Muratic Acid on cylinder walls?

[KennyV]

BTW...
At the time I was unsure that there was not more damage, so to 'test' run the engine I didn't want to ruin a new head gasket. So instead of buying a new one I sprayed both sides of the old one with copper coat. Torqued in sequence to the proper value... That is the head gasket that is still in that engine. KennyV

 

[BXpanded]

The muratic acid will indeed work. In years past, it was a pretty common procedure on 2 stroke motorcycle engines that had siezed. Take something like a slightly dull knife blade and peel off as much aluminum as you can without scratching the cylinder wall. Then use the acid. Follow with a hone or 400 grit sandpaper to get a slight crosshatch pattern on the cylinder wall. Apply some oil as the cylinder will rust in a matter of a few hours.

 

[Pops15]

As far as other engine issues, I don't have an inside mic (or whatever it's called) to mic the cylinder, so I'm going to try and use a compression ring to see if the cylinder egg shaped....hopefully it didn't. The picture of the cylinder looks scored worse that it really is....There are small lines in the cylinder, but NONE that you could even hang your fingernail on. The other 2 pistons look fine, and all 3 rod bearings are ok. No visible cracks in the head or block deck. I did a leakdown, and all the valves are sealing well.

My concern (which I don't have the tools to determine) is something got warped (cylinder, deck or head). I'm gonna remove the metal somehow, deglaze/hone all 3 cylinders, replace the bad piston, and all 3 sets of rings......and keep my fingers crossed. Would you replace the other 2 pistons also? Not to sound cheap, but they're $150.00 each. ($300.00 is alot of money right now )

There's an old saying.....
There's never enough money to do it right, but there's always enough to do it over!
Once you get the aluminum off the cylinder wall, and hone the cylinders you can use a ring and a feeler gauge to check for taper, but you'll need a mic or a bore gauge to see if its goose-egged. If you don't have one take the block to someone that does.
Spring for all new pistons, rings and bearings. Check the wrist pins and rods for galling. As bad as that piston is I'd consider replacing that rod too.
A friend overhauled a JD engine for his BIL. He ordered most of the parts through a local auto parts store (not one of the box stores like Auto Zone). He saved a considerable amount of money by doing so.
Hope you don't find anymore damage.
Pops

 

[cjmmbrock]

I seriously doubt your temp sending unit is bad. It can not conduct heat well in air as it will in water. Thats why I also like a oil temp gauge.

Here is the way a lady mechanic explained it to me. Turn you oven on 350 and open the door and stick you hand it. You can keep it there all day. Now do the same thing but put a pot of water in there and now stick your hand in the water. See what I am getting at?

Chris

The temperature sending unit was bad......the electrical connector was broken completely off the sender.

Water conducts heat 25 times more effectively than air. Water either draws heat away from your body (if its colder than body temp) or puts heat into your body (if its hotter than body temp) 25 times faster than air, thats why it effects your body more dramatically than air.....but 230 degrees F is the same whether its water, air, or tranny fluid. The radiator was drained, but not the block, so there was a little coolant in the system. I'll bet the steam would have tripped the sending unit if it would have been working.....oh well

 

[cjmmbrock]

BXpanded and Pops, thanks for the replies.

I didn't think about the local stores...good idea. I got zeroed into the John Deere dealer because of the other items I HAD to buy from them, and didn't think to check the other places. I'll call around on Monday.

 

[cjmmbrock]

BTW...
At the time I was unsure that there was not more damage, so to 'test' run the engine I didn't want to ruin a new head gasket. So instead of buying a new one I sprayed both sides of the old one with copper coat. Torqued in sequence to the proper value... That is the head gasket that is still in that engine. KennyV

That's awesome! It's nice to hear a story with a happy ending for a change.........btw, I see Butler, KS on your profile.....I bought this tractor from a guy in Yates Center. Not too far from you, huh?

Chris

 

[schmism]

cyliner hone FTW

 

[Just Bill]

Hello
While you have it apart it would be a good idea to have the rods checked at an automoyive machine shop.
If the big end is egged they can resize them and put them back in spec.
It would also be a good idea to have the head checked out and a valve job to put everything in top condition.
It will be easier and cheaper to do it now than having to revisit it at a later date.
Bill

 

[Chilly807]

If you're going to hone or deglaze the liner anyway, there's no point in fiddling with the muriatic acid. It's meant to be used on engines you can't hone, like chrome over aluminum chainsaw or motorcycle cylinders. Lightly scrape all you can get off, then sand gently to keep what's left from clogging the stones on the hone or deglazer.

A deglazer won't correct out of round, it'll just resurface the existing condition. The hone will, but go slow. As soon as the liner cleans up enough to satisfy you, stick a new ring in and measure the end gap. If it's within limits, you're okay. If not, you'll have to go with an oversize piston if one is available for that engine.

You're better off to borrow or buy an inside mic or bore gauge. Even if the ring gap is ok, the piston to cylinder clearance needs to be checked. A set of inside calipers will work, but they aren't the best.

Typically you want about a 45 to 60 degree crosshatch pattern.

Unless the other pistons have visible damage, clean them up, deglaze the other cylinders, and fit new rings. It would be safer to put in new ones, but if you keep that up you might as well put a new engine in.

Just my opinion,

Chilly

 

[cjmmbrock]

Thanks again for all the replies.

Chilly,
It's hard to tell from the pictures but the aluminum buildup was pretty tall (I'd guess around .020). You may be right, a hone job may have cleaned it up I was just worried that it was too much of a "chunk" for the hone to grind down without taking too much cylinder wall with it.....but I am a rookie at this game.

I plan on doing just what you said....New piston and rings to replace the bad one, and re-ring the other 2 cylinders (of course after deglazing all cylinders). I would love to replace all pistons, bore the block if needed, etc....but like you eluded to, by the time I replace and repair everything I could buy a short block assembly.

Thanks again,
Chris