Auto to manual , pilot bearing question

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Mopar92

Mopar92

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I'm having so much fun driving my 73 Duster slant. Everything else I have is big block and small block. But this slant is just cool. I want to start gathering parts to swap it to a 4 speed. What's the trick to the pilot and swapping over on these 198 slants? Thanks.
 
The swap will lose the first gear TC torque multiplication going to a manual trans. To make it up you will need to add about 10 to 20% more gear to the diff. And that will bring the cruise rpm up the same percent.
The 198 cannot afford to lose that TC. I know you can slip the clutch out higher, but that gets old in a hurry. If you are looking for a little more pep, there are other ideas.And easier too. And probably less expensive too.
Honestly, I don't see this as a good thing to do.I know you didn't ask for an opinion, but .....
But in answer to your question, it is a non issue. If the crank won't accept the tranny, you simply cut the input shaft off a bit and switch to a ball-bearing pilot.
 
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Well, next year or so I'm doing a V8 swap. A mild 318 or stock 360. I already have to do the hump, the pedals, etc. figured I'd enjoy it while getting 1/2 the job done. I have 2.76,3.23, 3.55, and 3.91 gears sitting in the shop. So it's not like I am married to this gear that's in it now.
 
Reports are that sometimes the crank bore is not finished for a pilot busing on all the production cranks after a certain year. So first thing is to pull the trans and see what you are facing there.

FWIW, while using a shorter rear gear was indeed 'normal' for a manual trans car, IMHO, it was not always the case and I would not worry over the rear gear for now. The manual trans 4 speed (OD 4th) trans in my '76 Dart Lite used a 2.76 rear gear with a 225. Never bothered me in the almost 1/4 million miles of driving one, and that was in the Appalachian mountains with all sorts of starts on steep hills. My wife couldn't drive it well however....
 
225 is nearly 14% larger, than the 198.
Torque multiplication inside the TC can be as high as 2.2 ratio.

Let's say the 225 makes 80 ftlbs at 1800stall, into a 2.76rear and 2.45low and 2.2TC. That makes 1190ftlbs.
Let's say the 198 makes 80/1.14 =70 ftlbs into the same 2.76rear and 2.66 low and ZERO stall(cuz it's a stick-car), so have to slip it out to the same 1800 = 514 ftlbs.
The 198stick would need 1190/514 x 2.76to have equivalent starting torque. That would be a 6.39 rear; (or plus 231%)
But let's say the factory 225-Tc can only muster a 1.5 ratio. The new number is 811 ftlbs. To compare, the 198stick would then need 811/514 x 2.76 =4.36s, (which is plus 58%)
But let's say the factory 225-Tc was exceptionally weak at 1.2 multiplication. The new 225 number is 649tlbs. To compare; the 198stick would need 649/514 x 2.76 =3.49s(plus 26%)
But let's say the factory tc had a big fat Zero torque multiplication. The new number is thus 551 ftlbs. To compare, the 198stick would need 551/514x 2.76 =2.90s, (Still plus 5%)
As for me, there is no way I would put a stick behind a 225 in an early A, never mind behind a 198 in a lwb Dart. That is just waaaay too much time and work, for,IMO,no good reason.
But hey, OP, just do it and report the results.Please.

But let's say you put the 3.09box behind that 225. The new 225numbers are 80 x 2.76x 3.09=597 ftlbs. How you(nm9) could find that "no problem", as compared to 1190...............IDK
But then again the stall-ratio is an instantaneous and fleeting phenomenon.
 
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Stall? Is a manual trans.. what am I not getting? Thanks for the reply.
 
You can have a pilot bushing made up by any machine shop! My neighbor can pump one out in about 20 minutes, and just did one last week! My crank was not drilled either, just gave him the inner and outer dimensions of the bushing and boom, done!
The outer diameter needs to be about .002 bigger than the hole, and the inner diameter needs to be about .002 bigger as well!
 
AJ/FormS said:
It's a comparison between a 225 auto to a 198 stick. I edited the post for clarity.
Click to expand...
My 225 Dart Lite was a stick as said..... no problems in the hills and mountains. Don't sweat it. If I wanted to take off fast, I revved it (to a higher torque point obviously) and slipped it more. And I never tore up clutches... that was my brother's job; he did that by riding clutches at stop lights... the bonehead!

