Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2399543
11/06/17 07:48 PM
11/06/17 07:48 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
OP
Taking time off to work on my car
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OP
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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One other semi-related question... Turbo Action has replaced my model of valve body with a new "Xtreme Action" series 17880XA. From what I recall, I paid around $200 for the 17680 about 10 years ago. The new one is almost $400, yet I don't understand what about the description justifies the significant price increase (even taking into account the 10 years between price comparisons). The features listed for the new vb are: •Race Only (No Trans Brake) >> SAME AS BEFORE •No Low Band Apply >> SAME AS BEFORE •Engine Braking 2- & 3-gear only >> SAME AS BEFORE •P-R-N-3-2-1 Pattern >> SAME AS BEFORE The 17880XA has a safe clean neutral and no need to use a button to backup. Provides full manual control only. No automatic features. Maintains stock shift pattern. No Band applied in Low Gear. Allows full engine braking in Second and Third gear only. This valve body is great for Drag Racing. Eliminates use of passing gear linkage. >> WHAT HERE JUSTIFIES THE BIG PRICE INCREASE? WHAT'S A CLEAN NEUTRAL DO FOR A STOCK SHIFT PATTERN, AND I DON'T NEED A "BUTTON" TO BACK UP NOW, EITHER.
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2399575
11/06/17 08:30 PM
11/06/17 08:30 PM
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Joined: Mar 2009
Posts: 2,490 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,490
Sydney,Australia
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trans brake needs button to back up . clean neutral would be reverse pattern Brad I have a griner rmvb . it was always quite harsh shifting at lower rpm/speed . Almost like someone ran into you , higher rpm smooth as shift . I just thought that was an end result 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
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2399691
11/06/17 11:28 PM
11/06/17 11:28 PM
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Joined: Jan 2003
Posts: 12,815 Benton, IL.
DaveRS23
Master of nothing...
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Master of nothing...
Joined: Jan 2003
Posts: 12,815
Benton, IL.
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The clunk at slow speeds is a result of the high clutch pack grabbing before the 2nd gear band completely releases. So, for a brief second both 2nd and high are engaged which kinda stops everything's forward motion and takes the play out of the drive line which produces a clunk. In more extreme cases, it can actually feel like you tapped the brakes. It comes down to a matter of timing between the 2nd gear band and the high speed clutch pack. And there are several ways to change that timing. The only way that I have been able to consistently deal with it is by putting a restriction in the high speed clutch port. Which slows the flow down so that it delays the engagement of the high speed clutch pack until the 2nd gear band fully releases while having no other impact. I use Dorman 3/8" expansion plugs (like mini freeze plugs) part number 555-115. They usually press right into the high speed passage but occasionally the opening will need a light touch-up with a drill bit first. Most of the time, the ones I have done want an opening somewhere around .090". It varies a little bit from tranny to tranny so I start a little smaller and test it. Then open the hole up a tiny bit at a time until I'm happy. And there is usually very little difference in the size that has no 2-3 overlap but has a flair up vs very little overlap and no flair up. Often, to get rid of all the flair at WOT, there ends up being a tiny bit of slap at slow speeds. So, for a track car, I set them up with no flair since the low speed clunk isn't as big a deal. While a street car, I may leave a small WOT flair so that there is no around town clunk. That being the preference of the owner. I usually just swing the valve body out of the way without removing it completely. And I put some grease on the drill bit when I re-drill the plug. The grease catches most (if not all) the tiny metal pieces. Open up the hole a tiny bit at a time and after a few times, you will have the best balance between the clunk and the flair. IHTH
Master, again and still
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2546719
09/06/18 03:17 PM
09/06/18 03:17 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
OP
Taking time off to work on my car
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OP
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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1. Bump 2. Somebody... please give me a good compromise restrictor size to use when I pull the valve body off in the immediate future. As much as I like testing different things, this really isn't something I want to have to go back & forth multiple times given the PITA factor. If I need to provide more info than what's listed already, let me know. Thanks - Brad
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2546878
09/06/18 08:12 PM
09/06/18 08:12 PM
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Joined: Jan 2003
Posts: 26,545 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 26,545
Rio Linda, CA
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FWIW, the orifice restrictor in the Transgo kit is .140" (#28 drill).
