Bell Housing

[aermotor]

The smart assed Dog jist "sed", "TO YOU, IGNORANCE IS BLISS"---Whut do I do, with a Smart Assed Dog ---I didn't know he knew the wurd, BLISS???--I always "wonder" how much of our Vocabulary, dogs absorb???
Bill Paranoid

The dog may be right. I doubt that many bellhousings have been inspected this extensively so there is probably many driving around with cracks. Has anyone seen a catastrophic failure and what were the results?

John

 

[midgetracer]

I have been wondering the same thing John. I have 6 other Model A Fords with this flywheel housing and I sandblasted them all, but probably did not scan them as seriously. I had a stash of housings from engines I tore down, but that stash is mighty thin now.

 

[midgetracer]

The B engine used only a top half of the housing and extended the oil pan for the lower half. They seemed to last while it seems that this is a weaker setup. Any ideas?

 

[Nathan_1929]

Man, I didn't realize the bell housings were so prone to cracking. No wonder there are so many for sale. I think I liked this issue better when I was ignorant of it

I have a stack of seven left-overs while I was building up my current truck.

I started with one cracked one, listed a wanted (crack free) ad here, and every single one that arrived until #8 was cracked just as much, if not more, than my original one.

The silver lining is I was refunded my purchase price of the 6 cracked ones.

 

[1930-Pickup]

The B engine used only a top half of the housing and extended the oil pan for the lower half. They seemed to last while it seems that this is a weaker setup. Any ideas?

It sounds like you can have a catastrophic failure of the entire lower section of the 'A' bell housing, and have no worries

 

[Railcarmover]

The B engine used only a top half of the housing and extended the oil pan for the lower half. They seemed to last while it seems that this is a weaker setup. Any ideas?

Ford made a bunch of improvements with the B...your other question was better,has their been a catastrophic failure of a flywheel housing?seems like we all ran across a bunch of cracked ones but if they dial out and don't shatter who cares about cracks?Id bet there's more cars on the road today with cracked flywheel housings than not..

 

[Lawrie]

What about the new reinforced ones the suppliers sell.
Lawrie

 

[1930-Pickup]

Age/stress cracks, and/or casting defects? Could they have been there since day one?

 

[Chuck Sea/Tac]

I don’t see why you couldn’t bolt to a jig and then weld, so it wouldn’t warp.

 

[BRENT in 10-uh-C]

Many here have overlooked the main reason why they crack. It is not really casting flaws but instead, stop to think of the duties this piece does. Yes, it holds the back of the engine, AND it is makes-up an integral part (-like 25%) of the frame by being a crossmember, but the biggest stress it receives is that it is the piece by which all forward & rearward motion of the vehicle is transferred thru. The motion or energy is transferred from the rear axle assembly thru the torque tube and pushes on the back of the transmission. All of this motion transfer goes thru the flywheel housing. Think about how much deflection happens as you are driving over railroad tracks or when bumps are hit. What about as the vehicle turns or as the frame is subjected to twisting?

With the above said, you can see why Ford was constantly redesigning this piece, and why the design was changed for 1932. Welding or pinning cast iron is a suitable repair method when an item is not being subjected to various stress-load differences, but in this scenario these type of repairs are short lived.

 

[Terry NJ]

Another part for Tod to replicate?
Terry

 

[Railcarmover]

That's interesting Brent,so basically engineering didn't take into account 'known' loads,the stress on the driveline by operation of the vehicle.With the absence of a computer it must have required a lot of 'fudge' to allow for operational stress.Not just the known movement but that movement under stress, railroad tracks,rough roads ect.An almost impossible calculation for a slide rule.That makes one thing certain,dont overlook the mating surface of the bell housing and flywheel housing,that need to be perfect for the bellhousing to provide support.Bolt condition and torque comes into play,in most applications its snug them up and go,maybe it pays to go a little deeper on that lash up..Ford did assemble with the transmission assembled to the engine,John Charlton might be on to something as well,the stress from routine maintenance and jacking the engine. maybe putting the trans /engine together as a unit is key..

Still begs the question...anyone ever have a catastrophic failure from cracks?

 

[Railcarmover]

Besides the outside ribs the reinforced one has the cast band that wraps from mount to mount..on the early the cast band stops below the mount on each side.

 

[Railcarmover]

I don’t see why you couldn’t bolt to a jig and then weld, so it wouldn’t warp.

Provided you preheated and used the correct rod..cast welding when the rules aren't follows often fails at the point where the weld meets the parent metal.I have one where the machinist avoided welding,he pinned the crack at the end..

