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#2588217 - 12/06/18 04:21 PM When is a Race trans not a race trans....
Moparmal Offline


Registered: 01/19/03
Posts: 3910
Loc: Melbourne.....Oz-land
Before I start, the subject question is rhetorical....but....

A few mths ago I got talked into buying a “Race” 727 with rmvb from a well known commercial trans company.

I wanted to go with CRT....but international shipping was just too much with our dollar so ended up going to a local retailer and buying a RMVB from CRT and billet servos from a seller on here.


Unfo my upgrade strategy didn’t go far enough....

A guy I know just had an issue with his “race’ trans, and on inspection, we found a lot of ‘heavy duty’ components simply weren’t included....which is kind of surprising as the company claims the trans is good for 800+ HP.

ANYHOW...my question is this.

If I change to a low band apply RMVB....how important is a bolt in sprag?

The motor will be making around 500hp at 3700lbs.



Edited by Moparmal (12/06/18 04:27 PM)
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#2588221 - 12/06/18 04:23 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
EV2Bird Offline
No more politics

Registered: 06/23/14
Posts: 4500
Loc: Kansas Roads Between 0 and 140...
Broken Arrow.

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#2588230 - 12/06/18 04:31 PM Re: When is a Race trans not a race trans.... [Re: EV2Bird]
Moparmal Offline


Registered: 01/19/03
Posts: 3910
Loc: Melbourne.....Oz-land
Originally Posted By EV2Bird
Broken Arrow.


Yep...that means a lot! :lol:


Edited by Moparmal (12/06/18 04:31 PM)

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#2588245 - 12/06/18 04:55 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
MR_P_BODY Offline
Master

Registered: 06/13/03
Posts: 51000
Loc: Romeo MI
A bolt in sprag is nothing more than a stock
sparg.. they are used when a sprag has spun
in the case and a stock one is put in.. A
super sprag has many more rollers and is much
less likely to blow.. you can pull the VB and
use a stock one
wave
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#2588256 - 12/06/18 05:14 PM Re: When is a Race trans not a race trans.... [Re: MR_P_BODY]
Moparmal Offline


Registered: 01/19/03
Posts: 3910
Loc: Melbourne.....Oz-land
Hi Mr P

I don’t know a lot about trans, I guess what I’m trying to pin down is - Does a low band apply VB take the risk out of spinning the sprag?

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#2588263 - 12/06/18 05:32 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
John_Kunkel Offline
I Live Here

Registered: 01/20/03
Posts: 19827
Loc: Rio Linda, CA
LBA takes a lot of load off the sprag but sprag failures have been known to happen even with Super Sprags and LBA. At you HP level it's less likely.

There is no universal agreement on what constitutes a "race trans", some of us believe that a lot of the "race" components are just glitter....nice if you want to spend the money but not needed at some power levels.
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#2588264 - 12/06/18 05:34 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
Doc Fiberglass Offline
I Live Here

Registered: 07/04/08
Posts: 18045
Loc: ...to Paradise from ParaICE !
I would invest in an alum or steel billet front drum


Edited by Doc Fiberglass (12/06/18 05:34 PM)
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#2588266 - 12/06/18 05:38 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
dvw Offline
master

Registered: 03/16/06
Posts: 7303
Loc: MI, usa
The only thing that take the entire risk out is a good high gear drum. That being said I've seen transmissions roll the sprag with LBA and stay together. My trans just busted up a Super Sprag (non LBA). It was no fault of the sprag itself (the output shaft roller bearing failed). The trans still functioned perfectly. In fact it went 1.25 60ft on its last pass. I've even seen Super Sprags break after axle failure. I ran stock drums and sprags forever. Never hurt a stocker. As far as power level the stock planets (foot brake) , clutches, shafts have all survived easily at well over 800. I'd suggest a steel carrier front planet if you run a trans brake.
Doug

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#2588290 - 12/06/18 06:32 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
hysteric Offline
member

Registered: 04/28/08
Posts: 72
Loc: Aus
Hey Mal.

