CS-8000 wrong mixture Help ?

[Cut4fun]

You would be amazed what will clean up on a piston and last for years.

 

I have fixed my own in a pinch when a piston isnt available for a saw and saved saws for guys that were just going to junk them because they counldt afford to fix them right.

 

I fixed a dolmar 166 alky saw that hung a ring in a transfer. What a mess cleaned up with a lot elbow grease. Oh try finding a stock oem 166 piston back then.'

Now there is wiseco 166 pistons and aftermarket 166 pistons to do the job right.

 

Here she is after rebuild running rich first few cuts checking it. Still running the same piston 2 years later.

 

[ame=http://www.youtube.com/watch?v=cTplf5etMes]Sachs Dolmar MVP 166 piped Hotsaw test - YouTube[/ame]

[ecodao]

Hi folks,

 

Ok i have stripped the head , and found that the barrel is only very lightly scored.

but the piston has got bad scoring on the exhaust side of the piston , plus it seems to have a small dent / hole in the centre of the piston..... would this have been from the hot running of just pure petrol ??

 

Pics: (sorry for bad quality , but decent camera is in the work Land-Rover)

 

 

 

 

 

Thanks

 

Steve

[Cut4fun]

Over here the replacement piston for the updated 8000 cyl and piston will be domed.

 

Here is a link showing new and old 8000 p+c kits. Best pics toward end of thread showing side by side pics. echo 8000 piston and cylinder pics - newest

[ecodao]

Thanks for that link , great photos

do you think i would have a problems fitting the new style piston into my old head ??? as i really dont wont to have to buy a new head as well !! :-(

 

i was hoping that i could just by a new piston and rings.

 

steve

[Cut4fun]

I have no clue, never talked to anyone that tried new P in old cyl. Trial fit with base gasket and check squish with solder.

The echo 8000 has a lot of squish area to spare in past, so check with new piston. Huge in other words.

 

If the combustion chamber is the same in both cylinders. The new dome part will give you a lot more PSI.

 

I'm thinking my 8000 cyl was up in the .48 squish and dropped cylinder down around .20-.22. Could have used a de-comp after that.

Edited December 20, 2011 by Cut4fun

[spudulike]

That ding in the top of the piston is someone using a solid piston stop and damaging the crown of the piston - had one in that put a crack in the top, reducing compression.

 

Make sure all that aluminium transfer is removed from the cylinder otherwise it will kill the new one. I usually use acid but some use Sodium Hydroxide.

 

If the cylinder is ok, fit a new piston and all should be good.

[ecodao]

Thanks Spud,

 

what is a `Solid Piston stop` ???

 

thank

[spudulike]

Thanks Spud,

 

what is a `Solid Piston stop` ???

 

thank

 

When working on saws, you need to lock the crankshaft to undo the clutch and/or flywheel. There are a number of ways of doing this: -

 

1) Air chuck with no stop

2) A double ended palstic stop

3) Rope inserted in to the plug hole

4) a solid screw in stop - like a spark-plug end with an extension from the middle that contacts the piston on top dead centre and locks it in place

 

I use a double ended one for small engines and rope if a clutch is really tight, the solid stops have a tendency to damage or crack the piston crown when pressure is exerted - not good:thumbdown: The 262 I did for a decent bloke in Bexhill is on this forum and have pictures of the damaged crown!

[ecodao]

Thanks for the informative answer. i am going to order a new piston and rings this week.

 

steve

[ecodao]

Hi there,

 

Thought I should post an update to close the thread so to speak.

 

After totally cleaning the cylinder head of all aluminium and doing the same to the Piston , and fitting a set of genuine CS-8000 piston rings.

she now runs well, it needed a good tune to begin with, but after 2 weeks of use all is well,I am still running it a bit rich and will adjust it down a bit next week.

Great saw,very powerful esp at mid range....but slightly heavy to use all day !!

 

if anyone can get hold of a CS-8000 piston please let me know as i would like to change it at some point in the future as you can see the piston top was not that great !!

 

BIG BIG THANKS TO SPUD !!!

your old school info was a great help

 

Thanks

 

Steve

Edited January 25, 2012 by ecodao
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