2000 RPM stall converter operation..........

[slocrow]

Gentelmen; Just exactly what is going on with a stall speed. All this talk about tire size and RPM's has got me thinking (always dangerous) about what's happening. Especially with mine being a 2000 one and 70mph being right around that rpm for most with 700R4's.
It's slipping until it locks up and it doesn't lock up until 4th, or overdrive. Is it also always slipping below 2000 rpm's too?
What's the difference between normal slipping prior to lock up and a stall slip. Thanks, Frank

[rumrumm]

I depends when lockup occurs--if your transmission shifts into 4th gear, it should lock up shortly after. I don't know exactly how much slippage there is prior to lockup. Since I have an internal hydraulic lockup on my 700R4, it locks up immediately upon shifting into 4th. There is not lag time like the 700R4 in my van.

[1FATGMC]

I don't know how you have your lockup operating, but if it locks going into 4th then it isn't going to slip no mater what your rpm is in 4th, unless it is defective like mine once was.

The 2000 stall is going to depend on the load.  If you hold the brakes and give it gas it will slip until 2000 theoritically, but 2000 might be an average number for that converter and it could stall at less or more than that with you motor/vehicle weight combination.

Also when the converter is not locked like in 3rd it is going to slip at different rates depending on the load.  Driving along on a flat road it might slip so the motor is running 100 rpm more than road speed if the convert was locked.  Give it gas to pass or climb a big hill (you don't have to worry about that there   ) and it might slip 300 rpm or so above road speed.

No matter what you should get good gas mileage with that car, at least 18-20 mpg minimum.  How is the motor setup, carb, cam, etc...

c ya,

Sum

[slocrow]

"I don't know how you have your lockup operating, but if it locks going into 4th then it isn't going to slip no mater what your rpm is in 4th, unless it is defective like mine once was."
Sum, it's via a pressure switch the passenger side. You know, an inline brake switch.

"If you hold the brakes and give it gas it will slip until 2000 theoretically" "when the converter is not locked like in 3rd it is going to slip at different rates depending on the load."
Correct, I understand that part. Like winding it up on the brakes. If it was kept in 3rd (or drive), there would be some amount of slipping always, under 2 grand.

I know too that if the converter is locked up and won't unlock as rpm or pressure drops, you'll stall when the car stops.
I'm having a hard time understanding the lock-up point, not the lock up. Though I guess, in my case, it should happen almost instantaneously, presuming the pressure is high enough.
At what rpm will it engage is the question or at what rpm will it disengage.
If this is all happening around 2 grand then you could be going from a solid driveline connection to a slipping status and back, continuously. Hence the GM problem of seeking, several years ago.
I took it out yesterday for a run and took another look at the numbers. Assuming the tach is correct, at 70mph I was turning 2300ish. Unless I blew a fuse for the power to the switch, that seems high but that's what it read. If I drop to 50 I'm well below stall and if the converter has unlocked, I'm slipping, around town. I guess that's the crooks of my reason for asking the question, when does it unlock?

"No matter what you should get good gas mileage with that car, at least 18-20 mpg minimum. How is the motor setup, carb, cam, etc..."
Yeah, right...................I wish. Running 70-75 back from K'Zoo last fall and mostly on highway, I got a 13.5 average. It's a Chevy 402BB, flat tops, Summit blue cam with some audible overlap, 750 Edelbrock manual on a Performer with a Unilite non vac dist and 9' advance. Rear wheel HP is around 275, if I remember. When on the dyno some fat was taken out of the carb.

Sorry for the long response but it is Winter and I am retired.........................Thanks, Frank

[enjenjo]

Frank, if you can convert to vacuum advance you will get better mileage.

[slocrow]

Frank, if you can convert to vacuum advance you will get better mileage.

Yupper Frank. I have it in the box and it was due for install last Summer. Another Mallory Unilite but with vac. Did you know that the cup on the vac dist is 1/2" taller then the non-vac type.
After much thought and conversation I'm opting to buzz the firewall this Spring. The old one comes out fine but that extra 1/2" prevents the dist from dropping down past the second step in the block, as it rubs the firewall.
I tried dropping the assembly some without much success and decided that the firewall change was best to avoid any on the road removal problems.
Just another cry for heat in the garage.....................Thanks, Frank

[phat rat]

A cry for heat? Does Maureen hear you or are you crying in private?

[slocrow]

A cry for heat? Does Maureen hear you or are you crying in private?

Oh for crying out loud...........................

[1FATGMC]

"I don't know how you have your lockup operating, but if it locks going into 4th then it isn't going to slip no mater what your rpm is in 4th, unless it is defective like mine once was."
Sum, it's via a pressure switch the passenger side. You know, an inline brake switch.

"If you hold the brakes and give it gas it will slip until 2000 theoretically" "when the converter is not locked like in 3rd it is going to slip at different rates depending on the load."
Correct, I understand that part. Like winding it up on the brakes. If it was kept in 3rd (or drive), there would be some amount of slipping always, under 2 grand.

I know too that if the converter is locked up and won't unlock as rpm or pressure drops, you'll stall when the car stops.
I'm having a hard time understanding the lock-up point, not the lock up. Though I guess, in my case, it should happen almost instantaneously, presuming the pressure is high enough.
At what rpm will it engage is the question or at what rpm will it disengage.
If this is all happening around 2 grand then you could be going from a solid driveline connection to a slipping status and back, continuously. Hence the GM problem of seeking, several years ago.
I took it out yesterday for a run and took another look at the numbers. Assuming the tach is correct, at 70mph I was turning 2300ish. Unless I blew a fuse for the power to the switch, that seems high but that's what it read. If I drop to 50 I'm well below stall and if the converter has unlocked, I'm slipping, around town. I guess that's the crooks of my reason for asking the question, when does it unlock?

