---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Sun 03/19/06: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:20 AM - Re: Connecting rod/bolt balancing questions (Gary Casey) 2. 08:51 AM - Re: Connecting rod/bolt balancing questions (gary.stiffler@kroger.com) 3. 10:18 AM - Re: Re: Connecting rod/bolt balancing questions (Hopperdhh@aol.com) 4. 11:45 AM - Re: Re: Connecting rod/bolt balancing questions (Hopperdhh@aol.com) 5. 12:06 PM - Re: Re: Connecting rod/bolt balancing questions (Archie) 6. 12:29 PM - Re: Re: Connecting rod/bolt balancing questions (Hopperdhh@aol.com) 7. 12:40 PM - carburated -> fuel injected (rd2@evenlink.com) 8. 01:11 PM - Re: carburated -> fuel injected (Konrad L. Werner) 9. 02:24 PM - Re: carburated -> fuel injected (rd2@evenlink.com) 10. 04:31 PM - Re: Re: Connecting rod/bolt balancing questions (Ed Chmielewski) 11. 09:48 PM - Re: carburated -> fuel injected (Konrad L. Werner) ________________________________ Message 1 _____________________________________ Time: 05:20:03 AM PST US From: Gary Casey Subject: Engines-List: Re: Connecting rod/bolt balancing questions --> Engines-List message posted by: Gary Casey I'll cautiously take what is probably the unpopular side of the discussion.. I don't understand the emphasis that gets placed on engine balancing. These engines run relatively slowly and the perceived vibration in airframe is usually dominated by the propeller. The propeller imparts vibration from a number of sources - one is its balance - the blades are at such a large radius that the slightest variation will result in more vibration than can be expected by the rotating parts of the engine. Second is the pitch variation from blade to blade. Again, the slightest pitch error operating at such a long lever arm will have a big effect on airframe vibration. finally, the airflow into the prop is not uniform around the circumference since it is affected by the airframe behind it as well as the mounting angle of the engine. The balance of either the reciprocating or rotating parts will have essentially no effect on the durability or output of the engine - combustion loads overwhelm any possible mismatch in weights. A couple of anecdotes that add evidence, but of course don't prove the point - a friend used to win drag races by building "dual displacement" engines - the inspectors would always check the displacement of the #1 cylinder so he would make the first crank throw a shorter stroke than the other three - engines ran great. I while back I helped one of my teenagers rebuild his turbo Chrysler 4- banger. He didn't have any money so we scrounged the parts and picked the best of the bunch to build the engine. Some cylinders had different connecting rods than others (a LOT different), others had different compression ratios. Ran smooth with good power for a long time after that. Another anecdote (urban legend?) - when Continental was trying to beef up their engines they introduced pistons with iron top ring glands, certainly heavier than the all-aluminum pistons they replaced. They approved servicing a single cylinder with the new pistons even though it would upset the balance - at least they didn't think the balance issue was a big one. Using what Continental does as the guideline is, of course, a risky thing. Certainly no one can argue that poor balance is a good thing, but I just don't think the emphasis that seems to be put on balancing is justified. What would I do? Certainly pick the rod bolts that are supposed to be the most reliable (whichever one that is) regardless of weight. I would match up the other parts the best I could with the tools I had and then I would bolt it together and go fly. Just another irreverent comment - a "good" aircraft engine will put out about 200 hp from 360 cu. in. displacement, or 1.08 ft-lb per cu. in. torque, and they are rated at the minimum power, not the average of the population. That is very good and very close to what a good automotive engine will produce. It is compromised because of the compromises necessary to meet all the other requirements: The idea is to build an engine that weighs the least, burns the least fuel, is the most reliable and lasts the longest while being built for the least cost. If I were starting from scratch there would be some things I would change, but it wouldn't deviate a lot from the norm. Gary Casey > > I am in the middle of overhauling a Lycoming IO-360-A1A for my > RV-7A. It > has come to my attention that there are 2 different rod bolts that > will work in > .... > Speaking of engine balance, what is considered good enough? Is 6 > grams at > the big end of the rods really bad, or good, or what? It looks > like I have > about 3 grams worst case on the recip end. The crank is good > (under 1 gram), > > and the piston/pins are only a couple of tenths apart. > > Thanks, > > Dan Hopper > Walton, IN > RV-7A N766DH Flying 144 hours. ________________________________ Message 2 _____________________________________ Time: 08:51:22 AM PST US Subject: Re: Engines-List: Connecting rod/bolt balancing questions Cc: From: