Rings Disintergrated

F

fattmeeney

New Member
I purchased new piston, rings and bearings to improve compression in the hunt for optimium performance/operation. I work with access to a complete machine shop, with all possible machining,tooling and metal finishing goodies one could think of, I am qualified and capable of using said machine's/tools.
After purchasing the parts (won't name name's till know what their prepaired to do about it all) I peddled to work and did the install throughout a 8 hour shift, I used all new hand made gaskets, high tensile caphead bolts, double checked everything and was using mic's to ensure things were within .02 of a mm, I used the company spec's to get measurements. The bore was honed, 2stroke oil was used on the bore to aid install.
....long story short after a warm-up of about 3-5mins, I gently putted up a hill whilst peddling, coasted over it not going over 4500rpm, I rolled down the hill used brakes to controll mine and engine speed, let go of brakes, hit the brakes and BANG, rear wheel lock up complete seize....
got home biggest piece of ring I've found so far is the size of a matchhead, there's powdery **** stuck in (install) oil residue on the head. The whole lot is seized, piston in sleeve. I haven't removed the cyl. head as the conrod is still attached, I don't know if it's bent though.
What I want to know is has anyone had a similar experience, know what might have caused it, Personally I beleive it was a manufacturing fault as I have installed many pistons in cars, bikes (both 2 and 4 stroke) and little moddle engines. Never had drama's before, nothing like this :(

will keep posted as to company's response and resolution, Will name and shame if a fair conclusion is not reached.
 
What a bummer. I think anytime you do internal surgery on an engine...it probably voids any warranties unless one of there contracted repair centers do the work. I also rebuild model airplane engines, but all warranties are void as soon as I open it up. However if I buy an O.S engine from Tower Hobbies and send it to Hobby services...there autorized repair center to be repaired....then they are responsible to send me back an engine that is guaranteed to be right and serviced using non defective parts. I can tell them I am an awesome model engine rebuilder if something goes wrong, but they still are not required to stand behind no matter how awesome I think I am.

I also rebuild K-Series Kohler engines because I am a John Deere 110 Tractor collector, but it is my responsibillity to inspect all the parts in a rebuild kit before I install them parts. Once they have been used or made a part of the engine..then the warranty is void. However if I can find a defective part in my kit before it is installed....then I can get them to replace that part at no charge.

I am not saying you are wrong, but I can very easilly see both sides of this arguement but regardless of my point of view...I am still sorry to hear of the problems you had. Hope you are able to get things back up and running.
 
yeah I can completely understand where your coming from, The company I purchased from doesn't offer a repair service that I could find, Only parts, complete engines or motor bicycles so I am unsure as to where the line is.
I like all things mechanical, but am by no means saying I'm some kind of guru or even trade qualified (yet...) however I have installed sleeve's, piston and rings before so had a good idea of what to do, I also did a little research before I got into the job as each engine is different so wanted a good method as example. I also inspect clean and if necessary lube all components before any sort of mod or build, with this particular job as I preped each part I the wrapped it in a clean cloth and put the whole part and cloth into a zip lock bag to keep contaminants from the cleaned item
I could understand how many claims the company may get from customers who may have made a mistake and caused their own problems and that resending parts would send them broke, it would be difficult to sort fact from fiction and what ever the result I will bear no annimosity to the company, I won't "shame" them as I have had alot more positive expeirence's and this is the first bad one, so no need to jump off the deep end, I am trying to be as easy going about the whole thing as possible, no need to cause stress for either party concerned, dispite what I mentioned in the first post, I would shame if the correspondance wasn't appropriate though, If I can be honest and cival, I expect the same back
I am disassembling the motor and taking as many photo's as possible at each step to try and identify the cause of the failure as I am keen to know, If by some slim chance it was my fault, I am man enough to stand up and admit when I made a mistake, and would apologize as I would expect the company to me.
Thanks for your post, It's always good to hear genuine advice or expeirence that has relavance rather then forum ranting, haha.
 
