064 Pipe Saw Conqueors Dave

[Definitive Dave]

So Day Two of my puzzlement

Day one back here for those who want to catch up on my failure

http://opeforum.com/threads/064-pipe-saw.3011/page-2#post-133905

With the coil removed the crank spun freely.
I removed the flywheel again and don't see any marks to show me if it had abnormal timing in the past.
It initially looked like the crank was bent but I was getting deceived by a dent on the tip of the crankshaft that made it look like it wasn't spinning true.
I pulled the clutch and found this.

remember to pull the brass sleeve carefully from the oil line before removing the oil pump so the cast nipple doesn't brake off, you can pry it out pretty easily with the long handle tuning screwdriver, the little freebie one that we all have tons of isn't the right shaped tip for this though.

But looking at both ends the crank seems fine and to spin true without wobble.
As far as signs of previous crank modifications all I noticed was the bottom of the big end bearing boll seems to have an odd texture to the metal. I compared to a handful of other 064 cranks I have and none have this texture/finish.

 

[Chris Zautner]

It maybe possible that they had the crank balanced.

 

[Definitive Dave]

I upgraded the fuel system by replacing the impulse line, installing an oversize fuel filter with more surface area and replacing the old cracked fuel line with a modified OEM line for MS290. Simply trim the carb box tab, pull it into position and shorten the intake end to fit the carb, easy peasy.




Checked the tank and line for proper seal.
Replaced the scored piston and bearing with new OEM, I use assembly lube and used 518 on the crankcase as a seal.

A few guys asked about using the OEM circlip tool and so I shot a video to show how easy it is.

I reused the bolts that were here initially and will have nice studs made in the future.
I gave it a pressure and vacuum test and it passed no problem.

 

[Definitive Dave]

So at this point the crankcase is good and saw is half reassembled so I installed the recoil and gave it a pull.
Even though it turns over easily with no spark plug installed, it gets tougher to pull with the pressure tester pigtail installed and once the tested is online I cant pull it any higher than 135.
I checked it on another recent saw acquisition and the gauge and I can easily pull 210+. I had my brother and a stout neighbor give the pipe saw a pull as well and it refuses to go over 138, it just cannot be pulled after that.

Looking to see if my thinking is accurate here - if all else is good and I cant check the squish because it pinches the .031 solder tight instantly and has to be taken apart to get the solder out. I think I need to add a base gasket.

Thoughts??

 

[mdavlee]

Probably less than .010" squish. I'd try a gasket just to see if you can turn it over then.

 

[huskihl]

Is your tester adaptor hitting the top of the piston?

 

[Definitive Dave]

I did check to make sure and the tester is shorter than the spark plug and I cant "hear" either one hitting the piston, I can basically continually pull it over one compression stroke at a time or about 18" of recoil rope, but it never goes over the 134-137 range.

OI also flushed the crankcase with fuel several times till all the little bits were clear poured out through a cloth

 

[huskihl]

What if you bent an L into your solder and checked through the plug hole just to get a general idea of your squish?

With the cylinder on, no spark plug or comp tester, does it rotate freely?

 

[Chainsaw Jim]

My 357/272 hybrid does the same exact thing. I gave up on trying to get a compression reading. It seems like the only way I can get it to turn over and spin is with the help of the spark.

 

[jmssaws]

What if you bent an L into your solder and checked through the plug hole just to get a general idea of your squish?

With the cylinder on, no spark plug or comp tester, does it rotate freely?

I check squish like this all the time.
It will build compression very fast so it probably just needs fuel and spark

 

[Definitive Dave]

When I bent the solder and tried to test through the plug hole it pinched so tight, it instantly cut the solder off, hence the little scratches on the top of the piston from me using curved tweezers to retrieve the pieces

I also inspected the wiring harness and installed a new coil, though I haven't tried to start it yet.

Without the plug it rotates freely.
It slow noticeably when I install the tester lead which is the adapter for the pressure tester that screws into the plug hole effectively necking down the size of the hole, it is the piece that has the Schrader valve in it.

 

[jmssaws]

Squish will be very tight and compression will be very high.

 

[Magic_Man]

My 288 from Randy is stout enough I can't take a compression reading on it either. Every other saw I have tested has been fine. I get to about 100lbs on it and I'm done.

 

[jmssaws]

It's because it climbs so fast.

 

[Magic_Man]

I also know Randy likes lot of case compression and I wonder if that plays into it as well.

 

[redoakneck]

Yer circlip video is a bit fast???

 

[Definitive Dave]

that makes sense, the first compression thump I hear jumps it from zero to 51 psi, the next pump jumps over 110 and then after that it jumps to 135ish and stays there, regardless of how much pulling and tugging it gets.

 

[Definitive Dave]

Yer circlip video is a bit fast???

you are just watching too slow


I bumped something on my phone while trying to prop it up to film and that is how it ended up.

 

[jmssaws]

that makes sense, the first compression thump I hear jumps it from zero to 51 psi, the next pump jumps over 110 and then after that it jumps to 135ish and stays there, regardless of how much pulling and tugging it gets.

It needs gas In the tank and a chunk of wood and thats it

 

[redoakneck]

you are just watching too slow


I bumped something on my phone while trying to prop it up to film and that is how it ended up.

I thought, man, that dude is freaking fast!!! You could do a hundred saws a day at that speed . X2 on the gas and wood