Flex Hone?
#1
03-10-2008, 10:48 PM
Flex Hone?
Flex hone?
I am real close to rebuilding an engine, I even have the engine ('93 4.3L CPI) and a few practice dumbies (2 old Lawn Boy self propelled mowers, and two riding mowers. I'm keeping one rider to mow my yard, the other three are gone this spring or as soon as I am done fixing them
With that said.
Flex hone is different from what? Dont' answer yet.
The 4.3 I have has a spun #1 rod bearing, she had a hell of a knock. The engine has 193,000. Give me some ideas on how to rebuild this thing on the cheap. I can tear itdown, clean it up, and replace justa bout everything myself. I did learn to rebuild a 700R4, and a 4L60E and have rebuilt three tranniesin as many years.I just bought a little boat and my tranny had no problembackingit up the drive on 4" of hard packed snow/ice.
Anyway,
I am looking for tips, tricks, and info on how toinspect parts,what are indicators that parts are beyond rework/repair and must be replaced?
I am real close to rebuilding an engine, I even have the engine ('93 4.3L CPI) and a few practice dumbies (2 old Lawn Boy self propelled mowers, and two riding mowers. I'm keeping one rider to mow my yard, the other three are gone this spring or as soon as I am done fixing them
With that said.
Flex hone is different from what? Dont' answer yet.
The 4.3 I have has a spun #1 rod bearing, she had a hell of a knock. The engine has 193,000. Give me some ideas on how to rebuild this thing on the cheap. I can tear itdown, clean it up, and replace justa bout everything myself. I did learn to rebuild a 700R4, and a 4L60E and have rebuilt three tranniesin as many years.I just bought a little boat and my tranny had no problembackingit up the drive on 4" of hard packed snow/ice.
Anyway,
I am looking for tips, tricks, and info on how toinspect parts,what are indicators that parts are beyond rework/repair and must be replaced?
#2
03-11-2008, 12:14 AM
RE: Flex Hone?
Pistons/Rods/Wrist Pins - you are inspecting for any cracks or erosions on the piston and between the ring lands on the piston. You need to make sure that the rods move smoothly on the wrist pins.
Crank - If the crank must be turned to clean up the spun journal, you will need over sized bearings on atleast that one journal. If one rod journal needs to be turned, I would have all of the rod journals turned the same amount just to keep things uniform. Same would be for the main journals, but if they don't need to be turned, leave them alone. All that would be necessary is a quick polish with some fine emry cloth.
Block - Here, you will want to start out by measuring the bores with a 2 or 3 post bore micrometer. Check this reading against the specs for the motor to determine if an overbore is necessary. If it is, kiss your stock pistons goodbye (or make a table out of them). If the bores are in spec, you need to be look for ridges at the top of the cylinder bore. You will need to remove any ridges at the top of the cylinder to reduce the risk of damaging the top compression ring and/or the ring land between the two compression rings. Once the ridges have been removed, it is time to hone the cylinder walls. A manual hone can be purchased at NAPA or quite a few other retailers. The purpose of the hone is to put a cross-hatch pattern into the cylinder walls to promote bedding in of the rings for a good seal. You will want a uniform pattern around the entire cylinder wall. You can use an electric drill with WD40 as a lubricant. If you have to have any machine work done, have the shop that does the work replace the cam bearings (and balance shaft bearings if applicable) while they are doing the work. They are a pain to do!
Heads - You might want to start with getting them magna-fluxed to ensure that there are no cracks in the head. Next you would want to have them checked for flatness at the head gasket surface. If both of those check out and your valve seats, valves, and valve guides look/feel good, a light hand lap of the valves to make a perfect seal would be prudent. After cleaning everything very well, replace the valve seals and reinstall the valve springs.
That's pretty much it... I think anyway... LOL
Crank - If the crank must be turned to clean up the spun journal, you will need over sized bearings on atleast that one journal. If one rod journal needs to be turned, I would have all of the rod journals turned the same amount just to keep things uniform. Same would be for the main journals, but if they don't need to be turned, leave them alone. All that would be necessary is a quick polish with some fine emry cloth.
Block - Here, you will want to start out by measuring the bores with a 2 or 3 post bore micrometer. Check this reading against the specs for the motor to determine if an overbore is necessary. If it is, kiss your stock pistons goodbye (or make a table out of them). If the bores are in spec, you need to be look for ridges at the top of the cylinder bore. You will need to remove any ridges at the top of the cylinder to reduce the risk of damaging the top compression ring and/or the ring land between the two compression rings. Once the ridges have been removed, it is time to hone the cylinder walls. A manual hone can be purchased at NAPA or quite a few other retailers. The purpose of the hone is to put a cross-hatch pattern into the cylinder walls to promote bedding in of the rings for a good seal. You will want a uniform pattern around the entire cylinder wall. You can use an electric drill with WD40 as a lubricant. If you have to have any machine work done, have the shop that does the work replace the cam bearings (and balance shaft bearings if applicable) while they are doing the work. They are a pain to do!
