Torque Converter Identification

[BudW]

Well said Kkritsilas.

The balance issue is something that Chrysler started to do in ’69 as a work around for the 440 6-bbl that uses heaver internal parts and trying to get that engine released sooner.
In about ’72 (more or less) Chrysler started to go with crankshafts made of cast iron instead of forged steel. Cast iron is not as strong as forged steel, but it comes out that forged steel is overkill in most cases. You can “build” an extremely stout engine with maybe 3-4 times the original horsepower and use a stock a cast iron crankshaft (but nobody wants too, if forged parts are still readily available).

Cast iron has a different density than forged steel - which requires the balance weights on crankshaft to be larger – and that is not possible in many cases – so additional balance weight was added on outside of engine (i.e.: harmonic balancer (front) and torque converter (rear)).

318 engines (all) and all engines with forged crankshafts (except for the 440 6-bbl engine) have a neutral balance to them (no external weighs).

All engines with cast iron crankshaft have externally balanced harmonic balancers and torque converters (except for 318’s) - and the amount of balance differs with engine (i.e.: 340 is different from 360, which is different from 400, which is different from 440).


About 15 years ago, maybe, the aftermarket came out with an externally balanced flex plate that takes the place of balance on the torque converter.
The aftermarket also came out with a harmonic balancer that weights bolt onto it so one can use one balancer for several engines, with add-on weights available for the different size engines.

Does this clear up the mud, just a bit?

 

[Justwondering]

getting there.

Whats the purpose of a torque converter again. I don't seem to be understanding that part.

 

[BudW]

This is a picture of a normal flex plate for our cars.

This is an aftermarket (neutral balance).

This one is aftermarket for a 360. All 360’s have cast iron crankshafts.

Notice the amount of material removed to compensate for balance weight.
Also note: this is so a person can use a neutral weight torque converter (finding a neutral balance converter is 100 times easier than finding a specific balanced converter).

This one balanced for a cast iron crank 440, for reference.

 

[Justwondering]

So you are externally balancing the engine so it doesn't waller itself out of the engine bay or the motor mounts

The torque converter is the thing an automatic car uses instead of a third pedal clutch?

 

[BudW]

The torque converter allows you to keep vehicle in gear when you are at a stop light.

When you apply the gas from a stop, it also multiplies the torque available to get car up to speed (not a big multiplication, but there enough to notice.
A torque converter loses its effectiveness when it car is cruising (about 10-15% loss of power - which the lock up clutch fixes).

In summary, the torque converter is the main difference between an automatic or manual transmission.

Note: some people say 5-10% slippage. I don’t know the percentage for sure, nor do I care to measure it. The percentage is not worth arguing about. The fact the slippage is there - is the issue, and most can agree with that.

Edit:
By the way, if you add a balanced torque converter in place that doesn’t need it (or vice versa), the engine vibration will want to shake your teeth out of its sockets - as well as everything else.

 

[Justwondering]

Ahhhhh.
Now its beginning to make sense.

So instead of my left foot mashing in the clutch pedal, the torque converter handles all that an more.

Okay..
Thanks

 

[BudW]

Automatics are so overrated. I prefer shifting.

 

[Justwondering]

There is a manual shift in my future if I can get and keep these automatics in good shape

 

[BudW]

I know she is talking about something else - but wouldn't Justwondering look cool driving her 4 (or 5) speed 5th Ave into town?

The next thing you know, the Duke boys will be there in person to show her how to jump cars and run away from the cops in her freshly painted orange "01" 5th Ave.
No wait, I must be thinking of someone else's dream . . .

 

[Justwondering]

lol --
Right now, if those boys came with cool weather, they can jump the car , the police, and paint the thing purple. lol

 

[BudW]

A question came up on slotted vs notched torque converters.
All FMJ's used a slotted converter.

This pic swiped from the internet, somewhere.

You can use a notched converter in place of a slotted one (or vice versa) if you change the front pump gears at same time.

