reversing a torque converter 1

[rictek]

I don't know why but, I woke up this morning with this puzzle on my mind. What components would need to change if you drove an automatic transmission the opposite way?

I think all car engines turn clockwise and most trans have an overrunning cluch. Except for the sprag, would the converter work or are the vanes going the wrong direction?

 

[patprimmer]

I think some Honda's go anticlockwise.

I don't know for sure as I never looked inside a converter, but I expect they will not work in reverse direction, or at least, not work well

Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Warpspeed]

All the helical gears in the gearbox would create thrust loads in the opposite direction. This may or may not shorten the life of some components. Oil pumps would turn the reverse way. I think you might have some rather interesting problems getting a torque converter to work backwards.

 

[carnage1]

the vanes are going in the wrong direction, the pump would turn backwards, and the sprags would be an issue, and some designs might have trouble with the bands being pulled the opposite way during engagement.
some engines do run coulterclockwise, and have timing belts that jump teeth if you turn the motor backwards. (very bad day at the tranny shop)

 

[rictek]

Thanks for the ideas guys. This is what I thinking, a new pump housing, and flip the roller clutch. It might live if you replace the trust washers with torrington roller bearings but the bands might shudder or not engage properly.

They make 7" and 8" racing converters for TF727,C-4,TH400, etc, I can imagine that someone would be willing to make one for reverse direction but I don't know if they make new guts for a stock application or if it is a completly custom design.

Carnage, What engines do you know run backwards? I asked a tranny shop about Honda but they told me they are clockwise too.

 

[Warpspeed]

Pretty sure some Hondas run backwards, because people that have fitted centrifugal superchargers have had to use some pretty strange reversed mounting methods.

Some of the marine engines run backwards where one of a pair of engines is modified. I believe they fit a gear drive to the cam instead of chain drive. All you need then is a reverse rotation starter motor. These are easy to find, because some starters face forward, and some face back towards the gearbox for different applications.

Not sure what you are doing there, but reversing the engine might be easier than reversing the transmission.

 

[GregLocock]

Some Hondas definitely run backwards. People who installed Honda engines into their MGs learnt this the hard way.

Reversing the run direction of an engine is non trivial in practice but in theory almost all you need are some new timing pulses, water and oil pump, and camshafts. I would expect many durability issues.

The efficiency of a fluid drive run backwards would be very poor, if it worked at all.



Cheers

Greg Locock

 

[patprimmer]

As far as reverse direction marine engines go, I have a little experience with Marineised American V8 car engines.

Normally the cam (via a chain drive) rotates in engine direction in the standard engine, and the cam (via a gear drive rotates counter to engine direction in the reverse direction engine, hence the cam and ancillaries driven by it like distributor and oil pump always turn the correct way.

Obvious differences are piston pin offset, water pump and starter. Less obvious are sump baffles, oil groves in the crank or bearings.

Alternators work both ways except for the cooling fan.

Most of these problems are overcome by the marine conversion changing these things for the above as well as other reasons, not the least being corrosion avoidance or resistance.



Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[rictek]

Thanks Pat. There is a lot of info out there on reversing direction of the engine because of the marine application but no so far that I can find of a reversed transmission.

I tore apart a trans I had laying here and I am going to cut open the converter too. Does anyone know of an automotive trans that runs opposite all the domestic applications?

 

[SMOKEY44211]

Could you subsitute your automatic for a manual transmission? Flip the rear end housing 180 degrees and we,re going foward without too many headachs.----Phil

 

[Warpspeed]

Be very careful trying to turn differential gears backwards, the teeth are not usually symmetrical. The pressure face is vertical, whereas the back of the tooth slopes away for clearance.

Sometimes a ring and pinion for a front diff can be used in a rear diff if it is inverted, just as Smokey suggests. But make sure the front pinion bearing which might then be up in the air does not run dry on you.

When trying to figure out problems like these, I find a bottle of good whiskey can help the thought process along rather well.

 

[carnage1]

are you looking for a reverse transmission or transaxel?

 

[rictek]

carnage1-yes, a small automatic transmission that runs reverse direction. I was thinking of making a geared reverser or it looks like a Hondamatic will work. I am designing a trike. Are there other import cars that turn anti-clockwise?

 

[s13sr20chris]

some mitsubishis turn counter clockwise.

 

[mgrumbles]

The honda engines (4 cylinders) I think Pre 2000 models rotated backwards. Look for a tranny from a small civic application with automatic.

MSG

 

[Dirtyd0g]

Some honda converters do turn backwards. The mitsubishi's that I have seen still have the roller clutch turning the same as domestics because the transmission is on the opposite side you have to consider rotation of the engine as some of the foreign motors turn in opposite direction of the domestics.
Alan

 

[gopnhcom]

There are several that run in the non conforming direction.

Precision of New hampton has them. they make 1500 TC's a day

 

[gopnhcom]

precision of new hampton 641 394 5955

 

[jons999]

Honda started making normal clockwise rotation engines a few years ago but i think all the of 1990's hondas were backwards. When you open the hood if the engines on the right side it runs counter clockwise if its on the left (passenger side) it's a normal clockwise engine. I seem to remember hearing about Smoky Yunick machining custom cams to make his Hudson Hornet race car engines run backwards. anybody know what he did for a transmission?

-Jon

 

[SMOKEY44211]

He flipped the rear end housing upside down. I'm not sure if he actually did it on the Hudsons but I know he ran a reverse rotation Offy in one of his early front engine Indy cars.---------Phil