Heads - You might want to start with getting them magna-fluxed to ensure that there are no cracks in the head. Next you would want to have them checked for flatness at the head gasket surface. If both of those check out and your valve seats, valves, and valve guides look/feel good, a light hand lap of the valves to make a perfect seal would be prudent. After cleaning everything very well, replace the valve seals and reinstall the valve springs.
That's pretty much it... I think anyway... LOL
#4
03-11-2008, 01:04 AM
RE: Flex Hone?
If you need to true up the heads( making sure the heads are flat) Have a machine shop do it for you cause if you wanted to do it yourself you would need the expensive equipment to do it!! Good luck on the rebuild, hope it all comes together and works for you!!
#5
03-13-2008, 11:52 PM
RE: Flex Hone?
Budget, you won't need half the stuff listed above. For race or high performance motors I build... I always go overboard. There is a big difference between rebuild, and remanufactured. I'll go over a rebuild as you are looking for a budget rebuild.
If she spun a rod, you'll need to make sure the rod end hasn't been completely damaged from heat. You'll see blue around the chamfer. If there is no blue, you are ok to take it and all the rods to the machinist to have him recondition either the damaged rod, or all if you prefer. (usually about 20-25 a rod) Have them tank and clean each piston and rod combo, make sure you get them to clean the ring groves. A simple tanking will not clean it in most cases.
Depending on how long the engine was driven on the spun rod, you may not be able to turn the crank. In that case you'll need to get either a crank kit, or junk yard diving. Autozone has cranks and most times they dont dig too far into it for cores like that unless they are REALLY bad, or snapped in half. This will most likely be the most expensive part of the build generally 197-235 depending on where you go for it. If you spun a main, then you need to take the whole thing to the machinist and have him determine if it will need to be line honed, or worse.. line bored.
Block, many sections
Cylinder walls
Easy way is to look in the bore. If there are no gouges, can still see some crosshatch, and there is huge ridge on the top of the cylinder wall (not the carbon buildup, but metal height difference) 9 times out of ten, you can just run a flex hone in it and call it a day. 75 strokes each cylinder using flex hone oil. Done right you can't tell the difference from a machinist run tool (both give a plateau finish) If there are gouges from a broken piston, or scuffing from the skirts etc, then you need to get a bore/hone.
Deck
I use a flat machinist bar and feeler gaugeto check my decks. If the block is a closed deck design as it is in this case, they should be fine unless it overheated. Pull the guide pins from the corners and set them aside. Remove as much gasket material as you can with a sharp, wide scraper. DO NOT USE ANY AIR TOOL GASKET REMOVERS ETC. After I get the big chuny stuff off, I go over it with a fine grit flat stone in the sovent tank until I get all the gasket off both sides. Then knock in the pins again.
Cam bearings
Unless you have the tool, you may have to take this to the machinist or a mechanic buddy to do. If you spun a bearing, you're most likely going to need them. You'll get great oil pressure at the crank and rods... but low pressure to the heads. Your gauge won't read this, so better safe than sorry.
Freeze plugs you can inspect and leave, or replace them. If you are taking it in for cam bearings, have him slap them in.
Heads
They are cast iron heads.... not aluminum so warpage is not as big of an issue. Check again with the straightedge, then clean off the gasket. Unless you are using Multi-layered steel or copper gaskets, you'll be fine. Composite gaskets have a little more tolerance. Just make sure every surface is clean of grit, grime, and oil. If you want to replace the seals then you can move on. You can tear down the head yourself if you have a spring compressor (20 bucks from Sears or PepBoys. Takes less than a minute to compress, pull the locks, release and set the retainer and spring to the side. Before you go yanking valves out, slide a valve to the bottom of its travel above the seal and check for side play. If it doesn't feel or sound sloppy your guides aren't worn crazy. Pull the valves out and set them aside in order. Grab a big flathead and pop the old seals off. Use a valve seal installer which is basically a piece of pipe the size smaller than the seals body. Just put the valve in, the seals come with a little cap for the valve end to protect the seal, then slide the sea
If she spun a rod, you'll need to make sure the rod end hasn't been completely damaged from heat. You'll see blue around the chamfer. If there is no blue, you are ok to take it and all the rods to the machinist to have him recondition either the damaged rod, or all if you prefer. (usually about 20-25 a rod) Have them tank and clean each piston and rod combo, make sure you get them to clean the ring groves. A simple tanking will not clean it in most cases.
Depending on how long the engine was driven on the spun rod, you may not be able to turn the crank. In that case you'll need to get either a crank kit, or junk yard diving. Autozone has cranks and most times they dont dig too far into it for cores like that unless they are REALLY bad, or snapped in half. This will most likely be the most expensive part of the build generally 197-235 depending on where you go for it. If you spun a main, then you need to take the whole thing to the machinist and have him determine if it will need to be line honed, or worse.. line bored.
