Bell housing alignment questions

[joe smith]

When doing this with a dial indicator, doesn't the dial indicator have to be perfectly centered to the bellhousing opening?? How do you do this??

And after you install offset dowels, how do you get the bolts back in??

 

[gkent]

Wherever you attach the indicator, when you rotate the crank it will turn in a perfect circle. However far it is from dead center will be consistent all the way around. The dial indicator is reading runout. Set it at zero anywhere in the hole, rotate the crank and it will indicate the variance from your starting point. Make sure it has some preload in it so that it can move both ways to show + and -.

The bolt holes are oversize enough to allow the slight movement required. In fact, you want bolts in place but not tight when you're dialing it it. Make sure the dowel holes are very clean as well as the dowels. Use proper mopar dowels so they fit the holes and lube them before putting them in. This way you can make adjustments without having to remove the bellhousing every time.

And its wise to start with stock, zero offset dowels.

 

[gkent]

And should you need them, I have sets of .014 and .021 offset dowels you can have for $20 plus postage. These are Mopar dowels from the P4120383 set.

 

[Daves69]

If it helps, notice in this MP picture, the size of this indicator requires it being setup on an angle.

 

[dvw]

Be careful .500" dowels are too large. Mopar uses .496". A .500" will pound in. But very difficult to remove.
Doug

 

[gkent]

A .500" will pound in.

DON'T EVEN TRY THIS. If need be you can buy 2" .496 pin gauges from McMaster Carr for under $5..

 

[zyzzyx]

At the risk of making this sound harder, (it's not) If you can affix the indicator stand like
Daves69 has it pictured you will have very good rigidity. Mag bases are handy, but there
isn't a large enough flat surface to attach it to! Next thing is try to use an indicator that
isn't too big and clunky. It will be hard to position. De-burr the block face and the bell
housing before starting, and use ALL of the bolts just finger tight. Make sure you "Sweep"
the bore two or three time to make sure your readings repeat. after you figure out what
bushing you need and install it, Sweep the face of the bell housing where the trans bolts
on to see if it has to be machined! This is just as important as the radial numbers. If it has
to be machined, you'll need to re check the radial numbers again. once you start indicating
it, you'll start to see how easy it is. Good luck!

 

[dvw]

Agreed. Standard dowels can be made from the shank of 1/2" bolts. Measure a few, they vary slightly.
Doug

 

[gkent]

Mag bases are handy, but there
isn't a large enough flat surface to attach it to

Bolt the flywheel to the crank. get a piece of 1/4" x 2" flat bar cut long enough to bolt across the flywheel using the pressure plte bolt holes. This now gives you the flat surface to clamp the mag base to.

Re-reading the original post, you do want the indicator centered in the hole but it doesn't have to be centered on the crank centerlin. See my cruse illustration below.

 

[Fran Blacker]

 

[monte]

you can also just remove one of the flywheel bolts to create a flat service for magnetic base.

 

[493 Mike]

RobbMcPerformance Bellhousing Alignment Dowels
Mike

 

[Jeremiah]

The Rob MC dowels are what you want to use. Nothing finer in my opinion.

 

[gkent]

Seriously, what makes them so great? List 5 benefits over a standard piece.

 

[cryplydog]

I use a small diameter starrett indicator like a last word type. Do all prep work as stated above. You can carefully drill through the bell housing and into the block flange with a 1/4" high speed drill to about a 3/8" depth and drive in a hardened roll pin in two places about 1/3rd. and 2/3rd. of the bolt circle. this way saves time for me when I disassemble for whatever reason. But, when you change block or bellhousing you have to indicate them again.

 

[vintage chromoly]

I used the Robbmc offset dowels.
They are nice. You can index them to where you need them, and then, lock them down.
The one thing I noted, was that one could probably put too much torque on the locking set screw, and maybe foul up the block with a crack. I’m not sure you could put enough *** into one, to crack the block, but I noted to myself, to not use Gorilla strength.

 

[493 Mike]

I used the Robbmc offset dowels.
They are nice. You can index them to where you need them, and then, lock them down.
The one thing I noted, was that one could probably put too much torque on the locking set screw, and maybe foul up the block with a crack. I’m not sure you could put enough *** into one, to crack the block, but I noted to myself, to not use Gorilla strength.

And, remember, the dowels are for alignment. The bolts do the work of fastening/clamping the bell to the block.
Mike

 

[Jeremiah]

Seriously, what makes them so great? List 5 benefits over a standard piece.

Damn...5? Is there a minimum word count?

 

[Jeremiah]

1) they are readily available in 2021
2) you don't need a dowel puller to remove then
3) they are the correct size (not .500)
4) they are easily indexed
5) they are guaranteed to be made in the USA

: D

 

[gkent]

2) you don't need a dowel puller to remove then

This is the only valid benefit over Mopar pieces.