Flywheel housing question

[Towd56]

I've read just about every post regarding how to align the housing . I know you should have no more than .006 between the 12, 3, and 9 o'clock positions.

Here is my million dollar question:

Once you bolt the housing to the trans- aren't all these tolerances going to change? Won't bolting the housing to the tranny "straighten" any variance you have?

I'm currently about .025 out between the three positions. I'm trying to wrap my head around this before I go cutting the housing.

[Tom Endy]

The shims at the top of the flywheel housing in the two ears is what aligns the top 180 degrees of the housing. The bell housing will pull the bottom 180 degrees into alignment. The shims are horse-shoe shape and are .010 thick. Sometimes a housing that is whacked out of shape slightly can be pulled into alignment by adding or subtracting thickness at one or more shim.

My experience has been that the thickness of the lower gasket is also a factor. Gaskets from suppliers are all over the map, most too thin. The reason for the .010 shims is to equal the thickness of the lower gasket when crushed down. Therefore the gasket should be around .010 - .018 thick. I purchase gasket material from Napa of the proper thickness and cut my own.

Sometimes a flywheel housing is so whacked out of shape you cannot align it and it should be discarded for a better one.

I have a theory of how they get whacked out of shape. People changing a timing gear jack up the front of the engine in order to get the timing cover off. If there are solid rear motor mounts, something has to give, the flywheel housing. Best to loosen the rear motor mount bolts when changing a timing gear, not always practical along side the road. Most flywheel housings are found with cracks at the lower two mounting holes.

The late 31 flywheel housings have support ribs at the bottom section of the housing to better protect it from being whacked. Sometimes they show up at swap meets. That is how I found mine.

Tom Endy

[Kohnke Rebabbitting]

Originally Posted by Towd56

I've read just about every post regarding how to align the housing . I know you should have no more than .006 between the 12, 3, and 9 o'clock positions.

Here is my million dollar question:

Once you bolt the housing to the trans- aren't all these tolerances going to change? Won't bolting the housing to the tranny "straighten" any variance you have?

I'm currently about .025 out between the three positions. I'm trying to wrap my head around this before I go cutting the housing.

Putting on a Flywheel housing is easy if you do it in the right order There are other posts on here where I lay them out. to much typing all over again.

Or call me anytime at 515-546-4551.

Herm.

[Patrick L.]

There are usually several ways to milk a cow. Generally there is the right way, wrong way and then my way.

Just another way for this problem. Mine was .032" out. I juggled shims for hours to no avail, or, not much avail. So, being too cheap or too lazy to find another housing,figuring things couldn't get any worse I went after it with a file and got it to about .010"

Then there is the pressure plate. I just turn a piece of round stock to the height you want [ .625"] and set the finger height to a slight drag on the round stock.

If the clutch disk is good along with the flywheel face then the clutch will now work nicely with no chatter.

[BILL WILLIAMSON]

Hang the housing from a wire & "ding" it with a small hammer. The proper sound, or "NOTE" will tell you if it has HIDDEN cracks. Try it on a known cracked one!
Bill Highcee

[SeaSlugs]

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Took me an hour or more to get it under the .006" spec, managed to get it under .001 playing with shims. Clutch is smooth as butter with no hint of chatter or roughness. Thats even with the solid type disc (not the spring loaded type).

I used a heavy mag base dial indicator stuck to the flywheel mount and rolled it a bunch of times. Made sure the flywheel to crank mating surface was clean as a whistle, properly tightened and checked it again, still under .001.

[Jim Brierley]

What Bill W. says is also a good way to check crankshafts.

[Towd56]

Thanks for the input. I spoke with Herm today and I am on the right path.

[sunnyorm]

re: million dollar ?

a couple of years ago, I asked my model a mentor friend (who's collected and restored over 40 years, and owner of 6 model a s) his answer was; he has never once believed it is that important.

[BRENT in 10-uh-C]

Originally Posted by sunnyorm

re: million dollar ?

a couple of years ago, I asked my model a mentor friend (who's collected and restored over 40 years, and owner of 6 model a s) his answer was; he has never once believed it is that important.

You know, everyone is entitled to be wrong! Have you ever wondered why (-if it wasn't that important) KR Wilson made tools to check it, and Ford mechanics were instructed to perform the checks outlined in the service bulletins??

