Cheap piston = BOOOOOM! (pics)

[griffonks]

I just ordered my first Golf Piston for an 011AV, my friend's saw. I warned him about the piston but he wanted to give it a shot. I'm not sure what the piston was that I took off of the saw, but the skirt had peeled- like a coating. The circlips had ears on them but the underside of the piston was coated with blowby so I couldn't read it. Might have been a Golf.

I'll check the new piston/ring close....

Thanks for the information.

Sent from my SCH-R530C using Tapatalk

 

[dozerdan]

a good set can make up for lower compression caused by excessive squish, poorly beveled intake/exhaust openings and even the shape itself.

OK I am lost. Please explain how a good set of ring will correct the compression cause by excessive squash. Are these magic ring? If the ring are bad you will have low compression. If you have a large squash you will have low compression. Replacing the rings will not change the squash.

Later
Dan

 

[spike60]

I have a Golf in a Jonsered 820. Has plenty of time on it and doing fine. Got it from Weimedog, and I think it might have been the only option for the 820. A lot of this is consistency and sometimes you just never know how with some brands.

Randy Watson IMO is the guy here who has the best grasp of how this whole aftermarket piston and cylinder game works.

 

[pioneerguy600]

OK I am lost. Please explain how a good set of ring will correct the compression cause by excessive squash. Are these magic ring? If the ring are bad you will have low compression. If you have a large squash you will have low compression. Replacing the rings will not change the squash.

Later
Dan

I would like to hear the explanation for this one my self.

 

[watsonr]

A crappy ring and crappy squish will give lower compression... fact
Crappy ring with tight squash will give better compression
A good ring with good squash gives the best compression.

It won't make up for squash, but will raise compression..... A better ring will give better compression.

 

[thomas1]

I think what Randy was saying is that some of the AM kits have various issues that are detrimental to higher compression readings and the rings that come with them don't help matters. Spending $10 on a Caber ring will help you gain back compression lost from the lower quality ring, thereby helping to mitigate the losses caused by the other issues.

In other words, running good rings will help get all the compression available on your particular cylinder, regardless of any other issues.

Correct me if I'm wrong.


Edit: damn slow connection.

 

[MS260 Fan]

I had the same thing happen to me with a white boxed piston kit bought from an Ebay seller from BC. It was deemed to be my fault because I obviously used my plastic ring compressor to drive the locating pin into the piston during the installation. I spent a ton of time taking pictures and describing the pin to the seller. At the end all I ended up with was a ruined OEM cylinder and a

 

[jockeydeuce]

I had the same thing happen to me with a white boxed piston kit bought from an Ebay seller from BC. It was deemed to be my fault because I obviously used my plastic ring compressor to drive the locating pin into the piston during the installation. I spent a ton of time taking pictures and describing the pin to the seller. At the end all I ended up with was a ruined OEM cylinder and a

We are talking about the exact same brand of piston, because I've bought from the same Ebay seller in the past, when the better pistons weren't an option, and I know this one that failed is the same as he sells.......

His story to you is complete BS!!.....If the fit on the locating pin is correct, there's no way you can drive it into the piston with a plastic ring compressor....The locating pins simply aren't a tight enough fit in some of these pistons.

 

[weimedog]

We are talking about the exact same brand of piston, because I've bought from the same Ebay seller in the past, when the better pistons weren't an option, and I know this one that failed is the same as he sells.......

His story to you is complete BS!!.....If the fit on the locating pin is correct, there's no way you can drive it into the piston with a plastic ring compressor....The locating pins simply aren't a tight enough fit in some of these pistons.

Still interested in the actual brand, have to be certain and specific. Tossing names and innuendo's around without absolute certainty and accuracy causes miss information to dictate the impression of what brands work and which don't. To me Meteor & OEM are the best options, but I have had successful builds with Golf, Forester, Espian, and now testing Huztl parts. I never used any thing from Baileys or the many others on the market.. such as hiway or mako. So brand was that again?

 

[splitpost]

just going off your pics and you say the ring hung the port ,i'm betting that it did not have the correct ring end gap.

 

[VI sawguy]

There are at least three different ebay sellers from BC selling aftermarket saw parts, you might want to make sure everybody is talking about the same ones. There are many different brands of aftermarket pistons that come in plain white boxes

 

[WHSH]

I am not sure if some one mentioned this, but I have seen this happen when you put at 1.2mm ring in a 1.5 slot. It has enought play to slam off a chunk of piston crown. Otherwise I don't ever see this happend. Some after market folks don't match the ring size to oem size. For example I had an 066 that I got an after market piston, and I always toss the crappy rings they come with and replace with cabers. I assumed that the AF pistoin rings were of oem spec and ordered cabers it. Never thought twice about it, intallled the rings, and went on my merry way. The saw blew within 10 min of start up and looked just like your photo. No cylinder damage but rings and piston went to the dust bin. It turned out the aftermarket rings were 1.5 and oem was 1.2, I will always double check in the future.

