|
When is a Race trans not a race trans....
#2588217
12/06/18 07:21 PM
12/06/18 07:21 PM
|
Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
Moparmal
OP
master
|
OP
master
Joined: Jan 2003
Posts: 3,943
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.
Last edited by Moparmal; 12/06/18 07:27 PM.
67 RO23 clone with 6.1 SRT Hemi and dual quads. Soon to have Drag Pak induction and Throttle body.
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588221
12/06/18 07:23 PM
12/06/18 07:23 PM
|
Joined: Jun 2014
Posts: 5,183
Porter67
master
|
master
Joined: Jun 2014
Posts: 5,183
|
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588245
12/06/18 07:55 PM
12/06/18 07:55 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
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 
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588263
12/06/18 08:32 PM
12/06/18 08:32 PM
|
Joined: Jan 2003
Posts: 25,748
Rio Linda, CA
John_Kunkel
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,748
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.
The INTERNET, the MISinformation superhighway
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588264
12/06/18 08:34 PM
12/06/18 08:34 PM
|
Joined: Jul 2008
Posts: 30,424
Florida STAYcation
dOc !
The village idiot's idiot
|
The village idiot's idiot
Joined: Jul 2008
Posts: 30,424
Florida STAYcation
|
I would invest in an alum or steel billet front drum
Last edited by Doc Fiberglass; 12/06/18 08:34 PM.
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588339
12/06/18 11:33 PM
12/06/18 11:33 PM
|
Joined: Mar 2011
Posts: 3,069
Michigan
A727Tflite
master
|
master
Joined: Mar 2011
Posts: 3,069
Michigan
|
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.
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588437
12/07/18 03:34 AM
12/07/18 03:34 AM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
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
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588453
12/07/18 06:35 AM
12/07/18 06:35 AM
|
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
tex013
top fuel
|
top fuel
Joined: Mar 2009
Posts: 2,458
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
Last edited by tex013; 12/07/18 06:36 AM.
New best ET 10.259@129.65 .
New best MPH 130.32
Finally fitted a solid cam,
stepped it up a bit more
3690lbs through the mufflers
New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm
Power by Tex's Automotive
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588489
12/07/18 10:31 AM
12/07/18 10:31 AM
|
Joined: Dec 2013
Posts: 4,669
Wichita
GY3
master
|
master
Joined: Dec 2013
Posts: 4,669
Wichita
|
The bolt in sprag, as others have said, is not necessary. The only reason I would use one is if the stock sprag was loose in the case or had obvious problems.
I tyically build 4-5 727's a year for local guys and never have an issue there.
The 727 in my car holds well over 700HP on spray and it is surprisingly stock! LBA Turbo Action fwd pattern valvebody, good clutches and steels and governor removed (not necessary, but just less parts to fail if removed.)
'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.
|
|
|
Re: When is a Race trans not a race trans....
[Re: dOc !]
#2588490
12/07/18 10:32 AM
12/07/18 10:32 AM
|
Joined: Dec 2013
Posts: 4,669
Wichita
GY3
master
|
master
Joined: Dec 2013
Posts: 4,669
Wichita
|
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 !! Which brand(s) have you used and why?
'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588517
12/07/18 12:06 PM
12/07/18 12:06 PM
|
Joined: Nov 2015
Posts: 874
Missouri
jwb123
super stock
|
super stock
Joined: Nov 2015
Posts: 874
Missouri
|
I have been racing mopars since 1974, never had a trans blowup or even burn one up, knock on wood. Always built my own. I have seen several of my buddies blow up over the years, lucky only minor injuries. With the damage possible to car and humans, it is only smart to use a good drum. I like the aluminum drum with the stainless sleeve, good friction surface and lightweight. The problem is most valvebodies do not hold the rear band in low gear, that plus the stress of not doing a burn out right is what causes the issue of sprag failure. I have used the low band apply valvebody, because it is safer, but in my testing the regular manual valvebody, that does not hold the band is a little faster. The low band was just not designed to be released quickly. Which is what you need for a clean 1-2 shift. Even with the modified low servo, just my opinion. http://www.tcsproducts.com/media/1/TCS_TF727_Performance_Transmission_Parts.pdf
|
|
|
Re: When is a Race trans not a race trans....
[Re: FurryStump]
#2588644
12/07/18 03:58 PM
12/07/18 03:58 PM
|
Joined: Jan 2003
Posts: 25,748
Rio Linda, CA
John_Kunkel
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,748
Rio Linda, CA
|
Correct me if I’m wrong but isnt the low band applied in all forward gears if you have LBA valve body. No. It releases on the 1-2 upshift.
The INTERNET, the MISinformation superhighway
|
|
|
Re: When is a Race trans not a race trans....