Block, many sections
Cylinder walls
Easy way is to look in the bore. If there are no gouges, can still see some crosshatch, and there is huge ridge on the top of the cylinder wall (not the carbon buildup, but metal height difference) 9 times out of ten, you can just run a flex hone in it and call it a day. 75 strokes each cylinder using flex hone oil. Done right you can't tell the difference from a machinist run tool (both give a plateau finish) If there are gouges from a broken piston, or scuffing from the skirts etc, then you need to get a bore/hone.
Deck
I use a flat machinist bar and feeler gaugeto check my decks. If the block is a closed deck design as it is in this case, they should be fine unless it overheated. Pull the guide pins from the corners and set them aside. Remove as much gasket material as you can with a sharp, wide scraper. DO NOT USE ANY AIR TOOL GASKET REMOVERS ETC. After I get the big chuny stuff off, I go over it with a fine grit flat stone in the sovent tank until I get all the gasket off both sides. Then knock in the pins again.
Cam bearings
Unless you have the tool, you may have to take this to the machinist or a mechanic buddy to do. If you spun a bearing, you're most likely going to need them. You'll get great oil pressure at the crank and rods... but low pressure to the heads. Your gauge won't read this, so better safe than sorry.
Freeze plugs you can inspect and leave, or replace them. If you are taking it in for cam bearings, have him slap them in.
Heads
They are cast iron heads.... not aluminum so warpage is not as big of an issue. Check again with the straightedge, then clean off the gasket. Unless you are using Multi-layered steel or copper gaskets, you'll be fine. Composite gaskets have a little more tolerance. Just make sure every surface is clean of grit, grime, and oil. If you want to replace the seals then you can move on. You can tear down the head yourself if you have a spring compressor (20 bucks from Sears or PepBoys. Takes less than a minute to compress, pull the locks, release and set the retainer and spring to the side. Before you go yanking valves out, slide a valve to the bottom of its travel above the seal and check for side play. If it doesn't feel or sound sloppy your guides aren't worn crazy. Pull the valves out and set them aside in order. Grab a big flathead and pop the old seals off. Use a valve seal installer which is basically a piece of pipe the size smaller than the seals body. Just put the valve in, the seals come with a little cap for the valve end to protect the seal, then slide the sea
#6
03-14-2008, 05:27 PM
RE: Flex Hone?
Great info guys. Thanks
I do have a few questions.
hand lap of the valves- can you explain that some more, I dont understand what you mean by Hand Lap.
Jimmyeatworld,
what about a new oil pump and timing chain?
I know it spun the #1 rod bearing. I tookthe oil pan off hoping it would swap to the '85 block, no go, the '85 is a two piece rear main seal. While I had the oil pan off I could move the piston around on the crank.I dont thinkthe crank bearings, cam bearing, or balance shaft bearings are bad, however the engine has 190,000 on her. How can I tell if those bearings are bad?
some more background. The last time Irebuilt an engine was in High School, back in '79-'80. I did it the once. I also have purchased a SBC Rebuild book that comes with the DVD with like 2 hours of info. As of right now I don't have a use for the engine. Although I will be looking for a off-raod truck again that it can go into.
I do have a few questions.
hand lap of the valves- can you explain that some more, I dont understand what you mean by Hand Lap.
Jimmyeatworld,
what about a new oil pump and timing chain?
I know it spun the #1 rod bearing. I tookthe oil pan off hoping it would swap to the '85 block, no go, the '85 is a two piece rear main seal. While I had the oil pan off I could move the piston around on the crank.I dont thinkthe crank bearings, cam bearing, or balance shaft bearings are bad, however the engine has 190,000 on her. How can I tell if those bearings are bad?
some more background. The last time Irebuilt an engine was in High School, back in '79-'80. I did it the once. I also have purchased a SBC Rebuild book that comes with the DVD with like 2 hours of info. As of right now I don't have a use for the engine. Although I will be looking for a off-raod truck again that it can go into.
#7
03-14-2008, 07:38 PM
RE: Flex Hone?
hand lap is just putting valve grind compund on the seat and angles and putting what looks like a suction stick and hand spinning the valve against the seat.
http://www.powrgrip.com/cgi-bin/powrgrip/V1275.html
The balance shaft front bearing is probably still good, the rear is mostly like a cam bearing. Mine had a few small scores in it, but it only gets oil... doesn't feed it anywhere, so I left it in.
http://www.powrgrip.com/cgi-bin/powrgrip/V1275.html
The balance shaft front bearing is probably still good, the rear is mostly like a cam bearing. Mine had a few small scores in it, but it only gets oil... doesn't feed it anywhere, so I left it in.
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