bellhousing alignment

[kyphur]

So, I redid the bell alignment by removing the second arm on the dial indicator base and it made a world of difference. Most of my readings were accurate on each pass. I think I was at fault on some readings due to how high I have the car lifted and how much I have to do a heavy long crunch in order to hold myself up to read the dial's face. Even in one of the pics below you'll see that I have one reading but the camera shows another.

click on the thumbnails for higher res:



The numbers on the outside with the circles are the second pass. There is the occasional inconsistency but nothing like the last time.

But I guess it's all for nothing if I'm going to have to replace the dowels...





Bleh...

I remember the dowels sitting a little deeper in the TH400 also but the TH400 also didn't have two pieces.

[kyphur]

Btw, this is what Ross McCombs said:

Ross McCombs wrote:
Your setup looks good. The bore on the trani plate is concentric with the dowel pins and should be 0,0 with the crank center. You will have to ignore all of the cutouts or use the inner part of the bore.

Thanks,
Ross McCombs
President/CEO
QuickTime Inc.

The only thing is that you can't really using the inner part of the bore since that's where the weld is and it's pretty bumpy.

Just got this from him also:

We actually cut a center bore on all of our T56 bells so you can dial them in. The center bore on our T56 bells are cut in at 0,0. The QuickTime bell is the only bell that you can align. You cannot even dial in an OEM T56 bell without a CMM machine. In addition, our bells are the only bells that are clearanced to fit the new T56 Magnum transmission. So these comments are exactly the opposite. We are making the bells as accurate as possible and as user friendly as possible. Post if you wish.

Thanks,
Ross McCombs
President/CEO
QuickTime Inc.

[KEISLER]

kyphur,

you did great. the proof is in the repeatability of your numbers.

and thanks for reporting your work back to the forum so others can use it another day.

regarding the dowel pins, if you can access the back of the block, try tapping them out another 100thou. obviously, you are getting some engagement already or you couldn't have hit these numbers. and even if you can't get more out of them, don't sweat doing the dial in again since you are just replacing straight pins with longer straight pins. you will be fine.

good thread

[kyphur]

kyphur,

you did great. the proof is in the repeatability of your numbers.

and thanks for reporting your work back to the forum so others can use it another day.

regarding the dowel pins, if you can access the back of the block, try tapping them out another 100thou. obviously, you are getting some engagement already or you couldn't have hit these numbers. and even if you can't get more out of them, don't sweat doing the dial in again since you are just replacing straight pins with longer straight pins. you will be fine.

good thread

Well I called around a couple of performance shops locally this morning to see if anyone had longer dowels and no one around here does.

You don't think I should get some offset dowels to bring it into closer tolerance? I can get the Moroso ones from Summit for about 13 (+5 for S&H) and get them before the weekend if I order today.

These are the Moroso ones I was looking at.

These are the Lakewood ones.

[KEISLER]

I do recommend getting the numbers within spec of 0.005. I recommend to order the parts.

[kyphur]

They're right at the .005 tolerance but I figured if I was going to be getting dowel pins I might as well get the ones for alignment and correct it down even a little more. If I get the .007 ones then I will be putting myself in the .002 range.

[KeislerGene]

They're right at the .005 tolerance but I figured if I was going to be getting dowel pins I might as well get the ones for alignment and correct it down even a little more. If I get the .007 ones then I will be putting myself in the .002 range.

Unless I am reading something wrong your maximum out number was 7 Thou right? If so your really only 3.5 out so I would not get any offsets I would get stock longer pins. I have them on the shelf. The new pins will probably bring it in even closer.

[kyphur]

Gene,

Let me make sure that I have the definitions straight:

Runout> Total distance from one side to the other at 180 degrees. Example:
Point A at 0 degrees = .008 (dial indicator's shaft length coming in)
Point B at 180 degrees = -.003 (dial indicator's shaft length going out)
Total runout = .005
Total Offset = .0025

Offset> Half of the runout number to make centering correct.

My total runout was .005 at the furthest places.

I didn't think it was offset that I was worried about more as the runout. The runout has to be under .005 to be within tolerence is what I understood, not the offset. Am I wrong here?

[KeislerGene]

Gene,

Let me make sure that I have the definitions straight:

Runout> Total distance from one side to the other at 180 degrees. Example:
Point A at 0 degrees = .008 (dial indicator's shaft length coming in)
Point B at 180 degrees = -.003 (dial indicator's shaft length going out)
Total runout = .005
Total Offset = .0025

Offset> Half of the runout number to make centering correct.

My total runout was .005 at the furthest places.

I didn't think it was offset that I was worried about more as the runout. The runout has to be under .005 to be within tolerence is what I understood, not the offset. Am I wrong here?

If the total indicated run out is 5 before you half it then you are truly only .0025 offset not need to add offset pins. Bolt it down and move on.

[kyphur]

If the total indicated run out is 5 before you half it then you are truly only .0025 offset not need to add offset pins.

So is the .005 that we're told is the limit of tolerance for offset or run out? So would you be able to get away with .010 of run out for an offset of .005?

[KeislerGene]

So is the .005 that we're told is the limit of tolerance for offset or run out? So would you be able to get away with .010 of run out for an offset of .005?

Yes if your TIR is 10 thou your run out is half so technically 5 thou out is within spec.

[dhawkins]

Gene,

Let me make sure that I have the definitions straight:

Runout> Total distance from one side to the other at 180 degrees. Example:
Point A at 0 degrees = .008 (dial indicator's shaft length coming in)
Point B at 180 degrees = -.003 (dial indicator's shaft length going out)
Total runout = .005
Total Offset = .0025

Offset> Half of the runout number to make centering correct.

My total runout was .005 at the furthest places.

I didn't think it was offset that I was worried about more as the runout. The runout has to be under .005 to be within tolerence is what I understood, not the offset. Am I wrong here?

Correct me if I'm wrong, but wouldn't this be a total runout of .011 (.008 - -.003)? I ask because I have the same question: My bell measures -.006 at 9:00 and +.004 at 3:00, and I was wondering if it would be worth it to get the offset dowels.

[kyphur]

Correct me if I'm wrong, but wouldn't this be a total runout of .011 (.008 - -.003)? I ask because I have the same question: My bell measures -.006 at 9:00 and +.004 at 3:00, and I was wondering if it would be worth it to get the offset dowels.

That's what I thought originally but nope. Remember that you're measuring offset from center not bell opening. If you added those numbers together that would mean measuring the bell's opening and not offest. The positive means that the bell is closer to center on that side while the negative means that it's further away from center on the opposite side. The zero you get is just a relative number to where you put the dial indicator and not a true zero.

What I had trouble understanding is if it's Offset or Runout that has .005 limit. Did Runout have .010 clearance with an offset tolerance of .005 or is it runout with a .005 and an offset of .0025? According to Gene it has a .010 runout tolerance with a .005 offset tolerance.

[dhawkins]

Ah. So I should be within tolerance, I would think, right?

[kyphur]

If your total run out is -.006 and .004 then you are well within tolerance at .002 and an offset of .001.

You just might want to make sure your dowel pins are long enough to engage the bellhousing properly.