[cstraub]

The parent company of Fluidamper supplied dampers to the diesel industry. Desiel are low rpm and for the most part operate in a very narrow powerband from idle to max power. Dampers for these engines were tuned based on the cranks metaluregic makeup and the rpm that it ran it. Since a given OEM produced engine will have strick QC the dampers once tuned and designed for the OEM application could be applied to every engine built.


Race engines. Based on the above using a 383 SBC as a base engine could you do the same? Lunati, BRC, Bryant, Windberg, Eagle, Crower, Scat, Norton, Callies, Moldex, GM, Manley....the list goes on.

 

[morepwr]

You guys are not telling me why - I want to know. Is that too hard?

I think others would like to know too. I don't need or want a personal consultation.

The "fluid" elastomer inside tends to not stay as mobil/flexible as it should over time. Such as when your car is parked for the off-season or winter.
Then you start it and it has a nasty vibration it never had before.

 

[Geoff]

You guys are not telling me why - I want to know. Is that too hard?

I think others would like to know too. I don't need or want a personal consultation.

Rick, I think you may be taking this hobby stuff a little too seriously.

You are a very valuable resource around here but your comments, even if this isn't the intention, are coming across kinda harsh and demanding lately.

CSTRAUB, that is a very logical explanation.

 

[Rick_L]

cstraub, so let me ask you this. What's "tuned" about a stock balancer? Or an ATI? You can buy a Fluidamper or for that matter any other in both 6" and 8" versions. Seems like that would affect the tuning too with that way of thinking.

At first glance, seems to me that the damping capacity increases with more mass on the balancer ring. The stiffness of the rubber (in the usual design) or the viscosity of the fluid (in the fluid damper) would affect the minimum rpm where you got some benefit.

morepwr, I'll buy into the cold affecting the balance, especially if the fluid volume doesn't fill the internal volume. But I always thought they were filled pretty full.

 

[cstraub]

Rick L,
An elastomer style OEM type damper by design will absorb homonics over a much broader rpm range and a much more varied material use. So for a street application they work fine. Yes you are correct the larger the damper the better it works. For a circle track car, marine use, or another venue where the engine sees sustained rpms I would use a large diameter. For a drag only deal where you want the quickest acceleration I would go a smaller diameter.

An ATI with its rubber rings can be "tuned" to a specific engine combo and rpm range. This is what is done done in Mooresville, NC as they have the type of equipment needed to do this. They run large diameter, 8" stuff down there.

 

[dcs13]

Summit has 2 that look pretty good, any thoughts:
http://www.summitracing.com/parts/SUM-C4265/
http://www.summitracing.com/parts/SUM-B64265/

 

[Rick_L]

Can't disagree with the recommendations for large and small, those are pretty well known.

I remain unconvinced that a Fluidamper is a bad thing except for the possibility of the cold weather deal. Which would make it a bad choice for a street engine in most parts of the country if true. No reason to think it isn't except that those diesels do have to run in cold weather too - so I guess I would have thought/hoped they used a silicone fluild that was immune to the cold temperature.

Thank you for continuing the discussion despite the grumpiness that Geoff spoke of.

 

[cstraub]

Can't disagree with the recommendations for large and small, those are pretty well known.

I remain unconvinced that a Fluidamper is a bad thing except for the possibility of the cold weather deal. Which would make it a bad choice for a street engine in most parts of the country if true. No reason to think it isn't except that those diesels do have to run in cold weather too - so I guess I would have thought/hoped they used a silicone fluild that was immune to the cold temperature.

Thank you for continuing the discussion despite the grumpiness that Geoff spoke of.

Think about what you just posted then think about a race engine. A diesel may change 1500 rpm max when changing gears. A drag engine may change 4000 rpm. A circle track engine the same. The fluid cannot react as quick as the engine is changing rpm in race engine. Therefore during decel or accel the fluid is damning at 1 rpm and the engine is at another. This cause tortional stress on the shaft. The end result is not good.

I think you stated you worked in a shop. You know you can't balance a crankshaft with a fluid damper on the crank. The weight runs constantly when spinning the crank.

 

[cstraub]

Thank you for continuing the discussion despite the grumpiness that Geoff spoke of.

Hey i am the new guy, I have to take my "beat in" before I am a member.

 

[Rick_L]

"A drag engine may change 4000 rpm."

Most don't even come close. You work very hard for that kind of a bog not to happen - that could only happen if something is very wrong. If you shift a Muncie from 3rd to 4th at 6500 rpm, it only drops 1500 rpm, less the slip. Other stuff is similar depending on gear ratios. On an automatic, the torque converter slip limits the drop that you'd theoretically have. If you shift an automatic with a high stall converter at high rpm, the engine goes back to somewhere around the stall speed.

But regardless, what you said about the fluidamper involves some facts you haven't substantiated. Why would it do that? (And still work on the diesel?)

As far as balancing a crank with a Fluidamper on it, what does it matter whether the inertia ring continues to spin if it's balanced? I will say this if it "spins" that easily - it's ineffective.

I don't work in a shop, I'm an engineer. And I've been racing/hot rodding for about 45 years now. And I've been a customer of some very good shops.

