Waterhorse machinging again

[WaterH]

So I decided to make a dynamic balancer for my 4BT. They make one for the marine versions that is suppose to smooth out the engine. I don’t have a problem with vibrations, but mine seems to eat belts. I’m thinking it is the pulses from a powerful 4 cylinder turning slow.

Anyways the one Cummins makes for it is basically a 30 lb. Chunk of iron that costs $3,000+. I think I can hack something up for that. First I needed a spacer to get the weight out from the pulley. I had a scrap chunk of 3 1/2” round stock I turned on the lathe and drilled some accurate holes on the mill. (Don’t you love digital readouts for hole patterns?)

I needed a big thick disc on this and first I thought of a disc brake. But I read you aren’t suppose to weld on them, so I thought I would get some mild steel plate from the scrapyard. I really wanted one inch thick plate, but I couldn’t find any at the yard that wasn’t a 1000 lb. So I ended up getting some 1/2” plate. I figure I’ll just stack it to get the weight. I took the plate and put it on my CNC plasma cutter and cut two perfectly round discs.

Drilled some holes and bolted on a suitable lathe holder.

Mounted in the lathe ready to make chips.

After some quality time I had two discs and my dog had sore feet. (How do you keep your dog out of the shop?)

The plan was to bore a big hole in the plates to insert the spacer and weld it together. Boring a hole is kind of a pain and now I’m thinking of bolting through the plates and spacer. It would be kind of like this with the blue pulley bolted to the crank. The only difference is I need to shorten the spacer by an inch so the discs are right next to the pulley.

What do you guys think? Should I bore the big hole or drill more precision holes for the bolts.

 

[ThePanzerFuhrer]

Your belt problem is not because of the 4 cylinder engine. Your belt problem is routing/alignment issues/wrong direction tensioner ect. Did you move the tensioner to the slack side of the belt yet?

The photos you posted of the belts it looks like the they have been slipping or there is a misalignment issue.

I have a 4 bt in a dozer and I just replaced the belt on it for the first time since it was new in 1980.

 

[WaterH]

Your belt problem is not because of the 4 cylinder engine. Your belt problem is routing/alignment issues/wrong direction tensioner ect. Did you move the tensioner to the slack side of the belt yet?

The photos you posted of the belts it looks like the they have been slipping or there is a misalignment issue.

I have a 4 bt in a dozer and I just replaced the belt on it for the first time since it was new in 1980.

The tensioner has been on the slack side for years. The routing is the same as a factory 6BT like this.

The only difference now is I eliminated the fan drive completely. There is no mis Alia ment that I can detect. When belts are not aligned, they usually fray on one side.

 

[lt1yj]

I agree with Panz.

My buddy is running a built 4BT that doesn't eat belts.

My brothers backhoe has a 4BT that probably has the original belt on it from the 90's. I know he hasn't changed it since he bought it in the early 2000's.

 

[M92PV4U]

The only difference now is I eliminated the fan drive completely.

So do you now have more or less belt wrap on the crank pulley?

 

[SLOWPOKE693]

So do you now have more or less belt wrap on the crank pulley?

I'd think it would be alot more.....

 

[AKnate]

I always thought it was Water Head 🤣🤣

 

[elbekko]

Could the fan have been acting as some sort of damper/mass for the pulses? Would explain why the factory stuff doesn't have those issues.
Maybe you just have a belt that's slightly too long?

 

[arse_sidewards]

I looked into fluid dampers a lot about a year ago for a project before deciding fuck it. On youtube there's a video fluidampr has with a cutaway showing theirs vs the competition. You can get an idea of clearance between the inner weighted damper ring and the outer casing from that. It's kind of a lot. The bitch is rattling around in there with 1/8 or something. You can't have too much mass and because you don't have to worry about shit flinging apart at 10000rpm in your application you want the biggest OD you can fit.

The fluid they use is silicone. Same shit that's in RC car diffs, viscous couplings and Subaru diffs. For automotive applications I know this sounds backwards but the thicker fluids tend to be the ones that burn up and wear out because forcing them to move generates so much more heat, or at least that's what the limited research from people fucking around with Subaru center diffs seems to indicate.

 

[ThePanzerFuhrer]

This setup has a ton of wrap.