 

[jockeydeuce]

There are at least three different ebay sellers from BC selling aftermarket saw parts, you might want to make sure everybody is talking about the same ones. There are many different brands of aftermarket pistons that come in plain white boxes

Still interested in the actual brand, have to be certain and specific. Tossing names and innuendo's around without absolute certainty and accuracy causes miss information to dictate the impression of what brands work and which don't. To me Meteor & OEM are the best options, but I have had successful builds with Golf, Forester, Espian, and now testing Huztl parts. I never used any thing from Baileys or the many others on the market.. such as hiway or mako. So brand was that again?

Alright.....You guys tell me!! Here's the boxes these come in.....I got these in a parts lot from a closed out dealer, so i don't know the original souce in this case.....There are no #'s or names on the actual piston!!



I posted this whole thing to share a failure with a cheap piston and maybe educate people on what to watch for..... I can't believe the tangent this thread has gone on!!!

There is nothing to suppose or diagnose!!!......The locating pin pushed in and the ring floated, and caught a port...Period!!!

I can see why people get fed up and leave this forum.....Everything turns into a witch hunt!.....If you experts can tell me what brand these are, I'm listening!!

 

[pioneerguy600]

Alright.....You guys tell me!! Here's the boxes these come in.....I got these in a parts lot from a closed out dealer, so i don't know the original souce in this case.....There are no #'s or names on the actual piston!!



I posted this whole thing to share a failure with a cheap piston and maybe educate people on what to watch for..... I can't believe the tangent this thread has gone on!!!

There is nothing to suppose or diagnose!!!......The locating pin pushed in and the ring floated, and caught a port...Period!!!

I can see why people get fed up and leave this forum.....Everything turns into a witch hunt!.....If you experts can tell me what brand these are, I'm listening!!

This one was as obvious as the nose on your face. I to have seen the white box pistons and neither the box nor the piston had markings to tell who made them or wherer they came from. Even the sellers did not know, they just get them from an am distributor.

 

[Modifiedmark]

Alright.....You guys tell me!! Here's the boxes these come in.....I got these in a parts lot from a closed out dealer, so i don't know the original souce in this case.....There are no #'s or names on the actual piston!!



I posted this whole thing to share a failure with a cheap piston and maybe educate people on what to watch for..... I can't believe the tangent this thread has gone on!!!

There is nothing to suppose or diagnose!!!......The locating pin pushed in and the ring floated, and caught a port...Period!!!

I can see why people get fed up and leave this forum.....Everything turns into a witch hunt!.....If you experts can tell me what brand these are, I'm listening!!

Wait it gets better, they will end up turning it around on you to be all your fault before its over.

 

[WHSH]

I think they are eastern indian made. was given a dozen of these that were salvageable but defective and they had the same white box. The skirts need to be beveled to avoid wacking the case. I fixed the skirts, knived the bridge, ground some fat off of them and put them in ported Dolmar 5100s with caber rings and they work great. I may be wrong but that is my guess.

 

[weimedog]

LOL sort of like the "mystery meat" lunches we all had in High School, no idea WHAT was in that brown pile! But we all knew it was probably alive once!

 

[dozerdan]

A crappy ring and crappy squish will give lower compression... fact
Crappy ring with tight squash will give better compression
A good ring with good squash gives the best compression.

It won't make up for squash, but will raise compression..... A better ring will give better compression.

I will agree with that but that not close to what you said to start with. You said.

"I agree and the more I hear from guys about these kinds of things... a good set can make up for lower compression caused by excessive squish, poorly beveled intake/exhaust openings and even the shape itself."

I want to purchase some of these rings. Do you sell them? It sounds like it will save me a lot of time when I port a saw. I will no longer have to set the squash, bevel the ports or worry about the port shape. Please send me a price list on these rings.

Later
Dan

 

[WHSH]

I think what you all mean by crappy rings might translate as a new ring bieng over service limit with its ring gap and being a spilt faced ring. The split face rings develope 10 psi less compression than a solid faced ring. Plus if the ring gap is over .010 new then you get more blow by than a good oem or caber ring. As with all aftermarket stuff you nead to know what makes them fall short and correct it. Generally its not materials, but fit and finish. Even the best aftermarket stuff is not Plug and Play. I have had AF stuff work just as well as OEM, but this if after I, grind, cut, exchange, polish or what ever to get it they way it should be.

 

[Modifiedmark]

Generally its not materials, but fit and finish..

I strongly disagree with that statement in regards to ring material.