Re Gearnut;
Sorry bit of a forum noob, what do you mean Chinese HT?
Yes the company is a reseller and source's the parts/componants from china. I don't know if they assemble the engine's or get them complete. From what I can find about them, and have heard they have a good reputation, Although I don't understand what is ment by "HT"
thanks for your time
 
is it possible you installed the piston backwards? on some engines, the ring opening will hang up on a port if not installed correctly.
 
"HT" is slang for "Happy Time." it comes from the butchery of the english language, as in "Happy fun time engine!"

it's the standard 2 stroke chinese kit.
 
I had something happen today.. Could be the rings.. Will find out tomorrow when we open it up.

But I want a much better motor now..

I feel the pain!
19 mph easy going ride and clunk engine stopped! Clutch works so I was out of the lock up with a quick squeeze of the clutch.
725 miles RIP China HT Girl
 
Not too sure that honing or even putting any cross-hatching on the cheap
chrome bore was a good idea. I know the plating in that barrel is super thin.
TiM
 
fattmeeney said:
yeah I can completely understand where your coming from, The company I purchased from doesn't offer a repair service that I could find, Only parts, complete engines or motor bicycles so I am unsure as to where the line is.
I like all things mechanical, but am by no means saying I'm some kind of guru or even trade qualified (yet...) however I have installed sleeve's, piston and rings before so had a good idea of what to do, I also did a little research before I got into the job as each engine is different so wanted a good method as example. I also inspect clean and if necessary lube all components before any sort of mod or build, with this particular job as I preped each part I the wrapped it in a clean cloth and put the whole part and cloth into a zip lock bag to keep contaminants from the cleaned item
I could understand how many claims the company may get from customers who may have made a mistake and caused their own problems and that resending parts would send them broke, it would be difficult to sort fact from fiction and what ever the result I will bear no annimosity to the company, I won't "shame" them as I have had alot more positive expeirence's and this is the first bad one, so no need to jump off the deep end, I am trying to be as easy going about the whole thing as possible, no need to cause stress for either party concerned, dispite what I mentioned in the first post, I would shame if the correspondance wasn't appropriate though, If I can be honest and cival, I expect the same back
I am disassembling the motor and taking as many photo's as possible at each step to try and identify the cause of the failure as I am keen to know, If by some slim chance it was my fault, I am man enough to stand up and admit when I made a mistake, and would apologize as I would expect the company to me.
Thanks for your post, It's always good to hear genuine advice or expeirence that has relavance rather then forum ranting, haha.
Click to expand...

You sound like a real standup type feller. Regardless of the cause or regardless of fault....still a real bummer and I know from my own experiences in my many hobbies that it is hard not to get aggrivated from time to time. I had a GMS 47 2 stroke airplane engine that I would have liked to have fed to the person who put it together, but after some time to think about it and cool down a bit..........I still wanted to feed it to someone!LOL Same goes for our cheap china "Happy Time" engines. They are great when working well, but I am expecting many days of aggrivation in my future purchases of elcheapo HT engines.
 
Last edited:
Hey everyone, cheers for the input :)

I installed the piston with the arrow on the top facing the same way as the arrow on the piston removed.
Yes it was a chinese motor, HT hahaha

The bore was almost glazed due to the worn piston rings being replaced, I didn't do anything drastic, just restored a good finish with a very light grade stone, The set avaiable in that diametre is very light
 
I second the concern about honing these cylinders. They do not have a cast iron liner like alot of other engines do. All they have is a very thin, like 0.010" thick chrome plated cylinder. I doubt if they are actually 0.010" though, most likely thinner than that.
Honing one is definitely out of the question.
I have de-glazed one before by wet sanding it lightly with 2000 grit sand paper. Yes I used a soap and water solution while sanding and I also washed the bejezus out of it afterwords.
Is the powdery stuff you were referring to grey in color? If so I bet is is aluminum from the cylinder as the chrome was too thin if even still there after honing.
 
timboellner said:
Not too sure that honing or even putting any cross-hatching on the cheap
chrome bore was a good idea. I know the plating in that barrel is super thin.
TiM
Click to expand...
That was my thought upon reading that the OP had done that. The hard chrome is microscopically thin, all the wear is supposed to be the rings and pistons. I would not be surprised that the crosshatch went through the plating at least enough that the rings tore off the rest then it was aluminum-to-aluminum with the rings scraping what was left of the hard chrome off.
 
