Pilot bearing in an A568

[turboshad]

Has anyone ever considered incorporating a pilot bearing onto one of the FWD trannies?

It seems that since I have been using 4 pucks that the input shaft bearings tend to go quickly. My thought is that much of this comes from the chatter that a 4 puck will produce combined with the frequency of use in daily driving. I can't help to think that some extra support closer to the clutch would help relieve some of the stress on the terrible design of using a tapered bearing on our input shafts.

To make it possible I would need to weld some high carbon steel to lengthen the input shaft past the clutch and then incorporate the bearing into the crank. From what I can tell I could machine a piece to press into the current cank bore and use a toyota bearing like what some of the RWD guys are doing.

So I'm curious if this has crossed the minds of anyone else or if I'm missing something and the chatter isn't the cause of my IPS bearing problems.

DJ

[2.216VTurbo]

Don't know anyone who has done it but I have wondered why they didn't If you close one eye and squint, the flywheel looks like it was kinda cut for one, or that's just extra space for the input shaft. Seems like the relief is larger than it would have to be...

Hey Shad, where's my set of tubular arms anyway?

[glhs0426]

Rage-Tek has done this for the T850 in the SRT4. What I can't grasp is the procedure to center the bellhousing centerline to the crankshaft centerline. I mean how do you read the dial indicator so you can adjust the offset with custom offset hollow dowels?

I've always wanted to do this in a manual fwd application, but the design made it impossible. Show us all please, right after the control arms hit the streets!

[Ondonti]

wouldn't you need a custom input shaft? I wouldn't complain about one of those.
Welding seems......

Still, if you could do it without having to remove the crank from the motor to install the bearing, I think I would like that.

What about the reverse of a pilot bearing...drilling out the hold in the end of the shaft a little bit more.
I hate that all my transmissions rattle even when i shim up the shaft.

[turboshad]

Hey Shad, where's my set of tubular arms anyway?

I already made them for you in the other thread. You just have to hit print

The control arms are not mandatory in having the car ready to drive to SDAC but I am pulling the engine tomorrow to re-locate the dowel bung and change the input shaft bearings so if I am going to try this than now is the time. I'm pretty confident that if they are not on my car by then that I will at least have something to show at SDAC though.


I agree that welding seems....... but there is more chance of it holding than not. And if not than the worst case is that I will have a chunk of metal that is pinched between the crank and input shaft which rotate together anyway. The piece will have nowhere to go and it will just be a failed project but shouldn't inhibit the engine at all. There really won't be alot of stress on it since the transmission is already designed to take all the radial loads. I think it should be acting as a support for what shaft flex there may be (liek clutch chatter) and not a main load bearing piece.

My plan was to weld an oversized piece onto the input shaft to extend it. The piece will need to be have a high carbon content and the input shaft will be preheated before welding. The temper that is lost in welding the input shaft should be pretty local and not effect the spline strength where it actually contacts the clutch. Once the piece is on I will put the input shaft in the lathe and turn it down to the proper size to make sure it is true with the rest of the shaft.

The dowel pins should have the transmission located pretty dead nuts center on an 8V old school tranny combo. In my case with the 2.4, I welded a new dowel bung onto the tranny which I didn't get centered. This resulted in my input shaft bearings dieing in just over 1000 miles. So I am building a piece that will bolt up and locate itself on the crank that will slide into the release bearing shaft size on with ID which is located centrally with the inner input shaft bearing housing. This will center the bell housing perfectly and then I will re-make the dowel bung and weld it back on in the proper place.

After that it just comes down to making a piece to adapt a current pilot bearing to the 2.4 crank. If a dakota bearing fits I will be lucky. If not I just need one smaller that the 2.4 bore and I cand make an adaptor. I would really like to stay away from machining the crank if I can.

There's my plan and it seems from your responses that I'm not out to lunch on my conclusions. It's just a matter of seeing if it will work.

[turboshad]

What about the reverse of a pilot bearing...drilling out the hold in the end of the shaft a little bit more.
I hate that all my transmissions rattle even when i shim up the shaft.

I read that again and it may have merit. My only worry would be taking material away from where the shaft needs it most. Right where the spline contacts the clutch. Definately something to look into a measure though.