The INTERNET, the MISinformation superhighway
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2546905
09/06/18 09:05 PM
09/06/18 09:05 PM
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Joined: Jan 2003
Posts: 12,815 Benton, IL.
DaveRS23
Master of nothing...
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Master of nothing...
Joined: Jan 2003
Posts: 12,815
Benton, IL.
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Brad, the restrictor size needed will depend on a number of factors unique to your tranny. And it will depend on which way you prefer to lean with a one time shot.
It looks like the range used here so far is somewhere between .090 and .125. Are you more concerned with the overlap or are you more concerned with a WOT flair? Pick your preference and go that direction.
Frankly, you are in a better position than anyone to pick a compromise size within the range noted here.
Good luck.
Master, again and still
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2546916
09/06/18 09:23 PM
09/06/18 09:23 PM
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Joined: Dec 2005
Posts: 12,331 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 12,331
Fulton County, PA
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Typically if running the driveline on jackstands at slow speed, there will be a "grab" or hesitation at the 2-3 shift if the shift is right at high speed. If not, it will flare. Bringing it all to a stop for an instant is too much overlap. Never used a restriction. Instead, I always used spring loads in the high drum and 2nd servo to get the balance I wanted. Spring pressures control how quickly or slowly things happen.
If the results don't match the theory, change the theory.
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Re: 727 Front Clutch Orifice Restrictor size
[Re: CMcAllister]
#2547032
09/07/18 01:35 AM
09/07/18 01:35 AM
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Joined: Jan 2003
Posts: 1,908 Nebraska
4406bbl
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,908
Nebraska
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Typically if running the driveline on jackstands at slow speed, there will be a "grab" or hesitation at the 2-3 shift if the shift is right at high speed. If not, it will flare. Bringing it all to a stop for an instant is too much overlap. Never used a restriction. Instead, I always used spring loads in the high drum and 2nd servo to get the balance I wanted. Spring pressures control how quickly or slowly things happen. This is the better way to go for street driving, more front clutch springs, put an extra rear servo spring in front servo, and play with clutch clearance. I never liked the restrictors, used it until trans was pulled to change or inspect front clutch. You are always on the hairedge of flareup if you try to eliminate the overlap.
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Re: 727 Front Clutch Orifice Restrictor size
[Re: 4406bbl]
#2547224
09/07/18 03:03 PM
09/07/18 03:03 PM
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Joined: Jan 2003
Posts: 26,545 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 26,545
Rio Linda, CA
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Problem with building a trans with "perfect overlap" (some overlap is required to prevent flareup) is that the setup changes with time. Disc wear, sealing ring wear all change the timing and the removable orifice is a quick/easy to change the timing.
The INTERNET, the MISinformation superhighway
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2547254
09/07/18 04:19 PM
09/07/18 04:19 PM
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Joined: Dec 2005
Posts: 12,331 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 12,331
Fulton County, PA
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If you watch - and listen - to video of AH cars on YouTube, you may notice a touch of flare on the shift to high gear in many of them. They are concerned with minimum ET and maintenance every few runs is not an issue for most.
If the results don't match the theory, change the theory.
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Re: 727 Front Clutch Orifice Restrictor size
[Re: BradH]
#2547371
09/07/18 09:06 PM
09/07/18 09:06 PM
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Joined: Jan 2003
Posts: 12,815 Benton, IL.
DaveRS23
Master of nothing...
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Master of nothing...
Joined: Jan 2003
Posts: 12,815
Benton, IL.
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I believe .150 will bang pretty good, too.
Master, again and still
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