Possible to install piston onto rod after the piston is in the barrel?

[Old Jock]

Another stupid question, but seeing new rings onto the Sporti is almost a forgone conclusion & given that I'm thinking of using a tapered ring compression tool to ease installation, I have a problem

Something like this



I'll need to install the piston into the barrel from the top.

I don't really want to take the bottom end apart (AGAIN.............. ...ARGHHHHHHHH) so I was wondering if it would be possible to remove the gudgeon/wrist pin, install the piston, shove it to the bottom of the barrel and then install the pin and circlips.

I'm wondering if there will be enough clearance on the bottom of the barrel and enough room to get the pin in without the rings popping out the bottom of the barrel when installing the pin

Anybody know?

[Don G]

Install the piston from the bottom of the cylinder, drop the piston over the rod and install pin and clips. May help to have an extra set of hands to support the cylinder.  DonG

[Antietam Classic Cycle]

Install the piston from the bottom of the cylinder, drop the piston over the rod and install pin and clips. May help to have an extra set of hands to support the cylinder.  DonG

That's they way I do it, except one circlip is already in and the pin is in part the way as well. Installing the piston in from the top would only be slightly different - just slide the piston down until you can fit one circlip and the pin part the way.

I can't say for sure whether there is adequate room between the piston skirt and engine case to work in your particular case, but on earlier Guzzi engines there is.

[TOMB]

Yes it can be done.
Awkward but it can be done.
You may or may not have to heat the piston to insert tbe wristpin fully, not sure itlf you are using a floating whristpin or fixed  pin..
TOMB

[pete roper]

I use Charlie's method with one clip already in place. If the engine is loose on the bench use the flywheel holding tool to keep the crank still at about TDC and one little trick I use if I'm working alone is use a couple of rubber bands around the rod to the studs to keep the rod central to the bore. You can then slide the barrel and piston down and use the grudge on pin to line up the piston with the little end without worrying about the rod flopping about. When the pin is home and the other clip installed just cut the bands off before dropping the barrel.

Whether the piston will need heating should be down to whether the pistons are cast or forged. Cast will need a bit of heat, forged and they should slip straight in. I reckon Sport pistons were forged.

Pete

[oldbike54]

 I may not be understanding the question ??? How do you slide the gudgeon pin (or in Pete's post "grudge on") into a piston after it is already in the cylinder ? I am missing something here .

 Dusty

 Edit .

 Are we talking about lifting a cylinder off of the crankcase enough to clear the wrist pin bosses with a piston at BDC ? Sure seems like a tricky way to install a wrist pin . Wouldn't it be easier to simply remove the cylinder , install the piston onto the rod , use some bent up hose clamps to compress the rings and slide each cylinder over the pistons ?

[Don G]

Dusty: The ring pack is in the cylinder, the pin hole is still accessible.  DonG

[oldbike54]

Dusty: The ring pack is in the cylinder, the pin hole is still accessible.  DonG

 I edited my post . Can see how it would work , it just seems an awkward way to perform the task .

 Dusty

[pete roper]

Bloody auto correct again!

You slide the piston down and out of the bottom of the cylinder bore until the bore for the gudgeon is below the bottom of the spigot. Slip the gudgeon in from one side and then wriggle the piston about while lining the pin up with the little end. Once it's lined up, slip it through, install the second circlip and then drop the barrel down onto the crankcase after cutting off the rubber bands if used.

Pete

[oldbike54]

Bloody auto correct again!

You slide the piston down and out of the bottom of the cylinder bore until the bore for the gudgeon is below the bottom of the spigot. Slip the gudgeon in from one side and then wriggle the piston about while lining the pin up with the little end. Once it's lined up, slip it through, install the second circlip and then drop the barrel down onto the crankcase after cutting off the rubber bands if used.

Pete

 I can certainly see how that might be better , will try it that way next time .

 I knew what you were trying to write Pete 

 Dusty

[5154guzzi]

I also like to assemble the piston half way in the bottom of the barrel with enough room to line the pin and rod up.  A pair of vice grips helps me , clamp it onto an engine stud after I get the barrel where I want it, so it stays put , giving me two hands to finish the assembly. If the engine is in the bike and assembled , I stuff rags around the spigot to keep the pin retainer from accidently falling into the block, especially on the racing type retainers that have no holes for the special pliers.

[Antietam Classic Cycle]

I edited my post . Can see how it would work , it just seems an awkward way to perform the task .

 Dusty

Not awkward at all, better than screwing around with a ring compressor while cylinder studs are in the way. Less chance of damaging anything. JMO.

[Wayne Orwig]

You slide the piston down and out of the bottom of the cylinder bore until the bore for the gudgeon is below the bottom of the spigot. Slip the gudgeon in from one side and then wriggle the piston about while lining the pin up with the little end. Once it's lined up, slip it through, install the second circlip and then drop the barrel down onto the crankcase after cutting off the rubber bands if used.

That is how I have always done it. Did not think about doing it any other way.

[guzzisteve]

I have this fancy BMW two finger compressor that works trick, slides right out of the studs.

[Phang]

I adopted Charlie's method as well.

Left the heat gun in the barrel while my finger pushing on the pin lightly, when the piston is warm enough, the pin slide in effortlessly.

[fotoguzzi]

those pics say a thousand words, thanks!

[Old Jock]

Thank you all for taking the time to explain it all to me

That settles it then

Still a bit away, doing a leak down check next week, then piston and bore dimensional checks followed by a close examination of the rings

This bike has been a challenge every step of the way

John