I’m not sure that one is any stronger or more reliable than the other – but the notched ones are cheaper to manufacture.

 

[Mopar&vettedude]

What is the stall on a factory converter on our cars? Or is there more than one for our cars? I've been tossing the idea around of doing a stroker kit on the 318 and punching it out to a 392. I wasn't sure if i should get a different converter or would i be ok with the factory?

 

[AJ/FormS]

What is the stall on a factory converter on our cars? Or is there more than one for our cars? I've been tossing the idea around of doing a stroker kit on the 318 and punching it out to a 392. I wasn't sure if i should get a different converter or would i be ok with the factory?

There is no one size fits all answer for that, but generally teeners are under 1900........ cuz they make pretty good torque, down there. With a 2.74 low gear however,and depending on the rear gear again, the stalls could be as low as 1750.

Your 392 stroker idea ........ might be OK with a stock TC, depending on your chosen cam, and resulting cylinder pressure, TM, and it's intended useage. But in all likelyhood it will just suck....... unless you had a higher one to start with...... But mostly, the 392 won't need the 2.74 low gear and, in fact,those A999ratios might prove to be a handicap. then again......depending on your useage; if the stroker managed 240ftlbs at 1800, with a 2.74low-gear, and a 3.23rear gear then , the math says
240x2.74x3.23x1.05=2230 and 4250 instantaneous. But the 1800 won't still be an 1800 with 240ftlbs input versus the 140 stock input. So maybe it's a 2200 with 240 input. But at 2200, maybe the stroker puts out more like 280; so now the numbers look like;
280x2.74x3.23x1.05=2600, with an instantaneous up to 4956, so what I'm saying I guess is wait and see,lol.
Best advice for a streeter is to chose your rear gear carefully, so you get best use out of second gear. I see no advantage in a 6000rpm cam and 3.23s cuz at that rpm you will be doing 52 in first/93 in second, while the speed limit is 65... ish. At 65 in second, the Rs might be 4200 and sure as heck somebody with a better combo is gonna waste you.
As for me, I like to be on or near the power peak, in second gear, at 60 mph, with enough head-room to hit 70/75 for passing...... with whatever rear that takes. but Still want to cruise 65<2800
So that would be 3.64s. With a 318/340 that would round to a max gear of 3.73s. But with the stroker 392, 3.55s will be fine. So then passing at 75 will be ~5350 with a 1.54second/and 5040 with a 1.45 second.
Ok now 60 will be 4300 with a 1.54 second/4030 with a 1.45 second.
So in this case, the A999 ratios look better.
So now you just build an engine for peak power at 4300 give or take. Which is like a teener cam lol.
Ok so say you put a 292/292/108 cam in there instead, which power peaks at ~5600. Well guess what; in 2.74 low gear, you will be spinning to shift rpm of 6000/47mph, then hitting second at 3220rpm and you got 13mph to get that sucker back up on the cam, and it will never happen. In fact she won't wake up until ~4600/64mph. But she will have a great sounding idle.
So what is the answer then?
Like I said ; Best advice for a streeter is to chose your rear gear carefully, so you get best use out of second gear.
If you want to hit all the targets you need an overdrive. Then you can run any rear gear you want and a matching cam for it, and still cruise at a reasonably low rpm.
So now With an A500;you can run a cam that peaks at say 5000,run 4.10s, and hit 60@4940 Badaboom, And at 75 for passing, those 4.10s will hit 6180 in second Badaboom. And 65=2285 in lock-up; Badaboom.
3 outta 4 ain't bad.You want lumpy idle for #4, I guess there'a always the "Thumpers"
Ok now we have a rear gear figured out,(4.10s),what will you need for a TC?
Well a 5000 power peak is about a 218@.050.. You might have a tough time figuring out a low enough compression ratio to run that with iron heads.... but you can make it work with aluminum real easy. In any case, you will have lots of cylinder pressure and therefore lots of low rpm torque. I would be willing to at least try whatever TC is in your car now. Lets say it was born an 1800, and now it's a 2200 behind the stroker. And lets use the 240 ftlbs@2200 again
240x2.74x4.1x1.05=2830 ftlbs to the road in first, with a possible; I'm gonna downgrade the 2.0 to 1.8 now, cuz with 4.10s it's gonna rocket off the line, so that gets you an instantaneous 4850 at zero mph. I tell you what; if you can hook that, you'd be pulling the wheels up.
Ok so back up just a lil;
now you have a 392 with an itty-bitty 218@.050 cam ripping down the hiway at 65=2285 in loc-up, with 27" tires, blasts to 60@ ~5000, has a great passing gear,and a great starter gear...... You see something wrong with that piture?
I mean besides it don't idle like JohnForce's rocket.
Me neither.
Well except, the cash outlay... A 360 will do almost the same dadgum thang, for way less money, in an A-body, and will make a bit better mpgs toboot.. I bored mine to 4.04 and called it a 340stroker. It's actually a 367. The 360 might give up a bit on the bottom, and a bit on the top..... neither of which is gonna make a lick of difference in a streeter.
Anyway, that's AJ's opinion

