Using a solid hub instead of a damper? Will this fix it
#1694289
11/04/14 11:50 AM
11/04/14 11:50 AM
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Joined: Jan 2003
Posts: 9,670 Lima, Peru
domingo
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EL Master
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EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
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HI! I have a rotating assembly for a HEMI that has been balanced using a solid HuB instead of a vibration damper (no elastomer or fluid). I was wondering if by using one of these gilmer pulley and belt setups I would absorb the harmonics just like on Blower equippped engines? My engine is gonna be naturally aspirated. http://www.ebay.com/itm/Mopar-Chrysler-B...b97&vxp=mtr
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Re: Using a solid hub instead of a damper? Will this fix it
[Re: B G Racing]
#1694291
11/04/14 05:17 PM
11/04/14 05:17 PM
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Joined: Jan 2003
Posts: 9,670 Lima, Peru
domingo
OP
EL Master
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OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
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Thanks for the reply Bob!
Well, let me explain a lil bit further...
Thing is I haev enough parts to put together a 500 cid HEMI from parts I have sitting on the shelf.
All these parts came as part of package deals or freebies when I bought some cars...so they came at practically no cost tome...still these parts are seconds, or brand new parts that got machined etc in a way that I woukd probably havent done, or had done....but they are what they are....either they remain on my shelf collecting dust, or I assemble them together and build a HEMI at almost zero cost to me.
Turns out that the rotating assembly I have is a 4.375" stroke bryant billet crank, childs and albert pistons and stock rods polished, resized and w new bolts installed. but the thing is that these have been already balanced by cutting the crank counterweights and then by having an offset balance flywheel and solid hub installed. The hub has a considerable offset balance, and the whole rotating assy has been balanced like that.
Yes, I could get a new balancer, new flywheel etc, rebalance and do it "right" but that will mean added costs which I dont want to incurr in since these are all "junk" parts.
So...having said this, I suppose that a way to make this work without having a time bomb is to use that gilmer pulley setup and then getting the belt driven cam gears???? Now that seems like I could do....
My total cost on building this hemi will only be labour, gaskets, bearings and piston rings. most everything else I already have! -cracked but welded heads, they dont leak, used rocker arms, the rotating assembly mentioned, a new MP siamese water block that had the core shift issues and says not to bore over 4.31", etc.
Be nice to build a HEMI that will last for at least a while and not spending much in putting it together....
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Re: Using a solid hub instead of a damper? Will this fix it
[Re: B G Racing]
#1694292
11/04/14 09:59 PM
11/04/14 09:59 PM
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Joined: Jan 2003
Posts: 5,895 Florida
Locomotion
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master
Joined: Jan 2003
Posts: 5,895
Florida
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Quote:
Balancers with no dampening effect will allow any harmonics from the cam and valve train to effect the crank.If you are running a N/A engine with a solid hub and balancer it would be wise to run a belt driven cam to interupt those harmonics.
Bob, shouldn't you have typed "Balancers with no dampening effect will allow any harmonics from the crank to effect the cam and valve train"?
While I don't have near the engine building experience that Bob has, personally, I would not run a solid hub on a crank for any reason, even if it was free. It can't be good even if a belt is used as a band-aid. You should look at the potential long term costs.
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Re: Using a solid hub instead of a damper? Will this fix it
[Re: Locomotion]
#1694293
11/04/14 10:29 PM
11/04/14 10:29 PM
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Joined: Jan 2003
Posts: 9,670 Lima, Peru
domingo
OP
EL Master
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OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
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Quote:
Quote:
Balancers with no dampening effect will allow any harmonics from the cam and valve train to effect the crank.If you are running a N/A engine with a solid hub and balancer it would be wise to run a belt driven cam to interupt those harmonics.
Bob, shouldn't you have typed "Balancers with no dampening effect will allow any harmonics from the crank to effect the cam and valve train"?
