked. I used a syringe (without the needle) to fill the radiator and then spun the engine over to get the water pump operating. The water level in the radiator didn't seem to be lowering, although it was moving, so I figured the pump needed a bit of priming. Long story short (yeah right) I ended up filling the water jacket from the water outlet point on the back of the cylinder and then the pump seemed to be circulating the water as it pumped.

For fuel I used ordinary gasoline (petrol where I come from) with about 5% WD40 added for a bit of lubrication. This wasn't mentioned in the instructions but I run all my models with a mix like this so I just did what I'm comfortable with. Getting the fuel into the tank was somewhat problematic as well, as the small filler opening kept getting an airlock, even using a syringe. Eventually I worked out the best way to fill the tank was to remove the fuel line at the carb then attach the syringe to the line and fill the tank from the bottom. Not really difficult to do but took me a good few minutes of frustration to think of it.

Finally it was time to attempt to start it up and I was a bit nervous. Most of us have experienced the hours of frustration that is sometimes required to get a new engine to fire up the first time and the rocker issue showed this engine had not been started at the factory. I was then very surprised to have the first pops occur in the first few spins of the flywheel, and a couple of second run within the first minute of trying. Over the next couple of minutes I kept getting bursts of activity, though occasionally the intake valve appeared to be not quite seating properly and needed a 'bump' to get it to fire again. Within maybe 5 minutes or so I had it running reasonably happily and the hit and miss mechanism was working consistently.

I was playing with the fuel needle adjustment trying to get more misses and fewer hits and was surprised that it's not as 'touchy' as others I've encountered, then all of a sudden the engine quit on me and refused to fire back up. I wore myself out flipping it and adjusting the needle, including shutting it all the way off to try and clear it from a 'flooded' condition and I took a few breaks to recover. Eventually I managed to forget which way was 'ON' of the ignition switch (it's not marked) and tried to listen for the spark but I couldn't hear it with the switch in either position (I could earlier). I assumed from this that the plug was wet and shorting out so I decided to pull it out and check.

It turns out there's not much room on the head and I had to remove the rocker post again to get a spanner on the plug. The plug was also tightened more than I would be comfortable tightening it, but it came out okay and wasn't damaged at all. It did come out dry though and it showed me that I wasn't getting a spark from the ignition at all. It turns out the little 'jump' that the engine gives on each hit was enough to overpower the thin elastic band holding batteries in place and one had popped out. A much more robust band was fitted and I haven't had that problem again.

I've only run a bit over a tank of fuel through it but I can confirm the radiator does get warm so the cooling system seems to work as intended. It runs a bit faster than I'd prefer but is quite small so that is somewhat to be expected.

In conclusion, I think this is quite a good little engine for the money (certainly far less than I'd want to be paid for making it, even without the active cooling system). I would recommend it to someone who's a 'hands on' type person and maybe has some experience with model engines but based on how 'fiddly' it is to fuel, prime the water pump, etc. and for the potential of having to fix a few minor niggles, I don't think it'd be suitable for a 'newbie' to the hobby.

Being that I didn't make it myself, I'm planning on building some sort of device for it to drive in the future, so I can personalise it a little bit. As delivered, the disc containing the magnet for the ignition has the OD machined to accept an o-ring so driving something should be trivial. I also plan on experimenting with some lighter governor weights and see how slow I can get it to run..

I know a few places online sell these and they all look the same in the pictures, but I don't know if they vary by supplier. I got mine from www.stirlingkit.com and their service was good. They did claim that each engine was supposed to have been started before being dispatched but I think the rocker issue means mine must have slipped through the system.

Thanks for reading if you got this far!
 

perko7

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Interesting little engine. I could possibly use one of them for an upcoming project, depending on its size. Had a look at the Stirling Engines site, couldn't find any dimensions though. Are you able to measure overall width/length/height/flywheel diameter and post that info on this thread? Thanks.
 

CFLBob

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A few days ago, YouTube offered me a video on a 4 cylinder engine that the guy got from Stirling Kits. It was the first I'd heard of them. He does a lot to get it running, but not as much as you do on this one - it's more like final assembly than troubleshooting the bent pin and all.

Like others have said, it would be cool to see a little video of it running.
 

Kevlamar

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I do not have the vertical model but i have purchased several of the horizontal ones by same builder. They are all supposed to be tested pre shipping but i suppose a few may slip through the cracks. They are well built for the price and run very well. however the biggest problem i have encountered so far is the way the flywheels are held to the shaft with only a simple set screw. there is no gib or even a slight indention in the shaft for the set screw to recess into. So it is only a matter of time before the set screw becomes loose enough for the flywheels spin on the shaft. by the time this happens the set screw will have already "chewed up" the shaft which can make getting the flywheel off the shaft a problem. To remedy this problem the flywheels need to be taken loose and shaft needs to be filed down or drilled so the set screws have something to hold onto.

Concerning making it run slower, this can be achieved by putting lighter springs on the governor

I have one turning a 1 pint, white mountain ice cream freezer and it gets a lot of attention!

hope this helps

(in this pic the belt is not connected. there is a 3/1 gear-down ratio on the belt side and another 6/1 gear-down ratio on the chain side which gives it a total gear-down ratio of 18/1 so it has plenty of power to actually freeze a batch of ice cream)
worlds smallest hit miss icecreem freezer .jpg
 
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