Did a piece of valve or debris get sucked in to another cylinder? Are those the only 2 pistons that got damaged?

Wasn`t that far from performance either . Dammit.

UNDERpsi69 : ya , half the valve had a party in 3 holes .
Pretty lucky the damage wasn`t worse.
Head is already fixed and the motor is at the machine shop. Upgrading pistons and Crank while we`re in there ..

Pulling the other motor to go thru the heads so the same thing don`t happen over there .


3rd hole :



https://cimg1.ibsrv.net/gimg/www.off...fdcda880c8.jpg

Well, that sucks big time. Most marinas, at LOTO go through a ton of fuel every week. But if your picture color is accurate of the fuel in the cup, orange usually means ethanol phase separation.
"Phase separation occurs when enough water contaminates the gasoline, causing the ethanol to attach itself to the water molecules, leaving two distinct layers in the storage tank, a gasoline-only layer at the top and an ethanol/water "cocktail" along the bottom"

This is detonation , stock 350 hp 454s in my buddies cruiser.At first I suspected bad gas because as he hand carts down 87 with ethanol that sat in the tanks for months.

After finding 3 more pistons with the beginning of the same damage I suspect the mechanic who installed new carbs a couple years ago advanced the timing too much to get them to run out.

Unbelievably all that piston debris exited out through the valves without causing too much damage. . Still had 80 pounds compression and valve seat looks tight except valves and head look like they been sandblasted with gravel .

Piston was about 1rpm from disconnecting from the wrist pin.
https://cimg9.ibsrv.net/gimg/www.off...eb5ec327f.jpeg
https://cimg0.ibsrv.net/gimg/www.off...adee3c150.jpeg
https://cimg1.ibsrv.net/gimg/www.off...2cbb85610.jpeg
https://cimg2.ibsrv.net/gimg/www.off...547d00948.jpeg

OUCH!!!! That SUX!!!!!!!!!
I only get fuel at the places that I know do high volume fuel sales.

I fear the same fuel situation with cars requiring higher octane.

This gas is garbage !
Since they were closed all of 2020 it`s probably 2 year old gas


https://cimg8.ibsrv.net/gimg/www.off...68c79287d7.jpg
https://cimg9.ibsrv.net/gimg/www.off...95be233b64.jpg
https://cimg0.ibsrv.net/gimg/www.off...4db943b835.jpg

For those unfamiliar with the lake my experience is Point Oasis carries dependable gas. I use their 93. All their gas is treated and they claim no degradation for up to 2 years. Have never experienced an issue in using it for years. The Formula dealer and PBC are also dependable. Not sure which place you got it near backwaters. One resort right across from their docks closed up years ago. The other place across the incoming cove use to only sell 87. Sad experience.

Dan, familiar with where you got gas and I have no doubt you got F’d by the gas there as it is a low volume place to get fuel on the lake (especially 91 octane). So sorry for your issues. Note to all that don’t frequent the lake much please reach out to us that boat there exclusively for dependable fuel sources.

Millstone Marina sells 93 as well, no issues for me and pretty certain they do a fair amount of volume there. So sorry to hear of this.