Should Chevy Join The Chain Gang?

[V8GMT360 Guy]

Loving the Monza... but the engineering challenges presented by a chain-driven RWD would be far from ideal. The development could prove costly, and designing the floor pan of the vehicle so a chain drive could fit might be awkward.

With a transverse mounted engine/trans, you'd have to put the chain and sprockets off-center on the vehicle, so using a traditional trans-tunnel design wouldn't work.

Not to mention the reliability would be suspect.

[ejfx]

My Eldorado has a chain drive and I fear breaking the chain everytime I open the throttle...

I like the Monza chop...however I dont dig the name.

Originally Posted by mkaake

a) chains in FWD transmissions are common... until GM brought out the 6 speed FWD transmission, all of their transverse trannies had chains. When the 6 speed was introduced, they moved away from chains to gears.

b) In general, gears are stronger than chains. For the torque you're talking about transmitting, hardened gears are the way to go...

c) Chains stretch over time, and have more mechanical points of failure. With a chain long enough to stretch to the rear area of a car, you're talking about many points of potential failure.

d) Chains cost more than gears... especially, again, chains long enough to reach the rear of the car.

e) Chain drives still have mechanical losses, tied to the quality and tolerances in manufacturing. I wouldn't expect to see any major improvements by using a chain drive vs. a traditional 'gear drive', especially at the tolerances that make economic sense in mass manufacturing.

Chains have their places, and they're still in use in your car - but these days, they're mostly regulated to turning cams underneath your front cover...

Well said mkaake...

[Beau]

Chain drive is a TERRIBLE idea from front to back, and would weigh a TON...
Chain drives aren't even a great idea in 2.5 foot closed arrays in a fwd tranny.

I think your idea here works, and the idea I'm talking about is your Chop for the "GT"

[Tek]

Originally Posted by Beau

Chain drive is a TERRIBLE idea from front to back, and would weigh a TON...
Chain drives aren't even a great idea in 2.5 foot closed arrays in a fwd tranny.

I think your idea here works, and the idea I'm talking about is your Chop for the "GT"

Well not a ton but 104 pounds if using 3/4" width roller drive chain allowing for 10' as said that would be 20' of chain +- a few inches. Ouch

[MonaroSS]

Originally Posted by Beau

Chain drive is a TERRIBLE idea from front to back, and would weigh a TON...
Chain drives aren't even a great idea in 2.5 foot closed arrays in a fwd tranny.

I think your idea here works, and the idea I'm talking about is your Chop for the "GT"

Well I don't like to guess these things. I can't find exactly what the 2.5 ft GM transmission chain weighs but I can calculate an approximation of what a 25 ft chain (ten times it's length) to go all the way back to the rear axle would weigh.

Steel weighs 495 lbs per cubic foot or 485 lbs per 1728 cubic inches.

The GM transmission drag racing chains for the transmission below are 7/8th inch wide by less than 5/8th inch high. 25 feet = 300 inches. So assuming the chain is solid steel then it is 7/8 x 5/8 x 300 inches (0.875 x 0.625 x 300) for a total of 164 cubic inches of steel. That's less than 1/10th of a cubic foot of steel (164 / 1728 = 0.0949 of a cubic foot). So we have now calculated that 0.0949 x 495 lbs = 47 lbs weight if the 25 foot long chain for my Chain Driven RWD Cruze is solid steel.

1 short ton = 2000 pounds so I don't think you are correct saying it would weigh a ton.
It in fact would weigh somewhat less than 47 pounds.

Does anyone know what a conventional 10 ft drive-shaft weighs?

[MonaroSS]

Originally Posted by Tek

Well not a ton but 104 pounds if using 3/4" width roller drive chain allowing for 10' as said that would be 20' of chain +- a few inches. Ouch

Hi mate,

You posted while I was doing my above calculations. Do you have a link to drive chain specifications as that weight of yours is twice what I calculated assuming solid steel and a wider chain?

Or are you quoting commercial drive chain for driving conveyor belts etc. They are a different animal and shape and weigh far more for a given width.

Thanks

[Sgt Beavis]

First I'd like to echo everyone's statement that the Monza chop is AWESOME. I would buy it, FWD, RWD, AWD, or even rubber band drive.

As to the proposed drive system. I think something that Ford worked on in the '90s would be a better solution.

The T-Drive.
http://www.drivingenthusiast.net/sec...ve/default.htm

The engine is kept transverse but the transmission is mounted to the middle of the engine block and drives the rear wheels.

The biggest advantage being that you can use one platform for FWD or RWD cars and save a fortune in development costs.

Ford was developing a straight 8 to use with this drive system but abandoned everything for the current modular V8.

Perhaps an idea whose time has come??

[95Olds88]

Those cars are just amazing, I love the red that is used also.

[goatgary]

MonaroSS, love your chops, ideas and commentary but as to chain drive, what happens when it is packed with snow and ice....or mud? Would inevitably happen even with a shroud.