gary.stiffler@kroger.com --> Engines-List message posted by: gary.stiffler@kroger.com >The factory recommends 1/2 ounce? >Well, keep in mind these are the same people that give us oil burners, >AD's on an engine that has not changed for over 60 years, 1/2 hp per cu. in. >And they still do not have it right. >They essentially have a captive following that buys this. >If they did not have that, they would have folded long ago. They have the same design and a captive following because the FAA along with our legal system makes competition unprofitable. Gary AA1B 160 Cincinnati OH ________________________________ Message 3 _____________________________________ Time: 10:18:17 AM PST US From: Hopperdhh@aol.com Subject: Re: Engines-List: Re: Connecting rod/bolt balancing questions --> Engines-List message posted by: Hopperdhh@aol.com Good points Gary, You got me to thinking! I'm an engineer, I ought to be able to figure this out! (Never mind that I'm an electrical engineer!) I calculated the imbalance force due to 3 grams at 2.177 inches (1/2 the stroke of an IO-360) at 2700 RPM to be 2.98 pounds. This is the centrifugal force which would cause the engine to vibrate. This comes from P=mv 2/r (from my college physics book) after making all the conversions to metric and back. Now, if I'm cruising at 2300 rpm at 60 percent of 200 HP, the average force which must be exerted on the crank throw at 2.177 inches is 1510 pounds. (In a 4 cylinder there is a power stroke every 180 degrees.) Actually the pulses probably go to 2 or 3 times this number. This pulsing is what makes the engine vibrate, or shake. Your point is well taken. Dan Hopper RV-7A In a message dated 3/19/2006 8:21:19 A.M. Eastern Standard Time, glcasey@adelphia.net writes: --> Engines-List message posted by: Gary Casey I'll cautiously take what is probably the unpopular side of the discussion.. I don't understand the emphasis that gets placed on engine balancing. These engines run relatively slowly and the perceived vibration in airframe is usually dominated by the propeller. The propeller imparts vibration from a number of sources - one is its balance - the blades are at such a large radius that the slightest variation will result in more vibration than can be expected by the rotating parts of the engine. Second is the pitch variation from blade to blade. Again, the slightest pitch error operating at such a long lever arm will have a big effect on airframe vibration. finally, the airflow into the prop is not uniform around the circumference since it is affected by the airframe behind it as well as the mounting angle of the engine. The balance of either the reciprocating or rotating parts will have essentially no effect on the durability or output of the engine - combustion loads overwhelm any possible mismatch in weights. A couple of anecdotes that add evidence, but of course don't prove the point - a friend used to win drag races by building "dual displacement" engines - the inspectors would always check the displacement of the #1 cylinder so he would make the first crank throw a shorter stroke than the other three - engines ran great. I while back I helped one of my teenagers rebuild his turbo Chrysler 4- banger. He didn't have any money so we scrounged the parts and picked the best of the bunch to build the engine. Some cylinders had different connecting rods than others (a LOT different), others had different compression ratios. Ran smooth with good power for a long time after that. Another anecdote (urban legend?) - when Continental was trying to beef up their engines they introduced pistons with iron top ring glands, certainly heavier than the all-aluminum pistons they replaced. They approved servicing a single cylinder with the new pistons even though it would upset the balance - at least they didn't think the balance issue was a big one. Using what Continental does as the guideline is, of course, a risky thing. Certainly no one can argue that poor balance is a good thing, but I just don't think the emphasis that seems to be put on balancing is justified. What would I do? Certainly pick the rod bolts that are supposed to be the most reliable (whichever one that is) regardless of weight. I would match up the other parts the best I could with the tools I had and then I would bolt it together and go fly. Just another irreverent comment - a "good" aircraft engine will put out about 200 hp from 360 cu. in. displacement, or 1.08 ft-lb per cu. in. torque, and they are rated at the minimum power, not the average of the population. That is very good and very close to what a good automotive engine will produce. It is compromised because of the compromises necessary to meet all the other requirements: The idea is to build an engine that weighs the least, burns the least fuel, is the most reliable and lasts the longest while being built for the least cost. If I were starting from scratch there would be some things I would change, but it wouldn't deviate a lot from the norm. Gary Casey > > I am in the middle of overhauling a Lycoming IO-360-A1A for my > RV-7A. It > has come to my attention that