ENG BALANCE

[dwilfong]

I am starting to balance my eng and would like to here from those that have done this before.

There are two theories on eng balance that I am aware of.

The first is to measure the complete weight of the rotating Assembly and use a % of that

The second is to weight the bottom end of the Assembly and the top separate then take a % of the top and add this to the bottom.

I have bin weighing every thing now for a few days and trying the two different methods.

The first method the total weight I have bin using 52%

The second I have used 33% of the top and added that to the bottom.

Thy came out to the same #

I have two different eng that I am going to do. one is a one piece crank VAC and the second is my RS 1.01

Made some razor blade setups to put the crank on.

As I checked my 1.01 have found that I do not have to pull the crank apart. the rod and needle assy is less than 52% of the total.

Also the crank dose not need weight added it needs it removed from the counter balance.

Now this is with a heaver than stock billet piston.

As for the one piece crank it needs weight.

I got some tungsten from McMaster- Carr 1/4 size. when I measured it ,it came out to a perfect G size drill.

Drilled a old crank and it pressed right in.

Now as to the slugs.

Do thy have to be the full length of the hole you drill or can thy come up short to make the balance?

 

[Kevin Krogness]

David here is a older thread on the subject. http://www.intlwaters.com/index.php?showtopic=52483&hl=%2Bengine+%2Bbalance

 

[John Beardslee]

Hi David,

We used to also stake the slugs in the crank using a center punch in a few places on each side.

Thanks, John

 

[dwilfong]

Thanks Kevin i was looking for that.

I knew it was talked about be for.

Know that just added to my confusion on what to do. :blink:

I tried Jacks way and it came out 2 time heaver on the bob weight than the way I compromise on the other theories.

With Jakes way I need to add weight to the counter weight on the 1.01

NOW WHAT

I went thew the posts and there are 5 diffrent ways to skin a cat. :mellow:

 

[Joe Warren]

Thanks Kevin i was looking for that.

I knew it was talked about be for.

Know that just added to my confusion on what to do. :blink:

I tried Jacks way and it came out 2 time heaver on the bob weight than the way I compromise on the other theories.

With Jakes way I need to add weight to the counter weight on the 1.01

NOW WHAT

I went thew the posts and there are 5 diffrent ways to skin a cat. :mellow:

Dave you ever consider putting the engine in the Boat and figuring out the other million problems that the boat can occur?? How come you always trying to re-engineer the engine? others are winning races with the engine the way is comes...... just saying!! Move beyond the engine & come to the starting line with a running Boat & Engage into the Race & Finish.... p.s. I have a ole 900 Holly Double Pumper off a Chevy BB from the jet boat days if you want to mount it on the vac??

 

[Elias Vazquez]

p.s. I have a ole 900 Holly Double Pumper off a Chevy BB from the jet boat days if you want to mount it on the vac??

LOLLOLOLOL!!!!!...I almost fell off my chair laughing at this one...you guys crack me up!!

 

[dwilfong]

Joe I put my eng in my boat almost every weekend and test.

O and it dose win races. The only time I don't finish is when my driving sucks after a long Sat night at the bar.

Hard to run around the other boats as thy get in my way.

Thats one problem with a fast boat the closing speed is a killer.

Like having moving buoys to run around.

Trying to have a discussion on eng balance here not a pissing match.

If you have some thing constructive to say go for it if not please refrain from the commentary.

O And I don't need your Holly I made my own carb.

Why don't you ask Ralph how my boat runs. He has see it in action a few time at the races in Brandon.

As far as the million problems thy are mostly all figured out.

I don't race for bragging right and prove to the world I am the master of the toy boat.

I just race to have fun.

 

[DON MAHER]

David,

If you have not talked to Scott Bouchie about your balance ideas, you should!

Don

 

[Mark Bullard]

Here we go again. These things just keep popping up every so often.

Ok set up for a crankshaft to be balance either by static or dynamic is a 60% of the rod/pistion/wrisit pin weight. What this means is that 60% of that weight is placed onto the crankpin for balance. So from there we can static balance the crank by adding or removing weight until the crank is static in any position we place it. This will be the best we can do as for we cannot aford to buy a machine that will dynamic balance the crank. I have two hard bearing dynamic balancing machines. The price tag on these machines are a total of $175,000.00. One machine handles up to 15000lbs and the other up to 200lbs. A machine to do our cranks would be about $20,000.00. But would be the best to balance with.

Most of our motors are pretty good but I hear that the VAC 45 has some balance problems. The 101 has the best balance that I have seen and would not even try to balance it because you would have to disassemable the crank to weight the parts and make a bob to install for balance and then reassemable for balance then disassemable then reassemble. I don't think so.

I have been hearing about 55%, 58% and other numbers. These numbers come from the fact that you can not get slugs to come out to a perfect balance. But you can get close and then grind from places to bring the crank to a perfect balance. But this may not be able to be done.

 

[dave roach]

You can't balance a single cly engine.

Dave Roach

 

[Joe Warren]

Joe I put my eng in my boat almost every weekend and test.

O and it dose win races. The only time I don't finish is when my driving sucks after a long Sat night at the bar.

Hard to run around the other boats as thy get in my way.

Thats one problem with a fast boat the closing speed is a killer.

Like having moving buoys to run around.

Trying to have a discussion on eng balance here not a pissing match.

If you have some thing constructive to say go for it if not please refrain from the commentary.

