Pilot Bearing Selection...

[Patrick T.]

I've ordered a new Centerforce 1 clutch assembly for my '67 327-350, I have a new GM part #14061685 roller pilot bearing, or I could use the standard bronze pilot bearing. The car will not be raced. Which one should I use? Thanks, Patrick

[Joe L.]

Re: Pilot Bearing Selection...

Patrick-----

If you're certain that the engine/bellhousing/transmission alignment is perfect, use the roller bearing pilot bushing that you have. Otherwise, use the oilite bronze bushing. The roller bearing pilot bushing is best, but it is not forgiving of any misalignment. The bronze bushing will "wear in" to accomodate SLIGHT misalignment.

You can determine the alignment condition by dial indicating the transmission front bearing retainer hole in the bellhousing relative to the crankshaft pilot bushing hole.

[Joe L.]

Re: Pilot Bearing Selection...

Patrick-----

If you're certain that the engine/bellhousing/transmission alignment is perfect, use the roller bearing pilot bushing that you have. Otherwise, use the oilite bronze bushing. The roller bearing pilot bushing is best, but it is not forgiving of any misalignment. The bronze bushing will "wear in" to accomodate SLIGHT misalignment.

You can determine the alignment condition by dial indicating the transmission front bearing retainer hole in the bellhousing relative to the crankshaft pilot bushing hole.

[Patrick T.]

Re: Pilot Bearing Selection...

Thanks Joe, I'm using the original bell housing and engine that have been together, since new. The pilot bearing in the crank now is the bronze type, and not that old. I could leave it in as is, but I'm thinking why buy a new clutch and not replace the bearing? I think I'll just install the new roller bearing.

[Patrick T.]

Re: Pilot Bearing Selection...

Thanks Joe, I'm using the original bell housing and engine that have been together, since new. The pilot bearing in the crank now is the bronze type, and not that old. I could leave it in as is, but I'm thinking why buy a new clutch and not replace the bearing? I think I'll just install the new roller bearing.

[Mark Ring]

Why is a roller bearing better?

I would love to know why the roller bearing is better than the bronze bushing. I have known about the bearing for many years (I believe they were originaly designed for trucks). The bushing works, never needs any attention, and is fairly easy to remove with grease and a wooden dowel at clutch replacement time. What do I get for using the bearing instead of the bushing? Less tolerant of misalignment and more difficult to remove?

Thanks in advance for all responses.

-Mark.

[Mark Ring]

Why is a roller bearing better?

I would love to know why the roller bearing is better than the bronze bushing. I have known about the bearing for many years (I believe they were originaly designed for trucks). The bushing works, never needs any attention, and is fairly easy to remove with grease and a wooden dowel at clutch replacement time. What do I get for using the bearing instead of the bushing? Less tolerant of misalignment and more difficult to remove?

Thanks in advance for all responses.

-Mark.

[Brandon K.]

You need to have a perfect input shaft as well

I just found out that if you are not using a new input shaft, check your old one very thoroughly for any slight wear prior to using the roller bearing. There is no inner race on the roller brg, and therefore will cause problems if there are any radial grooves, even slight ones. I bought a new roller brg, but decided to go back with the bronze one instead.

Brandon

[Brandon K.]

You need to have a perfect input shaft as well

I just found out that if you are not using a new input shaft, check your old one very thoroughly for any slight wear prior to using the roller bearing. There is no inner race on the roller brg, and therefore will cause problems if there are any radial grooves, even slight ones. I bought a new roller brg, but decided to go back with the bronze one instead.

Brandon

[Joe L.]

Re: Why is a roller bearing better?

Mark------

Yes, the roller bearing pilot bearing has been around for a long while; it is not new, at all. Originally, it's application was the light duty diesel engine used in light trucks.

The only advantage to the roller bearing that I'm aware of is that it will maintain perfect alignment since it is far less susceptible to wear. I'm sure that it also has a higher load carrying ability than a bronze bushing, but I don't see this as much of an advantage for a pilot bearing.

Personally, I would only use one if I was certain of the initial alignment by following the measurement process that I described earlier. Actually, it's not a bad idea to do that anyway. If I performed that process and found the alignment to be perfect, I'd probably use the roller bearing. If I found it to be just slightly off, I'd probably leave it as-is and use the bronze bushing. If I found it significantly off, I'd correct it to perfect and probably use the roller bearing.

[Joe L.]

Re: Why is a roller bearing better?

Mark------

Yes, the roller bearing pilot bearing has been around for a long while; it is not new, at all. Originally, it's application was the light duty diesel engine used in light trucks.

The only advantage to the roller bearing that I'm aware of is that it will maintain perfect alignment since it is far less susceptible to wear. I'm sure that it also has a higher load carrying ability than a bronze bushing, but I don't see this as much of an advantage for a pilot bearing.

Personally, I would only use one if I was certain of the initial alignment by following the measurement process that I described earlier. Actually, it's not a bad idea to do that anyway. If I performed that process and found the alignment to be perfect, I'd probably use the roller bearing. If I found it to be just slightly off, I'd probably leave it as-is and use the bronze bushing. If I found it significantly off, I'd correct it to perfect and probably use the roller bearing.

[Brandon K.]

How do you correct the alignment?

Alignment could be off because of getting the block line bored or just due to manufacturing tolerances, so how do you go about correcting it?

[Brandon K.]

How do you correct the alignment?

Alignment could be off because of getting the block line bored or just due to manufacturing tolerances, so how do you go about correcting it?

[Joe L.]

Re: How do you correct the alignment?

Brandon-----

The procedure is far too involved to go into here. I'm not sure if it's in the Chevrolet Service Manual, or not. The complete procedure has been published in various automotive magazines but I don't recall which ones or which editions at the moment. It should be covered in "automotive encyclopedia"-type books or comprehensive general automotive repair manuals, though.

[Joe L.]

Re: How do you correct the alignment?

Brandon-----

The procedure is far too involved to go into here. I'm not sure if it's in the Chevrolet Service Manual, or not. The complete procedure has been published in various automotive magazines but I don't recall which ones or which editions at the moment. It should be covered in "automotive encyclopedia"-type books or comprehensive general automotive repair manuals, though.