there are 2 different rod bolts that > will work in > .... > Speaking of engine balance, what is considered good enough? Is 6 > grams at > the big end of the rods really bad, or good, or what? It looks > like I have > about 3 grams worst case on the recip end. The crank is good > (under 1 gram), > > and the piston/pins are only a couple of tenths apart. > > Thanks, > > Dan Hopper > Walton, IN > RV-7A N766DH Flying 144 hours. ________________________________ Message 4 _____________________________________ Time: 11:45:26 AM PST US From: Hopperdhh@aol.com Subject: Re: Engines-List: Re: Connecting rod/bolt balancing questions --> Engines-List message posted by: Hopperdhh@aol.com When I read my listing as it came over the internet, I see that the carat symbol was deleted making it seem that I got the formula for centrifugal force wrong. I'll spell it out: centrifugal force equals mass times velocity squared divided by radius. Dan In a message dated 3/19/2006 1:19:22 P.M. Eastern Standard Time, Hopperdhh@aol.com writes: --> Engines-List message posted by: Hopperdhh@aol.com Good points Gary, You got me to thinking! I'm an engineer, I ought to be able to figure this out! (Never mind that I'm an electrical engineer!) I calculated the imbalance force due to 3 grams at 2.177 inches (1/2 the stroke of an IO-360) at 2700 RPM to be 2.98 pounds. This is the centrifugal force which would cause the engine to vibrate. This comes from P=mv 2/r (from my college physics book) after making all the conversions to metric and back. Now, if I'm cruising at 2300 rpm at 60 percent of 200 HP, the average force which must be exerted on the crank throw at 2.177 inches is 1510 pounds. (In a 4 cylinder there is a power stroke every 180 degrees.) Actually the pulses probably go to 2 or 3 times this number. This pulsing is what makes the engine vibrate, or shake. Your point is well taken. Dan Hopper RV-7A In a message dated 3/19/2006 8:21:19 A.M. Eastern Standard Time, glcasey@adelphia.net writes: --> Engines-List message posted by: Gary Casey I'll cautiously take what is probably the unpopular side of the discussion.. I don't understand the emphasis that gets placed on engine balancing. These engines run relatively slowly and the perceived vibration in airframe is usually dominated by the propeller. The propeller imparts vibration from a number of sources - one is its balance - the blades are at such a large radius that the slightest variation will result in more vibration than can be expected by the rotating parts of the engine. Second is the pitch variation from blade to blade. Again, the slightest pitch error operating at such a long lever arm will have a big effect on airframe vibration. finally, the airflow into the prop is not uniform around the circumference since it is affected by the airframe behind it as well as the mounting angle of the engine. The balance of either the reciprocating or rotating parts will have essentially no effect on the durability or output of the engine - combustion loads overwhelm any possible mismatch in weights. A couple of anecdotes that add evidence, but of course don't prove the point - a friend used to win drag races by building "dual displacement" engines - the inspectors would always check the displacement of the #1 cylinder so he would make the first crank throw a shorter stroke than the other three - engines ran great. I while back I helped one of my teenagers rebuild his turbo Chrysler 4- banger. He didn't have any money so we scrounged the parts and picked the best of the bunch to build the engine. Some cylinders had different connecting rods than others (a LOT different), others had different compression ratios. Ran smooth with good power for a long time after that. Another anecdote (urban legend?) - when Continental was trying to beef up their engines they introduced pistons with iron top ring glands, certainly heavier than the all-aluminum pistons they replaced. They approved servicing a single cylinder with the new pistons even though it would upset the balance - at least they didn't think the balance issue was a big one. Using what Continental does as the guideline is, of course, a risky thing. Certainly no one can argue that poor balance is a good thing, but I just don't think the emphasis that seems to be put on balancing is justified. What would I do? Certainly pick the rod bolts that are supposed to be the most reliable (whichever one that is) regardless of weight. I would match up the other parts the best I could with the tools I had and then I would bolt it together and go fly. Just another irreverent comment - a "good" aircraft engine will put out about 200 hp from 360 cu. in. displacement, or 1.08 ft-lb per cu. in. torque, and they are rated at the minimum power, not the average of the population. That is very good and very close to what a good automotive engine will produce. It is compromised because of the compromises necessary to meet all the other requirements: The idea is to build an engine that weighs the least, burns the least fuel, is the most reliable and lasts the longest while being built