Meteor Piston to tall?

[mheim1]

Anybody ever had a new piston bottom out on the crank so it won't turn over?
Just tried to replace the piston of a 361 and found this problem.
Took it of and measured the total height and it was 0.3mm taller than the original one. If the hole for the pin is a little bit low as well (hard to measure), the whole thing just sits to low.
Thinking about grinding half a mil of the bottom now.

 

[awful knawful]

can you put the piston pin in between the 2 pistons (1/2 in one, 1/2 in the other)? this will give you a good side by side view of the difference in height.

 

[mheim1]

can you put the piston pin in between the 2 pistons (1/2 in one, 1/2 in the other)? this will give you a good side by side view of the difference in height.

Good idea.
Thanks.
Difference is 0.1mm at the bottom and 0.2mm at the top.
Didn't think a 10th of a mil would make a difference.
Turned out it didn't.
Still kept hitting with 0.1mm removed (the Meteor piston has a 0.3mm thicker wall, that might have caused that.
Kept going; now the piston is a full mm shorter and seems to fit fine.

 

[hotshot]

Gotta watch the aftermarket parts

You also should have great compression with a taller deck heigth, but may
want to check the squish if you plan to leave the jug gasket out.


I had to send an imported piston back to Canadian E-Bay seller "barryydm", as the width inside the wrist pin bosses was a over 1mm (.045") too wide.

The crank pin bearing would not have known where to go...

 

[mheim1]

You also should have great compression with a taller deck heigth, but may
want to check the squish if you plan to leave the jug gasket out.


I had to send an imported piston back to Canadian E-Bay seller "barryydm", as the width inside the wrist pin bosses was a over 1mm (.045") too wide.

The crank pin bearing would not have known where to go...

Put a new base gasket on and got a whopping 80psi.
Tried to salvage the cylinder, but Iguess that score was to deep.
Now I need a new cylinder as well.
Nothing ever goes smooth.

 

[blsnelling]

Checking the squish is a must in this case. Shortening the intake skirt will change port timing.

 

[mheim1]

Checking the squish is a must in this case. Shortening the intake skirt will change port timing.

:censored:
Well, I need a new cylinder anyways; might as well buy a kit. Any recommendations besides OEM?

 

[blsnelling]

I think your only choices are OEM and a BB kit from Baileys. Check with your local dealer on price too. LINK

 

[mheim1]

I think your only choices are OEM and a BB kit from Baileys. Check with your local dealer on price too. LINK

I saw that BB kit from Baileys and your evaluation of it a few years ago (didn't have time to read all 15 pages ).
I also came across this one from Northwood:
LINK
but it replaces the 1135 020 1210, which I believe is a 341 cylinder.

 

[mheim1]

Update:
Got a replacement OEM cylinder from a member here in pristine condition. Mounted it on with a new 0.5mm gasket and pulled 150psi.
Measured the squish at 0.7mm (0.0275").
Should be ok, right????
I am planning on using this saw as my go-to saw, maybe open up the muffler a little bit as well.

 

[pioneerguy600]

You are well within the safety limits at .0275, you could run with .010 less and still be fine.

Pioneerguy600

 

[Fish]

I had a piston that had the same problem, turned out that the oem had a bevel on the inside skirt that the aftermarket one did not have, and that was
what was hitting. Ground a bevel and it was fine.

 

[Jacob J.]

I had a piston that had the same problem, turned out that the oem had a bevel on the inside skirt that the aftermarket one did not have, and that was
what was hitting. Ground a bevel and it was fine.

That's been my experience as well. Opening up the windows also helps in some cases as the aftermarket pistons can be more restricted than OEM.

One Wiseco piston I had for an early Mac engine had walls and skirts so thick, I had to thin them down manually to keep the engine from "cold-seizing" even though it had the same clearance that the OEM piston did.

 

[Kingsley]

Got to do it.

Title of thread should read:
Meteor piston too tall?

Just ignore me,
Grammar Nazi

 

[mheim1]

Got to do it.

Title of thread should read:
Meteor piston too tall?

Just ignore me,
Grammar Nazi

Always get that wrong :bang: (not from around here).

Thanks for all the feedback guys (including the above).