394 and Hydramatic from 62 98

[Guest]

Don,

What exactly is the Roto "torque multiplier" if the coupling is not a torque converter? So far, I thought the only difference b/w converter and coupler was the pitch of impeller and turbine veins, thereby multiplying torque.

Also, if the coupling drains after 1st, what keeps continuity or communication within drivetrain?

Finally, I'm still pondering the ramifications of the stator in the coupling. So if the Roto's twin-coupled predecessors had no stator, were they simply less efficient?

Great stuff,

John

__________________________________________________________________________

The Torque Multiplier or "Accel-A-Rotor" as Olds calls it is a fixed position stator. As said before it was used in Roto Hydramatic and is the only coupling driven automatic to use one. As said before fluid couplings have straight vain blades while torque converters have curved vanes and most cars with converters use a stator.

Ok when the Roto is in 2nd gear the coupling is empty, the front clutch is applied, reverse cone is released, neutral clutch is applied, the sprag clutch is effective, and the rear overrun band is released. Remember the Rotos coupling is controlling clutch action just the same as the old controlled coupling dual coupling hydramatic was in the small coupling or how the original hydramatic's front clutched worked. So when Roto's coupling is empty there is no fluid between the engine and the trans-it's in full mechanical connection (very effecient!)

Thirdly, if there was no stator there would be no torque multiplication. If no stator was there you would have at breakaway a 2.93 to one first gear instead of with multiplication a 3.50 to one first gear. As engine rpm and transmission speed increase in first gear the stator becomes ineffective and all you have is 2.93 to one at the end or top of first gear. This terminology of two ratios in one led some people and in some books to also call Roto a four speed automatic---but I can assure you it is a three speed.

Don

[Bee-Oh-Pee]

Thanks, Dan. I have to be careful what I ask for! The terminology is getting a bit clearer, although I know all the stuff about cones and clutches engaging and being effective would have a lot more meaning to somebody who knows automatic-trans theory.... I'm still on that steep learning curve.

The whole purpose of my pursuit is to apply this theory to what I sense happening in my Roto when I drive, to more or less determine its state of health (other than just the car’s moving forward!).

As I mentioned, I certainly can't sense any ratio change before the BIG 1-2 shift. It also feels fairly sluggish off the line; and not in a carburetion sense; it runs like a top. It just doesn't "jump" the way a lot of other cars with similar (or worse) power, weight, and final drive ratios seemed to.

BTW, is the tranny "locked up" in 3rd as well as 2nd?

Finally, as a technicality, is a stator "fixed position" by definition? I think of a stator as something that "stands" (Latin root) or remains stationary, like the stator of a motor or generator. Is there any other kind?

Best,

John

[Guest]

Thanks, Dan. I have to be careful what I ask for! The terminology is getting a bit clearer, although I know all the stuff about cones and clutches engaging and being effective would have a lot more meaning to somebody who knows automatic-trans theory.... I'm still on that steep learning curve.

The whole purpose of my pursuit is to apply this theory to what I sense happening in my Roto when I drive, to more or less determine its state of health (other than just the car’s moving forward!).

As I mentioned, I certainly can't sense any ratio change before the BIG 1-2 shift. It also feels fairly sluggish off the line; and not in a carburetion sense; it runs like a top. It just doesn't "jump" the way a lot of other cars with similar (or worse) power, weight, and final drive ratios seemed to.

BTW, is the tranny "locked up" in 3rd as well as 2nd?

Finally, as a technicality, is a stator "fixed position" by definition? I think of a stator as something that "stands" (Latin root) or remains stationary, like the stator of a motor or generator. Is there any other kind?

Best,

John

________________________________________________________________________

John, if you want to get into theory it is best to have the service manual, now for Pontiac and I don't know about the Olds manual, but Pontiac has a service manual just for Hydramatic. From 1961-1963 Pontiac has Three Hydramatic's, Super Hydramatic 4 speed (315), Roto Hydramatic, and Tempestorque. In 1964 they have Super Hydramatic, Roto model 10, and ST300. Olds has from 1961-63 Roto model 10, Roto model 5 for F-85. For 1964 Olds has model 10 Roto and the NEW Jetaway- which is the ST300.