for the least cost. If I were starting from scratch there would be some things I would change, but it wouldn't deviate a lot from the norm. Gary Casey > > I am in the middle of overhauling a Lycoming IO-360-A1A for my > RV-7A. It > has come to my attention that there are 2 different rod bolts that > will work in > .... > Speaking of engine balance, what is considered good enough? Is 6 > grams at > the big end of the rods really bad, or good, or what? It looks > like I have > about 3 grams worst case on the recip end. The crank is good > (under 1 gram), > > and the piston/pins are only a couple of tenths apart. > > Thanks, > > Dan Hopper > Walton, IN > RV-7A N766DH Flying 144 hours. ________________________________ Message 5 _____________________________________ Time: 12:06:06 PM PST US From: "Archie" Subject: Re: Engines-List: Re: Connecting rod/bolt balancing questions --> Engines-List message posted by: "Archie" Gentlemen; This topic is far more complex than you believe. I will not go into the finer details, but you are superficially bouncing numbers and quotes but not doing any correcting. "good enough" is not good enough, "perfect" is. Although not analogous, would you want a heart surgeon telling you: "while I am in there, will do the least required" When teaching machinery dynamics as part of my physics course, the text was Machinery Dynamics by Holowenko.Check it out, and be surprised. As far as durability is concerned, how long do you think an electric motor's bearings will last if it was not in balance, or your aircraft gyro. Forget RPM, it is either right or wrong, although geometrically progressive. Vibration was mentioned. That is only a resultant indicator. A number of factors can cause vibration, such as compression imbalance. (just pull a spark plug lead while an engine is running) Many other causes are culprits also, but too involved to discuss here. If you are not going to do a perfect dynamic and kinematic balance to your engine, why seek a way to avoid it? No more from here....... Archie ________________________________ Message 6 _____________________________________ Time: 12:29:45 PM PST US From: Hopperdhh@aol.com Subject: Re: Engines-List: Re: Connecting rod/bolt balancing questions --> Engines-List message posted by: Hopperdhh@aol.com Archie, Is this subject so complex that only you can understand it? You asked several questions in your post, but you are not interested in the answers. First of all, what is your definition of perfect? It must be the accuracy or resolution of your equipment. Apparently your scales only weigh to .01 grams. What if I needed my rods balanced to .001 grams, isn't that closer to perfect than what you could handle? Good enough is not perfect and neither is your work. You are very naive if you think anything in this world is perfect. There is a very good reason why Lycoming has built thousands of engines which were terribly out of balance yet give perfectly (ha) satisfactory service in the field. That reason is that they don't need to be perfect, only good enough. Dan In a message dated 3/19/2006 3:06:47 P.M. Eastern Standard Time, archie97@earthlink.net writes: --> Engines-List message posted by: "Archie" Gentlemen; This topic is far more complex than you believe. I will not go into the finer details, but you are superficially bouncing numbers and quotes but not doing any correcting. "good enough" is not good enough, "perfect" is. Although not analogous, would you want a heart surgeon telling you: "while I am in there, will do the least required" When teaching machinery dynamics as part of my physics course, the text was Machinery Dynamics by Holowenko.Check it out, and be surprised. As far as durability is concerned, how long do you think an electric motor's bearings will last if it was not in balance, or your aircraft gyro. Forget RPM, it is either right or wrong, although geometrically progressive. Vibration was mentioned. That is only a resultant indicator. A number of factors can cause vibration, such as compression imbalance. (just pull a spark plug lead while an engine is running) Many other causes are culprits also, but too involved to discuss here. If you are not going to do a perfect dynamic and kinematic balance to your engine, why seek a way to avoid it? No more from here....... Archie ________________________________ Message 7 _____________________________________ Time: 12:40:49 PM PST US From: rd2@evenlink.com Subject: Engines-List: carburated -> fuel injected --> Engines-List message posted by: rd2@evenlink.com Hello listers, I was wondering, can a carburated Lycoming O-360-A4M 180 HP Penn Yan conversion be converted to fuel injected? I understand most cylinders have bosses for fuel injectors (plugged on the carbureted models). Not sure if our engine has such bosses and how to check. Thanks for any pointers. Rumen ________________________________ Message 8 _____________________________________ Time: 01:11:25 PM PST US From: "Konrad L. Werner" Subject: Re: Engines-List: carburated -> fuel injected --> Engines-List message posted by: "Konrad L. Werner" Rumen, Yes, you