 

[CarterKraft]

So I decided to make a dynamic balancer for my 4BT. They make one for the marine versions that is suppose to smooth out the engine. I don’t have a problem with vibrations, but mine seems to eat belts. I’m thinking it is the pulses from a powerful 4 cylinder turning slow.

Anyways the one Cummins makes for it is basically a 30 lb. Chunk of iron that costs $3,000+. I think I can hack something up for that. First I needed a spacer to get the weight out from the pulley. I had a scrap chunk of 3 1/2” round stock I turned on the lathe and drilled some accurate holes on the mill. (Don’t you love digital readouts for hole patterns?)

I needed a big thick disc on this and first I thought of a disc brake. But I read you aren’t suppose to weld on them, so I thought I would get some mild steel plate from the scrapyard. I really wanted one inch thick plate, but I couldn’t find any at the yard that wasn’t a 1000 lb. So I ended up getting some 1/2” plate. I figure I’ll just stack it to get the weight. I took the plate and put it on my CNC plasma cutter and cut two perfectly round discs.

Drilled some holes and bolted on a suitable lathe holder.

Mounted in the lathe ready to make chips.

After some quality time I had two discs and my dog had sore feet. (How do you keep your dog out of the shop?)

The plan was to bore a big hole in the plates to insert the spacer and weld it together. Boring a hole is kind of a pain and now I’m thinking of bolting through the plates and spacer. It would be kind of like this with the blue pulley bolted to the crank. The only difference is I need to shorten the spacer by an inch so the discs are right next to the pulley.

What do you guys think? Should I bore the big hole or drill more precision holes for the bolts.

everything on a pilot/hub not sure if that is the question.

How you plan to balance the disc?

 

[WaterH]

So do you now have more or less belt wrap on the crank pulley?

As Slowpoke said, more wrap.

I always thought it was Water Head 🤣🤣

Sometimes I go by that.

Could the fan have been acting as some sort of damper/mass for the pulses? Would explain why the factory stuff doesn't have those issues.
Maybe you just have a belt that's slightly too long?

When I first got it on the road, I had an idler pulley in place of the fan drive. The belt had a much longer run from the crank to the pulley. I always thought it bounced a lot with it like that. The belt lasted longer, but the idler broke its mount twice. Then I made a new bulletproof mount. Then the new idler gave up. Someone told me they run theirs with out any fan drive/idler for years, so I tried that. It doesn’t bounce as bad and it runs quieter at idle, but I’ve gone through two belts in 3 months.

I looked into fluid dampers a lot about a year ago for a project before deciding fuck it. On youtube there's a video fluidampr has with a cutaway showing theirs vs the competition. You can get an idea of clearance between the inner weighted damper ring and the outer casing from that. It's kind of a lot. The bitch is rattling around in there with 1/8 or something. You can't have too much mass and because you don't have to worry about shit flinging apart at 10000rpm in your application you want the biggest OD you can fit.

The fluid they use is silicone. Same shit that's in RC car diffs, viscous couplings and Subaru diffs. For automotive applications I know this sounds backwards but the thicker fluids tend to be the ones that burn up and wear out because forcing them to move generates so much more heat, or at least that's what the limited research from people fucking around with Subaru center diffs seems to indicate.

The stock 4BT uses just a crank pulley. The stock 6BT uses a heavy pulley with a rubber ring tuned to the harmonics of the 6 cylinder. The Cummins 6.7 L uses a fluid damper. I have tried all three on mine .

As far as “felt” vibration, the one from the 6BT seems to be the smoothest and that’s what I’ve been running. Im thinking that the reason it feels smoother is strictly because of the added weight. The rubber part maybe bad because it’s tuned for a 6 cylinder. The fluid damper actually balances the rotation, but I think I just need the weight to even out to pulses. That’s what they have on the marine 4BT engines.

One of the reasons mine may have more bounce to the belt is I have a big alternator and AC compressor. They can’t speed up and slow down as quick as the stock units, so the belt gets less stress on it.

Anyways, it’s worth a try, just not for over 3 grand.

 

[WaterH]

everything on a pilot/hub not sure if that is the question.

How you plan to balance the disc?

What are you doing up? I’m up because my wife is in surgery. (I’m in the waiting room)

Anyways, I can ballance it with my helicopter balancer, but to tell you the truth, I don’t think it will be out much because it will be all machined from steel.