 

[SeaSlugs]

Many here have overlooked the main reason why they crack. It is not really casting flaws but instead, stop to think of the duties this piece does. Yes, it holds the back of the engine, AND it is makes-up an integral part (-like 25%) of the frame by being a crossmember, but the biggest stress it receives is that it is the piece by which all forward & rearward motion of the vehicle is transferred thru. The motion or energy is transferred from the rear axle assembly thru the torque tube and pushes on the back of the transmission. All of this motion transfer goes thru the flywheel housing. Think about how much deflection happens as you are driving over railroad tracks or when bumps are hit. What about as the vehicle turns or as the frame is subjected to twisting?

With the above said, you can see why Ford was constantly redesigning this piece, and why the design was changed for 1932. Welding or pinning cast iron is a suitable repair method when an item is not being subjected to various stress-load differences, but in this scenario these type of repairs are short lived.

Good point - majority of the motion of the car is controlled by those 4 bolts holding the housing to the frame. front and rear springs arent setup at all to transfer motion (also might account of why there are so many broken center tie bolts) (makes you wonder how float a motor really affects all this)

also dont forget about the front axle wanting to drive the lower half of the bell housing (and thus flywheel housing) backwards so pot holes, RR tracks, speed bumps, IL roads, etc are pushing backwards while the car driving forward. Tire spinning and grabbing shock load, then combine with rearward forces of bumps that piece is in constant flex.

My AA's wasnt cracked but the rear axle pushes and pulls on the 3rd crossmember so all the rear axle stress is to the frame and not the trans or dual high. Only stress it could potentially have is from the front axle pushing on it which i think is alot more stable. I managed to get it dialed in at .001 when I attached the trans then slipped it all in. Clutch is smooth as warm butter.

 

[SeaSlugs]

Age/stress cracks, and/or casting defects? Could they have been there since day one?

this brings a good point as well - just because it was installed crack free how many are cracked now? How many speed bumps, curbs, potholes, rough roads, dumping clutches have you guys hit?

Some of these cracks could have been there for 50 years and not cause an issue.

 

[jimalabam]

Hey Bill Williamson: Last time wife and I checked our Schnauzer had a vocablulary of 51 words. hee heee...

 

[BRENT in 10-uh-C]

That's interesting Brent,so basically engineering didn't take into account 'known' loads,the stress on the driveline by operation of the vehicle.With the absence of a computer it must have required a lot of 'fudge' to allow for operational stress.Not just the known movement but that movement under stress, railroad tracks,rough roads ect.An almost impossible calculation for a slide rule.That makes one thing certain,dont overlook the mating surface of the bell housing and flywheel housing,that need to be perfect for the bellhousing to provide support.Bolt condition and torque comes into play,in most applications its snug them up and go,maybe it pays to go a little deeper on that lash up..Ford did assemble with the transmission assembled to the engine,John Charlton might be on to something as well,the stress from routine maintenance and jacking the engine. maybe putting the trans /engine together as a unit is key..

Still begs the question...anyone ever have a catastrophic failure from cracks?

I am not sure that is an accurate statement that engineering did not take into consideration about road condition and stresses, but to get an accurate picture, you must go back and realize the evolution that brought them that far. Up until 1927, all of the 'push/pull' forces were transferred through a sheetmetal oil pan housing and the energy was transferred into the frame through the front crossmember in an area we call the crank bearing on a Model-A. Ford engineering realize their pan was the source of issues and in late 1925 they tried to add rigidity to by introducing mounting lugs on the transmission housing.

If you look at how the energy is transferred in the AA, it utilized a rigid-mounted crossmember, but I think Ford engineering felt the system on the Model A would be sufficient. As time progresses and they realized there were failures, they did make small running changes to try to eliminate the cracks. In all likelihood, one could argue that if you have a cracked housing, then somewhere along the way gross neglect and abuse have been subjected to the vehicle. So is it really Ford's fault this was a design issue?


To answer your last question, I think much more thought needs to go into this. Under normal circumstances in an hobbyist environment, I don't feel like using the work catastrophic would ever be a consideration. I have seen plenty that were cracked, and upon disassembly for a restoration, they were scrapped and an uncracked replacement was used.

 

[Railcarmover]

I dont mean a catastrophe like some one got hurt,I mean more than just finding a cracked housing and changing it,where it caused a mechanical failure resulting in a out of service condition,for instance. I could see perhaps a hard shift issue,or a severe clutch chatter..anyway,here's an earlier non reinforced housing

 

[d.j. moordigian]

classic cracks from the lower support bolt holes..general vehicle operation causes it in my opinion,its a design flaw.The bell housing load is equal all around,the flywheel housing is only supported on the upper half by the block.

The repaired one I have they just pinned the cracks,no weld...have another one weld repaired from bottom damage repair..that one was all over the dial,deviation of .020,reckon the weld heat had something to do with it.

It's original!,....second style and very early..
The first style had a plug in the flywheel housing for setting the timing..