Maybe because I grew up driving in hills and mountains, it was no issue. If you didn't learn fast to rev up and slip the clutch and start an inline 6 pickup with a 3-on-the-tree and a load on back, on a 20+% grade at a stoplight/sign with some moron crowding up behind you, you were in trouble. LOL Get out of the flat lands AJ !
 
We have hills, but we call 'em speed bumps and I like to get air over 'em whenever I can. Shazzam!!
I'm a dump it and go kindof guy. That's partly why me and the 292/508 didn't hit it off.
I leave the slipping to the Mustang boys.
 
BTW, I was thinking about your calcs, and the 1800 RPM stall and 2.2 torque multiplication factor does not make sense for normal day to day driving, just when it is floored from a stop. So using that kind of number to say if something is 'driveable' or not does not make sense to me. The actual wheel torque levels for accelerating in normal driving would well below those numbers.
 
OK maybe I need to tell you about my winterbeater engine.
Back in winter of 99 or maybe 2000. I would yank the 360/4spd out for the winter. In it's place I put a 73 teener,with a stock long block. Just a TQ and I left the TTIs in there. And I put a 904 behind it with about a 2400 stall. The 3.55s came out and 2.73s went in. 14 hours to do the swap, on the September long-weekend.
So this pkg was a real blast for winter,and I enjoyed it very much. I think I ran this combo for 2 or 3 winters. But one winter, I wanted to run the 833-od and GV to see how that went. Well even with the 3.09 low, take off with 2.73s was lame.And that poor S was sounding just like the Mustang boys with their little 5ohohs, and that deep low 5-speed they have. So in about 2 blinks of an eye, the 3.55s were back in. So now I had a starter gear of 10.97 again. But to take off on a par with the 2400TC and 2.73s , the stick was still lame. Well since I had the double od, and also had 3.91s; in they went. This gave me a starter gear of 12.08,and a cruiser gear of 2.16. The 3.91s now took off with the M/T, like the automatic did with the 2.73s. I think 3.73s would also have been enough, but I didn't have those, and the teener was quite happy to cruise at 1750=65
This was my experience.
If you do the math on that; 3.91/2.73 = plus 43% gear to break even. So Ima guessing that was what the TC was worth; at least 43%. Since the torque-multiplication factor in the TC is in fact fleeting; The 2.2 (estimated) ratio, falling to 1.00 in just a second or so, Plus the 2400 stall, were worth the average of plus 43%. With the 3.91s, I also did not HAVE to rev it to 2400 to get good take off. With a heavy flywheel, it was more of a blip the throttle and slip it out kindof deal. That is why I think 3.73s would have been enough. But the 3.55s kindof sucked. And that in itself is a wonder, cuz the 367 has no problems with blip-it and go, with those same 3.55s.

The following winter, the 904/2400 went back in.lol
And the winter after that I had a different winter beater. I sold that teener to my son who put it into an 84 D100. Eventually he tired of that truck and I bought it back for the teener/904; which I have yet to make use of........ :(
 
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It is not a matter of the math. It is a matter of what performance you expect/want: i.e. thee definition of your term "good take off". I would never expect a 198 or 225 /6 to take off like a 318 or my son's 340 or my old 351C... not even close. But it'll still drive to the grocery store just fine and so is 'driveable' IMHO.

Your experience is valid in a limited sense, but the low gear behind the teener did not make it so it could not be driven. It was just slower off of the line. You need to tie some sort of minimum g's acceleration for so many seconds before any specific starting torque discussion makes any sense as a yardstick.

And take your good gearing setup with a starter gear of 11 or 12 and put a 1 ton load in the vehicle, and all of a sudden, per one individual's seat-of-the-pants G definition, it will become 'undriveable'. A loaded, 318-powered logging truck with 2 speed rear axle and granny gear, will not come anywhere close to your g-levels of 'good take-off' but that does not make it undriveable nor useless.

Just IMHO and I hope I don't offend: You're using a definition of 'driveable' that does applies to a certain set of requirements and uses, but does not really fit what the OP's car is with a 198.
 
nm9stheham said:
...Maybe because I grew up driving in hills and mountains, it was no issue. If you didn't learn fast to rev up and slip the clutch and start an inline 6 pickup with a 3-on-the-tree and a load on back, on a 20+% grade at a stoplight/sign with some moron crowding up behind you, you were in trouble...
Click to expand...

That's how I learn to drive a standard shift when I was about 13.....Thanks for the memories!
 
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