 

[Mopar&vettedude]

I'd have to pull specs off the cam again, it wasn't anything radical. It was more of a slightly more aggressive than stock cam. Plus I'm planning on running the 302 casting heads to boost compression along with staying with a flat top piston. Its more or less just a stout summer cruiser nothing extreme for racing or anything. Just something to light the tires up every once in a while lol

 

[Mopar&vettedude]

Cool thanks for the info aj! Much appreciated, definitely helps

 

[BudW]

What is the stall on a factory converter on our cars?

Getting back to the original question. This is from my 1977 FSM (Factory Service Manual):

My 1986 FSM only says torque converter stall “between 1700 to 2000 RPM” is OK.

All the above figures (this post) is for stock (ie: un-modified) engines.
Once the engine is modified, then who knows what the correct stall speed will be.
BudW

 

[Duke5A]

As mentioned by @BudW, stall RPM is also a function of torque produced by the engine. Strokers make tons of low RPM torque and are known for a torque curve that is broad and flat. Building a 392 will absolutely increase the stall RPM of the factory converter and will most likely put it right where you want it for a street car. I would leave the converter alone until after you build the motor and evaluate afterwards.

Also, do not put any money into 302 heads if you plan on stroking the motor. Even hogged out they will be a bottleneck on such a motor. Since you get pistons anyways with a rotating kit you don't need to constrain yourself to 302 heads for their closed chambers. If you need to watch the budget then Engine Quest retrofit Magnum to LA iron heads are the best deal. Otherwise I'm a fan of Eddie heads.

 

[Oldiron440]

Converter stall also depends upon the compression ratio and camshaft choices that you make. I also agree with buying the best heads you can even some of the Eldelbrock heads constrict power on the small mopar compared to other makes, Ford and GM.

 

[Mopar&vettedude]

As mentioned by @BudW, stall RPM is also a function of torque produced by the engine. Strokers make tons of low RPM torque and are known for a torque curve that is broad and flat. Building a 392 will absolutely increase the stall RPM of the factory converter and will most likely put it right where you want it for a street car. I would leave the converter alone until after you build the motor and evaluate afterwards.

Also, do not put any money into 302 heads if you plan on stroking the motor. Even hogged out they will be a bottleneck on such a motor. Since you get pistons anyways with a rotating kit you don't need to constrain yourself to 302 heads for their closed chambers. If you need to watch the budget then Engine Quest retrofit Magnum to LA iron heads are the best deal. Otherwise I'm a fan of Eddie heads.

Hmm. I didnt think that would effect the performance of the motor. I wouldve figured closed chamber higher compression? Those engine quest heads are complete correct?

 

[Mopar&vettedude]

So basically if i leave the motor stock then the heads I have would be ideal?