Is there suppose to be a difference on the rear of the crankshaft where the input shaft of a manual tranny goes opposed to an auto tranny?

 

manual cars just have a flywheel and auto cars have a flex plate. no difference in cranks, otherwise youd see people that do m6 swaps doign crank swaps.

 

indeed!

 

A few hours ago, I was out in the garage making preparations for putting my newly built 396 LT4 back into the car. When I was about to bolt on the flywheel, I noticed that the pocket on the crankshaft that the M6 input shaft goes into is too shallow!

 

So...does the tip of the tranny's input shaft make any contact at all with the rear of the crank, or does the flywheel and clutch assembly make up the full length of the input shaft?

 

There is no difference in the crankshaft, itself, but with an auto tranny, there should be no pilot bushing/bearing installed in the center, rear of the crankshaft.

 

Thanks Shoebox...now I know what's missing, there isn't a pilot bushing/bearing there! Now...please tell me, does it have to be pressed in or what, and which is better, bushing or bearing?

 

Get a brass pilot berring. The roller ones have been known to fall apart. Then grease it up a little and use a rubber mallet to hammer it in.

 

Flat side in, chamfered/beveled side out.

 

Hang on just a minute guys!!! While the stock LT1 350 cast cranks from GM are ALL drilled for the pilot bearing/bushing, (so they can be interchanged between manual and auto transmission applications), keep in mind that carlos64030 is dealing with a 396 STROKER motor which will, of course, have an AFTERMARKET stroker crankshaft. Now not ALL aftermarket stroker cranks are "pre-drilled" for a pilot bearing/bushing, (i.e. for MANUAL transmission applications) The "depression" he is seeing at the back end of the crank may just be the "locating/guide" hole in the stroker crank forging/casting where his engine builder/balancer/machiner is SUPPOSED to drill and ream a pilot bearing/bushing hole when he is TOLD that this motor is meant for a MANUAL transmission application

Carlos you are on the right track when you ask if the input shaft of the manual tranny should "make any contact" with the crankshaft. The answer is NO it should NOT make any CONTACT with the crank, BUT yes, about 80% of the input shaft bearing area length will extend INTO the pilot bearing/bushing when the tranny and pilot are installed correctly. Or, to answer your other question, NO the clutch and flywheel will NOT take up ALL the length of the input shaft, the input shaft needs to extend into the pilot bearing/bushing. Hope this info helps???

 

Hey 97 6speed z...thank you very much for that heads up! The transmission thing never even came up when I talked to my engine builder. I'm glad I noticed this before I started to drop the motor back in! Thanks goes out to all that responded to this post.

 

Carlos64030, you're welcome! That's what makes this board sooooo........ GREAT Just one person trying to help out another

 

so the manual transmission input or output shaft, does not go in to the crank than?
what do the splines on the trans shaft slide and lock in to please and thank you?

 

Wow! Back after eighteen (18) years on this one!

Smitty, first off, a manual transmission's INPUT shaft is the one at the FRONT of the trans, (on our cars), and every thing I said (above) eighteen (18) years ago still applies. The very "tip" of the INPUT shaft rides within the pilot bearing, which is pressed into the rear of the crankshaft. The "splines" on the INPUT shaft are there for engaging the driven disk of the clutch, and are free to float as the clutch engages/disengages, but don't "lock in" to anything.

The transmission's OUTPUT shaft, (at the rear of the trans), has "male" splines to engage the "female" splines inside the drive shaft yolk, which attaches through a U-Joint to the driveshaft itself. Again, nothing "locks in" back there either, it's also free to float as the suspension travels.

Hope this answers what you've asked?

 

HOLY THREAD REVIVAL, BATMAN!!! I made this post way back in 2003 and it's been resurrected from the dead. Good info never gets old and it's awesome that this forum is still around and loaded with valuable info that people can refer to.

Btw, I still have the same car... 1997 WS6 T/A.