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Internal Balancing?

Old 01-19-2003, 10:37 AM
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Default Internal Balancing?

Internal.....external whats the differance?could someone explain the process in balancing a rotating assembly???
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Old 01-19-2003, 10:52 AM
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Hello, Dyno!!
The difference bertween internal and external balancing is the internal balanced engine uses a flywheel and harmonic damper that are neytral balanced. That is, if you spin them, they will run smoothly with not vibration or bounce. The external balance units have offset weights that will make them shake and vibrate if spun independently. OEM 4" stroke and bigger cranks have a weight on the flywheel and damper. They must be used on the crank they were made for, and, if you balance a rotating assembly, they become unique to that assembly.
If you internally balance, the flywheel and damper are neutral balanaced. You can use these on any internally balanced assembly and you don't have to place the flywheel in any certain position. This makes race assemblies easier to work with.
It also means the ends of the crankshafts are not subjected to the forces of the out of balance pieces on each end.
Neutral balance on the cranks that are normally externally balanced usually requires the use of "Mallory Metal" or Tungsten or some other metal denser than the crank metal. This is done by drilling holes in the bob weights of the crank and filling them with the heavy metal. Done correctly, this makes a stronger, longer lasting engine. The higher the rpm, the more important this is. A boat engine at 3500 can do without internal balancing and if you go to 5000+ only once in a while, you can get by OK.
I know not many of you run your boats very hard but a few will run them as hard as you can You guys need internal balancing

Last edited by blown1500; 01-19-2003 at 11:07 AM.
 
Old 01-19-2003, 09:25 PM
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Sorry about messing up your thread dyno, some guys just think other peoples work ethics are wrong.



Travis

Last edited by traviss; 01-20-2003 at 06:26 PM.
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Old 01-20-2003, 09:04 AM
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traviss
If ANY balance shop asks for ONE PISTON AND ONE ROD, you need to load up your stuff and never darken that dooragain
Each piston and wristpin MUST be weighed and equalized!! You wouldn't expect it, but pins can be very different in weight, even on high dollar stuff(JE, Ross, Weisco-----) and pistons can be off also. Rod BOLTS can be several grams different, not to mention the rods!!
Pin locks, rings, and bearings-I can see them needing only one cylinder set of each as these are pretty consistent. the other parts you mentioned are needed. Also, anything that goes around with the crank should be included-ie. clutch cover, drive hubs, etc. whenever possible.
 
Old 01-20-2003, 09:58 AM
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Originally posted by blown1500
traviss
If ANY balance shop asks for ONE PISTON AND ONE ROD, you need to load up your stuff and never darken that dooragain
Each piston and wristpin MUST be weighed and equalized!! You wouldn't expect it, but pins can be very different in weight, even on high dollar stuff(JE, Ross, Weisco-----) and pistons can be off also. Rod BOLTS can be several grams different, not to mention the rods!!
Pin locks, rings, and bearings-I can see them needing only one cylinder set of each as these are pretty consistent. the other parts you mentioned are needed. Also, anything that goes around with the crank should be included-ie. clutch cover, drive hubs, etc. whenever possible.
Agreed..............You need to get all of the stuff (per cylinder stuff - Piston, PIN, Bearings, Rings, etc, to within whatever the tolerance is - most likely within a couple of grams). When I received my Pistons / pins, etc, I was given the weights. Each set of pistons was within 1.5 Grams (variation). I checked them (myself), and there were always within 0.1 g of what was marked on them. The pins were the same way. I gave the rods to the shop who balanced my assy's, and they also said they were within 1.5 grams of what was marked.

A good shop will also include a certain amount (I think maybe 5 grams or so) for the oil that resides on the assy.

Also, if you need to change your Pins on the rebuild, you need to check that, especially if changing Pin manufacturers.

Dyno - I don't recall where you're from, but if you're on the east side of the state, check out diamond.

http://www.diamondracing.net/
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Old 01-20-2003, 10:45 AM
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Thanks, Ratchet,
I am in the Charlotte area. If you get good parts, they usually are close but you never know and you need to check!!! Need more info on Diamond-location or ##.
Thanks a lot
 
Old 01-20-2003, 06:17 PM
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Yep, Travis, 35 years ago, we knew better than that!!
There weren"t too many shops around here that balanced back then. Holman Moody was one. They did my work then and I had to bring EVERYTHING that went on the rotating assembly-all bearings, all rings, all pistons, rods..............
The best shop I know of now is Hendrick Motorsports. They weigh the air around each part!!!!!
They allow for deposite buildup-which is practically nothing. If you bring them one piston and rod, they will laugh you out of the county
 
Old 01-20-2003, 09:17 PM
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Originally posted by blown1500
Thanks, Ratchet,
I am in the Charlotte area. If you get good parts, they usually are close but you never know and you need to check!!! Need more info on Diamond-location or ##.
Thanks a lot
No problem............

They are located in Mt Clemens, Michigan. On their website, they have a toll free # 877.552.2112 I forgot the direct number. What I did when I had mine balanced was give them the average weight (with everything being within a range of 1.5 grams, I felt this was sufficient).

The guy you'll most likely talk to is Ron.

It's hard to find someone you can trust, especially when you have a lot of coin wrapped up in something, but so far, I haven't heard of anyone using them that's had bad luck with them. I have nothing to gain by giving them my recommendation, it's just cool to be able to pass on something good every now and then, instead of having to start out a post by saying "I got screwed when..........." As with anything, who knows these days though.

Give them a call, I'm sure they'll send you a brochure & price list.

If you need anything else, feel free to PM me.
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Old 01-20-2003, 09:26 PM
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I agree! Everything within the entire rotating assembly needs to be weighed and balanced---it's the smarter way of balancing and internal balancing is wiser yet.

Last edited by KAAMA; 01-20-2003 at 09:29 PM.
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Old 01-21-2003, 08:15 AM
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Hello, Guys,
Hello, Travis,
There are a lot of machine shops around the Charlotte, NC area.
There are several good ones. There are a lot of shops like the one you described. Some think they know what they are doing. One told me, when I asked how he checked piston to wall clearance on a bore job he said "I bore it untill it feels right. It's just going to break anyway" That man had many loyal followers who to this day swear by his work. I checked a few of his machining jobs and found them horrific to me. I no longer will take a job that is done by the shops I know do poor work. If I check one and find too many or too bad an error, I stop. The purpose of this forum is to help you guys make a better boat, engine, what ever. I am often wrong, but I try to learn from my mistakes. I have learned a lot from you guys and I really appreciate it. If you thought the shop you mentioned did good work, you will be much happier with a good shop. Numbers and engineering facts don't lie. If someone tells you they think 2+2=3. and you had not been taught otherwise, you might believe them. Somewhere, sometime, someone figured out that 2+2=4. We are still trying to figure engines out, but the knowledge is increasing every day. I want to be on the leading edge. I want you guys to be there too. I have seen too many unsuccesful projects caused by shoddy or uneducated procedures and theories. I have been a victim of this, from others AND from myself. I would like to think we all want to improve anything we do.
I talked to a friend yesterday that does work for Rick Hendrick of Hendrick Motorsports. He has built and dynoed almost anything you can think of-Winston Cup, Craftsman Truck.......
Now he is Rick's personal "mechanic" He says a boat is the hardest of all to make succesful!! Rick is a boat nut and so is his son, Ricky. My friend says he is trying to figure boat engines out and learns every day.
Have a great day

Last edited by blown1500; 01-21-2003 at 08:26 AM.
 

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