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Chris727

Cylinder sleeving?

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Chris727
Hi. I discovered 12HP briggs on my newly aquired B12 is unfortunately already bored 30 over. It has a pretty good groove at the top of the bore and lots of scratches, piston appears to have a little wobble. The former owner who was an A-C mechanic mutilated this thing. Anyway, it seemed to run all right (minimal smoke) but I needed to replace the head gasket and install an the air baffle which goes behind the flywheel, which was missing, maybe causing it not to cool right. So when I had the head off and saw an oily mess and the 30 oversize piston I kind of freaked. I think I can get away with using it the rest of the summer but by fall it will need a good overhaul. Has anyone ever had one of these engnines sleeved. I've been told they have to leave part of the old bore at the bottom to help hold the sleeve in place. Has anyone had success with this? The only machinist I know has refused to do any sleeving. Does anyone know what the going rate is for sleeving? I'd hate to think this motor is toast as it was still running ok. Thanks in advance. Chris

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Al
Hi, I have put sleeves in them. I have sold my boring bar, and have had one done since.Seems to me is was about 150.00. You are correct, it is comon to leave a lip at the bottom of the cylinder about 1/16 of an inch for the sleeve stop. If the cylinder is bored to the correct size they will hold without the lip. Next the sleeve is installed, and you saw off the excess unless it is a precut one. Then you set the bit out and bore the top off flush with the block. I used to bore about .001 to .002 under for the sleeve. This gives an interferrence fit. We used to use sleeve seal, and freeze the sleeve. Next we would bring the sleeve from the freezer wrapped up. Then we would heat the cylinder with an acetylene rich flame and a rose bud tip. Not directing the flame against the wall, but down through the bore. When the block was hot we would unwrap the sleeve and put it in the cyl, put a block of hardwood 2x4 across it and drive it in with a heavy hammer. 50 years ago, I used white lead and oil on the sleeve. Later I used to buy "sleeve seal" when I could no longer get that, an old guy I knew said to use brake fluid. It seemed to work well. When you start to put the sleeve in you have about 10 seconds to get it driven home, or you just scrapped a sleeve and you learn how to saw it off and bore it out. My 2 cents worth and its free, value accordingly, Al Eden

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LBS
Down here in TN, it costs about $35 to get a single cylinder engine sleeved. I just had a two cylinder Lombardini diesel done and it cost me $130. The local machine shop I use, bores a lip around the top of the cyl and the sleeve has a thicker ring on top to keep it in place. Lawrence

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Chris727
The $35 job sounds almost too cheap. Is that for a quality job? Al's description makes it sound like a pretty involved procedure. Though I wouldn't want to go more than $75. Hopefully the crank and rod will be ok and at the end of the season I'll get it freshened up. Thanks for the tips. Chris

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LBS
Chris, If you would like, I can get the PH number for BATES ENGINE AND AUTOMOTIVE in centerville, TN. they do very high quality work and I know it would not be over $75. They may be willing to have you ship it in to them. If I can remember, I will call them tomarrow and ask what thay would charge, and give you their PH#.

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Al
HI, That sounds like a heck of a deal. Up here boring a cyl is 40 to 65 depending on the shop. With the sleeve, you have to bore, then install the sleeve, then it needs to be bored out. This doesn't include the cost of the sleeve. Did the engine you had have dry sleeves? These are removable with a sleeve puller. They are prefinished and when pressed in are ready to run. They have a retainer shoulder at the top to anchor them. 8N Fords are like this. This process is not used too much any more. In this Briggs or a Kohler the block is not set up for a sleeve and a "repair sleeve" would be used. They come in a length like 10" and 1/8 or 3/32 wall and you cut them to length. They are unfinished inside and have to be bored to size after installation. Al Eden

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msiebern
Some interesting numbers (costs). I just picked up my K321 from the machine shop and while I didn't have it sleeved, I wondered what anyone else thought about the prices. I have used this shop for years and never questioned or thought about the pricing. Here is what they did and their charges: Clean block - $12 Bore Cyl .010 - $38 Grind Valves - $24 Check & Grind Crank - $42.50 TOTOAL LABOR - $116.50 I know there might be some regional differences in price stucture for labor. This shop is in N.E. Indiana.

