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Re: 727 and burnouts
[Re: PC-CHARGER]
#1961398
12/02/15 12:45 AM
12/02/15 12:45 AM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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The major reason for a non LBA valve body is to eliminate overlap in the 1-2 shift. In an LBA valve body the low reverse band has to release while the intermediate band applies. If the release of the LR band is too fast or the INT band to slow, you will get a flare in the shift. If the opposite is true, you get a bind up. Even when it is timed perfectly, there is still a short period of time when they are both applied and cause a slight delay in the shift.
In a non-LBA valve body, the sprag or roller is holding the LR drum and when the shifter is moved to second the Int bad applies and the roller clutch unlocks as it is turning in the direction in which it freewheels so the release is immediate. No overlap to deal with.
This is correct and is why RMVB were no low band apply for many years. Basically a faster shift and no worrying about any shift overlap from two elements on at the same time. You wont get a flare but you can have a drag if the kickdown (second gear) band applys before the L/R band releases. It wont flare if the L/R band releases to fast because the overrunning clutch (sprag) will still be holding just like in a no low band apply. Ron
Last edited by 383man; 12/02/15 12:48 AM.
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Re: 727 and burnouts
[Re: Tempest]
#1961548
12/02/15 07:14 AM
12/02/15 07:14 AM
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
Swedcharger67
enthusiast
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enthusiast
Joined: Dec 2010
Posts: 208
Norrland, Sweden
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Excellent info guys! Many thanks. Now I know why things are the way they are and I can rest peacefully 
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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Re: 727 and burnouts
[Re: Tempest]
#1961819
12/02/15 04:51 PM
12/02/15 04:51 PM
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Joined: Jun 2006
Posts: 5,161
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,161
CT
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Moparts has scared the poop out of me with 727 explosions. I remember when I bought my first MoPar when I was 16, a '67 440/727 GTX, and thought it was bulletproof. All I ever heard was the 727 is a tough rugged mother, 8 3/4 tough as nails behind a Torqueflite. Didn't know anything about RMVB, but the car had one, which I figured out once I got it running.
Nice running 440, I used to put that sucker in low, punch it and absolutely annihilate the H78-14 white walls off the back of it. Had 6000 RPM in about 15 feet, didn't know better, it sure was fun, and that tranny snapped 2nd gear real nice. Never hooked in first, and never really pedaled it though. And never drove it really on the street much, just pulled it out and went around the neighborhood leaving H78 lines all over the road since it was rough and I didn't own it long.
Spend enough time on here and you think a 727 is a ticking time bomb made out of glass. I always thought it was the best 3 speed automatic. This site makes me afraid of a non-LBA 727. Maybe I got lucky. I don't even like to go near the starting line when a 727 MoPar is launching now.
Last edited by GTX MATT; 12/02/15 05:02 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: 727 and burnouts
[Re: Tempest]
#1961824
12/02/15 05:00 PM
12/02/15 05:00 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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I went with a "cheetah" valve body. It has low band apply. Besides manual shifting, it will also up-shift automatically if you leave it in drive. I come out of the water box in drive ( 1st) and feather the throttle as it upshifts in to 3rd applying more power as I leave the box. Works great.
Fastest 300
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Re: 727 and burnouts
[Re: Crizila]
#1961829
12/02/15 05:15 PM
12/02/15 05:15 PM
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
Swedcharger67
enthusiast
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enthusiast
Joined: Dec 2010
Posts: 208
Norrland, Sweden
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More excellent info! Yes Transman, I didn't think of that, but wheel hop could certainly be a bad case with a non-LBA valve body. Interesting Crizila, sounds like the Cheetah would be my type of valve body! The more I learn, the more satisfied I am with still having the stock (although modified...) valve body! 
