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Thread: Honing engine cylinders - with a Flex-Hone

  1. #1

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    Honing engine cylinders - with a Flex-Hone

    I am about to hone the cylinders on my dismantled Continental A-80, using a newly acquired Flex Hone and wonder if anyone has experience of this tool.

    It is recommended by the makers that the cylinders are washed out afterwards with warm soapy water. To avoid any risk of causing corrosion of the steel liner, would it be better to use, say, kerosene? I'm wary of using water anywhere near my irreplaceable cylinders.

    I plan to use some plain motor oil with the hone - the fluid sold by Flex Hone is not easy to come by over here. They do suggest this is OK - but not quite as good as their product.

    Thanks for any comments.

    Ian

  2. #2

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    Not airplane cylinders but some other cylinders I bored and honed this summer I started using a honing tank (a bucket) with water soluble cutting oil. I always wash the cylinders out with hot soapy water, then dry thoroughly, That's the only way I know of to get all abrasive residue out. Once dry wipe the bore with oil and it will be fine.

  3. #3

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    If you are sure you have true cylinders by all means use this hone. But if your cylinders are out of round just a little, this type of hone will make matters worse. Because all cylinders after use go out of round a little I avoid using these types of hones because that little amount the cylinder was out by the time you use this style hone it is a lot more out of round. Use a hone that is locked into position with a screw not spring loaded or like you describe.

    Now you may ask how can a cylinder go out of round when a round piston is stuck in them. It has to do with thrust loads applied when the compression happens and the throws of the crank. Even piston rocking or tipping will induce some wear on the cylinder after many hrs of use. Think in terms of thousands of hrs. This is why cylinders need to be check with a Micrometer before boring to check size.

    Good engine rebuilding practices or those who are the best at this type of work will not use a spring hone or flex hone. Not if you are looking for hundreds of thousands of trouble free miles from said engine. If you are running it down a track or on a track and then taking it back apart you may find those mechanics using this style hone.

    My 2 cents.

    Tony

  4. #4

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    As to washing. The block should be washed with mild soap and plenty of water. Then wipe the cylinder with a clean rag. If any discoloration is found on the rag wash again. Any of this residue left behind will wear the cylinder and rings prematurely. It usually takes a couple really good washing to get all this off. Use a soft brush when washing not a rag. The brush will get into the honing hatches and not just ride on top.

  5. #5

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    Many thanks for your advice, Marty and 1600vw. I'm grateful for all the help I can get.

    My A-80 has, as far as can be determined, had only a few hours running time (- as claimed by the vendor, many years ago - ) and surprised me by being very close to the original tolerances in most places and within limits elsewhere. I couldn't detect any significant out of round in the cylinders.

    I've had the crankshaft measurements confirmed & the crank crack tested, so am hopeful the engine will be good for the few hours I'm likely to be able to put on it.

    There seems to be no escaping washing out the honed cylinders with soapy water and I'll follow your advice regarding this.

    Thanks again!

    Ian

  6. #6
    Larry Lyons's Avatar
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    You can wash most things with water, if i'm concerned about corrosion I do it on a sunny day and lay the part in the sun for a few hours. The heat and warm air circulating has never failed to remove every drop of moister. I even washed a very expensive single lens reflex camera once that had been dropped in the ocean (salt water and I removed the battery immediately) using this trick, worked like a charm, I still have the camera and it works over 40 years later, now film for it is another subject. One time I did nto have the option of a sunny day so I just put the item in the kitchen oven set on its lowest setting. As there was some plastic and fragile components involved I left the door open and monitored the temp by laying my hands on it. You can take 104 degrees F for an extended time anything hotter will not be comfortable long term, 120F takes a few seconds to burn you. Most any plastic can take 150F for a short time.
    No matter how far you push the envelope; its still stationary!

  7. #7

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    Many thanks for that Larry and reassuring to know there's not likely to be a problem as long as I dry the cylinders properly and quickly, followed by oil.

    I've just set the first cylinder up in my workshop and have finally sorted out the correct rpms to use for the size of the hone, calibrated my variable speed drill & adapted the trigger so I don't exceed the max rpm for the hone. As soon as I have some urgent chores out the way, I'll get on with the honing - hopefully early next week.

    Many thanks again.

    Ian

  8. #8

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    Quote Originally Posted by Larry Lyons View Post
    You can wash most things with water, if i'm concerned about corrosion I do it on a sunny day and lay the part in the sun for a few hours. The heat and warm air circulating has never failed to remove every drop of moister. I even washed a very expensive single lens reflex camera once that had been dropped in the ocean (salt water and I removed the battery immediately) using this trick, worked like a charm, I still have the camera and it works over 40 years later, now film for it is another subject. One time I did nto have the option of a sunny day so I just put the item in the kitchen oven set on its lowest setting. As there was some plastic and fragile components involved I left the door open and monitored the temp by laying my hands on it. You can take 104 degrees F for an extended time anything hotter will not be comfortable long term, 120F takes a few seconds to burn you. Most any plastic can take 150F for a short time.
    Fire restoration companies use water and ultra sound to clean fire damaged goods. If you have a TV that had been in a fire they will immerse this TV into a vat of water with ultra sound waves going through this. After soaking for so long they will remove the Tv or whatever, give it a good blow dry using compressed air then off to the dehydrator room or the room with a dehumidifier in it for a few weeks. These are wooden style rooms about 100'x100'. The goods can stay in them up to a few weeks before all water is removed.

    But water alone will not remove the material left from honing or boring a cylinder. It takes a soap water mix to remove every drop of the cut material. It will also take more then one washing to do it correctly. Warm water is best. If cold water is used you may never get it all out. A brush is used over a rag. The rag will not get into the hatch marks and remove the left over material and the water will not just rinse it out.

    Here in the midwest if you wash a bare metal piece. Then put it out in the sun. Come back in a few days and it will have a coating of rust already forming on it. You can leave the bare metal dry with no water on it in the shop corner and in a few weeks it will have rust on it. Now if your shop is air conditioned you will not have this. Things rust fast around these parts of the country if left unpainted for more then a few weeks.
    Last edited by 1600vw; 11-26-2016 at 06:38 AM.

  9. #9

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    Thanks for the excellent advice 1600VW. Just remembered I have a dehumidifier, so I'll use that as well.

    I'll use a suitable brush/rag and warm water with soap/detergent and wash several times to make sure, followed by plenty of oil/ preservative; we have a damp and salty atmosphere here in Devon and it's pretty chilly in my garage - not ideal conditions. I have some "XMP Metalguard" and will try that as a coating to prevent rusting.

    Thanks again.

    Ian

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