"No matter what you should get good gas mileage with that car, at least 18-20 mpg minimum. How is the motor setup, carb, cam, etc..."
Yeah, right...................I wish. Running 70-75 back from K'Zoo last fall and mostly on highway, I got a 13.5 average. It's a Chevy 402BB, flat tops, Summit blue cam with some audible overlap, 750 Edelbrock manual on a Performer with a Unilite non vac dist and 9' advance. Rear wheel HP is around 275, if I remember. When on the dyno some fat was taken out of the carb.

Sorry for the long response but it is Winter and I am retired.........................Thanks, Frank

I forgot you had a big block  :oops: .  I guess if you want to have more fun you are going to have to pay for it   .

I'll bet frank is right that the vac. advance will help some.  Changing to a q-jet would probably also help.

If your lockup switch is in the 4th pressure port it is going to lock anytime it is in 4th regardless of the rpm and/or road speed.  The brake switch has nothing to do with it locking up except to unlock it if it is in 4th and you have the brakes on.  You riding the brakes to hold that big block back       .

Now you could possible be hunting back and forth between 3rd and 4th, but I think you would feel that.  There is a part that can be added to the 700 to prevent that.  It won't then downshift until you have over 2/3's throttle.  I have that and like it.

Drive that baby out here next summer and let me take a look at it.  I think you and Ken going down the highway together would look real nice   .

c ya,

Sum

[sirstude]

You just don't have enough motor in there.     The Impala (4000lbs) with a ZZ502 gets about 15 with 2200rpm at 70.  Aint no substitute for horsepower.  I do have a vacuume advance and an 870 Holley.  Just got to brag a bit.  If you are going to have 7 bolt valve covers, make it big.

Doug

[phat rat]

I agree with Doug. I'm running the 425hp 454 crate w/750 Holley, vacuum advance, 3.42 gear/700R4, 3700# car and have pulled as high as 19.5 mpg, it's consistently 18 mpg and above on the highway at 70+mph

[Dave]

Whats the big deal anyway.  :?:  :?:  Come on Franks got the money and mileage aint a problem :!:  He just has a lot of free time so he creates problems for you guys to figure out. :?:  I read the post right after he posted it and I said to my self.. SELF.. Franks bored again.. What the old retiree wants is a 7 second 32 ford that cools good and gets 22 miles to the gallon and if he can get you guys to figure it out for him that saves him more money for the wife to take trips and him to go to car shows.. Oh ya there is a little issue with ride height too that maybe you all could help him out with :!:
How am i doin Frank  :?:  :?:  :?:  I expect a nasty email now.. Is there a nasty email reporting link on the rrt ?
Dave        

ps: i did like the pic of the 32 specially without the hood sides so the junker cools...

[phat rat]

Whats the big deal anyway.  :?:  :?:  Come on Franks got the money and mileage aint a problem :!:  He just has a lot of free time so he creates problems for you guys to figure out. :?:  I read the post right after he posted it and I said to my self.. SELF.. Franks bored again.. What the old retiree wants is a 7 second 32 ford that cools good and gets 22 miles to the gallon and if he can get you guys to figure it out for him that saves him more money for the wife to take trips and him to go to car shows.. Oh ya there is a little issue with ride height too that maybe you all could help him out with :!:
How am i doin Frank  :?:  :?:  :?:  I expect a nasty email now.. Is there a nasty email reporting link on the rrt ?
Dave        

ps: i did like the pic of the 32 specially without the hood sides so the junker cools...

Feeling good tonite huh Dave

[Dave]

Whats the big deal anyway.  :?:  :?:  Come on Franks got the money and mileage aint a problem :!:  He just has a lot of free time so he creates problems for you guys to figure out. :?:  I read the post right after he posted it and I said to my self.. SELF.. Franks bored again.. What the old retiree wants is a 7 second 32 ford that cools good and gets 22 miles to the gallon and if he can get you guys to figure it out for him that saves him more money for the wife to take trips and him to go to car shows.. Oh ya there is a little issue with ride height too that maybe you all could help him out with :!:
How am i doin Frank  :?:  :?:  :?:  I expect a nasty email now.. Is there a nasty email reporting link on the rrt ?
Dave        

ps: i did like the pic of the 32 specially without the hood sides so the junker cools...

Feeling good tonite huh Dave

Dammit Jack you could at least agree with me :?:
Ya know im right .. All you gotta do is agree and ill tell ya how nice your trailer looks.
:!:  :!:  :cry:  
Dave
It really does look good..........

[phat rat]

Whats the big deal anyway.  :?:  :?:  Come on Franks got the money and mileage aint a problem :!:  He just has a lot of free time so he creates problems for you guys to figure out. :?:  I read the post right after he posted it and I said to my self.. SELF.. Franks bored again.. What the old retiree wants is a 7 second 32 ford that cools good and gets 22 miles to the gallon and if he can get you guys to figure it out for him that saves him more money for the wife to take trips and him to go to car shows.. Oh ya there is a little issue with ride height too that maybe you all could help him out with :!:
How am i doin Frank  :?:  :?:  :?:  I expect a nasty email now.. Is there a nasty email reporting link on the rrt ?
Dave        

ps: i did like the pic of the 32 specially without the hood sides so the junker cools...

Feeling good tonite huh Dave

Dammit Jack you could at least agree with me :?:
Ya know im right .. All you gotta do is agree and ill tell ya how nice your trailer looks.
:!:  :!:  :cry:  
Dave
It really does look good..........

rather than saying feeling good maybe I should've said CHARITABLE    

than ks for the compliment on the trailer