The service manuals give you a power flow chart where you can see which components are in action through the gears.

Question #2. No the trans is not locked in third because the fluid coupling is filled.

Question 3. There are two types of stators. Fixed and variable pitch or switch pitch. Roto is a fixed type meaning the vanes don't change pitch angles. It works like this; The torque coming out ( force of oil acting on the driven side of the coupling) of the coupling will be greater than that entering. However, the driven torus will be turning much slower than the driving torus. When accelerating the car, the torque multiplier comes into effect. The engine turns the coupling drive member and this delivers oil against the vanes of the driven member, forcing the driven member to rotate. After the oil has acted on the driven member, it is delivered to the torque multiplier, There it's direction is changed so that it strikes the back sides of the driving member vanes. this adds driving force to the force already being delivered by the engine. As a result, greater turning effort (torque) is delivered to the driven member. As such the torque is multiplied. As car speed increases, the differences in speed of the three members of the fluid coupling decreases. At cruising speed, there little difference. Under those conditions the oil flows nearly straight through the stator so that the stator does not change it's direction of oil flow. Thus the entire torus (coupling) becomes a fluid coupling and operates as other two element couplings function.

This is a picture of a Torque converter with a stator, the stator is the small turbine cutaway to the left: http://upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Bauma_2007_ZF_Drehmomentwandler.jpg/220px-Bauma_2007_ZF_Drehmomentwandler.jpg

Don

Edited December 8, 2011 by helfen (see edit history)

[PONTIAC1953]

________________________________________________________________________

Charles, this is more like the chicken VS the egg. Pontiac knew the Roto took less space so they designed the floor around it. As far as floor interior dimensions they are the same, but what a waste of money for two dies. I also know people who have put T-400's in Bonnevilles and still had to modify the floor to get the right engine/trans driveshaft angle correct. The G/P sits lower than the same bodied Catalina due to suspension alteration- the body and frame are the same on the two-two door hardtops.

D.

hi don, you're wrong about why the 1962 grand prix sits lower than a catalina, the body is designed to sit lower on the frame, even thomas bonsall wrote about this in his book, pontiac, they built excitement. charles coker, 1953 pontiac tech advisor.

[Oldsfan]

*puts on Moderator hat*

Gentlemen,

Right, wrong or indifferent, this is not a place to discuss '62 GP body mounting. There is another forum for that. Let's keep this HydraMatic related, please.

Thank you.

*removes Moderator hat*

[Guest]

Your right Oldsfan, this is no place for a specific Pontiac Hydramatic question regarding body floors so I will PM Charles with my latest findings. I wonder if you might be able to tell me if a 62 Starfire has a different ride height or overall height than a 98 two door coupe???

Don

[D Yaros]

I do not know about the "ride height" on the 98 vs. Starfire. What I do know is that the S-F is based on the 88 chassis/body.

[Guest]

I do not know about the "ride height" on the 98 vs. Starfire. What I do know is that the S-F is based on the 88 chassis/body.

_______________________________________________________________________

Well, sounds like the same marketing as the G/P-both using the smaller platform for a sport / Luxury vehicle. If anyone out there has the 62 Olds Chassis Service manual the overall height is in there. I would be curious to know the difference.

Don

[Guest rsd9699]

I would think that the difference in a S/F verses an 88 would be the spring rates to provide a different ride/handling. I would think that would be true of the G/P verses the Catalina. I would also expect the "wide track" ride/handling to be different between a G/P and a S/F. Same would be true for a Wildcat. I have driven the three and I chose the S/F for getty-up-and-go and the ride verses the other two.

In 1970, these three cars were 8 years old and sold for 300 to 500 dollars - the S/F was $500

and the G/P was $350 and the W/C was $450 - all were loaded and a/c and were well keep one owners.