The tranny rattle is definately a driving force it this too. I can't stand finally having a smooth quiet engine and then the horrific clatter when I let the clutch out

[Ondonti]

Well the stock shaft already has a little "dimple" in the middle and I think at least some of the shaft passes all the way through the disc. Find out how much you can spare. Maybe a drill bit hit to the stock dimple is all you need. I dont know much about what a pilot bearing requires to be effective.

[glhs0426]

I understand how you are going to center your engine/transmission combination. Very ingenious. How far does the input shaft protrude from the front of the clutch? If it is enough for a bearing to locate the shaft you could make something that presses into the crankshaft similar to this:


This piece presses into a V8 Chrysler engine not orginally machined for a manual transmission pilot bearing. You could machine a piece that steps out from the end of the crankshaft and meets the input shaft, bringing the bearing to the input shaft instead of bringing the input shaft to the bearing.

John

[Ondonti]

i don't know how much roller bearings would like the splines. Maybe a weird crankshaft "pulley" that the input shaft can plug into.......

[glhs0426]

Definately the end of the input shaft would have to be machined down or a sleeve made for the end of the input shaft. Hence the question of how far the input shaft extends through the clutch.

[turboshad]

Definately the end of the input shaft would have to be machined down or a sleeve made for the end of the input shaft. Hence the question of how far the input shaft extends through the clutch.

Not very far at all which is the sucky part. I will have the engine out tomorrow so can take some more detailed measurements but from th 568 I just did for a guy, the marks where the clutch was riding were about 1/4" at the most from the end of the input shaft.

[glhs0426]

Well the stock shaft already has a little "dimple" in the middle and I think at least some of the shaft passes all the way through the disc. Find out how much you can spare. Maybe a drill bit hit to the stock dimple is all you need. I dont know much about what a pilot bearing requires to be effective.

Not very far at all which is the sucky part. I will have the engine out tomorrow so can take some more detailed measurements but from th 568 I just did for a guy, the marks where the clutch was riding were about 1/4" at the most from the end of the input shaft.

If the clutch is a good 1/4" away from the end you could gun drill the end of the shaft. (The center of the shaft really is of no consequence for strength?) Press a bearing into the crank and press a "pilot" shaft into the bearing which inserts into the end of the drilled input shaft. Of course the bearing would need to be special bearing since both inner and outer races of the bearing would be fixed.

What would weaken the shaft more, gun drilling or welding?

[turboshad]

Well I pulled the trans and found the clatter wasn't the input shaft bearings at all but the center hub of the clutch. It is totally loose and clanks like a mo fo. That being said, Allen should be happy to hear that I think I will hold off on the pilot bearing project. I have a fair amount on my plate that I want to get done before I put the car back on the road in May. One less project will be nice. I do still think our trannies could benifit from one and it may still be a project for down the road last time.

I did make the alignment tool I was talking about to make sure the trans and engine were perfectly inline. I posted pics in the 2.4 swap section but will throw them up here also since I talked about it. The shaft that slides into the TOB bore is .001" undersized and the other end locates on the crank like the flywheel does.

[2.216VTurbo]

So you will be ready for Cincy now eh? I figured you'd be spending all your time on your 'research' projects...

Clutch pics?

[turboshad]

I sure hope Cincy is in my future. I'm doin my darndest.

Here's a pic of the clutch as requested. I can fit a .028" feeler gauge into the gap. She makes a real racket in neutral.

[glhs0426]

Wow! You know you have to rent that tool out for swaps now. You just had to post pics.

It can be used for a go/no go gauge for checking engine/transmission combinations.

pm me for rental agreement, better yet, I'll pick it up at SDAC.

[2.216VTurbo]

Hmm, I was expecting something uglier than that... Are the springs 'loose' in their cages? That can clatter when they are. First clutch I bought with the Eurethane encased springs ZI though it would be sliced bread. Turned out those loosened up too with time I bought a couple clutches with those telltale little laser cut reliefs on the cage corners, hope they're not at issue. I've twisted the center out of a Clutchnet and an OE style Sachs. BTW I am really liking my Yellow PP and stock organic style disc I put in the Rampage. Streetable like stock and holding the 75 shot on 8.5" slicks no problem