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Al
HI, Sounds like Mikes prices are on the reasonable side. We typically pay a little more for those services I have had 3 boring bars, these are designed for cylinder boring. I had an old Storm, then a Van Norman, and the Last was a Quick-Way. To bore these blocks one has a table that is has a precision ground top made out of about 1 to 1.5" thick steel, blanchard ground on both sides. In an automotive engine, the boring bar sets on the deck and the bar is anchored (held) by an anchor thru the adjacent cylinder. We used a long 3/4" threaded rod that went through a piece of steel tubing that was passed through the main bearing saddles. You then center the bar in the bottom of the cylinder and tighten the anchor. Next you bring the bar up and set the bit. With small engines youi use the table and the bar is anchored to the table top which has a hole in it to bore through. The engine is placed under the table top and roughly centered in the hole. Then there is a clamp that pushes the block up against the bottom of the table and holds it there tight. Loosen the bar anchor and lower the bar to the bottom of the cylinder and center it with the centering fingers. Tighten the anchor so the bar can't move and retract the fingers raise the bar insert and adjust the bit and make shavings. The reason the bottom of the cylinder is used instead of the top is that is normally has almost no wear. Unless you can center on the unworn area above the top ring, the cylinder is worn on the thrust side much more than the compression side and you will be centering on an oval cylinder with much more wear on one side than the other. This will cause you to not bore the cylinder where it is supposed to be, but it will be moved in the direction of the thrust side. Also one needs to deck the top of the block. The top of the block will have the bolt holes all pulled up slightly as will the area around the exhaust valve. Usually a long heavy flat mill file will fix these little ridges. If they are bad, clamping the block on the table of a Bridgeport or similar mill and taking the high spots down with an end mill or a shell, cutting ONLY to the point that the lowest area is just starting to show contact with the mill. You don't want to lower the deck just take the high spots off. If this is not done, the block will not be bored straight, as it will not clamp with the cylinder at right angles to the table. I usually cut .0075 on a 010 over bore, and about .0175 on a 020. Normally if it miked like it might possibly clean at .010 that is what I would try, if it didn't clean, then another cut of .010. The boring bar cut is rather rough, they have 2 cutters, a fine and a coarse. You can do a coarse .005 and a fine.003 for .008. You still have to finish the cylinder to size with a hone. This MUST be a rigid hone like a Sunnen or an Ammco. You start with a 100 grit stone dry and take it to .009, this cleans all of the tool marks out and gets the cylinder to within .001. Next a 280 grit stone with honing oil, take it to 010. Next use a 500 grit stone and plataeu the cylinder using oil. This stone doesn't get used long enough to take any metal out. Since the 100 grit still has a few valleys after the 280 takes its peaks off, the cylinder under a mirco scope would look like a hill that the top had been buldosed off and the flat was scratched up with 280 grit ridges. Now the 500 grit just shaves the 280 peaks off and leaves the flats with the 500 REALLY fine marks. This is the recommended method of preparing cylinders. I used to build race engines and cylinder finish is important, important, important, as the finish controls the lubrication that that is stored in the valleys. Sorry this got so long. Next, It can be done in a Bridgeport very easily. Just clamp the block to the table, deck it for reassembly purposes. Then drop the spindle down to the bottom of the cylinder and put a dial indicator mount in the collet and move the table until you are centered. Remove the indicator and put a boring tool or flycutter in and bore it. Still must do the final with a hone. You can also oversize to 010 with a hone, take the first .0075 out with a 100 grit dry, then finish as if it were bored. The only problem is if the cylinder is really worn, the center line will move to the worn thust side a couple of thousanths on the top and the bottom will stay centered. On these engines you would probably not notice it. On a 9000 rpm Chevrolet with 12/1 pistons it would not be tolerable, or if it was, you would see tail lights and accuse the guy that had it right of cheating. On final thing, when honing the hone must be stroked up and down at a rate that provides a crosshatch pattern of 30 to40 degrees. Al Eden

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