Best Way to Unseize an Engine

[legendre]

Kano Kroil is some good stuff.. about the best commercially-produced penetrant I’ve ever worked with.

"Kroil – the Oil that Creeps!" 😉

[brook-n]

Ahh yes…… As they say, " Kroil it don’t spoil it" good old Kano Laboratories. Definitely one of my favorites! I have used just about all of their products over the years, I could not agree with you more reivertom. After I do a rough clean of the bore with good old gasoline to remove any loose particals I use one of their products called ExRust. It works pretty quick
In short time you start to see rust breaking down into that what I call butter scotch color as the rust breaks down. Next I use Penephite Graphited Penetrating Oil also a Kroil product,
This is what I use with regulated air pressure to wick down around the piston plus a little heat. Yes it cost money, but in most cases I can free up a powerhead in short order. Other members have had great luck with a product called Gibbs Penetrating Oil. Everyone has their favorite mystery juice, any petroleum based solvent with a little heat usually does the trick. Yeah it can be a smokey mess , but I don’t think there are too many of us that have not spent a Saturday or Sunday afternoon in a smoke cloud trying to free something up.

Respectfully
Brook N.

[The Boat House]

• This reply was modified 5 years, 5 months ago by The Boat House.
• This reply was modified 3 years, 2 months ago by The Boat House.

[chinewalker]

On a few occasions where the piston was particularly stubborn, I have decided to sacrifice the piston to save the block. Of course, this depends on rarity, access to replacement, etc. The last one I did was a Mark 55 that had one pistons more or less encrusted to the cylinder wall. I sleeved a tube over a drill bit and bored a hole through the dome of the piston. I then used a chisel to crack the wrist pin bosses in the piston skirt to the point where I could remove the connecting rod. With access to the hole in the piston dome, I was able to use a combination of hacksaw and chisel to cut through the piston at two places to collapse it in on itself. Slow and carefully so as to not cut into the cylinder wall. It worked, and a good honing & new (used) piston later, it became a good runner.

[brook-n]

Hi Scott,
I agree, In most cases I look at the piston as being the part to sacrifice if needed as well. Years ago after learning the hard way with the grease method I made a piston pulling fixture that grabs around the rod on the wrist pin end and pulls the piston out through the back side of the bore. ( done mostly on single cylinder Rowboat Motors and opposed twins ) one of the best tools & fixtures I have made for working on Rowboat Motors. there has only been one piston that I have not been able to get out to date that I had to machine out. But much like yourself a good cleaning, hone and in some cases a new used piston & rings it was back up running with nice compression and bounce. I have pulled out a few pistons for fellow club members as well.

Respectfully
Brook N.

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