# Silent chain drives, AKA inverted tooth drive chains.



## MalcolmB (Jun 10, 2008)

I've been trying to find more information about this myself. Silent chain has some big advantages, apart from low noise. Mainly the fact it can operate at much higher speeds than standard chain, though it does need to run in an oil bath. All I've come up with so far is this: http://chain-guide.com/applications/1-6-3-inverted-tooth-chain.html

"The notch on the plates can engage with the sprockets from only one direction. The chain is not for reversing applications."

I having trouble visualising this though. What's your application?


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## DJBecker (Nov 3, 2010)

MalcolmB said:


> "The notch on the plates can engage with the sprockets from only one direction. The chain is not for reversing applications."


I believe that this statement means that the back side of the chain cannot engage a sprocket. All sprockets will be in the same plane, "inside" the chain loop, and turning the same direction.

In contrast, a roller chain can have a regular sprocket as a tensioner. The tensioning sprocket will be on the "outside" of the chain loop and spin in the *reverse* direction. This would be a "reversing application".

You can drive the chain in the opposite direction, "operate in reverse", without a problem.


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## Zak650 (Sep 20, 2008)

Hi,

The "silent" chain you are refering is really quite common, it used to be called a hy-vo chain I believe. It's used to drive camshafts in V8 engines. They do require a lot of lubrication and are not applicable to an unenclosed situation. They also are assemble as a unit and don't have a masterlink. This limits them to mass produced lengths, if it's what you need great, but a custom length is not an option.


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## MalcolmB (Jun 10, 2008)

DJBecker said:


> I believe that this statement means that the back side of the chain cannot engage a sprocket.


Damn, I never thought of it that way. That makes much more sense. Thanks.


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## coulombKid (Jan 10, 2009)

MalcolmB said:


> I've been trying to find more information about this myself. Silent chain has some big advantages, apart from low noise. Mainly the fact it can operate at much higher speeds than standard chain, though it does need to run in an oil bath. All I've come up with so far is this: http://chain-guide.com/applications/1-6-3-inverted-tooth-chain.html
> 
> "The notch on the plates can engage with the sprockets from only one direction. The chain is not for reversing applications."
> 
> I having trouble visualising this though. What's your application?


I love the Dana 44 because: 1) It's cheaply available. 2) A wide selection of after market ratios are available. 3) A wide selection of very good limited slip differentials are available. 4) When I build "upscale" the Corvette C4 DANA 44 IRS can be had.
I want to replace the ring gear with a silent chain sprocket, then saw off the casting pinion snout and weld on a flange to gasket and bolt on the input sprocket/bearings/and U-joint yoke assembly. The drive shaft yoke must point toward the drivers side wheel to work properly with a shorty "glide" with an identical chain drive mounted on the tail housing so that the transmission output yoke points toward the pump end of the transmission on the passenger side of it.
A Kostov 10" with a KansasEV glide that has the chain case on the rear is about 36" overall length so the shorty drive shaft with slip yoke would be 12" long at most. This allows a rear wheel drive, mid engine design with all the heavy parts low to the ground. This would chew up the back seat area but on the Karmann-Giha the back seat was an after thought and on the last years of production they didn't even bother to put it in. The Ghia reportedly has a sub-frame that supports motor and trans-axle. Us old grey-bearded welders would duplicate the sub frame to bolt to the body and rework the floor to accommodate the new drive train. 
The chains won't tolerate GL-5 so the Dana would need to be filled with a much lighter oil. For an open Dif, Dexron should work OK. The sprocket sets need to have a 4:7 tooth ratio on both sets to achieve a 3.5:1 over-all final drive ratio in high. With a transverse glide my cable shifter will work OK. The kansasEV glide apparently doesn't use the kick-down linkage or the vacuum modulator so paying the price buys simplicity. I've never dealt with the Porsche 914 but I suspect the same drive train assembly would be awesome in that body too. Hope I live long enough to pour the amps through the glide and a LSD on a sticky track.


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## coulombKid (Jan 10, 2009)

Zak650 said:


> Hi,
> 
> The "silent" chain you are refering is really quite common, it used to be called a hy-vo chain I believe. It's used to drive camshafts in V8 engines. They do require a lot of lubrication and are not applicable to an unenclosed situation. They also are assemble as a unit and don't have a masterlink. This limits them to mass produced lengths, if it's what you need great, but a custom length is not an option.


