mopowers
Well-Known Member
Got the case cleaned up. Boy, what a pain in the butt that was. Now I just have to wait for the parts to start coming in so I can put this ***** back together.
727 Build for Mid-10s
- Thread starter mopowers
- Start date
-
CudaFactHackJob
Well-Known Member
Sometimes they take a whole can of Easy-Off.
Duane
Well-Known Member
Can you explain in more detail here. What do you mean by pointing up and why would that affect the band adjustment?
Duane
Well-Known Member
A high pressure valve body usually means a transbrake. You said you were going to use a manual shift, they are usually lower pressure.
Duane
Well-Known Member
Posted in Tom Hands torqueflite book is a pic of a smooth and a grooved clutch disc. It specifically states that smooth clutches are to be used in the rear clutch only and the parallel grooved are to be used in the front to allow oil to exit quicker in rapid clutch applications.
Both styles shown were red altos and it said both styles are available thick or thin.
CudaFactHackJob
Well-Known Member
Sorta like a rain tire I guess. But I don't buy it. TH400s have all smooth clutches. The reds are available in thick smooth for the direct clutch. I'll go with Alto's ideas on recommendations.
Duane
Well-Known Member
i here ya. You could go with the theory that the smooth ones would give you more surface area too.
CudaFactHackJob
Well-Known Member
I measured the width of the grooves and multiplied by the total length. A grooved plate has 20% less surface contact area. A four plate smooth has the same contact area of a five plate grooved.
transman
Well-Known Member
Not quite true. They were available in smooth, radial lined, and waffle patterns. Trucks and heavy duty applications typically had either the radial lined or waffle in the forward, direct and intermediate clutch packs. Higher end cars like Cadillac and the like used only smooth plates to the best of my knowledge. Again, just my experience.
A couple of good performance builders I know, will also use the HI ENGERGY friction plates as used in the 518 and 618 series of transmissions. A lot depends on how hard you're going to beat on the thing and to a point the builders experience. In your situation though, I'd go with the performance with the ALTO'S.
Duane
Well-Known Member
Sounds like this comes down to a shift quality issue. Smooth clutches offering perhaps a smoother less aggressive apply.
Duane
Well-Known Member
Perhaps that is why I see a common recommendation of 4 smooth clutches in the rear drum and 5 grooved clutches in the front, to get the same surface area but with more aggressive shift qualities from 2-3 gear change.
CudaFactHackJob
Well-Known Member
The reason that grooved clutches are used in 2nd and 3rd gear applications is because the oem and most aftermarket clutch material is inferior to Alto's Red Eagle material. They need grooves to dissipate heat. The forward clutch is applied at idle and remains applied thru all shifts. Not a shift quality issue; shift quality is easily varied with changes in pressure. I have heated various clutch and band materials and have found that the Red Eagle is superior to all except kevlar.
Duane
Well-Known Member
I was referring to the issue of clutch counts.
It is common to see grooved or waffled front clutches and smooth rears. I was just suggesting that the 20% less clutch surface is perhaps why you usually see a recommendation for 1 more clutch in the front than the rear to make up this difference. After the 2-3 shift you would have equal surface area in both clutch packs.
In the back of the Tom Hand book there are build recommendations from about 6 different builders including Tom himself.
All of them recommend the red alto clutches, and all of them recommend a parallel grooved front clutch and a smooth clutch rear for a performance build. I know the instructions for a griner transbrake when used in a 904 specifically says the front clutch must be 5 disc.
Duane
Well-Known Member
What size rear tires and rear axle ratio are you planning on?
That may have an influence on your trans build as far as ideal gear ratios.
CudaFactHackJob
Well-Known Member
The third gear clutch is applied under high rpm and greater pressures than the forward clutch. The forward clutch is applied at idle, whereas the direct clutch is applied commonly in a racing application at 8k rpm and greater. The two clutches are called upon to deliver totally different performances. Fact is, the most common repair in a TF is replacement of the direct clutch. I'm not on here to post what somebody else has already recommended. I post what I recommend based upon my own experiences and conclusions. I don't care what somebody's book says; I've NEVER read a book about transmissions. Just because Alto makes a grooved clutch doesn't mean that they recommend it. They are in business to sell clutches; and many builders believe a grooved clutch is necessary in the direct pack; because that's what it came with. So they manufacture a grooved clutch so they won't miss out on sales; period. The oem direct clutch is grooved because the materials used by Chrysler are inferior. If my supplier sends me grooved Altos; I send them back; it's just a waste of time, money, effort, and available space. If I put together a seven plate direct pack, it's more than TWICE as strong as a grooved four pack clutch.
I have torn many 727s apart. Some indeed come without the grooves clutches in the direct drum. Kim
Here
mopowers
Well-Known Member
The valvbody I'm getting is set at 155 psi. Is that considered low pressure? Low enough to not worry about a thinner rear clutch piston?
Rear gears are 4.10s w/ a 30" radial tire. Any thoughts on how that would influence the list of necessary transmission parts?
Thousands of trannies are out there without it. Tires and gears don’t really matter. Kim
Duane
Well-Known Member
My thoughts were on your first gear ratio with that big of a motor.
I know you are only predicting 10 second ets, but that motor will make a bunch of torque at 512 cu.
My friend has a high 8 second Daytona with a 500 inch.
He went to a 2:28 first gear to get it to hook up. 4:10 rear with 33 inch tires. He got rid of some first gear ratio.
Duane
Well-Known Member
I would say that pressure is in between. Why not buy the taller piston and fix the issue, then if you decide later to add a brake or turn the pressure up more, you won't have to take the trans apart.
IMHO. Most brakes are 170-200 psi that I know of. My old turbo action manual shift was 125 psi. I would go with a 3.8 lever too just in case. I know Paul Forte of turbo action told me with 190 psi he recommends a 3.8 as anything higher is too aggressive at that pressure.
Duane
Well-Known Member
Fair enough.
Duane
Well-Known Member
I ran my last 904 build like that too. I never said it doesn't work.
I think it's a shift tuning thing as I said. My 904 at 125 psi with 4 thick front clutches at 7200 rpm was too soft and slow of a shift.
This time I will follow the recommendation with 5 clutches parallel grooved to speed the apply for et gain. But the 904 has much less surface area than a 727.
Duane
Well-Known Member
What were the clutch counts on those?
mopowers
Well-Known Member
Got another question for you guys.
Since my trans in a '68 model year, I need to get a 71+ pump support/stator in order to use an aftermarket billet steel front drum. Are there any other parts that I need to change in order to use the wider-bushing style front drum? I've been told the rear clutch piston retainer needs to be either replaced with a 71+ unit, or machined down to to work with the 71+ pump support/stator.
Since my trans in a '68 model year, I need to get a 71+ pump support/stator in order to use an aftermarket billet steel front drum. Are there any other parts that I need to change in order to use the wider-bushing style front drum? I've been told the rear clutch piston retainer needs to be either replaced with a 71+ unit, or machined down to to work with the 71+ pump support/stator.
-