 

[cstraub]

"A drag engine may change 4000 rpm."

Most don't even come close. You work very hard for that kind of a bog not to happen - that could only happen if something is very wrong. If you shift a Muncie from 3rd to 4th at 6500 rpm, it only drops 1500 rpm, less the slip. Other stuff is similar depending on gear ratios. On an automatic, the torque converter slip limits the drop that you'd theoretically have. If you shift an automatic with a high stall converter at high rpm, the engine goes back to somewhere around the stall speed.

But regardless, what you said about the fluidamper involves some facts you haven't substantiated. Why would it do that? (And still work on the diesel?)

As far as balancing a crank with a Fluidamper on it, what does it matter whether the inertia ring continues to spin if it's balanced? I will say this if it "spins" that easily - it's ineffective.

I don't work in a shop, I'm an engineer. And I've been racing/hot rodding for about 45 years now. And I've been a customer of some very good shops.

I am talking gear changes in a drag engine, from idle to launch, to peak. I have never seen a drag car come to the line that one didn't nail it in the water box from idle to peak. One also clears the carb in staging lane.

Fluid style dampers work on diesels because you have guys like CAT/ Cummings/Detroit spending millions of dollars perfecting a damper to work on a series of engines. I don't know many enthusist that spend that kind of money on a damper? **** its hard enough convincing them that they need a $900 oil pan, **** all it does is hold oil.

You need to go to a shop and have them put a fluid damper on a crank and let them spin it. You wont' like what you see.

So how long have you had a fluid damper on your engine?

 

[cstraub]

If you ever take an engine apart that has had a fluid damper on it look for what is referred to as an S harmonic. If you were looking at the engine on the stand from over the top of it looking down on the main caps. If you draw an S it would hit the Rear, No. 3, and No.1 If you pull the caps and have a pattern of wear in the center of cap and the block that looks like an hour glass, not as wide in the center of bearing but wider as you go to the edge of the bearing on the front and the rear of the bearing but on 2 and 4 you have nothing then this is referred to as an S harmonic and the crank is flexing in the block. This info comes from Scat many years ago.

 

[Rick_L]

You've described symptoms but not causes. I guess I need to know why.

I ran a small diameter Fluidamper for two seasons, maybe 75-80 passes and probably 100 dyno pulls on a 3" stroke SBC making about 2.5 hp/ci and never saw anything close to what you describe. In fact the bearings were never changed and never "marked". A 9000+ rpm engine.

Yeah ok I rev that engine from 0-9500 at some point in the day. I'm thinking/saying that under load is what matters. I can rev it out of gear all I need.

You don't state reasons the Fluidamper is any different from anything else in this regard.

Years back there was a pretty good, fairly technical, but understandable white paper comparing the balancers on the market. Do you have it or have read it? I need to see if it's on the net somewhere. It was written by someone who developed one of the friction clutch type balancers that are not all that common any more. It was a fairly unbiased description comparing the designs.

 

[cstraub]

You've described symptoms but not causes. I guess I need to know why.

I ran a small diameter Fluidamper for two seasons, maybe 75-80 passes and probably 100 dyno pulls on a 3" stroke SBC making about 2.5 hp/ci and never saw anything close to what you describe. In fact the bearings were never changed and never "marked". A 9000+ rpm engine.

Yeah ok I rev that engine from 0-9500 at some point in the day. I'm thinking/saying that under load is what matters. I can rev it out of gear all I need.

You don't state reasons the Fluidamper is any different from anything else in this regard.

Years back there was a pretty good, fairly technical, but understandable white paper comparing the balancers on the market. Do you have it or have read it? I need to see if it's on the net somewhere. It was written by someone who developed one of the friction clutch type balancers that are not all that common any more. It was a fairly unbiased description comparing the designs.

Your shop must have been Nickens. Thats a stout piece at 2.5 We ran B/EA back in the 80's 288 to 305 CID when the 18 degree stuff came out.

I did not read that article but would like to if you can find it. I will try and find Liebs article.

 

[Rick_L]

I had Nickens do some work for me once or twice and I used to buy pistons and rods from them - mainly because they stocked them. Mostly I used some other Houston sources, but I got to where I did my own piston work, head maintenance, and manifold mods. Before that, Reher-Morrison. I never could quite afford a "turn key" engine - to build one I either had to use parts I had from a previous build or do part of it myself.

When I quit, 2.5 hp/ci was not quite good enough. I was going to have to start fresh again and decided not to do that.

 

[cstraub]

I had Nickens do some work for me once or twice and I used to buy pistons and rods from them - mainly because they stocked them. Mostly I used some other Houston sources, but I got to where I did my own piston work, head maintenance, and manifold mods. Before that, Reher-Morrison. I never could quite afford a "turn key" engine - to build one I either had to use parts I had from a previous build or do part of it myself.

When I quit, 2.5 hp/ci was not quite good enough. I was going to have to start fresh again and decided not to do that.

Those motors are nothing more then baby PS engines. They will make a millionaire a middle class man in short order.

I know Allan and Todd Patterson quite well. I still do some work for Stefs so I am able to keep in touch on what is going on.

If you can find that article I am interested.