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-   -   How much input shaft into the pilot brg? (http://www.hotrodders.com/forum/how-much-input-shaft-into-pilot-brg-228919.html)

31ROC 01-28-2013 05:30 PM

How much input shaft into the pilot brg?
 
In the middle of my conversion from 700R4 to Muncie 4 speed, and wondering how much of the tranny input shaft should be into the pilot bushing?
If I remember correctly, the 700R4 didnt have anything in the pilot bearing, and by my calculations, because I have to shim the tranny away from the bellhousing a bit for proper hyd T/O brg clearance, I will have about .410 of the input shaft into the pilot brg....is this acceptable?
Thanks!

techinspector1 01-28-2013 05:56 PM

Don't know if it would be acceptable to everyone or not, but I'd run it like that. Never really read a spec on it as far as minimum engagement.

Edit: Being curious by nature, I googled and found this post on another site. It was posted by "KeislerJeff" and I have to assume that he has some connection with Keisler Engineering, the transmission guys.

"As a rule of thumb, you need a minimum of 3/8" engagement of the input into the pilot bearing in order to properly support the input shaft. Anything less, and you run the risk of damaging the input, anything more, is just icing on the cake. :D"

He went on to recommend a roller bearing instead of a bronze bushing, stating that they want to retain the centerline of the input shaft without the "wallowing out" of a bronze bushing, which allows the shaft centerline to wander.

There are two sides to every story though and I would prefer a bronze bushing due to the fact that even when it's worn out, it will still support the shaft to some extent. When a roller bearing goes out, it's "get your tools out" time.

31ROC 01-28-2013 06:00 PM

I tend to agree, especially when I saw that an automatic doesnt even use a pilot brg, or at least this 700R4 that came out didnt.....just looking for opinions...
thanks

Bryan59EC 01-29-2013 06:33 AM

Automatics dont really use a pilot bearing because the converter is always spinning with the engine.

However----most that I have seen the Torque converter "fits" into the back of the crank and centers that way---before the flex plate bolts are snugged.

So---Automatic----not bushed but centered.

31ROC 01-29-2013 06:43 AM

Quote:

Originally Posted by techinspector1 (Post 1639828)
Don't know if it would be acceptable to everyone or not, but I'd run it like that. Never really read a spec on it as far as minimum engagement.

Edit: Being curious by nature, I googled and found this post on another site. It was posted by "KeislerJeff" and I have to assume that he has some connection with Keisler Engineering, the transmission guys.

"As a rule of thumb, you need a minimum of 3/8" engagement of the input into the pilot bearing in order to properly support the input shaft. Anything less, and you run the risk of damaging the input, anything more, is just icing on the cake. :D"

He went on to recommend a roller bearing instead of a bronze bushing, stating that they want to retain the centerline of the input shaft without the "wallowing out" of a bronze bushing, which allows the shaft centerline to wander.

There are two sides to every story though and I would prefer a bronze bushing due to the fact that even when it's worn out, it will still support the shaft to some extent. When a roller bearing goes out, it's "get your tools out" time.

WOW...that sounds like my .410 (input shaft into bushing)will be OK? and I agree with the bushing, GM had those for years, and I never had an issue....thanks again!

timothale 01-29-2013 08:00 AM

double sealed bearing.
 
My older Brother used to have the Warn Parts Franchise in Reno Nevada and did a lot of Jeep engine conversions, He used to always use Double sealed pre lubricated bearings, and some times have to make and adaptor ring to install them. A regular ball bearing can get contaminated with clutch plate dust and wear prematurely. .


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