While I don't have near the engine building experience that Bob has, personally, I would not run a solid hub on a crank for any reason, even if it was free. It can't be good even if a belt is used as a band-aid. You should look at the potential long term costs.
But dont blown engines run solid hubs?? Why not run a solid damper with a belt?? Wouldnt it be the same??? And I could also add the belt driven timing gears....
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Re: Using a solid hub instead of a damper? Will this fix it
[Re: Locomotion]
#1694297
11/05/14 01:37 PM
11/05/14 01:37 PM
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Joined: Mar 2006
Posts: 9,910 Eighty Four, PA
B G Racing
master
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
Quote:
Balancers with no dampening effect will allow any harmonics from the cam and valve train to effect the crank.If you are running a N/A engine with a solid hub and balancer it would be wise to run a belt driven cam to interupt those harmonics.
Bob, shouldn't you have typed "Balancers with no dampening effect will allow any harmonics from the crank to effect the cam and valve train"?
While I don't have near the engine building experience that Bob has, personally, I would not run a solid hub on a crank for any reason, even if it was free. It can't be good even if a belt is used as a band-aid. You should look at the potential long term costs.
Read my post carefully,I never suggest running a balancer/dampner with out harmonic control.However many applications are run and have been run with only a hub and a timing wheel.We ran many this way years ago on injected engines when we never drove any accessories of the crank and drove the fuel pumps off the cam.Most all blower applications are run with out a Balancer/dampner.I tried to explain the purpose of the componant as far as torsional twisting and harmonics and the effects caused by the use and non use of the componant.We qualified the issues by saying that is why you find most cranks use this way crack.To further explain harmonics tend to kill bearings,cause cap metal transfer and loosen or stress componants.Torsional twisting with out any means of returning to centerline alignment will stress the crank and cause it to crack as well as throw any accurate indexing out the window.A good example is take a blowen engine,in many cases the twisting under load will cause the pistons on some cylinders to travel higher in the bores. To further explain there are more harmonics generated at the valve train componants than at the crank.If the crank is creating harmonics than you have a wacked out balance and the engine should have never been run.The first and most critical part of any engine is a strong,balanced rotating assembly,without this the engine is going to self destruct and everything else is moot point.As far as harmonics the 16 cam lobes,16 lifters,16 pushrods,16 rockers,16 valve springs,cam drive,pump drives and related componants can reek havoc on an engine.Listen to most any good solid running engine and the most predominate noise you will here and vibration you feel will be from the valve train.A good rotating assembly balance will cost you a few hundered dollars,a good valve train assembly will cost you thousands of dollars.
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Re: Using a solid hub instead of a damper? Will this fix it
[Re: domingo]
#1694298
11/05/14 01:51 PM
11/05/14 01:51 PM
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Joined: Mar 2006
Posts: 9,910 Eighty Four, PA
B G Racing
master
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
Thanks for the reply Bob!
Well, let me explain a lil bit further...
Thing is I haev enough parts to put together a 500 cid HEMI from parts I have sitting on the shelf.
All these parts came as part of package deals or freebies when I bought some cars...so they came at practically no cost tome...still these parts are seconds, or brand new parts that got machined etc in a way that I woukd probably havent done, or had done....but they are what they are....either they remain on my shelf collecting dust, or I assemble them together and build a HEMI at almost zero cost to me.
Turns out that the rotating assembly I have is a 4.375" stroke bryant billet crank, childs and albert pistons and stock rods polished, resized and w new bolts installed. but the thing is that these have been already balanced by cutting the crank counterweights and then by having an offset balance flywheel and solid hub installed. The hub has a considerable offset balance, and the whole rotating assy has been balanced like that.
Yes, I could get a new balancer, new flywheel etc, rebalance and do it "right" but that will mean added costs which I dont want to incurr in since these are all "junk" parts.
So...having said this, I suppose that a way to make this work without having a time bomb is to use that gilmer pulley setup and then getting the belt driven cam gears???? Now that seems like I could do....