[BILL WILLIAMSON]

Originally Posted by Jim Brierley

What Bill W. says is also a good way to check crankshafts.

Jim,
And what is the equivalent PIANO note you're searching for?
Bill W.

[Towd56]

Followed HERM's advice and was able to get it within .001 at top and both sides. The bottom is still out about .020. But I believe tranny will pull that in.

One note I wanted to mention - I would have sworn the housing was in nice shape and not cracked. I had bead blasted it clean as a whistle and couldn't see a crack. When I had it magna fluxed- 3 cracks showed up. FYI - don't trust your eyes!!!

[CarlG]

Originally Posted by Towd56

Followed HERM's advice and was able to get it within .001 at top and both sides. The bottom is still out about .020. But I believe tranny will pull that in.

One note I wanted to mention - I would have sworn the housing was in nice shape and not cracked. I had bead blasted it clean as a whistle and couldn't see a crack. When I had it magna fluxed- 3 cracks showed up. FYI - don't trust your eyes!!!

I had the same thing happen to me. Had to end up getting a good one from Berts.

[marc silva]

I have often thought about why does the flywheel housing crack. After removing my engine and transmission to install a new engine I noticed my flywheel housing was almost cracked in half at the starter. Then it hit me. How can the engine be bolted solid at the rear, and granted it is in rubber but in my opinion it is basically a solid mount compared to springs in the front. I know the frame flexes but think about it. The motor hangs off the rear mounts causing some stress on the flywheel housing as the front bounces on the springs. Am I incorrect in my thoughts?

[1crosscut]

Herm... I'm going to start charging you royalties for using pictures of my engine!

[Kohnke Rebabbitting]

Originally Posted by 1crosscut

Herm... I'm going to start charging you royalties for using pictures of my engine!

Wow, I don't want to have to go back to Photo shopping, Dave

Herm. !

[Kohnke Rebabbitting]

Originally Posted by Towd56

Followed HERM's advice and was able to get it within .001 at top and both sides. The bottom is still out about .020. But I believe tranny will pull that in.

One note I wanted to mention - I would have sworn the housing was in nice shape and not cracked. I had bead blasted it clean as a whistle and couldn't see a crack. When I had it magna fluxed- 3 cracks showed up. FYI - don't trust your eyes!!!

One thing yet, take the top reading now and by an equal amount of shims added to the two bolts, make top and bottom read the same as close as you can get. This will give the transmission a 4 point square area to bolt to.

Then leave it set for 24 hours, and touch up any warping changes, if any.

Herm.

[SeaSlugs]

Originally Posted by 1crosscut

Herm... I'm going to start charging you royalties for using pictures of my engine!

I think your Miracle Whip has gone bad... Or it just needs whipped again - never know with that axle grease...

[1crosscut]

Originally Posted by SeaSlugs

I think your Miracle Whip has gone bad... Or it just needs whipped again - never know with that axle grease...

No such thing as bad Miracle Whip... just get ornery sometimes. Herm sure does nice work.

[J and M Machine]

Originally Posted by marc silva

I have often thought about why does the flywheel housing crack. After removing my engine and transmission to install a new engine I noticed my flywheel housing was almost cracked in half at the starter. Then it hit me. How can the engine be bolted solid at the rear, and granted it is in rubber but in my opinion it is basically a solid mount compared to springs in the front. I know the frame flexes but think about it. The motor hangs off the rear mounts causing some stress on the flywheel housing as the front bounces on the springs. Am I incorrect in my thoughts?

Yes: Part of it is the way the engine is hung along with the wishbone pushing against the flywheel housing. Everytime you hit a pothole it causes pressure on the wishbone thereby putting pressure on other parts.
Since the flywheel housing is secured to block with only four bolts naturally all stress will occur where it is at edge of block. We have successfully repaired these using our metal stitching/crack repair methods.

I wouldn't advise anyone to weld them as the weld can't flex like the parent metal can. The weld just makes it crack more.


I have enclosed pictures of typical cracks we see on regular basis with flywheel housings.

The late 1931 flywheel housing has extra reinforcing ribs and an internal band to add strength to a flimsy area. Even still with this added support they still crack.
http://www.jandm-machine.com/metalStitching.html

[SeaSlugs]

I always wondered where they crack... Thanks!

[Towd56]

The cracks shown by J and M are nearly identical to where my housing was cracked. Couldn't see them until magna fluxed