288 Piston in a 660

[drf256]

Got a few of @Duke Thieroff pistons in the mail. Overall good construction. The skirts are thinner than the meaty-or which is probably where most of the weight difference emminates from.

Gonna give it a go with this piston.

 

[drf256]

More pics.

Duke’s has bigger windows. Narrower pin boss locations which allows for overall thinner/lighter pin bosses. Also, the meteor is super meaty and radiused at the skirt/crown internal interface.

 

[drf256]

 

[drf256]

 

[Squareground3691]

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Ever deal with Wiseco pistons

 

[drf256]

Ever deal with Wiseco pistons

Initially bought one from DD for this build. Was 066, but the skirts were just as narrow as the stocker. Was waiting on Dave for version 2.

Have a buddy close thst has the blue skirted 288 wiseco. It has the 1mm stainless ring that chews up Stihl oem plating though.

 

[drf256]

Got jug machined for the build. The band had some dents in it from prior debris in the chamber.

 

[drf256]

Took 75 off base and 30 from band. Was enough to tuck the bottom ring in the intake roof at BDC.

Im at 100 ex and 84 intake.

Squish came in at 15, so I’ll be sanding 3 more thou out of the band.

 

[drf256]

660 vs 288 skirt.

 

[Tractorsaw1]

Look at the width on that 288! I have heard a lot about doing these but looking forward to how the super wide turns out!

 

[Vintage Engine Repairs]

Good work Al!

 

[ferris]

Do you talk we @tree monkey he has build strong 066 with 288 pistons. I think he knows a lot about that build

 

[tree monkey]

It’s not worth doing unless you can get the exhaust port below 160

 

[drf256]

I’m at 158-160 ex duration now.

 

[srcarr52]

With the 066 piston I find they run best between 160-163° exhaust duration. 064's like the exhaust a tad shorter.

 

[drf256]

65% of bore is 35mm. That’s exactly the width of the 066 piston skirts.

 

[thompsoncustom]

I fell like this thread is going to make me do this to my 660 clone at some point.

would love to see a video of this thing running when you get it all together.

 

[drf256]

Band cleaned up OK. Not the prettiest, but pretty isn’t always fast.

Be a while before it runs, as case halfs out for powder still.

The stock 66 piston just covers the port, but id be a bit nervous running it, though the wings might hold it together. Squish around 19.

 

[srcarr52]

Is this thing running yet?

 

[drf256]

Is this thing running yet?

Nope. Busy time of the year here.

Saws are winter and rainy day work.

Just got cases back from powder.

Stay tuned.