 

[CarterKraft]

What are you doing up? I’m up because my wife is in surgery. (I’m in the waiting room)

Anyways, I can ballance it with my helicopter balancer, but to tell you the truth, I don’t think it will be out much because it will be all machined from steel.

Have to be 300 miles South to meet a customer at 10sam, that required a 4:15 departure

I am just always surprised to see how much lightening holes are drilled into solid objects.

 

[arse_sidewards]

The rubber part maybe bad because it’s tuned for a 6 cylinder.

It will be fine. A damper is like a shock absorber. Any sort of damping is indefinitely better than nothing and perfection is somewhat of an impossible moving target.

The fluid damper actually balances the rotation, but I think I just need the weight to even out to pulses. That’s what they have on the marine 4BT engines.

Pound for pound "damped" weight is going to be better at reducing acceleration at the pulley than "unsprung" weight that's hard mounted to the crank.

One of the reasons mine may have more bounce to the belt is I have a big alternator and AC compressor. They can’t speed up and slow down as quick as the stock units, so the belt gets less stress on it.

Yeah that ain't helping. Maybe throw a clutched/overrunning pulley on the alt.

Anyways, it’s worth a try, just not for over 3 grand.

Agreed

helicopter balancer

Your what?

 

[WaterH]

It will be fine. A damper is like a shock absorber. Any sort of damping is indefinitely better than nothing and perfection is somewhat of an impossible moving target.

They have active dampers on helicopters that definitely need to be tuned to the vibration. I don’t know if the rubber on the 6BT is that engineered.

Your what?

I have an electronic balancer that I use on helicopters. It works on all kinds of stuff. It’s kind of like the tire balancers at tire shops, but they are designed for people that don’t understand balancing. I have used mine to balance the tires on my truck. I’ve even used it to balance a fan on a giant AC condenser. It basically gives you a clock angle and IPS. (Inches per second)

 

[slow600]

where do you have your idle set? i have my 4bt idling at/around 900 to help smooth things out, fluidamper did helped me some but not worth the $500.

will take a pic of my belt routing later...because i dont remember how its ran.

 

[WaterH]

where do you have your idle set? i have my 4bt idling at/around 900 to help smooth things out, fluidamper did helped me some but not worth the $500.

will take a pic of my belt routing later...because i dont remember how its ran.

My idle is about 900 too.

 

[GLTHFJ60]

I'd think it would be alot more.....

The red line is exactly the belt routing on my 4bt. I've had it for 70-80k miles in my land cruiser over a decade and I have never had a belt wear out. I carry a spare just in case but i've never used it.





Also, for the OP, a dynamic balancer is not just a chunk of steel, that's a mini flywheel stupid. You already have one of those. Fluidamper makes a model for the 4bt, but it won't fix the belt issue.

 

[ThePanzerFuhrer]

Here you go waterhead

RARE OEM Cummins 3.9 4bt Diesel Engine Harmonic Counter Balancer | eBay

<p>RARE OEM Cummins 3.9 4bt Diesel Engine Harmonic Counter Balancer. If your looking at this you know what it is. Very rare and hard to come by. Shows some surface wear but will clean up nicely. Comes as seen in the photos. Free shipping to the lower 48 states only. </p><br /><br /><br /><p>C3 </p>

www.ebay.com

 

[GLTHFJ60]

This is an actual fluid filled harmonic balancer. This is what I'm running on my 4BT. Part number 3925233.

Cummins Damper Viscous Vibration 3925233 for sale online | eBay

Find many great new & used options and get the best deals for Cummins Damper Viscous Vibration 3925233 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Read more here from when I bought mine.

Harmonic Balancers

www.4btswaps.com

 

[CarterKraft]

Here you go waterhead

RARE OEM Cummins 3.9 4bt Diesel Engine Harmonic Counter Balancer | eBay

<p>RARE OEM Cummins 3.9 4bt Diesel Engine Harmonic Counter Balancer. If your looking at this you know what it is. Very rare and hard to come by. Shows some surface wear but will clean up nicely. Comes as seen in the photos. Free shipping to the lower 48 states only. </p><br /><br /><br /><p>C3 </p>

www.ebay.com

A counter balancer is completely different than what he is building, what he is building is also completely different from a harmonic balancer, what is he building? A flywheel?

