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727 Fatal oem design flaw disappointment

66Satellite47 said:
Did he have an explanation for the planetary failure?
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A low gear burnout. He has line lock and a 500 horse 440 now. 1-2nd gear is easier along with some bolt in pieces inside.
 
451Mopar said:
The sticker shock of adding an unexpected $1,500+ to a transmission build would have most of us posting something?
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An aluminum drum is around $650, not $1500. Heck the parts to build a 900hp plus trans are barely $1500 depending on how fancy the valve body is.
Doug
 
My car runs stock servos, input and output shafts, front clutch hub, planetary carriers (aluminum), and pump gears. The only one of these components that showed signs of failure was the front planet carrier. Didnt actually fail but it was on it's way. It was swapped with another stock part about 500 passes ago. Even ran the stock pressed in low roller clutch for a few seasons. Never had an issue. It was in perfect condition.when I upgraded to a Super Sprag. My sons turbo car trans is the same except for a steel front planet.
Doug
 
dvw said:
An aluminum drum is around $650, not $1500. Heck the parts to build a 900hp plus trans are barely $1500 depending on how fancy the valve body is.
Doug
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I was thinking of my build. TCS Steel Drum $675, A&A Ultimate Sprag $205, Bullet Steel planetary Gear Set $499. So OK, only $1379. The Planetary gear set is a bit overkill for many, but still $880 for Drum and Sprag is not cheap. My trans has many more upgrades than those 3 parts, but I was just limiting the responds two a few basic safety and durability parts.
 
With all the green light ''go'' to whom ever let off first racing and from a running start in first gear, lots of down shifting from third to second in a course of maybe five years, '77 to '82 and nothing came apart unexpectedly. I was happy with my 727A with a console shifter. 383ci, 2 Carter 4 bbl. AFB's, (I had a Eddy 383 Torker topped with a Carter in the early days), Thrush straight though mufflers, L60x15 on the rear, 3:91 in a sure grip 8-3/4'' diff. , solid motor mounts, super stock springs, Gabriel adjustable 60/40, 50/50, 40/60 front shocks, oh and Lakewood (yes I was a teenager then) traction bars. It was all fun and games till I went from first to second then straight though to reverse then back in to 3rd/Drive racing a Ford (and it's funny he still never passed me, I wonder if it had anything to do with the rear tires bouncing off the road?). It was not long till I went in to ''Winters Racing Transmissions''. Some words I remember being mentioned were, Fairbanks and Cheetah, the trans. with the strips painted on it, (wait, Cheetahs don't have strips ???) and some kind of special torque converter. I have been happy since that day, at least with the Transmission, ''which will not have the strips'' I was told, and that ''Mouse maze'' shifter (see the ''Drive Angry'' Charger) with a cable going to the trans.
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Kim, that's top notch stuff. IMHO a LONG way from what the OP would require.
 
Been bleeding Mopar since'70..upgraded factory extra hd hemi trans build per All Factory Race SS spec/race service bulletin parts.Despite all Factory race seminar s, DC & MP guidance, Afaik, No Factory race SS trans drum/sprag issue warning or any corrective part avail during my SS upgrade trans built stored unit.Per all the helpful responses, I'm sure factory Race engineering long-time knew a powder-iron dum=immenent Bomb !
 
So...now got to pop open sure thought , good to go safe unit again for massive $ rebuild when most anyone intuitively would know (if informed it's in there) a "sintered-iron" (metallurgy Jib-Jab for glued, pressed , powered iron) Anything has no Extra HD (factory term, not mine) reasonable functionality in a factory max hi- perf application (except internally cheap out & cause predictable customer investment loss)
 
You seem to have a dislike for sintered metal. Even though it costs more than a casting, the stronger result and better wear qualities make it worthwhile. Why do you think sintered connecting rods are so popular? Sintering gives a more homogeneous cross section with fewer chances of inclusions, and usually results in a lighter over-all product.
 
Cojohnso1 said:
Automatics should be outlawed. I really feel one is missing alot of the "Muscle car" experience with an auto. And racing? There is a reason Pro stock rule #1. No auto trans! (Ok. I made that part up by rule #1. But still no auto's allowed.)
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That's crazy talk !! You can't outlaw automatics, your wife/daughter needs something to drive, also.
 
Never personally knowing used cast, sintered, powdered, any processed "iron" in any crank or con-rod application for my hi-perf builds & so far...No catastrophic separations.. yet, .....simple luck or old school intuitive, "if it absolutely Must stay together" to best minimize massive, expensive, total collateral destructive consequences......better do it Steel forged or billet the 1st time or significantly risk causing somebody a real bad day.......tom.
 
Opps....yeah...must've mapped over from the datin site !! .....lemme figure howda fix that....
 
70rcode, feel free to design & build your own version of a 727. I know a couple of local guys that did that with Ford & GM manual transmission in the '70's, the Ford unit became the standard in NASCAR.
Not many 727 explosions have occurred given the untold millions of hard driven miles and countless million runs down the dragstrip. If you know how to drive, by knowing the sprag concern and upgrading the internal parts to match any major increase in power & torque, your legs will be safe.
Not sure how you could have missed the warnings about what causes sprag failure & possible front drum failure. That was common knowledge to anyone building 727's dating to the early '70's for me.
I had 20 years hard core bracket racing, don't recall seeing any 727 explosions. Sure saw plenty of Glide failures. In the '80's when NHRA required SFI trans shields, the product I bought for my 727 needed major modifications to position it to cover the front drum area. Obviously designed for a Glide, where the rear drum explodes. But that product was approved by NHRA. I knew how to protect my legs & modified the product.
 
Cojohnso1 said:
Did that myself. My one 727 auto. '74 Duster. 451. I redid engine. Ditched the 452 heads (That performed well for their times.) for Brodex B1/BS heads. New rods/pistons. New custom grind Comp cam (Mechanical flat lifters) Compression went from 10.5:1 pump gas to 12.4:1 E-85 fuel. By estimates went from 500+ horse to 600+ horse. 727 has bolt in sprag with Kevlar bands. Rear 8 3/4" Mosier 40 spline axles with spool. And what did I forget? DRIVESHAFT! The car was snorting mad and ready to put down a possible sub 10 sec run. Let the two step button go at amber? And the driveshaft exploded so fast the car didn't move. (Thus exploded before line clocks let go.)

Moral of the story? Im still the weak link!

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Cojohnso1 said:
Did that myself. My one 727 auto. '74 Duster. 451. I redid engine. Ditched the 452 heads (That performed well for their times.) for Brodex B1/BS heads. New rods/pistons. New custom grind Comp cam (Mechanical flat lifters) Compression went from 10.5:1 pump gas to 12.4:1 E-85 fuel. By estimates went from 500+ horse to 600+ horse. 727 has bolt in sprag with Kevlar bands. Rear 8 3/4" Mosier 40 spline axles with spool. And what did I forget? DRIVESHAFT! The car was snorting mad and ready to put down a possible sub 10 sec run. Let the two step button go at amber? And the driveshaft exploded so fast the car didn't move. (Thus exploded before line clocks let go.)

Moral of the story? Im still the weak link!

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How do you like running E85?

I am planning a n engine build and prefer high compression.
 
I have never ever blown up a 727 on the street or bracket racing. Lots of hard running on the street without a care in the world. Neutral drops, rolling backwards and slamming it to drive. I’ve never even burned out a 727. But I have refreshed my race car ones. Kim
 
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