O And I don't need your Holly I made my own carb.

Why don't you ask Ralph how my boat runs. He has see it in action a few time at the races in Brandon.

As far as the million problems thy are mostly all figured out.

I don't race for bragging right and prove to the world I am the master of the toy boat.

I just race to have fun.

Somedays I`am just Glad mine will start. The Only MASTER of Toy Boats I ever knew said... YOU WILL NEVER BECOME RICH AND FAMOUS AT THE SAME TIME ................. RACING TOY BOATS!!!

 

[dwilfong]

Joe I put my eng in my boat almost every weekend and test.

O and it dose win races. The only time I don't finish is when my driving sucks after a long Sat night at the bar.

Hard to run around the other boats as thy get in my way.

Thats one problem with a fast boat the closing speed is a killer.

Like having moving buoys to run around.

Trying to have a discussion on eng balance here not a pissing match.

If you have some thing constructive to say go for it if not please refrain from the commentary.

O And I don't need your Holly I made my own carb.

Why don't you ask Ralph how my boat runs. He has see it in action a few time at the races in Brandon.

As far as the million problems thy are mostly all figured out.

I don't race for bragging right and prove to the world I am the master of the toy boat.

I just race to have fun.

Somedays I`am just Glad mine will start. The Only MASTER of Toy BoatS I ever knew said... YOU WILL NEVER BECOME RICH AND FAMOUS AT THE SAME TIME ................. RACING TOY BOATS!!!

So true Joe.Sorry I was so abrupt with my reply.

Just have bin spending to much time on this new setup and I am a little frustrated.

That 100mph wall for a heat race boat is a bastard.

Never thought that last few MPH would be so hard and still keep the boat on the water in race conditions.

This TOY BOAT ain't going to kick my ass.

Mark thanks for the input. I know you can not balance a 1 cyl eng.

A compromise is the best we can do.

 

[Albert Araujo]

Joe I put my eng in my boat almost every weekend and test.

O and it dose win races. The only time I don't finish is when my driving sucks after a long Sat night at the bar.

Hard to run around the other boats as thy get in my way.

Thats one problem with a fast boat the closing speed is a killer.

Like having moving buoys to run around.

Trying to have a discussion on eng balance here not a pissing match.

If you have some thing constructive to say go for it if not please refrain from the commentary.

O And I don't need your Holly I made my own carb.

Why don't you ask Ralph how my boat runs. He has see it in action a few time at the races in Brandon.

As far as the million problems thy are mostly all figured out.

I don't race for bragging right and prove to the world I am the master of the toy boat.

I just race to have fun.

Somedays I`am just Glad mine will start. The Only MASTER of Toy BoatS I ever knew said... YOU WILL NEVER BECOME RICH AND FAMOUS AT THE SAME TIME ................. RACING TOY BOATS!!!

So true Joe.Sorry I was so abrupt with my reply.

Just have bin spending to much time on this new setup and I am a little frustrated.

That 100mph wall for a heat race boat is a bastard.

Never thought that last few MPH would be so hard and still keep the boat on the water in race conditions.

This TOY BOAT ain't going to kick my ass.

Mark thanks for the input. I know you can not balance a 1 cyl eng.

A compromise is the best we can do.

David, 90+ in lanes one to three and reliable is almost impossible to beat. That's good enough for me as far as heat racing goes.

See ya

 

[stan simpson iv]

I'd be happy with 80+ "in heat racing" ...

 

[Albert Araujo]

Ok guys,

Save yourself a ton of aggravation and call Scott Bouchie. I recently had all my cranks balanced and slugged by him and they came out AWESOME! His work is second to none and the price is more than fair. By the time you buy what you need and do it yourself you will end up spending five times what he charges.

This is a no brainer so just call him and get it done.

 

[Albert Araujo]

BTW, every time I look at my twin in that Avatar picture I get a woody. :0)

I know i'm either running away from Joe and Ralph or trying to lap them. HAHAHAHAHA!

 

[dwilfong]

So true Albert !!!!!!!! Scott dose great work. He is the one that got me started on balancing my eng ordeal.

Stan come on you where keeping up pretty good at the last race.

 

[Jeff Lutz]

So true Albert !!!!!!!! Scott dose great work. He is the one that got me started on balancing my eng ordeal.

Stan come on you where keeping up pretty good at the last race.

David, no matter what percent balance you put on the 101, loctite the front bearing housing to the case with red loctite. It will make it more rigid. I know it makes it a pain taking it apart, but will help out the engine at speed. Take a good look at your bearing housing and case face and you will see the movement from flexing on the faces. On the old 100 s I use to balance my cranks, I'm about to try the percentage I use to run on the old motors on the 101's with some custom pistons.

 

[dwilfong]

Jeff I just changed the bearings and did notice what you are talking about. I checked the front bearing and it tightened up some but no rumble. swapped it out and got the end play back.

I have checked the balance on the 1.01 and found with the billet piston it is real close. with the stock piston you need to take some off the crank.

This is using 52% of the rotating mass equation. The vibrations are much less with the heaver piston when running on the bench.

It is spooling up real nice and nothing is breaking any more.

 

[Norm Doerr]

100 MPH Heat racing boat... From what I have seen you have the power, LOTS of power. Maybe look at the boat? The thing looks like a Fuel Altered drag race car, (overpowered).

Just sayin