The Jalopy Journal
Discussion in 'The Hokey Ass Message Board' started by BloodyKnuckles, Feb 10, 2009.
Hate to hijack a thread but I got a Q for the Buick tranny guru. I need a little schooling here. Whats the diff between the SP-400 and the ST-400. I have a 65 401 sitting in my shop that I'm saving for the next project and I am assuming that it has the SP-400 attached to it since it has the extra wire on the plug and the extra switch on the carb linkage. Im looking for an old Panel truck to put it in to haul my stuff to the swap meets and the 401 and sp 400 ought to make for a nice hauler. So anyway, what are the specifics on the ST-400?
debbie??? could she drive a 32 with a mini skirt on? big 80's hair?
Sounds like an awesome project!
SOMBODY PHOTOCHOP THAT THING!!!!!
SP has become slang for "switch pitch", ST is super turbine, or just a plain old T-400.
Have a look at the tranny pan, if it has an impression in it that looks like the heel of a shoe [along with the extra wire], then it's the coveted SP.
In it's stock form, it was a "stop gap" measure to give the BIG cars of the day a little more "oomph" when acellerating hard. The switch on the carb would activate the SP when full throttle was applied. Most of them were also wired into the brake light circuit so the SP would activate when you hit the brakes... Like for example when your sitting at a stop light. The higher stall would keep the car from creeping.
How it works...
A torque converter works on the same principals as a paddle wheel steam ship, only inside the converter, the "river of water" [tranny fluid] is contained inside the outer diameter. The engine spins the fluid, and it splashes into fins [these are the boards on the paddle wheel]. The faster it spins, the more fluid pressure it builds against the fins, untill eventually, it can no longer resist, and it transfers energy thru the shaft to turn the transmission. The "point at which it can no longer resist" is the stall speed.
The SP uses a special converter that has "movable" parts inside it, and a special pump that has a solenoid built into it that moves the parts inside the converter. When 12volts is applied to the solenoid, it moves the input shaft forward about 1/8 of an inch. This causes a set of fins inside the converter to move forward, opening up the "gap" between the sets of fins, and giving the fluid [which is building pressure] a place to escape to, allowing the stall speed to increase by about 1200 more RPM's.
Before we get into a big debate about my explination being wrong, I'll come right out and admit it is, but I'm trying to explain it in the most basic and simple terms. In reality, it's a little more complicated, but what I'v explained does cover the basics of what's going on inside a SP-400.
In the SP "world", there are 2 companies that tout themselves as the switch pitch experts. One is in Texas, and the other in Minnesota. I call the owners of both of these companies my personal friends..... But I will only spend money with the guy up north. I wont go any further into the details, but I'm droping a serious hint here, so pay attention!!!!!!!! PM me if you must know.
There is one other thing I want to bring out on this T-400 discussion, and that's valve bodies. [as per zman's comments]
When GM dis-continued the SP [cost savings], cadillac introduced the 472, which is a low RPM torque monster. Buick introduced the 455, which is also a torque beast, but it was designed to spin to 5000+ rpm's. Buick's solution to the loss of the SP was to use valve bodies with the largest internal passages of the entire GM line. The increased capacity of the large passage VB's allowed the buicks to seriously kick down when you wanted to pass!
I know one guy with a 71 225 who can kick it to 1st gear when he stomps it at expressway speeds!
To that end, the next time your at a junk yard and see a 455/T-400 buick built between 1968 and 1972, consider snatching up the VB and saving it for your next performance T-400 buildup.
Cool, will be following this thread.
Keep us posted.
Cool project! I love stuff like this. Its going to be a killer gasser. Im looking forward to seeing more of this build.
