T-15 vs. T-14 in a 225V6

Since I have to have a pilot bushing made anyway, I was thinking of making one with the step down like shown in the picture. To my thinking, I should be able to build the bushing out past the end of the crank to capture the proper amount of the input shaft.
As it is, with the T-15 stick-out = 8.5"
So if the original T-14 adapter is 2-7/8" thick
And the BOP bell-housing depth is 6-5/16" total = 9-3/16
With total depth 9-3/16 minus 8.5" T-15 stick-out leaves 11/16"
That 11/16" puts the end of the input shaft flush with the end of the crank.
The pilot bushing would have to stick out 1" to capture the input shaft.
This allows for the in-out thrust movement of the crank. Does this make any since to you guys. I would still have to have the adapter hole enlarged to fit the T-15 from the T-14 adapter. Your input please.

 

Sparky I looked deep in all your old posts and couldn't find much info on your install so maybe I am going to too much trouble. Hope the guru's will chime in and show the way. If what I show actually is a good idea then I also propose this. Instead of boring the hole in the T-14 adapter, I would remove the T-15 drive gear bearing retainer and plug it's four holes. Tack weld the T-90 bearing retainer in the T-14 adapter which will allow me to use my existing throw-out bearing and clutch fork. A gasket between the tranny and adapter will seal the lube. What y'all think.

 

OK so I should try to find someone to swap a T-15 for my T-14 then normal the rest. Tnx Sparky.

 

Mainly I am stating that the standard pilot bushing is about 3/4" OAL (deep).
The engine/bellhousing mounting flange is roughly even with the centerline of the pilot bushing.

Your idea for an elongated step down bushing has potential.
It's certainly not the norm but might work.
The only concern would be a small increase of crankshaft eccentricity.

Sounds like a bad idea.

I think Sparky used an aluminum aftermarket adapter that was 1-5/8" thick.

 

On second thought...
Looks like the pilot bushing length is limited by the clutch driven disk.
You could possibly elongate the pilot bushing by 1" before it hits the driven disk hub.

 

Yes I considered this. The driven disk hub extends +/- 3/16" towards the crank. Should not exceed 5/16" on a badly worn disk. What I don't have is the thickness of the flywheel. The amount of bushing capture on the end of the T-15 shaft cannot exceed 1". Are we still within the ballpark?

 

Just a thought - is it possible to modify the factory adapter to work? It would have to be reduced in thickness... is the transmission side machined to look like the back of the T-14 retainer, or just clearanced?

 

Tim the factory adapter that is on the jeep was for a T86 which was re-drilled to accept the modified T-90 (j-shaft) and the T-14 oem adapter is the same thickness as existing (T-86) of 2-5/8". The mating surface of adapt to tranny is flat. Both sides are flat and yes they could be milled considerably to narrow the gap. I was just trying to do this to limit the total number of parts that had to be modified.

 

Barely so....

Measured 2 different NOS driven discs also measured a used "Perfection" disk.
These are all .75" + - .020" gap from the flywheel mounting surface to the driven disk hub.
A badly worn driven disc will shorten the distance a few thousands.
If need be the driven disc hub could be ground down by a few thousands.
So figure that .75" is the maximun pilot extension allowable


Here's my figures:
start /// 8.9375 1971 bellhousing depth
minus // 8.5000 T15 stick out length (estimated)
minus//// .375 pilot bushing seat distance from the engine mount (average)
equals////.0625 gap from tip of maindrive to pilot seat

take//////.75 maximum pilot extension allowable
minus/////.0625 gap from tip of maindrive to pilot seat
equals////.6875 maindrive tip inside of pilot bushing (maximum)

Standard maindrive pilot bushing is .75" depth.

Got that ?

 

Thats great ken. Looks like I will have a capture of almost 3/4" on the end of the shaft. From looking at the shaft end of the T-15 I can see a polished section where the original pilot had been wearing and it measures just slightly over 3/4" so I feel that it will work. I will be grinding some off the disk hub. I had checked that earlier and knew it was going to happen. Ken this is great and would like to get going on this and see how well it will work but have to find a machine shop to make the pilot and bore the adapter. For some reason I feel I am still missing something. Maybe it will come to me later. I certainly appreciate this great help.

 

The Borg Warner T15 has the perfect strength to weight ratio for use with a 225 Dauntless.
And I particularly like the T15 gear ratios.
So I really like the concept of combining the 1971 bellhousing directly onto a T15 then directly onto the D18.
But I forsee a couple of other issues.

I don't have a T15 to look at.
I thought the T15 used the "Jeep 4.125" index bore, but I'm hearing ortherwise.
So.... What is the T15 index bore ? Is it "Jeep/ Ford 4.848" ?
If so then perhaps the bearing retainer could be turned down to fit the BOP index bore ("GM 4.686") ?
Yes / No any one ?

Next I feel the need to rehash this drivetrain length issue.
I figure that the standard bellhousing, adapter and transmission length should be 16.9375" (17" + or - 3/16").
Installing the T15 with the 1971 bellhousing will force you to either relocate the D-225 brackets from standard
or else force you to relocate the rear engine support (transmission) crossmember.
Relocating the rear engine support crossmember will mandate propeller shaft length modifications.

 

I have a T-15 sitting on the floor of my shop. What is an index bore? If I knew what you were referring to maybe I could get that measurement for you. I am not a machinist.

 

The "Index Bore" is used to center or locate the transmission to the bellhousing.
The big hole in the rear of the bellhousing is the Index Bore.
This mates to the transmissions bearing retainer.
Early Jeep always used a 4.25"" index.
Some later Jeep used 4.848"
Ford uses 4.848"
GM uses 4.686"

 

I thought that is what you were talking about but wanted to be sure. Will have that for you in the morning.

 

The first picture = from the outside of hole to outside of retainer = .125"
The second pic = from outside edge to inside edge =.468"
The third pic = from out to out overall =4.687"

And I remembered what I forgot earlier and that is I don't have the outside diameter needed for the large pilot bushing..

 

O.K., very interesting.
So the T15 bearing retainer index is 4.686 (GM standard).
I don't see any way to turn down the bearing retainer to fit a 4.25" diameter bellhousing index.
So that means the 1971 D-225 bellhousing must be precision bored out to 4.686 in order to accept the T-15.
The early D-225 bellhousing without adapter is already 4.686".

Off hand I don't have the O.D. for the crankshaft pilot bushing.
I imajine that's been discussed before. Anyone Know ?

Can you provide me the OD of the T15 release carrier tube ?
The portion of the bearing retainer that the release carrier bearing slides on.

 

The OD for the carrier tube is 1.40"