 

[ThePanzerFuhrer]

A counter balancer is completely different than what he is building, what he is building is also completely different from a harmonic balancer, what is he building? A flywheel?

Shhh! He we need to see this thing play out. I want to see him try to build a counter balance setup

Imo What he is making is gonna do nothing other than break the crank pulley mounting bolts off

 

[WaterH]

A counter balancer is completely different than what he is building, what he is building is also completely different from a harmonic balancer, what is he building? A flywheel?

You get it. I don’t understand why it’s so hard for everybody else. I’ve allready tried the fluid damper and it does not help the belt bounce. This may not work either, but it has promise. Obviously, if you keep going heavier, there will be no more excellerating/de-excelleration. That might rediculas heavy. I’m hoping just a little more weight will solve the problem.

They make “back stop” idlers for the newer Cummins. That might help or it might make it worse.

 

[WaterH]

This is an actual fluid filled harmonic balancer. This is what I'm running on my 4BT. Part number 3925233.

Cummins Damper Viscous Vibration 3925233 for sale online | eBay

Find many great new & used options and get the best deals for Cummins Damper Viscous Vibration 3925233 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Read more here from when I bought mine.

Harmonic Balancers

www.4btswaps.com

Yes, I’ve allready tested those and they didn’t help. I’m not trying to smooth the motor vibrations. (It’s allready good that way) I’m trying to make a more constant load on the belt.

 

[GLTHFJ60]

Nothing you bolt on to your crank will fix your belt problem. If you think adding a few lbs to the front of a 30# crank will change anything you're delusional.

Also, the viscous dampener I linked is very different than the stock 6bt "harmonic balancer" if that's what you already "tried".

You're barking up the wrong tree.

EDIT/ADD: Load on the belt varies by AC compressor and alternator load only. Water pump is constant. The load will always vary.

 

[M92PV4U]

As Slowpoke said, more wrap.

I couldn't see how it could be less, but I could see how less wrap would be a problem.
Are you sure that the pullys are square with each other?

 

[ThePanzerFuhrer]

Are you sure that the pullys are square with each other?

Waterhead says it’s straight . This is what I lean towards also. Just the way the belt lays in his pictures leads me to believe it’s either a misalignment or slipping issue.

 

[WaterH]

Nothing you bolt on to your crank will fix your belt problem. If you think adding a few lbs to the front of a 30# crank will change anything you're delusional.

Also, the viscous dampener I linked is very different than the stock 6bt "harmonic balancer" if that's what you already "tried".

You're barking up the wrong tree.

EDIT/ADD: Load on the belt varies by AC compressor and alternator load only. Water pump is constant. The load will always vary.

I could tell a difference when I bolted the 6BT on and it weighs a lot less than 30 lbs.


As I said in the earlier post, I tried all three of these.

The one on the upper left is a fluid damper. It did have a beneficial effect on the belt bounce, but I didn’t like the bigger drive pulley and there were clearance issues.

Not sure why everyone is against me trying this. I’ve made some of my best engineering accomplishments doing tests like this. If it doesn’t work, so be it. If it causes the truck to blow up, so be it.

Anyways, the question I actually asked about was how I should machine the discs to fit on the spacer. I decide to go with my first idea after I found a boring bar I had forgotten I bought. Did the first disc. Turned out nice.

The fit is near perfect. I might have to use slight press. (It will be welded)

 

[WaterH]

I couldn't see how it could be less, but I could see how less wrap would be a problem.
Are you sure that the pullys are square with each other?

Waterhead says it’s straight . This is what I lean towards also. Just the way the belt lays in his pictures leads me to believe it’s either a misalignment or slipping issue.

I’ve checked misalignment multiple ways. I don’t believe its out anywhere. Now slipping is another issue. Yes I believe it’s slipping. (At least after it starts making noise) I just put another brand new tensioners on it. The old one is not very old and it feels just as hard to back off. Do serpentine pulleys ware out? Is there something to look for? I suppose if the 6BT pulley is somehow shot, this new flywheel will work good with the old 4BT pulley. Then I’ll think I cured it with the weight when it was the pulley. lol.