661 went boom

[smokey7]

So what are some things that can cause a pin to pop out? I wonder if one is improper press fit tolerances? Then my next suspicion is too high of crown temperature causing them to fall out. The reason I wonder is if it would have popped in Stock form from all of the autotune issues. No blame just curious

 

[Gunn]

Can the pins be staked to keep them from backing out?

 

[paragonbuilder]

Well that's good Brett! Nothing you did could have caused that. Just one of those things...


Sent from my iPhone using Tapatalk

 

[spencerpaving]

Yea...I'm glad to find that is a easy fix and not one of those problems that takes hours to find the cause

 

[paragonbuilder]

Yea...I'm glad to find that is a easy fix and not one of those problems that takes hours to find the cause

Are you going to build it the same this time?

 

[MustangMike]

Sucks that it need a new cylinder! Pistons aren't that bad!

 

[spencerpaving]

Are you going to build it the same this time?

yea..maybe with a little something different. ..

 

[paragonbuilder]

Are you going to do a build thread?


Sent from my iPhone using Tapatalk

 

[Marshy]

yea..maybe with a little something different. ..

Do you remember what compression was when it left your shop?

Detonation and over heating can cause the pins to come out. What octane did the guy use, and what's the piston wash look like?

 

[MustangMike]

Do you remember what compression was when it left your shop?

Detonation and over heating can cause the pins to come out. What octane did the guy use, and what's the piston wash look like?

Could too much timing also contribute?

 

[Basher]

Do you remember what compression was when it left your shop?

Detonation and over heating can cause the pins to come out. What octane did the guy use, and what's the piston wash look like?

Bingo, there was scoring going on before the pin came out.

 

[Coltont]

The one I have here has a 4700 on it and runs great.

That's what's on my saw and it's a fair weather saw. It doesn't run worth a crap when it gets hot out.

 

[jmssaws]

That's what's on my saw and it's a fair weather saw. It doesn't run worth a crap when it gets hot out.

Sounds like it might be bad

 

[Marshy]

Could too much timing also contribute?

Yes it can. Too much advance can cause detonation and over heating. The top of the piston has a lot of information on it if you know what to look for. @spencerpaving, when you get a chance post a pic of the piston top for us.

Here is a good read. It is focused on 4 strokes but the principals are mostly the same.

http://www.contactmagazine.com/Issue54/EngineBasics.html

 

[paragonbuilder]

Yes it can. Too much advance can cause detonation and over heating. The top of the piston has a lot of information on it if you know what to look for. @spencerpaving, when you get a chance post a pic of the piston top for us.

Here is a good read. It is focused on 4 strokes but the principals are mostly the same.

http://www.contactmagazine.com/Issue54/EngineBasics.html

Chances are it would not have lasted for a year of heavy use if that was the issue.

 

[paragonbuilder]

But I'd still like to see the top of the piston Bret...


Sent from my iPhone using Tapatalk

 

[paragonbuilder]

And the carnage in the cylinder!


Sent from my iPhone using Tapatalk

 

[Adirondackstihl]

found the problem. ..locating pin fell out on the bench when I pulled the jug

Sent from my SCH-I545 using Tapatalk

Yep
Totally your fault
Sheesh

 

[Adirondackstihl]

Did that 661 have one of them there "Grenade" stickers on it by any chance?

 

[paragonbuilder]

Did that 661 have one of them there "Grenade" stickers on it by any chance?

Who pulled the pin? [emoji23]