How to save this cylinder without a trip to the machine shop

[Cooper40]

Hey it's Cooper again with the '49 plymouth that I posted about a few weeks ago.

My brother and I just got the engine free yesterday. He was down on the flywheel and I was up top banging on the #6 piston with a peice of wood and a hammer. We determined it was 6 by taking off each of the rod bearings and trying to turn the engine over. As you can see, the cylinder doesn't look to great. Now I really don't have the money to take this to a machine shop and get it re bored. I want to try to do this all at home if I can. I want your guys advice. Should I try and hone the cylinder a little? I dont have any experience honing but im eager to learn. Again, this is all a learning process. I would love to be able to save this cylinder if I could. 

[Sniper]

I don't think a hone will fix that.  You seem to have a real crusty looking ridge at about 8 o'clock in #6.  Unless you can scrape that off I think it would mess up any hone job you tried.

[kencombs]

If it had rust locking it up I'd try putting the piston in all the way down to the bottom.  Then use something like plumber's putty to seal the edge of it to the cylinder wall.'

 

All that to prevent the vinegar you pour in from escaping.   Let it set overnight, remove piston and rinse well.   If the rust is gone and no pits are evident, run a rigid hone through and and see what it looks like.   I have no use for the ball type hones as they don't expose defects like a rigid will.

[Los_Control]

Pictures are always deceiving .... I see some dark spots that might be low spots. If you can catch your fingernails on them .... you need bored.

That cylinder is so rough I would use my big wire cup wheel on my 4" grinder .... they are just about the right size for our small 3" cylinders.

 

As @kencombs stated you need a rigid stone hone where you can actually change the stones starting with a coarse stone then ending with a medium stone.

Just for information, the fine stone would be for a modern engine that has much tighter tolerances ... not good for a old engine like ours.

 

Just clean it the best you can and accept the results as they come ..... You already said it is not going to a machine shop.

 

If those dark spots are low spots, a good cleaning will help but oil will always leak past the rings & burn some oil.

Who knows how much .... assuming you get the rest of the cylinders cleaned it may just be a puff of smoke when taking off .... maybe it will blow a occasional smoke ring.

Just no way of telling what the oil consumption would be like with only 1 slightly bad cylinder  ..... It will burn oil though.

 

So have fun with it, get it back together then keep going & get it driving & stopping .... decide what you want to do later. When you have more information.

 

[Ivan_B]

2 hours ago, Cooper40 said:

Should I try and hone the cylinder a little?

I think you'll need a re-boring machine for this one ?

[Hickory]

 It's your car. These cars will run with broken piston lands, leaking valves ect. If you don't mind some smoke or running a little loopy. Hone it ring it and drive it. Save some money and have a winter project.

[Bryan G]

This is what my worst cylinder looked like when I started; that's Marvel's Mystery Oil inside. I made a pledge: NO machine shop. I cleaned it out by hand real good, then honed the heck out of it. I think I've put somewhere around 8-9k miles on it since then. The engine runs great; I've never been behind it when it was going down the road so I couldn't tell you if it smokes. No clouds in the rear view mirror. I have to feed it lots of oil, but I suspect a lot is running out of various places onto the ground. The spark plugs, including this one, all look the same and stay clean. My vote: give it all you got. What have you got to lose? Worse case, later one you can DRIVE it somewhere where the engine can be pulled.

 

 

[Cooper40]

@Bryan G That's what I was thinking of doing first. Doing it by hand. What material did you use? 

[Hickory]

What I used back in my penny punching days was a vinegar soak, thena 3" flap wheel for a quick run then a lot of rigid hone. And then I used a ball hone. Some don't like a ball hone I do like the cross pattern from one. But they don't even things up so use both. That's me but before making a plan really clean up the pistons and check the piston lands. If they have cracks or broken then a new plan should be made. These engines are very forgiving but you don't want to cause more damage.

[Bob Riding]

This worked well for me. Lisle 365000 Ridge Reamer

[Matt Wilson]

You just need to be VERY careful using a ridge reamer.  You can easily remove too much material without even realizing it, and end up removing cylinder material in the region where the rings would ride.  This has happened to me, even though I thought I was paying really close attention to the positioning of the reamer.  I still don't know what I could have done differently, and I didn't realize I had done anything incorrectly in the rebuild of two engines until the machinists (two different machine shops, years apart) informed me and recommended against their use. After the first shop mentioned it to me. I thought I must have just not paid good enough attention to detail when using the reamer, so I was extra careful with the second engine but it still wasn't right.  Instead of using a ridge reamer, they recommended beating the pistons out of the block, which of course destroys them and the rings, but in a full rebuild, that doesn't matter, other than not allowing you the opportunity to see their condition.

 

If that cylinder has a ridge, then I think there are two approaches I would consider:  One is to leave the piston and rings in there, and try to clean up and hone the cylinder with the piston in place, but you'll obviously have to be extremely careful about keeping the cleanup and honing debris from getting onto the piston and into the piston-to-cylinder gap.  The second approach is to pound out the piston and rings, knowing you will destroy them, then clean up and hone the cylinder, and install a new piston and rings - that is, assuming you can find a single piston and a single ring set of the correct size for your cylinder.

Edited August 20, 2023 by Matt Wilson

[Bryan G]

14 hours ago, Cooper40 said:

@Bryan G That's what I was thinking of doing first. Doing it by hand. What material did you use? 

I think this is the one I bought:

https://www.amazon.com/Lisle-23500-Stone-Type-Glaze-Breaker/dp/B0002SREPO/ref=asc_df_B0002SREPO/?tag=hyprod-20&linkCode=df0&hvadid=385480448341&hvpos=&hvnetw=g&hvrand=1025463572215892955&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9007979&hvtargid=pla-572010054663&psc=1&tag=&ref=&adgrpid=79419941500&hvpone=&hvptwo=&hvadid=385480448341&hvpos=&hvnetw=g&hvrand=1025463572215892955&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9007979&hvtargid=pla-572010054663

Really, this model is a bit too light-duty but it did okay for me. I try very hard to only buy American-made tools. I didn't want to spend the money for the really good Lisle hone. I know Harbor Freight has some stuff but I try to steer clear. Do what you got to do I did use some 320 grit sandpaper in some spots, by hand. Lots of WD-40 & paper towels for cleaning, and cheap motor oil for lube. Now, I didn't have a ridge to deal with. My engine didn't have that many miles since a rebuild, but had sat for 20 years. I'm still not sure what got into that cylinder to mess it up so bad.