Actually some vendors claim they will complete the chain to a specification but the number of links has to be a multiple of two. As such, half links we fall back on in roller chains, are not an option. The good news apparently is that the chain teeth, by design, tend to climb the sprocket teeth under torque eliminating the need for an idler. If you've re-manufactured the 4T65E then you've seen this in action. Once one has the chain and sprocket set is in hand then the shaft to shaft distance is critical. I would get this distance from the chain and sprocket manufacturer before firing up the Bridgeport mill with the correct boring bar. From my Wiki search I see the first racing transmission using these chains throughout was built in 1912.


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## MalcolmB (Jun 10, 2008)

It sounds like you know what you're doing. I'm a grey-bearded welder as well, but don't have your familiarity with transmissions. Wish I did, as I'd love to build a reliable two or three-speed setup. I want to have a go at building a simple reduction box first using an off-the-shelf silent chain. I see the Dana unit was first used on the Jaguar E-type, so it has a good pedigree.


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## Woodsmith (Jun 5, 2008)

Silent chain was used on some Range Rover transfer boxes and so are fine running in both directions in that application.

I can't see why it wouldn't work on your axle if you can fabricate it.

Need to consider the chain tensioning issue. The RR transfer box didn't have a tensioner so I am not sure how tight it was fitted to the drive sprockets of it it just had some acceptable play.


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## coulombKid (Jan 10, 2009)

Woodsmith said:


> Silent chain was used on some Range Rover transfer boxes and so are fine running in both directions in that application.
> 
> I can't see why it wouldn't work on your axle if you can fabricate it.
> 
> Need to consider the chain tensioning issue. The RR transfer box didn't have a tensioner so I am not sure how tight it was fitted to the drive sprockets of it it just had some acceptable play.


The 4T65E manual shows the wear limit for the chain and sprocket set in decimal inches of sag. Unlike the TH375 the modern automatics have a slight reduction of speed making the shaft center distance a little more difficult to calculate. I have considered mounting flange bearings with slightly over sized bolt holes and then drilling dowel pins after the measurement like engine blocks are doweled to keep bell housings lined up. The chain needs just enough slack to lubricate correctly and compensate, without failure, for thermal expansion of all the hard parts. I would expect to have to drill a small bleed squirt-er orifice near the back of the PG to oil the chain (with drain back) like the holes we drill in rods to squirt oil on the bottom of pistons when we are using WAY to much laughing gas.


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## piotrsko (Dec 9, 2007)

UH,, I don't recall Gia's having a different motor / trans set up than a bug. Type 3's do which is why most of the trike conversions used those "pancake" motors. when you pull a type 3 motor you have to support the trans axle.

I believe the pan stops at the firewall and the engine / trans is supported by the trans mount arms. There might be a brace to the back of the engine (front is front).


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## EVfun (Mar 14, 2010)

Karmann Ghia frame.

Imagine removing the floor boards (#24, qty, 2) from the frame assembly (#22.) The VW Beetle and Ghia have a central frame that splits into two parts to go around the transaxle (sometimes referred to as the pickle fork.) The structural frame is the hump in the center of the floor. There is no room for any sort of driveshaft unless the stock frame is cut away from some point and a new rear frame created. The VIN number is located on the frame tunnel about six inches forward of the back of the floor boards. If you mess with that you will likely have to deal with state inspection issues.

A traditional beach buggy, like mine, is made by using a Beetle frame (same frame, different floors) and cutting 14 inches out of it, starting a couple inches behind the e-brake and ending a couple inches in front of the VIN number. Then you bolt a lightweight fiberglass body on it that also doubles as support for the floor boards. (and disregard any notion of side impact protection)


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## coulombKid (Jan 10, 2009)

EVfun said:


> Karmann Ghia frame.
> 
> Imagine removing the floor boards (#24, qty, 2) from the frame assembly (#22.) The VW Beetle and Ghia have a central frame that splits into two parts to go around the transaxle (sometimes referred to as the pickle fork.) The structural frame is the hump in the center of the floor. There is no room for any sort of driveshaft unless the stock frame is cut away from some point and a new rear frame created. The VIN number is located on the frame tunnel about six inches forward of the back of the floor boards. If you mess with that you will likely have to deal with state inspection issues.
> 
> A traditional beach buggy, like mine, is made by using a Beetle frame (same frame, different floors) and cutting 14 inches out of it, starting a couple inches behind the e-brake and ending a couple inches in front of the VIN number. Then you bolt a lightweight fiberglass body on it that also doubles as support for the floor boards. (and disregard any notion of side impact protection)


If I needed to remove an OEM VIN I'd have to get the sate of Arizona involved. I took my pickup truck to inspection when I brought it into the state with the titles from all the donor trucks. The inspector could see I owned it all and just affixed a state of Arizona VIN to the door frame opening.


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