siezed piston in a SEL 1520

wyvern · siezed piston in a SEL 1520

Hello all,

I have taked on the restoration of a sel 1520 for a friend who has had it since childhood. Unfortunately the aluminium cylinder became siezed at some point and the con rod was snapped off. Consequently I will make another, however I am having problems removing the piston from the bore. I have drilled the majority of it out but the remainder is still stuck fast. I have stopped short of going any larger than 4.5mm for fear of damaging the bore. Can anybody recommend the best way to proceed? I understand that the bore is 1/4" so would I be best to drill 1/4" followed by a 1/4" reamer or should i heat the assembly with a blow torch and carefully extract it that way.

Many thanks

Guy

scorpion2nz

I would not have drilled so large .
I would have used a smaller drill
right through piston and let thin penetrating oil in then
after a while inserted the tang of a rat tail file or similar (taper square end)
and heated and gently twisted and hoped for the best .
you could still try it now but I would expect much success
Drill most of it out now and reaming may be you best bet
or set up in lathe and bore it out CAREFULLY

kevininasia

Before trying anything like more drilling or boring, I would slop some penetrating oil in it, leave it for a week and then try to fabricate a little hook that would reach down through the 4.5mm hole you already made and pull the piston out from behind.

Good luck, whatever you try.

Bear

I'm no expert but I would second using heat. depending on the makeup up the piston as well. several light heatings and allowing to cool could break it free from the corosion by the expantion and contraction, I would also use a good penatrating oil as well. but you must be careful with heating aluminium as it can warp. because of this I recomend heating in a oven and not using direct flame so it will for the most part heat evenly and not develop a hot spot from a flame. after heating I would take a soft punch and lightly tap the piston to shock the corosion, a wood dowl would be best so it won't mar anything more than it is from corosion.

Wallace

Try the oil, leave it in there overnight if you have to. I've found 3 in 1 tends to work well, others swear by using WD40.
I usually go for boiling water as the heat source as no real damage can be done.

I don't know if the cylinder is one piece, or more accuratly does it have an end cap/plug? If it doesn't, maybe doing the above combo and a blast of compressed air will send it flying out. Don't give it the compressed air via the boiler, or lines, take the cylinder off so nothing can blow.

wyvern

Hi guys thanks for your advice. In the end I heated the cylinder (separating it from the main block) and managed to extract the remnants from the cylinder with a chopstick! Hopefully this engine should be running soon

Ta

Guy

MrMamod

igy569

I love this forum!!!