Amazon: 1964 Amazon 122S restoration project

[Juular]

I think the idea has several parts.

The piston and block will expand and then contract at different rates causing the surfaces to seperate.

The inclusion of ATF and a wick stops the petrol from being explosive, rather a slower burn.

The ATF will boil and encourage it to seep down the cylinder walls.

Shocking with a freeze spray is one idea, but not commonly done as it can encourage cracking / warping of parts. Still, if I have no success it's another thing to try.

If nothing else it will be good fun.

[Othen]

Originally Posted by Laird Scooby

.......... or better still, a video! Not that i'm a pyromaniac or anything but there's something about watching "thermal therapy" on a stuck-in-bore piston!

... the Towering Inferno - I can't wait!!!!!!

:-)

[Laird Scooby]

Originally Posted by Juular

Shocking with a freeze spray is one idea, but not commonly done as it can encourage cracking / warping of parts. Still, if I have no success it's another thing to try.

If nothing else it will be good fun.

Very true - hence my suggestion of spraying it on the underside of the piston or the con-rod side. That way all warping/cracking should be confined to the piston which is easier and cheaper to replace than a block. All that said, at the moment the block and piston siezed in it are effectively scrap or a strange looking paperweight so whatever you manage to achieve however you do it is likely to be a bonus.

I suppose if all else fails, you could have the reluctant piston machined out as part of a rebore then drop the twin carb head/manifold etc on top which might give you a few extra cc and retain the original engine number while converting to B20B (or B18B depending on size), all depends how far and which way you want to go on the oily bits.

[Moomoo]

Red-block coffee table !

[Juular]

Originally Posted by Moomoo

Red-block coffee table !

Might have to see about strengthening the foundations on the house..

[c1800]

Suggestion: prior to setting it on fire, use a mix of ATF and acetone, which creeps better than diesel or gasoline. Seal the top of the bore to prevent evaporation and let it sit for a few days. Might require a few top ups. Good luck.

[142 Guy]

I am not quite 'getting' the heat / fire solution to piston removal. The aluminum piston has a higher coefficient of expansion than the iron block, so heat is just going to make for a potentially tighter fit. The sticking problem is caused by rusting of the rings to the bore, not sticking of the piston to the bore. If the plan was that heat would create a thermal shock that would fracture the bond, it is going to be pretty hard to get a really rapid temperature increase on the iron block in order to generate a thermal shock like you can do when you take a torch to a rusted manifold nut. Ditto with freezing, although a little liquid nitrogen or a dry ice mix might do the trick if the thermal shock doesn't crack the block.

I had the same issue on my B20E after it had been stored for about 15 years with no cover on the intake and exhaust. The cylinders with open valves breathe in atmospheric air due to ambient temperature changes and when the air has a high moisture content you have the inevitable condensation and rusting. For removal, I used a 4x4 piece of wood post (3.5"x3.5" actual with the corners trimmed to firm fit in the bore) and a 15 lb sledge hammer. I wrapped the connecting rod in a heavy towel wrapped with tape to keep it in place and protect it from damage when the piston popped out. I mounted the engine vertically on some wood blocks so that I was pounding down on the 4x4 and there was enough clearance below the engine to allow the piston and connecting rod to be ejected out the bottom safely. I think two hits did it and with the 15 lb sledge I did not have to hit really hard. In my case the rusting of the rings on the bore was bad enough that it required a 0.030 overbore. Depending on the severity of the rusting, there is a real risk that one of the rings may fracture and the end scratch the bore on the way out.

I did read of one person who claimed that by drilling the piston full of holes they were able to weaken it enough to facilitate removal. I can't vouch for that. It might be doable if the piston is stuck near the top of the bore. Much more difficult if the piston is very far down the bore.

[Ron Kwas]

142 Guy;

Big thanks to you for pointing out the inconsistency with science of this "fire and brimstone technique"...usually it's Derek or me! ...for frozen-in-place-pistons, the best technique is still, and will continue to be, to soak-in penetrating lubes for as long as you have time, and when you can't wait any longer, impact persuasion with a block of wood just as you describe...it rarely fails, and the risk for collateral damage is small!

Cheers

[Juular]

Thing is, it has been sitting for 6 months with a mixture of ATF and a thinner (I can't remember which one I used). Hitting it with a sledgehammer so far hasn't been able to budge it.

May as well try everything before I resort to splitting the piston. If it doesn't come out, I'm unlikely to spend any money boring out to sort any damage, given I have a non seized engine with a better head.

I bought the car in the knowledge I'd probably be binning the engine, so there's absolutely nothing to lose at this point.

[Juular]

As much as I was really looking forward to a barbecue, I decided it wouldn't be a loss to go out and buy a bigger sledgehammer. Oh well!