Author Topic: Had a really clean 55 on the shelf, soooo  (Read 468 times)

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Offline KilliansRedLeo

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Had a really clean 55 on the shelf, soooo
« on: August 13, 2013, 04:50:30 pm »
I put the piston out of a Stihl 028S in it using the stock OP cylinder. Ran but nothing to write home about.

Looked around in the parts room and found a Meteor CP jug for a 55, swapped jugs. Dry it blew 165 pounds, a squirt of mix in the jug and it was at 172. Started it up and did a basic tune, let it sit idling for two tanks of fuel. Checked compression, 190 pounds.

Tomorrow will put b/c on it and put it in some wood.

Sort of a fun project, might take a couple thousandths off the bottom of the jug, maybe. Ended up with .029 squish because the dome (3mm) would hit the slope of the chamber at .020! 028S piston is 1mm taller than the stock piston plus the dome.

Both saws use 10mm pins but you must take some metal off the inside of the PP boss to fit the Husqvarna rod and insure proper oiling but no big deal, a few minutes with a good file. You must use the pin for the 028s.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

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Offline Cut4fun .

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Re: Had a really clean 55 on the shelf, soooo
« Reply #1 on: August 13, 2013, 05:35:18 pm »
Cool project and will have to give it a try if I even get another 55 in.   8) 8)

Offline KilliansRedLeo

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Re: Had a really clean 55 on the shelf, soooo
« Reply #2 on: August 14, 2013, 10:48:43 am »
Nice air injected 55s are getting hard to come by. I just got another off fleece bay for 170. However that one is already sold. When it comes in I am going to let the buyer try both the 028s version and the stock 55 to see if he wants me to do the same mod to his new saw.

There a lot of 028S pistons out there, I used a Meteor, which was an a/b spec piston. If I come by a Stihl 028S a-spec piston I may also try that.

Sorry, no pics on the project since my camera went south and I am still trying to figure out what new one to buy. Any recommendations?
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
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Offline David Young

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Re: Had a really clean 55 on the shelf, soooo
« Reply #3 on: August 14, 2013, 12:05:16 pm »
[i]I put the piston out of a Stihl 028S in it using the stock OP cylinder. Ran but nothing to write home about.

Looked around in the parts room and found a Meteor CP jug for a 55, swapped jugs. Dry it blew 165 pounds, a squirt of mix in the jug and it was at 172. Started it up and did a basic tune, let it sit idling for two tanks of fuel. Checked compression, 190 pounds.

Tomorrow will put b/c on it and put it in some wood.

Sort of a fun project, might take a couple thousandths off the bottom of the jug, maybe. Ended up with .029 squish because the dome (3mm) would hit the slope of the chamber at .020! 028S piston is 1mm taller than the stock piston plus the dome.

Both saws use 10mm pins but you must take some metal off the inside of the PP boss to fit the Husqvarna rod and insure proper oiling but no big deal, a few minutes with a good file. You must use the pin for the 028s.
[/i]

wow! I didn't know that would work.
So you have a 028s piston in a closed port 55 cylinder made by meteor? sounds like the best of both worlds with that kind of compression it must run really well.

look forward to the report


Does it seem strong?  how is idle and the rev?

Offline KilliansRedLeo

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Re: Had a really clean 55 on the shelf, soooo
« Reply #4 on: August 14, 2013, 12:30:05 pm »
Idle and rev are great. Will sit at 2500 and run through an entire tank without quitting. Revs quickly however I have it set for 11,000 wot right now for break-in. Will tune again after a few tanks. The thing with a 16 bar 3/8 050 will run right with my 362XP. The 362 was never a killer saw but  will out run a stock 55.

After break-in I plan to DP the muff and see what happens.

This is a mod you can do yourself using only hand tools and a little patience, not complicated at all. However you must be careful to measure the squish and dome clearance! You cannot go without a base gasket! Everything required to do this is available off-the-shelf. It also has the advantage of yielding two pistons an OEM clone out of the c/p kit and the 028s, so if something should go wrong you have the stock piston as a backup.

If you plan to do this and have questions, PM me I'll be glad to answer any and all. ;D

Yes, I used a Meteor CP cylinder kit 46mm and a Meteor 028S piston also 46mm but 1mm taller and the dome measures 3mm at the highest point.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

 

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