Echo CS 620 Piston-Frustrated

[cedarshark]

Rebuilding the top end on an Echo CS 620P. New OEM piston. The pic below is from the IPl. You will note the two thin washers on each side of the connecting rod. I find it impossible to keep the washers & piston lined up correctly to insert the wristpin. Has someone with experience come up with a way to align these parts without a special tool or something ?

I appears these washers are to prevent excessive side play of the piston on the wristpin. Is it even necessary to reinstall the washers ?

 

[Adirondackstihl]

Try a little grease.

Yes they are necessary

 

[cedarshark]

Try a little grease.

Yes they are necessary

Tried using grease to stick the washers to both sides of the piston boss. The wristpin is pretty tight and must be pressed in with a "c" clamp or tapped in with a brass hammer. Either way disturbs the alignment and stops the wristpin from going in further.

 

[ncfarmboy]

Not being a smart A be paitent you can get em in. I use a small drift pin inserted in the other side of piston pressing against the wrist pin to help keep them in place.
Shep

 

[WSE]

Turn the saw on its side is all I ever do. Should push right through with your finger. If you have to use force something is wrong.

 

[cedarshark]

Not being a smart A be paitent you can get em in. I use a small drift pin inserted in the other side of piston pressing against the wrist pin to help keep them in place.
Shep

Good advice and thanks. Were this a wristpin that could be pushed in with a finger, it would have been a snap. Both the old/new wristpin had to be tapped in and out with a hammer or a "c" clamp. I believe Echo uses very tight tolerances. I ended up using both wristpins inserted into the piston enough to hold the washers,then slid the piston over the connecting rod and tapped it through and pushed the old wristpin out the other side. I like your idea about the small drift pin. that would effectively do the same thing.

WSE, I ended up turning the saw on its side and that works better. With your comment about pushing the wristpin through with your finger, I believe I will take very fine sandpaper and smooth up the inside of the piston bosses next time if the wristpin is that tight. Thanks for your help.

The new piston w/ washers is in and the cleaned up jug is on. Waiting on the new collar that drives the oiler worm and the saw will be ready to finish assembly and fire it up.

Should get a 600P on Wednesday with a toasted top end and I will get to have all this fun again. It wont be as frustrating this time.

WSE, if you have a 600P piston kit in your shop, would you send me a PM ? Thanks

 

[rmh3481]

No sanding on the wrist pin. If you need more clearance, warm the piston up in hot water or a toaster oven.

 

[Adirondackstihl]

No sanding on the wrist pin. If you need more clearance, warm the piston up in hot water or a toaster oven.

X2

 

[cedarshark]

Duly noted and thanks. I have done many Stihls and never seen a wristpin as tight as this Echo.

 

[WSE]

Something can't be right I've had about a half dozen of these apart they literally slide in with no excessive force needed.

 

[fordf150]

Echo has a special tool for pushing the wrist pin out and in I believe. Don't remember what it is made to fit...just remember seeing it in the tool catalog.

 

[cedarshark]

I

Something can't be right I've had about a half dozen of these apart they literally slide in with no excessive force needed.

I don't have a lot of experience with Echo. I have done top end jobs on a 440, 550evl and all were difficult to get the wrist pin out and in. I may just be unlucky.

This 620 was run with the chain brake on until it melted the collar that drives the oil pump worm. Previous owner then burnt the paint off the bar, ruined the chain and lean scored the top end. The replacement piston is OEM with new wrist pin and bearing.

 

[cedarshark]

Echo has a special tool for pushing the wrist pin out and in I believe. Don't remember what it is made to fit...just remember seeing it in the tool catalog.

I wish I had one!

 

[WSE]

I


I don't have a lot of experience with Echo. I have done top end jobs on a 440, 550evl and all were difficult to get the wrist pin out and in. I may just be unlucky.

This 620 was run with the chain brake on until it melted the collar that drives the oil pump worm. Previous owner then burnt the paint off the bar, ruined the chain and lean scored the top end. The replacement piston is OEM with new wrist pin and bearing.

The old EVLs were press fit so I concur with you there. I hope your rod isn't warped do to overheating or something crazy like that.

 

[cedarshark]

The old EVLs were press fit so I concur with you there. I hope your rod isn't warped do to overheating or something crazy like that.

I briefly considered this possibility but dismissed it as the old piston was only scored on the exhaust side. I removed the limiter caps on the walbro carb as I was curious how lean the factory setting was. It was a half turn off bottom...pretty lean. I checked the rod for heat dis coloring and none was evident. The clutch drum is a beatiful shade of blue though

 

[johnny5ny]

No sanding on the wrist pin. If you need more clearance, warm the piston up in hot water or a toaster oven.

And the wrist pin in the feezer.....overnight.

 

[Miles86]

Howdy-
double check your part number- just in case murphy is on your case
I use a hair dryer to heat up the piston just prior -and use the install special tool or a wood dowel slightly smaller that the wrist pin-, that will keep everything lined up (dowel pushed out as pin slides in)and the pin should slide right in. Use motor assembly grease on all internal parts.

 

[cedarshark]

Howdy-
double check your part number- just in case murphy is on your case
I use a hair dryer to heat up the piston just prior -and use the install special tool or a wood dowel slightly smaller that the wrist pin-, that will keep everything lined up (dowel pushed out as pin slides in)and the pin should slide right in. Use motor assembly grease on all internal parts.

miles86, does the Echo tool have a way to keep the parts aligned or do you have to use the tool in conjunction w/ the dowel rod ? Also, does the tool fit multiple saws ? Thanks.

 

[fordf150]

I don't think anything is wrong...the echo trimmers and saws I have done were all a very tight fit for the pin. I will post a pic of that tool in the morning and see if I can find a list of equipment it is designed to be used on. I have had a few saws...Stihl and echo that I thought the removal tool would be nice to use on but never had one tough enough to get me to spend the money on

 

[mountainlake]

Use a small socket or rod slightly smaller the wrist pin and the length of the bearing and washers combined plus a little grease, the socket will come out as the pin goes in. Steve