Flywheel Housing Alignment
 

Hi All,


I have been running a indicator around this housing. Red book says there should be a maximum of .006 variation. Is this what other engine re builders are getting? I seem to be getting some erratic readings that don't make a lot of sense.
Thoughts? Thanks, Steve
https://i.postimg.cc/ygst0fTH/fly-housing.jpg

Re: Flywheel Housing Alignment
 

80 years later most clutch housings are either distorted or cracked.


Beyond the linkage mounting ears, I found it necessary to shim at the point where the housing meets the block at the four bolt holes.


I kept records of each combination until I found the point with in limits.


It takes patience.

Re: Flywheel Housing Alignment
 

I cannot tell from the picture, but, is your engne sitting on the engine stand horizontal or vertical. If it is sitting horizontal - as you turn the crankshaft the shaft will move forward and back a few thousands of an inch -the distance of the thrust movenent in the shaft. This affect the measurments in your dial indicator.


Turn the engine vertical or at least 45 degrees so all the thrust is moving down. The shaft will ride against the thrust surface of thebabbit and you will get a more consistant dial reaaduing.. clear as mud??? ken

Re: Flywheel Housing Alignment
 

That's good to know, I added and removed shims where the accelerator bolts go but that was not helping much. Taking the time to work that detail out must improve operation and shifting.

Re: Flywheel Housing Alignment
 

The engine is sitting vertical on a Wilson engine stand. Sure makes it easier to work on..

Re: Flywheel Housing Alignment
 

The critical locations for measurement are 9, 12, and 3 o'clock. Also be sure to check the flywheel wobble. All important to minimize clutch chatter. Good advice from Ken regarding axial movement of the crank during measurement. Please share the final result. Good Luck.

Re: Flywheel Housing Alignment
 

This method of gauging run out is confusing. Suppose the snap ring diameter in the case exceeds the .006" limit due to it being out of round in a free state? This has nothing to do with the engine shaft. It seems to me this dimension should be verified before trying to determine if the case is concentrically located relative to the shaft. It appears there are 2 locating pins that locates the case. These were used to machine the snap diameter that is being indicated. Once you verify that the case is within spec then you can use the setup shown in the photo to check run out relative to the case.

Re: Flywheel Housing Alignment
 

I went through 6 used housings before I found an true one,Ford did about 8 revisions in production,the best are late '31's,they have ribs on the outside along the bottom.An easy test for cracking is to balance it with one finger and whack it with a wrench,it should ring...if it clanks its cracked.

The reason its done is to insure crankshaft/transmission input shaft alignment,so the clutch disc fully and evenly contacts the flywheel on application.

Re: Flywheel Housing Alignment
 

DO NOT shim under the 4 housing bolts, as this will warp a usable housing in the wrong places.

The first thing is you have to have a level crank flange, and also a crank that is centered, in the babbitt, between the main, bolt holes. with out it your wasting your time. If that is off, your housing will be also. It is flange, to housing is what your trying to level. So if your crank is left or right by .010, The pilot shaft will be off, out of alignment, also.

Many Guys think you have to have some kind of level flywheel housing. I have never had one I couldn't level, no big deal. We have built in access, of 350 A engines, and many more then that, in babbitt jobs, where the customer also wanted us to install the flywheel housing.

You have to do two steps, to get a level, 4 point contact, to bolt the bell housing to.

First, get 9:00, and 3:00 to read the same, just the sides, first. Coarse adjustment, will not work. You have to have Brass, shim stock in, .001, and .002 thousandths, when you need it.

Movement for the side adjust, is set by shims put under the two top bolts, From side to side, chances are, your shim packs, will be different thicknesses, and 9 & 3 should be with in 1, to 2 thousandths.

When that is done, now you do the top, and bottom, 12, and 6, the only thing that is important here is that they both are, the same. This movement here, up or down, what ever you put in, or take out, they have to be equal, both sides.

They may, or may not be close to the sides, but what you want is that the bell housing will be square, with the flywheel housing, and engine.

We always let the first adjustment set for 24 hours for warping, and also the 12, and 6 setting.

Herm.

Re: Flywheel Housing Alignment
 

Herm, I'm a bit confused as to your shimming process. Not clear to me where you use shims, other than the two top bolts that take the .010" slotted shims. Could you expound as to your shimming? The photo that shows Indian Head shellac applied on the top portion of the gasket. What's going on there? Shims under the gasket, or???