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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Re: 727 and burnouts
[Re: Swedcharger67]
#1961835
12/02/15 05:25 PM
12/02/15 05:25 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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As I tell everyone... DONT DO STUPID STUFF with the 727 and it wont blow... I still have a stock drum in the race car.. if you ever have to get out of the pedal SHIFT IT out of low... I've had this trans in it for 15 years and I have NEVER blown up a 727(driving mopars for 50 years) 
Last edited by MR_P_BODY; 12/02/15 05:26 PM.
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Re: 727 and burnouts
[Re: A727Tflite]
#1961836
12/02/15 05:25 PM
12/02/15 05:25 PM
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Joined: Jun 2006
Posts: 5,161
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,161
CT
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I know about the issue with sprags and LBA or not, relating to shock, freewheel at 2X the RPM and taking apart the drum. There are plenty examples out there. My question is, does it seem this is predominately an issue w/ slicks and racing?
Back in the day, we used to do burnouts all the time in 1st, pedal the car on and off the throttle with street tires and I never once heard of a 727 coming apart on the street back then. Granted HP/TQ was not what it is now for a healthy 440 like now.
Just trying to get a better understanding if this is just a slicks/track issue as I've always started burnouts in 1st. The reason I'm asking, I now have a fairly quick 440 and guess at the very least I should add a blanket to the trans. But I have no plans to run slicks.
Its due to roller spit back and shock load. The ORC has rollers and waffle springs. Spit back comes from when the rollers get locked then unlocked then locked again - think wheel hop. Slicks will compound the problem since you load the ORC more each time after it is unlocked - then you either spin the ORC cam in the case or you cock the rollers then things go to Haiti after that.
When I started with Chrysler I authorized ALL the transmission replacements for the U.S. - and cop cars (especially NY cop cars) broke the ORC with regularity. And they didn't have slicks on them. They had manual low block out - that prevented manual low band apply even though the cops thought they had them in low gear.
Came from two basic events - running across railroad tracks deep throttle (wheel hop)while in first gear auto, and neutral drops. So did it go into low and not apply the low/reverse band, or it just wouldn't go in? And they took the ORC out in 1st gear auto, but did that explode the drum? I'm a little confused.
Last edited by GTX MATT; 12/02/15 05:27 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: 727 and burnouts
[Re: GTX MATT]
#1961842
12/02/15 05:32 PM
12/02/15 05:32 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I know about the issue with sprags and LBA or not, relating to shock, freewheel at 2X the RPM and taking apart the drum. There are plenty examples out there. My question is, does it seem this is predominately an issue w/ slicks and racing?
Back in the day, we used to do burnouts all the time in 1st, pedal the car on and off the throttle with street tires and I never once heard of a 727 coming apart on the street back then. Granted HP/TQ was not what it is now for a healthy 440 like now.
Just trying to get a better understanding if this is just a slicks/track issue as I've always started burnouts in 1st. The reason I'm asking, I now have a fairly quick 440 and guess at the very least I should add a blanket to the trans. But I have no plans to run slicks.
Its due to roller spit back and shock load. The ORC has rollers and waffle springs. Spit back comes from when the rollers get locked then unlocked then locked again - think wheel hop. Slicks will compound the problem since you load the ORC more each time after it is unlocked - then you either spin the ORC cam in the case or you cock the rollers then things go to Haiti after that.
When I started with Chrysler I authorized ALL the transmission replacements for the U.S. - and cop cars (especially NY cop cars) broke the ORC with regularity. And they didn't have slicks on them. They had manual low block out - that prevented manual low band apply even though the cops thought they had them in low gear.