My total cost on building this hemi will only be labour, gaskets, bearings and piston rings. most everything else I already have! -cracked but welded heads, they dont leak, used rocker arms, the rotating assembly mentioned, a new MP siamese water block that had the core shift issues and says not to bore over 4.31", etc.
Be nice to build a HEMI that will last for at least a while and not spending much in putting it together....
Domingo, to address your situation,if the rotating assembly was balanced with this external weighted hub and flywheel then some one is compinsating for heavy rods and pistons used on a lightened crank that may have been setup for a light aluminium rod assembly and it would be very expensive to add heavy metal to the counter weights.It's always easier and cheaper to balance to a lighter assembly,you just need to remove metal.You can add any neutral balance dampner to the assembly as long as you attach it to the weighted hub or have a custom dampner made with the same offset weight added to it,similar to some Chevy dampners that have the bolt on weights.They can be use on internally balanced assemblies without the weight and on externally balanced assemblies with the weight.
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Re: Using a solid hub instead of a damper? Will this fix it
[Re: B G Racing]
#1694299
11/05/14 02:09 PM
11/05/14 02:09 PM
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Joined: Jan 2003
Posts: 9,670 Lima, Peru
domingo
OP
EL Master
|
OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
|
Quote:
Quote:
Thanks for the reply Bob!
Well, let me explain a lil bit further...
Thing is I haev enough parts to put together a 500 cid HEMI from parts I have sitting on the shelf.
All these parts came as part of package deals or freebies when I bought some cars...so they came at practically no cost tome...still these parts are seconds, or brand new parts that got machined etc in a way that I woukd probably havent done, or had done....but they are what they are....either they remain on my shelf collecting dust, or I assemble them together and build a HEMI at almost zero cost to me.
Turns out that the rotating assembly I have is a 4.375" stroke bryant billet crank, childs and albert pistons and stock rods polished, resized and w new bolts installed. but the thing is that these have been already balanced by cutting the crank counterweights and then by having an offset balance flywheel and solid hub installed. The hub has a considerable offset balance, and the whole rotating assy has been balanced like that.
Yes, I could get a new balancer, new flywheel etc, rebalance and do it "right" but that will mean added costs which I dont want to incurr in since these are all "junk" parts.
So...having said this, I suppose that a way to make this work without having a time bomb is to use that gilmer pulley setup and then getting the belt driven cam gears???? Now that seems like I could do....
My total cost on building this hemi will only be labour, gaskets, bearings and piston rings. most everything else I already have! -cracked but welded heads, they dont leak, used rocker arms, the rotating assembly mentioned, a new MP siamese water block that had the core shift issues and says not to bore over 4.31", etc.
Be nice to build a HEMI that will last for at least a while and not spending much in putting it together....
Domingo, to address your situation,if the rotating assembly was balanced with this external weighted hub and flywheel then some one is compinsating for heavy rods and pistons used on a lightened crank that may have been setup for a light aluminium rod assembly and it would be very expensive to add heavy metal to the counter weights.It's always easier and cheaper to balance to a lighter assembly,you just need to remove metal.You can add any neutral balance dampner to the assembly as long as you attach it to the weighted hub or have a custom dampner made with the same offset weight added to it,similar to some Chevy dampners that have the bolt on weights.They can be use on internally balanced assemblies without the weight and on externally balanced assemblies with the weight.
Well yes, probably the way to go would be to figure out a way of fabbing a dampner with the same balance offset as the solid piece I have on the engine right now....That way I could spend the money there instead of buying one of those expensive camshaft belt drives!!! Uhmmmm.....Ill take a closer look at that solid offset balance I have there and will see what can be done.....
Maybe I can sacrifice an old elastomer HEMI damper and make it the same offset balance....
Thanks to all you guys for the heads up and being insisting enough to have this sink into my thick skull!!!
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