Ron

[Guest chequenman]

_______________________________________________________________________

Well, sounds like the same marketing as the G/P-both using the smaller platform for a sport / Luxury vehicle. If anyone out there has the 62 Olds Chassis Service manual the overall height is in there. I would be curious to know the difference.

Don

I have a Chassis Service Manual but I haven't a clue where the ride height or overall height would be printed......? :confused:

[Guest rsd9699]

the ride height is generally listed as the spring heights in the service manual. The owners manual would likely provide the ride heights but they allow for nearly 1 inch of variance as the springs settle.

Ron

[Guest]

I have a Chassis Service Manual but I haven't a clue where the ride height or overall height would be printed......? :confused:

________________________________________________________________________

It would be in the very beginning where you would find dimensions like wheelbase , track, etc. Unfortunately they don't give frame to ground clearance like new cars do, but they do give overall height and that is all I need and If you don't mind the front and rear track.

Don

[Guest chequenman]

________________________________________________________________________

It would be in the very beginning where you would find dimensions like wheelbase , track, etc. Unfortunately they don't give frame to ground clearance like new cars do, but they do give overall height and that is all I need and If you don't mind the front and rear track.

Don

Overall height "88", Super "88", Starfire, & "98", is 55.6" inclusive, and the wheel tread for front and rear is 61.0" for all models. :)

[Guest rsd9699]

I would think that a Pontiac would be nearly the same height and the width would be about 1 inch wider to give it the "wide track" effect.

A quick net search says the Cat. is 62.5 tread - front and rear - did not find a height but it came equipped with 8.00 by 14 tires so that is another fact to consider - tires size plus spring sag.

Ron

[Guest]

I would think that a Pontiac would be nearly the same height and the width would be about 1 inch wider to give it the "wide track" effect.

A quick net search says the Cat. is 62.5 tread - front and rear - did not find a height but it came equipped with 8.00 by 14 tires so that is another fact to consider - tires size plus spring sag.

Ron

_________________________________________________________________________

Ron, this should really be moved off the hydramatic thread. For Pontiac there are EIGHT different height specifications depending on model. The tallest at 55.6" and the lowest at 53.4 and the rest in-between. I don't want Oldsfan to get bent so if you want to keep going please start a new one. A thanks to Chequenman for the Olds information!!

Don

[Guest rsd9699]

Mr. Moderator, can you break this into 2 threads?

Ron

[Guest Julian]

tt

[Guest Julian]

q...instead of a fluid coupling (torque converter) type thing, this tranny has what appears to be a clutch disc like thing that mates to the fly wheel.. what kind of gizmo was that??

[Guest]

We already covered that on this thread,

4 Weeks Ago #27

helfen

Senior Member

Join Date: Jan 2010

Location: vulcania

Posts: 1,081

Re: 394 and Hydramatic from 62 98

Quote:

Originally Posted by Julian

Yep.. these heads have 23 on them...

q...instead of a fluid coupling (torque converter) type thing, this tranny has what appears to be a clutch disc like thing that mates to the fly wheel.. what kind of gizmo was that??

__________________________________________________ _____________________

First, don't consider a fluid coupling and torque converter the same because their construction is different. Couplings use straight veins and converters are curved veins. Roto Hydramatic has about a eight inch fluid coupling with a stator. It is the only transmission that has a fluid coupling and a stator. Normally stators are used in automatic's with torque converters. The answer to your question is Roto hydramatic equipped cars do not have a flex plate like most automatics because the fluid coupling is not large enough and when drained in 2nd gear do not provide enough inertia for smooth vibration free operation so Hydramatic Division provides a flywheel just like on stick shift cars. This is what your seeing. If your looking for the fluid coupling you cannot see it because it is located behind the pump. This is a shock for the young and un-initiated person who pulls one of these transmissions from a engine looking for a fluid coupling!

Don