[Re: John_Kunkel]
#2588729
12/07/18 07:26 PM
12/07/18 07:26 PM
|
Joined: Oct 2004
Posts: 2,814
Connecticut
FurryStump
master
|
master
Joined: Oct 2004
Posts: 2,814
Connecticut
|
Correct me if I’m wrong but isnt the low band applied in all forward gears if you have LBA valve body. No. It releases on the 1-2 upshift. Ok thanks!
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588763
12/07/18 08:30 PM
12/07/18 08:30 PM
|
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
tex013
top fuel
|
top fuel
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
|
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. If building a big sprag will not hurt , strut bar yes a heavy duty or billet one us good Low band apply only way to go especially street driven If you are starting from scratch and are seriouslly racing put a billet drum in . Though my footbrake trans has a stock drum , it was 65/6600 throuh the traps Tex
New best ET 10.259@129.65 .
New best MPH 130.32
Finally fitted a solid cam,
stepped it up a bit more
3690lbs through the mufflers
New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm
Power by Tex's Automotive
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2588908
12/08/18 01:53 AM
12/08/18 01:53 AM
|
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
tex013
top fuel
|
top fuel
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
|
Mal,
Sprag failure is a bit luck of the draw in my opinion .
High HP and or high rpm needs a drum .
Make your own call after adking and thinking . Then hang on for the ride
Tex
New best ET 10.259@129.65 .
New best MPH 130.32
Finally fitted a solid cam,
stepped it up a bit more
3690lbs through the mufflers
New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm
Power by Tex's Automotive
|
|
|
Re: When is a Race trans not a race trans....
[Re: dart games]
#2589029
12/08/18 02:08 PM
12/08/18 02:08 PM
|
Joined: May 2003
Posts: 6,560
Downtown Roebuck Ont
Twostick
Still wishing...
|
Still wishing...
Joined: May 2003
Posts: 6,560
Downtown Roebuck Ont
|
And contrary to popular belief, it doesn't take big horsepower to do that. If the sprag/overrunning clutch fails, a stone stock 318 is capable of causing that kind of carnage. A drum explosion is strictly a product of RPM x first gear ratio, 2.45. Kevin
|
|
|
Re: When is a Race trans not a race trans....
[Re: Twostick]
#2589037
12/08/18 03:09 PM
12/08/18 03:09 PM
|
Joined: Jan 2003
Posts: 20,169
Park Forest, IL
slantzilla
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 20,169
Park Forest, IL
|
And contrary to popular belief, it doesn't take big horsepower to do that. If the sprag/overrunning clutch fails, a stone stock 318 is capable of causing that kind of carnage. A drum explosion is strictly a product of RPM x first gear ratio, 2.45. Kevin I saw one let go in a 340 Barracuda dialed 13:70, so yes, it can happen to anyone.
"Everybody funny, now you funny too."
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2589307
12/09/18 01:09 PM
12/09/18 01:09 PM
|
Joined: May 2008
Posts: 5,399
Aurora, Colorado
451Mopar
master
|
master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
|
Currently putting together a 1966 727. More HD than race, the Super Sprag and Billet drum are out of the budget.
Changes so far have been replacing the 19-spline input shaft with a 24-spline input shaft so torque converter choice is easier. Rear vent, and sprag lube hole from the cooler return. Threaded restrictor plug in case. FT-2 Shift Kit using the stock '66 servos, stock 3.8:1 band lever.
Have an old rebuild kit where all the clutches were supposed to be Alto red eagles, but bulkpart shipped alto read eagle rear clutches and Raybestos Green (High Energy) front clutches. Kolene steels for both clutch packs.
The trans looked pretty good and stock with maybe one rebuild (low mileage car.) No stripped threads in the case, sprag still tight in the case, but previous rebuilder had many of the sprag roller springs installed backwards. Might install a later dual "O"-ring rear band pin.
Haven't decided on bands yet. The stock bands look fine and thinking of reusing them, but I have a new Mopar Performance Front band on the shelf. I think it is Kevlar? Not sure if I should install it or not.
Need to still get a trans cooler and maybe a deep pan.
|
|
|
Re: When is a Race trans not a race trans....
[Re: 451Mopar]
#2589343
12/09/18 02:04 PM
12/09/18 02:04 PM
|
Joined: Dec 2013
Posts: 4,669
Wichita
GY3
master
|
master
Joined: Dec 2013
Posts: 4,669
Wichita
|
Currently putting together a 1966 727. More HD than race, the Super Sprag and Billet drum are out of the budget.
Changes so far have been replacing the 19-spline input shaft with a 24-spline input shaft so torque converter choice is easier. Rear vent, and sprag lube hole from the cooler return. Threaded restrictor plug in case. FT-2 Shift Kit using the stock '66 servos, stock 3.8:1 band lever.
