Another 273 commando build .. This one will be a "BEAST"

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stroker402

stroker402

1968 dart GTS convertible
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Just landed another Clean 273 commando short block . short block is completely taken apart except for 6 pistons and rods .. crank is out . engine is with stock specs . all standard bearings .. I got 2 pistons out , rest are stuck.
Question is ...... what solvents are you guys using to free up these stuck pistons in the bores also ................ to loosen the rings in the piston lands ? I tried the blaster , tranny fluid , acetone couple other penetrating oils . I filled the bores (4 at a time ... on side ) with penetrating fluids and trans fluid to cover the 4 pistons in the bores and letting it sit for a while. Oh yeah..... I have one piston soaking in a gallon can of carb cleaner. Thanks !
 
Question: Are you wanting to save the pistons?? They may or may not be serviceable after you get them out. That said, take a piece of hard wood and a hammer, give the pistons a wack on the crowns and then from the underside, go back and forth like that, keep them wet with PB, Kroil. Patients is the key here.
 
stroker402,
Pics of the removed Piston/Rod asy's ?
And :) pics of the associated bores.
Humble Thanks.
 
JBurch said:
Question: Are you wanting to save the pistons?? They may or may not be serviceable after you get them out. That said, take a piece of hard wood and a hammer, give the pistons a wack on the crowns and then from the underside, go back and forth like that, keep them wet with PB, Kroil. Patients is the key here.
Click to expand...
Yep .. got to save the pistons . been tapping the pistons both ways with wooden pole and mallet .
 
Take two forced air kerosene heaters , you know, 75,000 BTU jobs , and point them at the front and back of the motor about 2 or 3 feet away.Heat that mother up slow and steady for a good long time this way and then tap .The heat may break it free enough for the oil to seep in as the block expands . Do this outside !
 
stroker402 said:
Yep .. got to save the pistons . been tapping the pistons both ways with wooden pole and mallet .
Click to expand...
That rarely works. If the pistons are rusted in and stuck, the bores will probably be pitted. It takes a overbore to clean them up.
 
I'll try that mystery marvel oil

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Heat that block up and get those pistons out without beating the **** out of them.You may get lucky and get away with a hone or not but if you beat them out you will never be able to use them in anything and blocks are out there pistons ?
 
valiantwagonguy said:
Heat that block up and get those pistons out without beating the **** out of them.You may get lucky and get away with a hone or not but if you beat them out you will never be able to use them in anything and blocks are out there pistons ?
Click to expand...
I like the idea of putting a little heat into them .
 
If the cyl are rusty get the rust off before removing pistons, I put the cyl down and use oil soaked 220 then 320 to clean the cyls then whip them out with WD40 on a rag once clean I use a wooden dowel rod to tap out the pistons
 
I have and would run a hone in the holes for the stuck pistons so when they do break loose they come out easier. I used Deep Creep soaking for 47 hours before using a block of wood tapping both ways and got them out. I have not tried it but heard Coke-A-Cola soaking will free them.
 
brian6pac said:
If the cyl are rusty get the rust off before removing pistons, I put the cyl down and use oil soaked 220 then 320 to clean the cyls then whip them out with WD40 on a rag once clean I use a wooden dowel rod to tap out the pistons
Click to expand...
cyl walls are all very clean , don't see any rust at all.
 
SeaFoam Deep Creep. I have been very impressed lately with it. I have had it work where everything else failed.
 
JBurch said:
Question: Are you wanting to save the pistons?? They may or may not be serviceable after you get them out. That said, take a piece of hard wood and a hammer, give the pistons a wack on the crowns and then from the underside, go back and forth like that, keep them wet with PB, Kroil. Patients is the key here.
Click to expand...
Just went through this with a 383 and it was insane how stuck they were. Cylinder walls loooked new after 4 hours and blistered hands.

Jake
 
stroker402 said:
I like the idea of putting a little heat into them .
Click to expand...
From the photos it looks like the motor could be stuck from bad gas being run thru it before it was shut down.I had this happen on my 48 Plymouth after a long storage.I was young and didn't know any better and fired it up after letting it sit for 3 years.Went back a week later and the motor was rock solid. I pulled the plugs and filled the cylinders with Marvel Mystery Oil and let it sit for a month.When I went back I put a battery to it with the plugs removed and spun it Then she ran fine. Those pistons may not be rusted in place is what I'm getting at so heat and oil may free it
 
The other thing you asked about is how to deal with stuck rings, I've had reasonably good luck with this method. I soaked the pistons in dip parts cleaner ( you have your Gunk, good start ) to soften/remove carbon build up, rinsed that off and then working one ring at a time, took a small ball peen hammer and lightly tapped the the ring into its groove, start at the gap and work your way around. The good sign you'll be looking for is when the portion of the ring opposite where you tapped it in will spring out.

As I said, I've had reasonable luck with this method, one ring would not give up, 2/3 of it was free around the piston, the last 1/3 just didn't want to give up; so I broke the ring and dug it out with out buggering up the groove. I reused these pistons in the first version of my "Mean Teen", went 13.92 at just a lick over 98 mph.
 
vibration might help the penetrant get into the crevices you need to break it loose. If you have a chunk of steel or brass, and an air chisel with an air control valve whip, you could spray the cylinder with whatever flavor penetrant you prefer(I like Mopar heater control solvent, myself), then starting with lower air pressure, use the air chisel to hammer on the scrap metal block on top of the piston(s).
 
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