Piston/barrel dramas

[jellywrestler]

Those that live in glass houses...........

should have sex in the basement...

[tri boy]

All of the preceding comments on the possible cause of the damage is exactly that, possible.
The probable cause is the Jellyman.
He can f**k a yellow bellied black snake, even if nobody is holding it head.

[FastFred]

it sounds like
someone is so stupid...they would inserted a window in a glass house!:-)



now lets wait and see if the rod is bent or not

but remember a bent rod is only one reason for it to happen
can we name 3 more ?

[Ned Kelly]

Those that live in glass houses...........

Should throw stones, but Keith Richards is much tougher to throw than Mick Jagger.

[bucketracer]

That is your Google search, internet based assessment, and, ........ Many is the spotty little kid that comes into a workshop, fresh from his education,

Your being really silly now .......

[husaberg]

Those that live in glass houses...........

should have great vege garden?

Should not smoke their own poppies?

Should give up when they are clearly wrong?

Should not post pictures of themselves on the net?

Should admit defeat when they are clearly out witted?

Should move to Europe and not feel the need to keep in touch?

Should aspire to be a scooter tuner in a country, without an extradition treaty with NZ?

Should not try and keep exaggerating there resume's when people in NZ have long memories?

[speedpro]

There are clips with the little tangs you can grab with pliers to insert or remove the clips. I have seen where a pin had been pushing and rubbing on a tang to the point where the little tang broke off. Probably why clips nowadays don't have tangs sticking up.

[bucketracer]

There are clips with the little tangs you can grab with pliers to insert or remove the clips. I have seen where a pin had been pushing and rubbing on a tang to the point where the little tang broke off. Probably why clips nowadays don't have tangs sticking up.

Dad says these were a real problem in TZ's as they would be cut through by the pin and break off damaging the engine. It was std practice to cut them off first when fitting new pistons.

[husaberg]

Dad says these were a real problem in TZ's they would be cut through by the pin and break off damaging the engine. It was std practice to cut them off when fitting new pistons.

There use to be the square ended ones too. I can't be arsed looking for a pic but they looked like a gearbox circlip holes and all. Well maybe I can.
But i guess the new piston that were in jelly's motor would have modern design circlips.
Did jelly find the remains of 1 or 2 circlips in the cases?
Mistakes can happen to the best of us sometimes.

[Buckets4Me]

Interesting point about the damage, it does resemble a triple clamp where the keys have been banging against it for yeats and years, so it could be something rattling around in the side gap of the piston, instead of melting/heat.

Is it odd that both sides have the same wear? WOuld it be 2 seperate pieces, one on each side, or a single piece of debris travelling through the gudgeon? Would there be damage any damage on the inside of the gudgeon? .

probably many pieces. if you look at what is left of the rings you will notice that there is a fair bit missing. And some of those bits are likely to find there way threw the pin (as thats much easier than betwen the piston and cylinder) you have the same thing happening both sides of the piston.

one side of the piston has more damage than the other
so I would like to know if the missing clip came from that side or not ?
and is the rod bent or not ?

if the rod is bent then why
and if it isn't then what made the clip come out ?

if the rod isn't bent then was there a broken ring ( looking at the pics I cant tell where it could have been broken ) or was there some material on in or around the little end pin?

[jellywrestler]

one side of the piston has more damage than the other
so I would like to know if the missing clip came from that side or not ?
and is the rod bent or not ?

There was only one circlip 'missing' well i found a third of it intact the rest had long gone.
the greater damage was on the side where the clip was out This is logical as teh clip would've hung around here in larger bits before breaking up and some travelling to the other side.
i made a Mandrel up to check the rod and am happy it's not bent.
Pressing the gudgeon out was done with a tool onto the piston so there was no forces in this process at all travelling down the rod, besides the gudgeoans were a little more than finger tight

[Buckets4Me]

to much end float on the crank ?
or side clearance on the big end
or twisted rod
is more posibilities

or someone missfited the clip this may be why speedpro DOSEN'T reuse clips

[husaberg]

to much end float on the crank ?
or side clearance on the big end
or twisted rod
is more posibilities

or someone missfited the clip this may be why speedpro DOSEN'T reuse clips

Sorry no Vespa pics here Neil
The rod bushing can be machined not square resembling the symptoms of rod misalignment

I found these pics and threads
http://www.foxwooddiesel.com/piston-damage-circlip
http://www.k20a.org/forum/showthread.php?t=41515
http://www.rallyanarchy.com/phorum/read.php?5,1989,2047
http://www.hadmac.com/piston_&liner.htm


Shhh...I don't think we are allowed to talk about speedpros circlips, as well as his conrod. It is a secret still after-all.
And sorry to keep you waiting Buckets4me one of the kids called out.

[Buckets4Me]

I found these pics and threads

pics and thread ????

I'll come back in half an hour and re read that post and see if I can understand it better


thats better

[TZ350]

Real life experience or something from the net that Bucket clued me into ........ well who knows ...

Here is a very easy way of checking for a bent rod. Its such a useful assembly check I am surprised someone else with a lot of industry experiance hasn't mentioned it.



Hold the barrel down and then with the piston at TDC slide a feeler gauge around the top, if the rod is even slightly bent it will be tighter on one side than the other. When I was working a lot with engines, this was a standard test done on every cylinder as a double check for alignment issues. You could also feel for broken rings this way too.

Circlips were always given a half turn in their grooves to be sure they were properly seated and there was no forgien matter caught behind them. If the clip was not properly in its grove when you turned it you would hear it click into place.

Turning the clips, now thats another industry trick that someone in the know could have told us about too.