My buddy has a 61 Special. reverse went out in that crappy air cooled 2 speed. So i talked him into a Buick 350/350 swap. Turned out great. Really woke that little Buick up. Take a look at the video clip. If you listen close you can hear it cherp 3rd. LOL
are you guys gonna get a room or what???
you know how we do it son!!!
why use a chevy 10 bolt when you can use a 87 t-bird independant rear?
there are rooms available? I thought they were being used as jack shacks... so I guess it's what...
hot damn using a t-bird rear is more trad then anything......rock out with your sock out!
only if you Jam out with your Clam out
As requested here are shitty pics of the donor;
My good buddy Animal delivered it today. Jeffery James and myself screwed around and looked at everything. It came with a new water pump, NOS tail light lenses, a good marine gas tank (metal), new battery cables, new brakes and master cylinder, power everything including seats.
It has so much I can use on the Skylark. The engine, the posi rear that's about 60" wide and big as shit, the front finned drums and a ton of other shit.
I am very happy with my purchase and can't wait to get started. Before I do anything I will get the engine running and drive the car.
Zman and Pir8Darryl,
What will I need to convert to a ST400 or SP400?
Zman, you got anything?
Detailed explination with pictures!!!!!
The good news is that if you find a T-400 with a nailhead bell pattern, there's a good chance it will already be a SP.
Manual BELLHOUSING and CLUTCH SON!!! Real hot rods have three pedals.
The only one I have here right now is the one for my '38. But I'll look and see what's around. Which I always do anyway...
Yeah about 50/50... but there are plenty out there. Thse adapting to the dynaflow crank is pretty easy. We just need to make sure you get the flexplate as well. But there are two schools of thought. One is to grind th e lip of the crank, the other enlarge the hole on the flexplate, I prefer the flexplate route. The and a bushing and you're ready to go.
I had a feeling the ST400 was another term for a T400 of those years. I am familiar with the concept of how the SP400 operates but thanks for some technical info on how it works.
Everything I have points to the ST400 being the first of the THM400's. In 64 for the Buicks and the Cadillacs. Haven't seen them referred to as T400's in any of the manuals. As I stated before the first year has some one year only stuff, but it can be upgraded... The Rivullac has a ST400. I seem to run in to about an even number of ST as SP's. I have an old thread from the Yahoo Nailhead list from about 7 years ago that goes over all the different stock converters that can be used.
From the wikipedia entry...
The THM400 (or the Turbo 400, which it is called by drag racers and car enthusiasts) is a 3 speed automatic transmission that was first introduced at the beginning of the 1964 model year in Cadillacs and Buicks (under the name Super Turbine 400). The following year, use expanded to Oldsmobile and Pontiac and to some full-sized Chevrolets (usually coupled to the Mark IV big-block V8). It can be identified by an oil pan in the shape of what some would call similar to that of the state of Texas.
Many of the Buick, Cadillac, and Oldsmobile THM400s produced between 1965-67 were equipped with a torque converter that incorporated the Switch-Pitch variable-pitch stator, which is sought after by collectors and drag racers. These can be identified outside the vehicle by a noticeably narrower front pump spline. Externally there are no differences from the non-SP THM400.
THM400s were not the only Switch-Pitch units used in GM vehicles - the Super Turbine 300 (ST300 or 300THM) had a similar setup as well as Buick's 1955-1963 twin turbine Dynaflow.
all this fancy tranny BOP tranny talk is all for not if you ask me- even if he wusses out and uses a auto - there still needs to be a fuckin STALL in it - 3000- 3500 at the might spin some gasser meats - wait, we are talking about a gasser right? Or is Heather going with the stock cam too?? Its no fun to watch a car all jacked up fall on its face when you hit the gas at the line
Here is a Photoshop courtesy of DRuss32;
I really liked it.
Tudor, don't worry too much. You'll be happy.
That Photoshop will look nice
but a nice little moon tank up front would look geat aswell
Now since this turd is in the way...can we use the trunk as a dining room table and eat our eat pizza off it...then we can just throw the pizza box in the trunk...done!!![/quote]
Ron (aka Tubs) making proper use of his new turd in the shop. Every member of the IRON LORDS can eat around the trunk and still have plenty of elbow room.
Ron the photoshop looks great but can you stuff that much tire without hackin????
That, and i'm unsure about white walls.....maybe just plain simple blackwalls?
i like the "walls" they go with the top, kinda tuxedo like! go for it Ron!
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