Just went through this with my 904. Said trans was built by a Sydney Chrysler
guru but when i found excessive band material in the filter the line given was "Its the filter doing it's job" Anyway turns out the rear band was shot and the rear clutches were burnt after 6 street meets and a 1k's

If you have the tools build it yourself or buy the bits and have some one local piece it together. You could try Pro trans or BBE automatics. Its not rocket science.

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#2588312 - 12/06/18 07:33 PM Re: When is a Race trans not a race trans.... [Re: hysteric]
Moparmal Offline


Registered: 01/19/03
Posts: 3910
Loc: Melbourne.....Oz-land
Hi again

Thks for the input. I have a really good local trans builder, just wasn’t sure what to swap out and what to keep.

I have a CRT rmvb that’s going in and billet servos - But I think I’m going to swap out the sprag.

I’m disappointed in this TCI Drag trans, has no bolt in sprag, no re-enforced front strut, only 3 pinion planetaries and no billet drum - I should have just paid the extra shipping and gone with another CRT.

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#2588339 - 12/06/18 08:33 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
Transman Offline
super stock

Registered: 03/27/11
Posts: 897
Loc: Michigan


Originally Posted By Moparmal
Before I start, the subject question is rhetorical....but....

A few mths ago I got talked into buying a “Race” 727 with rmvb from a well known commercial trans company.

I wanted to go with CRT....but international shipping was just too much with our dollar so ended up going to a local retailer and buying a RMVB from CRT and billet servos from a seller on here.


Unfo my upgrade strategy didn’t go far enough....

A guy I know just had an issue with his “race’ trans, and on inspection, we found a lot of ‘heavy duty’ components simply weren’t included....which is kind of surprising as the company claims the trans is good for 800+ HP.

ANYHOW...my question is this.

If I change to a low band apply RMVB....how important is a bolt in sprag.

The motor will be making around 500hp at 3700lbs.



A standard 727 properly assembled without any tricks, will easily handle your power and vehicle weight. The billet front clutch retainer will keep you from getting hurt and breaking the case if you have a driveline issue.

Take a look at an old Direct Connection catalog which shows “race” transmissions available.
These were new, production transmissions built at the transmission plant, using production parts. No bolt in ORC, billet drums, etc.

The problem that I have seen repeatedly is the builders ability to know what is good and what is questionable when reclaiming some of the parts.

Another reason why some builders insist on using new drums, planetaries, etc.
If it fails they can blame the supplier of the part while taking the risk out of the equation.

This same mentality is seen in some dealer repairs,

Not criticising, just stating some findings and facts.

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#2588391 - 12/06/18 10:23 PM Re: When is a Race trans not a race trans.... [Re: Transman]
Moparmal Offline


Registered: 01/19/03
Posts: 3910
Loc: Melbourne.....Oz-land
I take your point, but some parts provide insurance against accidental abuse.

I guess I just assumed a ‘drag race’ transmission would at least have a bolt in sprag -

I wasn’t expecting a billet drum or servos, (although CRT do priovide a billet servo in their race model...so not sure why TCI can’t?)

Buit with the motor rebuild nudging 500fw....I want to at least make sure noted weak links are fireproofed.

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#2588400 - 12/06/18 10:44 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
Twostick Offline
master

Registered: 05/20/03
Posts: 5120
Loc: Downtown Roebuck Ont
I wouldn't lose any sleep over 3 pin planetaries. The aluminum spline will fail before a pinion will.

My trans guy used to remove 2 pinions on a 4 pin on his SS Hemi car. Never broke a pinion but spun the splines out of a few.