Re: Flywheel Housing Alignment
 

The gasket cement go's on the top, and bottom of the gasket, I just stopped in the middle of the job, to take a picture.

Ok, you have 4 bolts in the middle of the housing, NEVER us shims there. The housing has to set level on the block, to seal the cam gasket, you would also take a chance on distorting, or cracking, the housing, and it is not needed for anything, anyway.

The The two bolts that are out side of the housing, at the Top, are the ones that will take shims, if needed. As far as shim thickness, there are times that a .010 thickness is to much, and you will not use it. 90% of the time, you will use, .003, .002, and .001 thousandths thickness.

NO. 1., The first thing you do is set 9:00, and 3:00, to as close to Zero as you can get, about zero, to .002. You will have a different thickness of shim packs under each bolt, most of the time. Leave that, 24 hours, and then readjust, as needed.

No2, second step, 12:00, and 6;00 have to be as close to the same reading, as possible, with each other, they do not have to be the same, as 9 and 3. Now again, you leave it for 24 hours. The shim packs this time adjusting will be even in thickness, +, or -, to get it right.

So what you have now is 4 equal points for the bell housing, to bolt to, 9 & 3, and 12 & 6. So now the pilot shaft, will bolt, in alignment with the pilot bearing, if the crank is ground, and set correctly.

If you use a to thin of a gasket, it sometimes does not take shims, don't remove metal, use a thicker gasket.

Herm.

Re: Flywheel Housing Alignment
 

Herm,


As a 'paint guy' I promise not to pretend to be a machinist if you promise never to attempt hand lettering.


I now understand setting the flywheel to the crank flange and the relationship to everything that goes on behind that point.
I always thought the issue was with the clutch housing alignment to block.


Since after 90 years of abuse most clutch housings are no longer factory true, how do you compensate for that ?


Jim.B

Re: Flywheel Housing Alignment
 

I've milled them and then have even hand filed once installed. Its a long process. Mine was the worst [ .032"] and could only get to .008", but its fine.

Re: Flywheel Housing Alignment
 

There is nothing you can do to change the alignment with the bell housing that bolts to the transmission, and flywheel housing, as it not adjustable. So, the flywheel housing, that, is what has to be square with the pilot shaft. So if you get 4 points, that are square on the flywheel housing, the bell housing has to bolt up in correct manner.

Herm.

Re: Flywheel Housing Alignment
 

I have had a lot of housings that were off .030 thousandths, and adjusting, and a little time to come back to shape, I have never had one, I couldn't align.

Herm.

Re: Flywheel Housing Alignment
 

[QUOTE=Kohnke Rebabbitting;1

So what you have now is 4 equal points for the bell housing, to bolt to, 9 & 3, and 12 & 6. So now the pilot shaft, will bolt, in alignment with the pilot bearing, if the crank is ground, and set correctly.Herm.[/QUOTE]

SO, whether doing the 9 & 3, or the 12 & 6, the same two top shim packs are used.?

Re: Flywheel Housing Alignment
 

Herms way works great, I’ve done it on several different engines. It’s amazing how the shims shift the run out.

Re: Flywheel Housing Alignment
 

Think about it as two separate operations, as they are.

1. is setting each side, to read the same, or not over .003, difference. Doing this you will have, uneven stacks of shims, most likely.

2. next, indicate top, and bottom, and get them to read the same. They do not have to read the same as the sides. When adjusting the top and bottom, what ever you remove, or add, both bolts will receive the same same.

You will be done when sides read the same, and top, and bottom read the same.

Remember, you have to give it time to warp, into it, ( Acclimate ) !

Herm.

Re: Flywheel Housing Alignment
 

I'm pretty patient, but, maybe not as patient as you. Plus you've done a whole lot more than I have. I don't think I've tried your method, I've just muddled thru. I'm also doing them in the car. I thought I might still get some shake at the .008", but, since it was mine I tried it. Its OK.

Re: Flywheel Housing Alignment
 

Herm, thanks so much for taking the time to go into such a detailed explanation and adding the excellent photos. I had to read through it a couple times, but after I got it it seems pretty simple, (in theory that is). What type shims do you use, as the horse shoe type seem to only come in .010 ?