Came from two basic events - running across railroad tracks deep throttle (wheel hop)while in first gear auto, and neutral drops. So did it go into low and not apply the low/reverse band, or it just wouldn't go in? And they took the ORC out in 1st gear auto, but did that explode the drum? I'm a little confused. No.. you couldnt pull the shifter into low position.. it had th blocker that didnt allow it.. the cops had a issue of forgetting to shift out of low.. they would just float the valves and half the time blow up the engines.. so the trans was in low BUT the shifter was in second so it would shift
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Re: 727 and burnouts
[Re: MR_P_BODY]
#1961855
12/02/15 05:52 PM
12/02/15 05:52 PM
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
Swedcharger67
enthusiast
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enthusiast
Joined: Dec 2010
Posts: 208
Norrland, Sweden
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and since the cops couldn't have the shifter in manual low...the low band wasn't applied, and full throttle in 1:st while wheel hopping over railroad tracks caused the overrunning clutch (sprag) to freewheel momentarily and they broke the sprag...
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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Re: 727 and burnouts
[Re: Swedcharger67]
#1961858
12/02/15 05:54 PM
12/02/15 05:54 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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and since the cops couldn't have the shifter in manual low...the low band wasn't applied, and full throttle in 1:st while wheel hopping over railroad tracks caused the overrunning clutch (sprag) to freewheel momentarily and they broke the sprag... They COULD have.. I never watched them on the job.. but most times they blew up the engines(before the blocker) EDIT If I recall correctly they started putting the blocker on in 74'
Last edited by MR_P_BODY; 12/02/15 06:02 PM.
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Re: 727 and burnouts
[Re: Swedcharger67]
#1961869
12/02/15 06:06 PM
12/02/15 06:06 PM
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Joined: Jun 2006
Posts: 5,161
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,161
CT
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and since the cops couldn't have the shifter in manual low...the low band wasn't applied, and full throttle in 1:st while wheel hopping over railroad tracks caused the overrunning clutch (sprag) to freewheel momentarily and they broke the sprag... Gotcha, but it didn't blow up the drum?
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: 727 and burnouts
[Re: GTX MATT]
#1961880
12/02/15 06:13 PM
12/02/15 06:13 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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and since the cops couldn't have the shifter in manual low...the low band wasn't applied, and full throttle in 1:st while wheel hopping over railroad tracks caused the overrunning clutch (sprag) to freewheel momentarily and they broke the sprag... Gotcha, but it didn't blow up the drum? It takes like 6200 rpm... if you blow the sprag the drum will spin 2.2 times the engine rpm.. from MOST testing on the drum it will self destruct at 13,000 rpm +/- some
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Re: 727 and burnouts
[Re: A727Tflite]
#1961931
12/02/15 07:16 PM
12/02/15 07:16 PM
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Joined: Jan 2003
Posts: 25,783
Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,783
Rio Linda, CA
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Back in the day, we used to do burnouts all the time in 1st, pedal the car on and off the throttle with street tires and I never once heard of a 727 coming apart on the street back then. Granted HP/TQ was not what it is now for a healthy 440 like now. Sure, we all did it but time is supposed to make us wiser. My very first 727 for pay was from a bone stock '69 Dart GTS 383 that rolled the sprag and took the case with it on the street.
The INTERNET, the MISinformation superhighway
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Re: 727 and burnouts
[Re: Tempest]
#1961963
12/02/15 07:57 PM
12/02/15 07:57 PM
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Joined: Jun 2006
Posts: 5,161
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,161
CT
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Why wouldn't a WOT downshift into first with the selector in D roll the sprag? Or can it? Sorry to hijack the thread but I can't help myself.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: 727 and burnouts
[Re: Tempest]
#1962007
12/02/15 09:09 PM
12/02/15 09:09 PM
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Joined: Jan 2003
Posts: 25,783
Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,783
Rio Linda, CA
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Once the trans shifts out of 1st gear the sprag just becomes a roller bearing...no load on it. Your car has the capability to do 2nd burnouts dry?
The INTERNET, the MISinformation superhighway
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Re: 727 and burnouts
[Re: MR_P_BODY]
#1962043
12/02/15 09:49 PM
12/02/15 09:49 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Ugh. I remember those days. Had a fleet of Diplomats set up that way - with 360's in them. Actually some of the best squads we ever had from a non-destructible drive train stand point. Suspension / steering was another story.
Fastest 300
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