[MonaroSS]

Originally Posted by goatgary

MonaroSS, love your chops, ideas and commentary but as to chain drive, what happens when it is packed with snow and ice....or mud? Would inevitably happen even with a shroud.

Not a shroud but fully encased in a sealed industrial grade plastic box, water/oil and air tight...

[Tek]

Originally Posted by MonaroSS

Hi mate,

You posted while I was doing my above calculations. Do you have a link to drive chain specifications as that weight of yours is twice what I calculated assuming solid steel and a wider chain?

Or are you quoting commercial drive chain for driving conveyor belts etc. They are a different animal and shape and weigh far more for a given width.

Thanks

25' of the GM Trans chain would most likely snap in half under load. I just searched for a strong roller drive chain, in the 104 pound case a 58,000psi spec that should carry the load at those lengths. Funny just watched an old "Junkyard Wars" episode the other day, guys made a hill climb vehicle, chain driven, 750cc? motor cycle, chain was maybe 12 foot total and broke. Sure it was "junk" chain and motor cycle spec, maybe a .520 but still you get the idea, its the length that will do it in. You will get the same effect with say log chain on the farm, a 10' length will hardly ever break, take 25' though and it will snap in the middle.

[rsbaker]

Originally Posted by MonaroSS

Actually my idea would be not just a chain guard but a fully enclosed and sealed oil-tight box. Oil would spray onto the chain for lubrication and then drain to the bottom of the box where an oil scavenge pump, like in a dry sump system, would collect it for re-use. So unless the box was actually holed, like putting a hole in your sump case, nothing would get in.

The chain drives in Eldorados were pretty robust and I don't ever recall hearing that there were any problems with them. I still see quite a few 1970s era Eldorados running around. They would have to be very durable to handle the 500Cid V8 and more than 4000+ pounds of Cadillac they had to move around and that's not including the 5000 pound tow rating that I think they had. If they were problematic we would not see any still around. I've seen plenty of Eldorados towing boats and Airstreams over the years. If it's designed right it should never fail.

[Tone]

What everyone is forgetting is that chains used in existing FWD powertrains are only handling engine torque, not engine torque multiplied by the gearbox.

That's a huge difference in torque.

Not sure how that effects the chain durability (coming after, rather than before, the gearbox).

Really, it would probably be cheaper and a lot easier to simply use a bevel gear to change the direction of travel and use a traditional prop shaft. It would maintain much of the packaging efficiency of FWD, and provide some of the handling advantage of RWD. It would still be fairly nose-heavy, though.

[MonaroSS]

Originally Posted by Tone

What everyone is forgetting is that chains used in existing FWD powertrains are only handling engine torque, not engine torque multiplied by the gearbox.

That's a huge difference in torque.

Not sure how that effects the chain durability (coming after, rather than before, the gearbox).

Really, it would probably be cheaper and a lot easier to simply use a bevel gear to change the direction of travel and use a traditional prop shaft. It would maintain much of the packaging efficiency of FWD, and provide some of the handling advantage of RWD. It would still be fairly nose-heavy, though.

But you forget it works the other way too. As I said, the front sprocket would be mounted on the shaft where the former front ring gear was, so that's 'after' the final drive ratio has reversed the torque increase of the gearbox. The front and rear sprockets would be the same size as in 1:1.

So using the example gearbox and final drive ratio in the quote below, the Drive Chain would actually experience less than engine torque in first gear (3.166:1 / 4.444:1 = 0.712:1) and way less in all other gears.

Originally Posted by The Transmission Bible

http://www.carbibles.com/transmission_bible.html

The table below shows some example gear ratios for a 5-speed manual gearbox (in this case a Subaru Impreza).

Gear Ratio RPM of gearbox output shaft.

1st 3.166:1
2nd 1.882:1
3rd 1.296:1
4th 0.972:1
5th 0.738:1

Final drive - it's important to note that in almost all vehicles there is also a final reduction gear. This is also called a final drive or a rear or front-axle gear reduction and it's done in the differential with a small pinion gear and a large ring gear. In the Subaru example above, it is 4.444:1. This is the final reduction from the output shaft of the gearbox to the driveshafts coming out of the differential to the wheels.

[MonaroSS]

Originally Posted by Tek

25' of the GM Trans chain would most likely snap in half under load. I just searched for a strong roller drive chain, in the 104 pound case a 58,000psi spec that should carry the load at those lengths. Funny just watched an old "Junkyard Wars" episode the other day, guys made a hill climb vehicle, chain driven, 750cc? motor cycle, chain was maybe 12 foot total and broke. Sure it was "junk" chain and motor cycle spec, maybe a .520 but still you get the idea, its the length that will do it in. You will get the same effect with say log chain on the farm, a 10' length will hardly ever break, take 25' though and it will snap in the middle.

Maybe you could explain the mechanism whereby a longer length of chain is appreciably weaker than a shorter length....

Unless you are talking about some compounding snatch shock I'm just not understand the physics of how that would be.