Have an old rebuild kit where all the clutches were supposed to be Alto red eagles, but bulkpart shipped alto read eagle rear clutches and Raybestos Green (High Energy) front clutches. Kolene steels for both clutch packs.
The trans looked pretty good and stock with maybe one rebuild (low mileage car.) No stripped threads in the case, sprag still tight in the case, but previous rebuilder had many of the sprag roller springs installed backwards. Might install a later dual "O"-ring rear band pin.
Haven't decided on bands yet. The stock bands look fine and thinking of reusing them, but I have a new Mopar Performance Front band on the shelf. I think it is Kevlar? Not sure if I should install it or not.
Need to still get a trans cooler and maybe a deep pan. This is the exact setup I do for guys that want a good street/strip trans. In addition, we usually add the governor of their choice if they want to leave it in drive and have it shift on its own at a desired rpm. I ALWAYS tell them to shift into 2nd during a burnout and to let me tear it down if they break a driveline component to check the sprag. I have used both stock bands and rebuilder bands with zero issues.
|
|
|
Re: When is a Race trans not a race trans....
[Re: 451Mopar]
#2589475
12/09/18 05:40 PM
12/09/18 05:40 PM
|
Joined: Mar 2006
Posts: 9,824
MI, usa
dvw
master
|
master
Joined: Mar 2006
Posts: 9,824
MI, usa
|
Might install a later dual "O"-ring rear band pin.
Haven't decided on bands yet. The stock bands look fine and thinking of reusing them, but I have a new Mopar Performance Front band on the shelf. I think it is Kevlar? Not sure if I should install it or not.
Need to still get a trans cooler and maybe a deep pan. I add RTV over the rear band pin depression at the outside of the case. never had one leak. If the old rear band looks good use it. I like the hard Red band best. I'd use the Mopar one you have. You can buy more Altos here, $6.80 each. In fact they carry near everything you might need. https://www.transpartsonline.com/TRANS_P...nsPartsType=727 But I've found the greens to hold up at 700Hp with no issue. Cant beat the 518 OD truck pan. free ship from Amazon, $39 https://www.amazon.com/gp/product/B00PH4...d=ATVPDKIKX0DERDoug
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2590071
12/10/18 09:33 PM
12/10/18 09:33 PM
|
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
tex013
top fuel
|
top fuel
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
|
Thx everyone for the advice. I have one last dumb question -
IF, I run a Super Sprag and a LBA valve body, is there any chance of the drum still over-running and exploding? .....or will these two items fix the risk? Yes Tex
New best ET 10.259@129.65 .
New best MPH 130.32
Finally fitted a solid cam,
stepped it up a bit more
3690lbs through the mufflers
New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm
Power by Tex's Automotive
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2590249
12/11/18 05:52 AM
12/11/18 05:52 AM
|
Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
Moparmal
OP
master
|
OP
master
Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
|
I think the separation of views is coming down to HOW a drum explosion may occur. Ruling out the common cause of no LBA valve body causing an over-running clutch.....I think I’m right in assuming only some form of drivetrain breakage would cause similar trauma. I’m prepared to bank on no major breakages at my power level - so hopefully the LBA VB and the Super Sprag will be enough fire proofing F this thinking is flawed...have at it 
67 RO23 clone with 6.1 SRT Hemi and dual quads. Soon to have Drag Pak induction and Throttle body.
|
|
|
Re: When is a Race trans not a race trans....
[Re: 451Mopar]
#2590301
12/11/18 12:04 PM
12/11/18 12:04 PM
|
Joined: Dec 2013
Posts: 4,669
Wichita
GY3
master
|
master
Joined: Dec 2013
Posts: 4,669
Wichita
|
On the race trans stuff, I though the TF-2 shift kit (or was it the B&M Trans pack?) used to include the HD front band strut? Was looking through the TF2 kit and no band strut, so ordered up one of the nice thick band struts this morning.
I've been using the TF-2 kits for over 25 years and never had one come with a HD band strut, so it must have been the B&M.
|
|
|
Re: When is a Race trans not a race trans....
[Re: dvw]
#2590396
12/11/18 02:51 PM
12/11/18 02:51 PM
|
Joined: Jan 2003
Posts: 25,748
Rio Linda, CA
John_Kunkel
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,748
Rio Linda, CA
|
Me. Never seen one in person either. (only pics)
The INTERNET, the MISinformation superhighway
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2590409
12/11/18 03:20 PM
12/11/18 03:20 PM
|
Joined: Dec 2005
Posts: 11,530
Fulton County, PA
CMcAllister
Mr. Helpful
|
Mr. Helpful
Joined: Dec 2005
Posts: 11,530
Fulton County, PA
|
After all these years, there's just no reason for anyone to be exploding a transmission. But...people still do, just like they still stick their foot under a mower, touch a stove to see if it's hot and blow their fingers off with fireworks.
