Rusted piston

midtown711 Sun Jul 16, 2023 7:16 pm

Hello all,
I picked up a complete 049 engine off of ebay for the command jeep. All parts are in good condition except piston is rusted solid to cylinder wall. Whats the best way to free it. I have it all apart. Im soaking it in pb blaster. No luck so far

Ken Cook Sun Jul 16, 2023 7:47 pm

The problem is that rust equates to pitting. Even if you get it apart, more than likely it's performance if it runs is going to be compromised. I've salvaged some by installing the piston upside down and using fine polish and a lap tool I made to polish out areas. Unfortunately, the cylinder itself usually ends up being the worst. Heat is what I use . I use a paint stripping heat gun and if that isn't enough, I carefully use the propane torch.

midtown711 Sun Jul 16, 2023 8:39 pm

Ken, Thank you for the info!

Coxfledgling Mon Jul 17, 2023 12:42 am

Hi midtown,

I think I would try putting some old car engine oil in an old saucepan, enough to cover the cylinder and heat using a camping cooker to heat the part. Heat to expand everything evenly and the old oils cleaning action on the rust.

Do it outside in dry weather. When old oil starts to smoke, turn off heat and try to move the piston.

A wood dowel as a punch to gently tap the piston crown, it's top, out.

Good gloves needed as the cylinder will be hot.

Several attempts may be needed.

Hope that works for you.

cstatman Mon Jul 17, 2023 11:22 am

are you sure its rusted, and not just dried glow fuel gunking up the works?

i like the ideas others presented here.

I am a HUGE fan of gently warming it with a heat gun. see if that will free it up.

if not?
https://coxengines.ca/top-end/cox--049-tee-dee-cylinder-and-piston.html