181se one ring vs two

[Lootbug]

Hi all,

I just got into a project 181se. Upon inspection I found it had a bad air leak at the cylinder base. So I pulled the cylinder and it was lacking a base gasket and had no sealant of any kind. While looking things over I noticed the piston had a couple of small cracks . This was disappointing as looking through the exhaust the piston seemed to be in decent shape. Which brings me to the question of what replacement piston to buy? I see HLsupply has a nice meteor one ring piston kit, and also have a double thin ring piston kit. Is there any noticeable performance difference between the two? The original piston is a thin ring if that makes any difference?

Thanks in advance.

Pics for funsies

 

[jmssaws]

Awesome wrap!

 

[srcarr52]

The original 181 piston is an ultra thin ring compared to the double ring piston HL supply has. No one makes anything equivalent to the stock piston in this case.

I'd stick with the meteor piston as it's of a known quality,

 

[Lootbug]

The original 181 piston is an ultra thin ring compared to the double ring piston HL supply has. No one makes anything equivalent to the stock piston in this case.

I'd stick with the meteor piston as it's of a known quality,

Thanks, that's some good info. Didn't realize there was an ultra thin ring also. I was leaning toward the meteor kit already so that helps solidify the decision .

 

[srcarr52]

Thanks, that's some good info. Didn't realize there was an ultra thin ring also. I was leaning toward the meteor kit already so that helps solidify the decision .

The original 181 piston is commonly known as a thin ring piston. But by modern standards 1.2mm is a thin option, 1.5mm is a standard ring.

 

[smokey7]

Wow I wonder who put it together with no gasket and no sealer. I'm shocked. Where are the cracks?

Also I'd probably go with a 2 ring piston if no porting is planned but a Meteor 1 ring piston would last a long long time.

Pay close attention to wrist pin clip orientation. If the opening is at 3 or 6 they can pop out easier.

 

[mdavlee]

I bet that's the small chamber cylinder if it's original to go with the thin ring piston.

 

[Lootbug]

Wow I wonder who put it together with no gasket and no sealer. I'm shocked. Where are the cracks?

Also I'd probably go with a 2 ring piston if no porting is planned but a Meteor 1 ring piston would last a long long time.

Pay close attention to wrist pin clip orientation. If the opening is at 3 or 6 they can pop out easier.

The first crack is a small vertical crack. It's just under the bottom ring in the middle of the piston pic. Second crack is under the first one, horizontal on the part that holds the piston wrist pin. They almost form a right angle in the pic.

I bet that's the small chamber cylinder if it's original to go with the thin ring piston.

Hmm so is there different cylinder sizes for these? Or just the combustion chamber shape, but the different pistons will still work?

 

[P.M.P.]

Should get it today and save https://www.hlsproparts.com/dealoftheday.aspday

 

[srcarr52]

I bet that's the small chamber cylinder if it's original to go with the thin ring piston.

All 181's I've ever had were the thin ring piston with small chamber. 281's switched to a larger ring and larger chamber. This and the fact that the cylinder is made by Gilardoni instead of Mahle are why it's the preferred cylinder of that series.

 

[Magic_Man]

My 181 had a small chamber with a single standard ring piston.