5500-6000 engine RPM with a broken roller clutch is all it takes. Lower horsepower applications can get by with a non-LBA valvebody, IF you drive the car correctly. At higher power levels, you have to apply that band to give the roller clutch some help. And you have to maintain the thing - take it apart once in a while and look at it - instead of running it till it quits. In any race style application, not putting a good drum in the thing is asinine.
If the results don't match the theory, change the theory.
|
|
|
Re: When is a Race trans not a race trans....
[Re: CMcAllister]
#2590416
12/11/18 03:34 PM
12/11/18 03:34 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
After all these years, there's just no reason for anyone to be exploding a transmission. But...people still do, just like they still stick their foot under a mower, touch a stove to see if it's hot and blow their fingers off with fireworks.
5500-6000 engine RPM with a broken roller clutch is all it takes. Lower horsepower applications can get by with a non-LBA valvebody, IF you drive the car correctly. At higher power levels, you have to apply that band to give the roller clutch some help. And you have to maintain the thing - take it apart once in a while and look at it - instead of running it till it quits. In any race style application, not putting a good drum in the thing is asinine. Well I guess I'm insane.. been running the stock drum since the 80s.. yeah I've tore it apart a few times for worn parts but NEVER blew it up.. no LBA.. dont pedal it in LOW.. SHIFT it.. they only blow in low gear so get out of low as soon as you can
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2590521
12/11/18 07:02 PM
12/11/18 07:02 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
If I have an LBA valve body, AND a Super Sprag, how can the drum explode? This is what I’m not getting  2 things here.. the LBA wont stop it fast enough and the super sprag isnt a save all.. it helps but it doesnt help all.. if you get on and off the gas the rollers go back then slam forward and tighten up to tight for the sprag and starts to come apart EDIT there is 3 ways to not have a explosion.. 1 is dont pedal the car under load.. 2 is buy a drum(alum or steel or 3.. put a 904 in it
Last edited by MR_P_BODY; 12/11/18 07:18 PM.
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2590585
12/11/18 09:41 PM
12/11/18 09:41 PM
|
Joined: Dec 2005
Posts: 11,530
Fulton County, PA
CMcAllister
Mr. Helpful
|
Mr. Helpful
Joined: Dec 2005
Posts: 11,530
Fulton County, PA
|
If I have an LBA valve body, AND a Super Sprag, how can the drum explode? This is what I’m not getting Chances are it won't, unless the rear band fails to apply due to broken parts (servo, band, etc.) AND the roller clutch has also failed due to driver error, parts failure, AND you have your foot in it causing the engine to free rev to 6000+. You have to decide if you want to trust that all of that won't happen at the same time.
Last edited by CMcAllister; 12/11/18 10:56 PM.
If the results don't match the theory, change the theory.
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2590607
12/11/18 10:42 PM
12/11/18 10:42 PM
|
Joined: Mar 2006
Posts: 9,824
MI, usa
dvw
master
|
master
Joined: Mar 2006
Posts: 9,824
MI, usa
|
Both Dizuster and I have failed roller clutches. His with LBA. We realized it was shuddering in low gear took it apart. Rollers were were wedged and twisted, many laid over 90 degrees. Nothing was damaged but the low roller. Mine has a Super sprag with non LBA valve body. It was recently disassembled for maintenance. The rear roller support bearing had lost it's press and slid out of the governor support. Being the rear drum has been converted to roller bearing, the drum is no longer piloted on the rear support. It pilots on the output shaft. This allowed the output shaft to wander around breaking a few tabs, half the springs and laying the rollers over at about a 20 degree angle. If it hadn't been removed for maintenance it wouldn't have been caught. Car worked perfect. Ran 1.25 60ft last two passes. Both cars have good drums.
Doug
Last edited by dvw; 12/12/18 08:14 AM.
|
|
|
Re: When is a Race trans not a race trans....
[Re: Moparmal]
#2590612
12/11/18 11:01 PM
12/11/18 11:01 PM
|
Joined: Dec 2005
Posts: 11,530
Fulton County, PA
CMcAllister
Mr. Helpful
|
Mr. Helpful
Joined: Dec 2005
Posts: 11,530
Fulton County, PA
|
You can have a failed roller clutch that will function well enough to get the car to the lanes and to the starting line (always start the burnout in 2nd). Then when you hit it, it fails completely, usually at full throttle. Happened to me long ago, with a 904 thankfully.
If the results don't match the theory, change the theory.
|
|
|
|
|
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 
And right or wrong I always use an aluminum front drum in a race build.