re Ckangaroo70;
Thanks mate, much appreciated. You talk as much crud as you like, kick up a big fuss and carry on like a pork chop, but at the end of the day all you get is upsett, stressed out and people having a laugh at your exspense. Stuff happens, say your naughty words, take a deep breath, move on and go have a drink. Most of the time motors aren't worth the stress, and if they cause stress it just makes it that much more satisfying when you hear it fire up for the first time... Very satisfiying

RE Honing;
The reason the rings wear first is because the chrome is hardend and is extremly durable provided the right precausions are taken. It is extremly hard but also unbelievably brittle. I started my apprenticeship in a company in W.A that specialised in the rebuilding/refurbishment of industrial hydrolic cylinders of all size's from about 22mm bore to 568mm was the largest I worked on. I know this is a different application but the princible is the sameyou hone to leave fine, very fine e.g. less then .001" in depth on the surface of the chrome so the oil has microscopic "ridges" to adhere to so that maxium lubrication by means of a constant film of oil between the two metal surface's. Using the correct tool and cutting oil the x-hatching is only visable with the right tilt of your head and the light on a good angle, there is no way you should be able to feel the marks. As for the jug I was using I depth mic'd .017" at the base where the taper is. This is more then enough. If you only had x2 bores for the same application with only.008" and only correctly honed one of them, I can promise you the honed bore would easily outlast the other, ande would guess by at least double the amount of time.
Using even the same grit paper or cloth as the proper honing set won't provide the same result, you can't apply equal pressure or time from one patch to the next, your "vally's and ridge's will be unequal in both intensity and depth, If you go to deep the ridge part is to pointy (like a knife edge) and will fold over with the motion of the piston, this then blocks the ridge from affectivly holding the oil so create's hot-spots or wear spots that can cause the chrome to break up. Long story short it IS really important, it is also Really important to do it Properly, with the proper tools. You can get a cheap set of honing stone's from your local carparts supplier... will last years if used with a good cutting oil/compond.
To those who don't hone or recomend not to, I would say try it you have nothing to lose. Do some research from a couple of different source's and make your own opinion.
Google honing ridge's and valley's, when I use these terms I want to stress that they are miniscule, you couldn't measure the depths with anything other then a laser of some sort hehe.
I don't like to preach or tell people how to do things so will end by saying, reader use your brain, find as much info as possible untill you think you know what the go is, the keep reading :)
Make your own mind up after you have all the facts so your confident in your actions, and be prepaired for "hic-ups" along the way...
 
That is interesting, considering that some guys over on the Hongdu-Solex thread honed their cylinders and enjoyed increased compression and power as a result. Of course, those cylinders might be made of a different grade of Chinese aluminum.
 
rohmell said:
That is interesting, considering that some guys over on the Hongdu-Solex thread honed their cylinders and enjoyed increased compression and power as a result. Of course, those cylinders might be made of a different grade of Chinese aluminum.
Click to expand...

The Hongdu-Solex engines have a cast iron cylinder.
I was the one in that thread that discovered that they hardly has any crosshatch honing from the factory.
 
Last edited:
wayne z said:
The Hongdu-Solex engines have a cast iron cylinder.
I was the one in that thread that discovered that they hardly has any crosshatch honing from the factory.
Click to expand...

Oh, Ok, sorry, I didn't know that.
Sorry for any confusion my post might have caused.
 
The non directional cross hatch finish plays a very import roll in a nice clean and even ring break in. This in turn plays a roll in better prolonged healthy cylinder compression. To the tune of a nicely promoted even wear pattern

I got into a habit over the years in automotive brakes. When I did a dust a bust on rear drum brakes. Clean and adjust. I would use aggressive sand paper to create a non directional surface on the cast iron brake service in a x pattern . Note ya cannot use aggressive sand paper on any of these cylinders. This would insure a nice even surface wear on the brake surfaces and also help when pads were heavily glazed.
 
You must log in or register to reply here.
Back
Top