Kevin

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#2588410 - 12/06/18 11:09 PM Re: When is a Race trans not a race trans.... [Re: Moparmal]
MR_P_BODY Offline
Master

Registered: 06/13/03
Posts: 51000
Loc: Romeo MI
How many rpm are you planning on
wave
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W-9 8.94 @ 151 NOW ON E-85
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#2588416 - 12/06/18 11:25 PM Re: When is a Race trans not a race trans.... [Re: MR_P_BODY]
Moparmal Offline


Registered: 01/19/03
Posts: 3910
Loc: Melbourne.....Oz-land
Originally Posted By MR_P_BODY
How many rpm are you planning on
wave


6700. Launches around 2500. Converter flashes to 3600.

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#2588437 - 12/07/18 12:34 AM Re: When is a Race trans not a race trans.... [Re: Moparmal]
MR_P_BODY Offline
Master

Registered: 06/13/03
Posts: 51000
Loc: Romeo MI
I was gonna tell you if the RPM was low enough
(below about 6300) you wouldnt have anything
at all to worry about.. RPM is what causes drum
failures.. IF the ORC fails that lets the drum
to spin 2.2 times the engine rpm..drums have
have been spun(used old drums)and they tend to
fail at right about 13K rpm which is close to
6,000 rpm but giving a cushion.. I have been
running a stock drum from day 1.. if you dont
do stupid stuff you dont have a issue.. I've
been turning my engines to about 8100 and some
as high as 9600rpm(not often to 9600).. that
was a test
wave
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Mike "Raff"...(180)Watching over us
CAR IS FOR SALE

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#2588441 - 12/07/18 12:49 AM Re: When is a Race trans not a race trans.... [Re: Moparmal]
Doc Fiberglass Offline
I Live Here

Registered: 07/04/08
Posts: 18045
Loc: ...to Paradise from ParaICE !
I would rather SPEND DA BUCKS on a good drum than CHANCE blowing up a trans ... losing the case .... destroying the valve body and MAYBE hurting the converter !!
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#2588452 - 12/07/18 03:12 AM Re: When is a Race trans not a race trans.... [Re: Doc Fiberglass]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 31700
Loc: Bend,OR USA
Originally Posted By Doc Fiberglass
I would rather SPEND DA BUCKS on a good drum than CHANCE blowing up a trans ... losing the case .... destroying the valve body and MAYBE hurting the converter !!
iagree A local high dollar racer had his engine, tranny builder cut some corners on a trans brake 727 which ended up exploding the front drum, came through the floorboards setting his driving pants on fire and hurting his left foot puke
A steel drum or a aluminum drum with steel liner or a all aluminum front drum will insure that you won't explode it work scope thumbs
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#2588453 - 12/07/18 03:35 AM Re: When is a Race trans not a race trans.... [Re: Moparmal]
tex013 Online   content
top fuel

Registered: 03/27/09
Posts: 1841
Loc: Sydney,Australia
Mal,
Sorry to see/ hear your results .
Lets just say i heard once what TCI means but i have not used them so thats not for me to say .
Here is a couple of my thoughts , as i am in Aus just like you . And i have built,worked in auto shops .
I have a foot brake B&M . Cracked old case and no BB core .
I ended up with a Griner RMVB . This trans ran 10.50s behind my 505 . It ran about 9 years with only regular servicing . Only broke 2 front flex bands , swapped to solid band solved that . No other issues. Still on my shelf for a spare .
Current trans has a brake and has gone 10.20s off the brake @4000 trapping just over 7000
This has a billet drum and is set for racing , though i daily drive it . And yes i paid $ for it , similar to importing a CRT .
Both trans have low band apply to help .
Fred @ Protrans here in Sydney built it .
I rang B&M when choosing theirs and they said 600hp is the round about limit as delivered .
I guess its all a pick and a poke . Who will look after you ?

Tex



Edited by tex013 (12/07/18 03:36 AM)
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#2588484 - 12/07/18 07:06 AM Re: When is a Race trans not a race trans.... [Re: tex013]
Moparmal Offline


Registered: 01/19/03
Posts: 3910
Loc: Melbourne.....Oz-land
Gday Tex.

So what is the story? I have a Griner/Cope RMVB to swap in.

Where I’m stuck is the d3cision on the sprag and 2/3 strut...I think the bolt in sprag is a must...haven’t heard much about struts failing.

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