chinese hit and miss engine

A friend brought round a little hit and miss engine , he has had it running once , but it doesn't want to run now. There seems to be no compression , has anyone got one of these? Should there be any compression ?

Regards

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Have a look on Smokstak forum, there is a long thread there, Gil Garceru has one that runs very well. Not sure if you need to join to see the images posted as attachments.

Gil has several videos of his on his youtube channel as Reddrryder

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I've seen a few Bang good hit and miss engines, the blue ones, from acquaintances. They ran really well for about 10 or 12 runs, then will not run.

On the ones I have seen the aluminum bores, not lined with steel and not chromed, wear out completely. I fitted a steel liner in one but it was prone to overheat afterward, and there was very little clearance around the head screws to fit it.

No idea whether they have changed the design along the way to add a steel or iron liner, but the early ones I saw were not designed with longevity in mind. Still makes a nice shelf model, running or not.

If they were any good they would likely not be for sale from that supplier. I reckon they only sell lines that are bought in cheap because the items are not first quality or are ‘surplus to requirements’ from manufacturing runs.

That's a totally incorrect statement.

thanks for the help . I will ask on that site if they should have some compression

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I had one of these. It does need compression of course. Make sure the valve push rod is fitted the right way around.

One end is flat and the other rounded. Round end to valve. If it's the wrong way the exhaust valve will not close and there will be no compression.

The only other thing that will give no compression is valves not seating properly or damaged piston O ring.

Compression will usualy improve on a model engine after a bit of running as the valves bed in.

I found the ignition cut out after a short run but this was solved by reducing the battery voltage to 3v, there must be some cut out in the electronic ignition circuit that did not like 4.5v. Engine now runs for as long as there is fuel in the tank.

These models are very well made, I would not like to make one for the price they sell for.

Hope this helps.

Model link

Edited By Engine Builder on 26/07/2019 09:12:54

Just because you bought something once that was no good, don't assume everything they sell is the same............................

Jim

As I have repeatedly stated, I recommend that people don’t buy anything from them that the buyer cannot afford to throw away. There customer service reeks - if it exists at all.

Just food for thought -

The hit and miss engine models and other engines from China are neat toys which can provide some fun for a finite time. Maybe the newer ones can be repaired easier when required than the older ones. They cost over $230 USD each now. This is a very fair price for what you get - as others said I would not want to try and beat this price to make them (unless I had a CNC shop with dozens of government sponsored brand new machine tools in the far east, and was paying a very low rate per hr to the labour force to run them)

You can buy some raw stock and a good bit of top notch tooling for a lathe or mill for same money and enjoy it for years and build PILES of models of all sorts with it.

You can buy a low cost but really capable 3D printer like the Ender-3 or Ender CR-10 for same money and print PILES of parts and model bits and casting patterns etc (see youtube - search for Myfordboy, as an example of how much diversity you can get out of a small 3D printer)

Mentioning it for consideration only - completely up to the individual how to spend the available coins. I am not compensated in any way by any firm for things said above.

Edited By Jeff Dayman on 27/07/2019 00:54:38

sorry I opened a can of worms , seems like this one needs a new Viton piston ring

regards

Looks like a worth while little motor. If after a while the bore becomes worn, I don't think it would be too hadt to lightly bore the cylinder and fit a cast iron sleeve, you would then need to make a new cast iron piston, the bore would probably be reduced a few thou from new, but it should then run for ever, shouldn't even need a ring with a good fitting piston.

Ian S C

Totally disagree with you, there are some items that are not up to standard but in the main all I have bought from there over the past 6 years have been fine and even great. There have been instances where goods have not arrived, not all there or broke in a short time but every time I contact them I have had a good proactive response and replacement even with extras to say sorry.

Must be your attitude when you contact them not done it yet , oh and I always have photos/videos at the ready.

Roger

Edited By Rockingdodge on 27/07/2019 15:45:12

Let's concentrate on the engine not where it came from.

Agreed JasonB, what ever it's like, it looks a good basis for a good little engine even if it needs a few mods to make it a bit more durable. At the price it's not too much as a static ornament.

Ian S C

an up date on my friend's engine

. I put a new o ring in it to no improvement , so I made a blank cylinder head , lo ! compression restored So it must be the valves leaking . Been trying to grind them in with some metal polish but they are so tiny !!!!!

regards