How do you install bell housing on 48 DeSoto?

[marcapra]

I have already installed the clutch housing, or bell housing as some call it, but now I'm worried.  The shop manual says that you need Special Tool C-870.  This is a tool that bolts onto the crankshaft flange bolts before the Fluid Drive is installed.  The tool has a long rod that sticks out of the housing.  Mounted on the rod is a micrometer that measures for out-of -round of the clutch housing bore, which should measure no more that .005", and the rear face of the housing, which should measure .002".  You measure the clutch housing bore by turning the crankshaft one revolution.  If it is out of the spec, you loosen the dowel pins and tap the housing until it is within spec.  The manual  says that if you fail to do this, you will get hard shifting and sometimes gear disengagement.  If I can't get this tool, is this something an alignment shop could do?  I do have a spare transmission main shaft for this car which is how I aligned the clutch to install it.

 

 

Thanks, Marc.

[Rusty_OToole]

You can do the same thing with a dial indicator, you need a magnetic base or some way to fasten it to the crankshaft. If you know a machinist or good mechanic this is a simple thing to check. If not, dial indicators are not that expensive.

[Gary_Ash]

Normally, the bell housing/clutch housing has a number of bolts that fit freely through the holes and 2 or 3 dowels pins with almost zero clearance.  If you didn't change the bell housing or engine, it should be aligned as it was at the factory.  The tight dowels will line it up.  Of course, you can check the alignment.  Harbor Freight carries both 1" dial indicators and a magnetic base.  If you can't maneuver the assembled magnetic base and indicator to have the tip run around the i.d. of the hole in the bell housing, you may need to bolt a piece of steel bar or angle iron to the flywheel to get another place to perch the magnetic base.

 

Be sure to remove the spark plugs as you turn the engine over by hand.  Mark the starter ring gear with a Sharpie about every 90 degrees so that you can take 4 readings per revolution and average them.  Gee, I hate lying on my back under the car doing this.  It's much easier if you have a helper who can turn the crankshaft using a socket wrench on the crankshaft pulley bolt or even tugging the fan belt over.

 

Usually, the dowel pins are not inserted when you put a non-matched engine and transmission together.  The free bolts are tightened just enough to hold the bell housing without it slipping by gravity.  When you figure out the high side, tap the housing gently with a big hammer to move it just a few thousandths.  Repeat the measurement process until the variation is in spec.  Then you need to tighten the bolts and re-drill the dowel holes.  It's sometime easier just to drill 2 or 3 new holes through the housing and engine flange and insert 1/8" or 3/16" roll pins and leave out the old dowels.  The roll pins will keep the housing from shifting under load and vibration. 

[marcapra]

Gary,  I did buy the magnetic base and dial indicator.  but how do you know if the magnetic base is perfectly centered?  Am I missing something here?  And yes, it is the same bell housing as went to the engine.  Both are original to the car.  It's been so many years since I installed it, I can't remember if it had dowel pins.

 

Marc.

[Gary_Ash]

The base doesn't have to be perfectly centered.  Just locate the base and arm so that the dial indicator tip can ride around the i.d. of the bell housing and record the numbers.

 

Here's a link to a video that shows the basics on a modern Chevy engine:

 

It's unlikely that offset dowel pins as used in this Chevy engine are available for your engine, which is why you may need to drill/ream new holes or use two of the old bolt holes with your old pins.

Still, since you are using the original engine with its matched bell housing, you shouldn't have to re-align anything. 

[marcapra]

Thanks so much Gary!!!  I wonder why doesn't the base have to centered? 

[joe_padavano]

1 hour ago, marcapra said:

Thanks so much Gary!!!  I wonder why doesn't the base have to centered? 

 

Because the location of the base is irrelevant.  What matters is the location of the tip of the dial indicator relative to the centerline of the crank.  By turning the crank, the base is automatically "centered" on the centerline of the crank.

[c49er]

I think You are way in over your head.

You can mount the dial indicator anywhere on a rotating surface as long as you can properly locate the indicator plunger.... preferably with a roller on the end in the bore of what you are checking.

But..why do you want to check it... because you read about it in the factory shop manual? Or just because it will be fun

Are your two factory locating dowels still in the rear of the block?

If you have the original bell housing to block don't worry about it already mentioned above.

 

If it was an automatic trans yes it might be necessary.... but then only if the front pump and seal/bushings were having wear/vibration issues.

[marcapra]

Thanks guys for all of your answers!  I really appreciate it!  Marc.