FrontEngineDragsters.Org Forum
Technical => Dan Dishon's Transmission Den => Topic started by: gasserx on March 13, 2015, 01:02:19 AM
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I have been looking around for a torque converter for a while now, and finally picked one up at another racers garage yesterday. I have not bought it yet, just brought it home to see if it fit.
It says TCI 254204 on it, and as far as i can find on the interweb its a TC for TH350/TH400.
Got home and tried to slide it on, and seems like it popped in twice (both set of splines). But isnt the PG and TH different? Or can the output shaft on my PG have been changed to accept TH converters?
I believe this is the same TC (from Jegs website) as the partnumber is the same, and i noticed something else - will this work with a bigblock only? It says 400, 454 & 455ci - or is this just recomendations from the manufacturer?
8'' Race Converter - Group 4
1965-90 TH350/400
400, 454 & 455ci
Wide Bolt Pattern (except variable pitch & lock-up)
Group-4 Race Converters
Excellent for big-block brackets, Super Street & Super Gas classes. Good top end horsepower, MPH & reaction.
Engine: Big Block
Displacement: 400-485ci
Vehicle Weight: 2400-3200 lbs
Stall Speed: 5000-5400 RPM
Pro Tree/Bracket
Gear Ratio: 4.30-Up
Tire Size: 28"-Up
Im a complete noob when it comes to converters - actually this is the first time i have ever tried to install one, as i have only worked with clutches before.
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I would send this information to the builder.
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On a tight budget almost anything will work--That 8 inch will not stall as high behind a small block as it would with big block but it will work until you can get a correct one--it will not be as fast as the perfect unit but for starters it will be fine. Good used units here are $450 range new they are from $850 and up --so get that one for a few hundred--stick it in and roll--any higher I would pass and keep shopping.
Used converters are usually crap unless you buy from a pal or trusted source so .....very risky on condition if you don't know seller--add that to cost if a bad converter fills your trans with crud and ruins it..
The right converter makes a combo but that being said they are like rubber bands and almost any 8 inch would do fine for starting out--knowing that engine you have-- something around 6000 stall designed for a small block would be ideal.
My used flea market converter is very loose but works great! Car loves it.
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For reference purpose the standard PG input shaft spline is .880 dia where as the "turbo" shaft is larger in dia.A turbo shaft will not fit a standard PG converter, but a standard input will fit a turbo style converter--just wont work. Check the spline pattern in the converter turbo is a fine spline and the PG is course spline
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Will it be to any help if i share a picture of the shaft on my trans?
Or count the splines?
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(http://www.speedfreak.no/wp-content/uploads/2015/03/IMG_1332.jpg)
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Thats a turbo spline input shaft---good to go ;)
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Thats a turbo spline input shaft---good to go ;)
Thanks a lot dre 8)
..oh, one more thing, i believe it should go a little bit further in?
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The thing to keep in mind is to call TCI and find out how much it will cost to change the stall on this used converter, and add that what you are paying for the use converter. I'm sure you don't want that total figure to be more than what a brand new converter will cost.
The ball park stall number you should be looking for is 1,000 to 1,500 RPM lower than your shift point. You see if you have a converter that stalls/ flashes at say 5,000, but you motor "comes on" at 6,000, your combo will struggle for 1,000 rpm. BTW converter flashing is where the RPM drops to right after the shift, which is the true stall speed. Plus if you get your converter working where you want, and then you increase your power, then the converter will flash at a higher RPM.
Good Luck, and have Fun
Jon Hansen, JrFuel "B" , Hayden Wheels, and JrFuel Dragster Association
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I will work out a perfect converter combo later, now i just want to get on in there so i can just try the car and to get my license 8)
Why cant i get the input axle the rest of the around 1" thats missing?
Any advice is good advice now...before i eat my cap and tear my hair off. Trying gently to turn and working it place, but not working ... :( >:( :( :-\
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If you pulled the input shaft out of the housing, what happened is that there are 2 steel sealing rings on the shaft, pull the shaft completely out and check the rings, they each should interlock with themselves, if not and the locking tab is broken then they have expanded to a point where they will not colaspe enough to go into where they should be
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Sounds like you got all the right advice. Just for future knowledge PG spline is 17 and Turbo is 30. Definitely check the sealing rings on the input shaft, but sometimes they are just stubborn!
Thanks for the question, Dan
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As far as shafts go: I ran the 4340 shaft with the PG spline for several years behind the injected 355 (640 hp) with never a problem. When we put the 377 6:71 setup in the car I installed a 300m turbo spline shaft with no problems so far. We really haven't leaned on it yet ( 58/58 ratio) but after sorting it out this year I plan on moving up to 15% over. I see the TS 300m is rated up to 1150hp. What is the life cycle on these shafts? I know anything can be broken but should I look to move up from the 300m ? The next step is the 2517NASA shaft rated at 1800hp. Thanks . George
Sorry no hijack intended. I saw questions on PG shafts and jumped in.
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The 300m shaft is more than anyone on this site will ever need. Mine is going on 12 years running low 7's @ 18 over
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Horse power is not the only factor when choosing an input shaft. Some things to consider are type of launch, foot brake or trans-brake, how hard your converter hits, and is your car suspended or solid. Solid cars tend to suffer from tire shake and this can be hard on everything including the input shaft. Another thing is does your car dead hook or spin. When all things are factored in it is always better to err on the over kill side, the last thing you need is an input shaft failure in the final.
Hope this helps, Dan
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If you pulled the input shaft out of the housing, what happened is that there are 2 steel sealing rings on the shaft, pull the shaft completely out and check the rings, they each should interlock with themselves, if not and the locking tab is broken then they have expanded to a point where they will not colaspe enough to go into where they should be
The two steel sealings look good, cant say there should be any problem with them at all.
Still havent been able to push it all the way inn.... it feels like its hitting something.
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Horse power is not the only factor when choosing an input shaft. Some things to consider are type of launch, foot brake or trans-brake, how hard your converter hits, and is your car suspended or solid. Solid cars tend to suffer from tire shake and this can be hard on everything including the input shaft. Another thing is does your car dead hook or spin. When all things are factored in it is always better to err on the over kill side, the last thing you need is an input shaft failure in the final.
Hope this helps, Dan
We use a trans brake and don't dead hook. We run a 12" Hoosier so there is usually some spin. Our local track is well prepared and we can run 60' in less than 1 sec. Tire shake has happened in the past but for 2015 we replaced the 1.80 with a 1.69 and out went the Mopar 742 and in went the Ford 9" .(4.30) Rigid FED.
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Sometimes the input shaft can be a pain to slide back in. Try putting a yoke in the trans to line up the planetary. Without a yoke the output shaft can "sag" causing just enough misalignment that the input shaft won't slide back in.
Dan
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I made it :)
It was the brass part with a hole in it that needed to be aligned.
Took a long screwdriver and just moved it into position, and voila!
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Additional question popped up...... From the specs on the converter it seems i need a flexplate with the large bolt pattern? Can i run into problems wich a 168 tooth flexplate to match the TQ and engine/starter?
Im pretty sure my block is a 1980-1985 based on the casting number on it.
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NO, the 168t is the common one, just make sure you purchase good ARP flexplate bolts for both converter and crank flange
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Thanks dre! I really appreciate your help! 8)
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Going a little iover kill on input shaft myself.More expence but less than breaking shaft and messing up new converter I am odering. By the way FTI is having 10% off till 4-15-15. They also have a deal that for 200 bucks you can get life time warranty and you have 1 year from purchase date of conveter to start warranty. Just food for thought. freinds seem to think that selling me a warranty on conveter means they will be out of business soon,not sure why they think that.