Re: 727 build up
[Re: Dodgem]
#1657065
08/10/14 04:07 PM
08/10/14 04:07 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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Quote:
Ultimate sprag and billet front drum for sure and a shield or blanket and a steel gear set would be advisable.
I'm not gonna tell you how to spend your money but isnt the Ultimate sprag a blow proof sprag.. if so then why the billet drum... I dont run either but I do have the bolt in sprag which isnt blow proof but I dont pedal it in low gear to break it.. if I spin or start to loose it I shift.. thats the only time you can break the sprag(in low gear)... but to the OP.. you have to change the vent location to the tailshaft for the trans brake
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Re: 727 build up
[Re: MR_P_BODY]
#1657066
08/10/14 08:44 PM
08/10/14 08:44 PM
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Joined: Jan 2003
Posts: 25,786 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,786
Rio Linda, CA
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No such thing as a "blow proof" sprag.
The INTERNET, the MISinformation superhighway
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Re: 727 build up
[Re: 540dust]
#1657068
08/10/14 09:29 PM
08/10/14 09:29 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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While I understand what you guys are saying..IF you DONT pedal a car it WONT blow the sprag.. if you loose traction on a 727 its a useless run(either in TT or finals).. if you want to get back on it SHIFT before you get back at it.. it will only blow in low
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Re: 727 build up
[Re: J_BODY]
#1657070
08/10/14 09:55 PM
08/10/14 09:55 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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Quote:
Break a few ring gear teeth, shock the driveline, you can roll a sprag.... and the drum can explode. Friends low 11 sec car did just this. We didn't know what caused it until we tried the pull the axles out of it and they wouldn't come out. Couple years later we saw another car break an 8.75 on the launch. The guys were going to throw a set of gears in it and go. Convinced them to pull the trans...where they found the sprag was a mess. Does it always happen? nope... prior to my friends car exploding I had broken a set of gears, and we put in another set and away we went... knowing what I know now there is no chance I'd do that again without a teardown and inspect.
I've broke rear gears before.. if you DONT get back on it, it wont blow.... I've run a 727 for about 45 years and NEVER blew a drum... it has to have the momentum to trash the sprag... I wont bother arguing about this.. but there have been 100s of thousands of passes with limited explosions due to hitting the power again
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Re: 727 build up
[Re: 67valiant]
#1657072
08/11/14 11:54 AM
08/11/14 11:54 AM
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Joined: Jan 2003
Posts: 16,925 NC
440Jim
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,925
NC
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Quote:
looking at going to a trans brake what should I swap out to make it better
- Aftermarket front drum (aluminum or steel) - safety item
- Plug front vent and relocate. Griner valve body instructions have a good location.
- Either put a relief hole (1/16") in the front drum pressure cavity, or the front piston.
- Heavy Duty or reinforced front servo strut (front band).
- 15 springs in the front clutch (many stock are 9)
- I like the "ported" reaction support between the large rings. See CRT web site, etc.
http://www.tciauto.com/tc/fileupload/download/download/?d=0&file=custom%2Fupload%2F121900.pdf
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Re: 727 build up
[Re: Crizila]
#1657074
08/11/14 07:13 PM
08/11/14 07:13 PM
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Joined: Mar 2006
Posts: 9,835 MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,835
MI, usa
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Quote:
Quote:
No such thing as a "blow proof" sprag.
Is there considerable strength difference between 3 and 4 gear planets?
I've never seen a planet gear itself break. The carrier or the roller bearing yes. The gear itself is not the weak point. The 3 gear style live fine in my 64, 9.20s@147. In fact I've seen old S/S trans with only 2. Doug
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Re: 727 build up
[Re: Crizila]
#1657075
08/12/14 05:07 PM
08/12/14 05:07 PM
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Joined: Jan 2003
Posts: 25,786 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,786
Rio Linda, CA
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Quote:
Is there considerable strength difference between 3 and 4 gear planets?
The weak point in the aluminum planetaries is the spline in the front planetary but there is more spline contact in the 3-pinion than the 4-pinion so the strength is a tossup between the two stockers.
It's rare to see the gear itself fail but it does happen.
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Re: 727 build up
[Re: John_Kunkel]
#1657076
08/12/14 05:19 PM
08/12/14 05:19 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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Quote:
Quote:
Is there considerable strength difference between 3 and 4 gear planets?
The weak point in the aluminum planetaries is the spline in the front planetary but there is more spline contact in the 3-pinion than the 4-pinion so the strength is a tossup between the two stockers.
It's rare to see the gear itself fail but it does happen.
In your pic there is some longer flatish steel strip type material... where did that come from.. my buddy had a 700r4 quit(all gears) and he has something like those strips of L shaped sorta straight steel.. he didnt see anything on a quick tear down but didnt take the sub assemblies apart yet.. sorta looks like a torrington bearing housing
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