should be able to convert the -A4M to Fuel Injection. Look at a cylinder around the intake port. You should see two plugs there. The upper plug is where you would put in the Fuel Injector for that cylinder. Perhaps one or more of your cylinders may have a primer nozzle installed in the lower port of any given cylinder? Good Luck, Konrad ----- Original Message ----- From: rd2@evenlink.com To: engines-list@matronics.com Sent: Sunday, March 19, 2006 1:35 PM Subject: Engines-List: carburated -> fuel injected --> Engines-List message posted by: rd2@evenlink.com Hello listers, I was wondering, can a carburated Lycoming O-360-A4M 180 HP Penn Yan conversion be converted to fuel injected? I understand most cylinders have bosses for fuel injectors (plugged on the carbureted models). Not sure if our engine has such bosses and how to check. Thanks for any pointers. Rumen -- ________________________________ Message 9 _____________________________________ Time: 02:24:03 PM PST US From: rd2@evenlink.com Subject: Re: Engines-List: carburated -> fuel injected --> Engines-List message posted by: rd2@evenlink.com Thanks, Konrad. I am told there are no such STC's on file (so we could look up what components are needed), so how do we assemble a list of needed components (besides the injectors)? _____________________Original message __________________________ (received from Konrad L. Werner; Date: 02:10 PM 3/19/2006 -0700) --> Engines-List message posted by: "Konrad L. Werner" Rumen, Yes, you should be able to convert the -A4M to Fuel Injection. Look at a cylinder around the intake port. You should see two plugs there. The upper plug is where you would put in the Fuel Injector for that cylinder. Perhaps one or more of your cylinders may have a primer nozzle installed in the lower port of any given cylinder? Good Luck, Konrad ----- Original Message ----- From: rd2@evenlink.com To: engines-list@matronics.com Sent: Sunday, March 19, 2006 1:35 PM Subject: Engines-List: carburated -> fuel injected --> Engines-List message posted by: rd2@evenlink.com Hello listers, I was wondering, can a carburated Lycoming O-360-A4M 180 HP Penn Yan conversion be converted to fuel injected? I understand most cylinders have bosses for fuel injectors (plugged on the carbureted models). Not sure if our engine has such bosses and how to check. Thanks for any pointers. Rumen ________________________________ Message 10 ____________________________________ Time: 04:31:31 PM PST US From: "Ed Chmielewski" Subject: Re: Engines-List: Re: Connecting rod/bolt balancing questions --> Engines-List message posted by: "Ed Chmielewski" Hmm, this should be good . Think I'll grab a beer and watch... Ed in JXN ----- Original Message ----- From: Sent: Sunday, March 19, 2006 3:27 PM Subject: Re: Engines-List: Re: Connecting rod/bolt balancing questions > --> Engines-List message posted by: Hopperdhh@aol.com > > > Archie, > > Is this subject so complex that only you can understand it? You asked > several questions in your post, but you are not interested in the answers. ________________________________ Message 11 ____________________________________ Time: 09:48:36 PM PST US From: "Konrad L. Werner" Subject: Re: Engines-List: carburated -> fuel injected --> Engines-List message posted by: "Konrad L. Werner" STC??? It is for an experimental aircraft, or is it not? If not then I do not have an answer for you. But if it is for an experimental, then you may contact Airflow Performance for their fine system (...or any of the major engine builders for their opinion on what parts are necessary to make it happen). Good Luck, Konrad Do not archive ----- Original Message ----- From: rd2@evenlink.com To: engines-list@matronics.com Sent: Sunday, March 19, 2006 3:16 PM Subject: Re: Engines-List: carburated -> fuel injected --> Engines-List message posted by: rd2@evenlink.com Thanks, Konrad. I am told there are no such STC's on file (so we could look up what components are needed), so how do we assemble a list of needed components (besides the injectors)? _____________________Original message __________________________ (received from Konrad L. Werner; Date: 02:10 PM 3/19/2006 -0700) --> Engines-List message posted by: "Konrad L. Werner" Rumen, Yes, you should be able to convert the -A4M to Fuel Injection. Look at a cylinder around the intake port. You should see two plugs there. The upper plug is where you would put in the Fuel Injector for that cylinder. Perhaps one or more of your cylinders may have a primer nozzle installed in the lower port of any given cylinder? Good Luck, Konrad ----- Original Message ----- From: rd2@evenlink.com To: engines-list@matronics.com Sent: Sunday, March 19, 2006 1:35 PM Subject: Engines-List: carburated -> fuel injected --> Engines-List message posted by: rd2@evenlink.com Hello listers, I was wondering, can a carburated Lycoming O-360-A4M 180 HP Penn Yan conversion be converted to fuel injected? I understand most cylinders have bosses for fuel injectors (plugged on the carbureted models). Not sure if our engine has such bosses and how to check. Thanks for any pointers. Rumen --