Adjusting the flywheel housing

[Russell Reay]

In my quest to identify the source of the clutch chatter, I am down to this stage. With 12:00 set at zero, 3:00 is 0.010" out and 9:00 is 0.013" out. A couple YouTube videos reference inserting shims under the four wired bolts as necessary to correct the variation. After loosening the motor mount bolts, the four wired ones, and the two on the throttle bracket, I think I can slip shims under the two top wired ones. My concern is that there isn't room for my fingers or a tool to access the space behind the throttle bracket to add shims. FWIW I know there is a gasket between the FW housing and the block. Before removing the FW I measured the wobble per red book, and found zero from 10:00 to 2:00, 0.005" out from 5:00 to 7:00 with a max of 0.007" out at 6:00. Observations and recommendations welcome.

[Jim Brierley]

Housing runout is very important, and I have no suggestions on how to cure it with it already installed, but also consider replacing your stock clutch with a diaphragm type. This is a major project, but I've had great success with it. It requires flywheel machining, etc. If interested send me an e-nail and I'll send you the chapter of my book that explains how to do it. [email protected]

[Keith True]

That machined surface on the flywheel housing HAS to be flat against the machined surface of the block.(with the gasket or course)If it's not the rear of the camshaft will gush lots of oil out of it.If you set the housing up correctly with the shims under the top ears under the throttle linkage,that part should be good to go.It's the crank surface that is off.Measure it with the flywheel in place.If it is off remove the flywheel,turn it 180 degrees and measure it again.

[Russell Reay]

When I built the car 4 yrs ago I read about the oil from the camshaft, so very purposely inserted the gasket. Minimal dripping from the cotter pin suggests the gasket is doing its job. The flywheel is a new Burtz and the clutch/PP are earlyV8/Chevy for the T5. Per Keith's comments, I can't recall what shims, if any, were used 4 yrs ago under the top ears. The thought of turning the FW 180* is worth trying.

[nkaminar]

The proper thing to do is to remove the flywheel housing and have it machined. But before you do that use your dial indicator to see if there is any runout on the rear of the engine were the housing mates. I gave up on an engine where the crankshaft was not square with the cylinder bores. It went in the junk pile.

The shims at the top where the throttle linkage mounts is used to compensate for the thickness of the gasket. No gasket, no shims. But the gasket is really important to control oil leakage.

[BRENT in 10-uh-C]

Sponsored Links (Register now to hide all advertisements)

IMHO you are chasing two different things. Clutch Chatter is generally caused by a worn Main (-Input) Shaft or Pilot Bearing. In the case of the T-5, most conversions I have seen use an adapter that is slid over the Input Shaft of the T-5 Transmission. IMO this arrangement is not good because it is easy to get those out of alignment with the centerline of the crankshaft.

If the above is indeed the issue, no amount of shimming the Flywheel Housing will correct that. It is also worth noting that the Shims ONLY purpose was to compensate for the Housing to Block Gasket thickness. The dial indicator is used to only verify the Flywheel Housing is warped. At that point, you have two options to properly correct the issue. You either replace the Flywheel Housing with a brand-new unit, -or you restore the original Housing as shown in the video below.

https://www.youtube.com/watch?v=2GDg5AT2TmI

[Russell Reay]

"Clutch Chatter is generally caused by a worn Main (-Input) Shaft or Pilot Bearing. In the case of the T-5, most conversions I have seen use an adapter that is slid over the Input Shaft of the T-5 Transmission. IMO this arrangement is not good because it is easy to get those out of alignment with the centerline of the crankshaft." This is a photo of the input shaft when I removed it. The gap was 0.147" . The sleeve was seated tight to the bottom when I assembled it last winter. Using a V8 throwout bearing. If this isn't good, what is the alternative?

[Klattu1929]

So looking from the back towards the engine, I checked runout at 3 o'clock, and 9 o'clock. Added shims to the top at the throttle bracket location to make the runout equal each other. Then checked runout at 12 o'clock and 6 o'clock, when adding/removing shims to bring into spec, you have to do both top bolts the same amount so not to ruin the setting from 3 and 6. This method worked perfect for my install.

Also I set mine and then added my throttle bracket after setting runout, I carefully loosened the all bolts slightly so when I added my throttle bracket my shims didn't fall out, then torqued everything up. Worked very well for me.

[The Master Cylinder]

Originally Posted by BRENT in 10-uh-C

https://www.youtube.com/watch?v=2GDg5AT2TmI

Good video and info Brent.

[Keith True]

Clamp that indicator to the housing,and see what the runout is of the crank itself.

[Russell Reay]

UPDATE: based on all the feedback, focusing on the 'why' not so much the 'what', and the fact that there was no correlation between the flywheel wobble and the crankshaft variations, and every surface has been scrupulously cleaned, I reinstalled the flywheel to follow Keith's instructions in #3 above. After snugging the FW bolts I checked the runout and found 0.003" out at the bottom. Too good to be true!!! Tried it again--same result. Torqued the bolts to 55#, and measured again--same result. I think I am good to go.

[Jim Brierley]

My tudor chattered something awful when I got it. It had float-o-motor's in it. I switched back to the stock mounts, that helped but changing to a diaphragm clutch completely cured it. Good luck!

[400A]

Does anyone have any experience with the newly made flywheel housings? Aluminum or ductile iron? I find most originals are cracked or warped or both.

[Terry Burtz, Calif]

Check out this housing that uses an o-ring and is 15x stronger.

[400A]

Hi Terry, that's a real nice looking housing! Will it work with all stock OEM parts (Engine block, bell housing, etc) and does it look exactly like an original from the outside? Seems like a wonderful upgrade over the OEM housing.

Many thanks for all that you have done for the Model "A" hobby.

[JayJay]

Originally Posted by 400A

Hi Terry, that's a real nice looking housing! Will it work with all stock OEM parts (Engine block, bell housing, etc) and does it look exactly like an original from the outside? Seems like a wonderful upgrade over the OEM housing.

Many thanks for all that you have done for the Model "A" hobby.

I have one of Terry’s new bell housings. To answer, in case Terry doesn’t:

1. Yes, it will work with original parts. You don’t install the paper gasket between bell housing and block (the O-ring seals the back of the camshaft) and you probably won’t need the shims on the top ears of the bell housing. The four inner bolts that fasten to the block are longer to accommodate the thicker casting but those are included in what you purchase.

2. I’m not a fine points judge, but from the outside it looks identical to my other bell housings to me. Terry can tell you exactly which iteration of the bell housing he laser scanned for the new version.

[katy]

Originally Posted by Terry Burtz, Calif

Check out this housing that uses an o-ring and is 15x stronger.

A link would help.

[400A]

Try this:

https://burtzblock.com/collections/all

[Terry Burtz, Calif]

Originally Posted by 400A

Hi Terry, that's a real nice looking housing! Will it work with all stock OEM parts (Engine block, bell housing, etc) and does it look exactly like an original from the outside? Seems like a wonderful upgrade over the OEM housing.

Many thanks for all that you have done for the Model "A" hobby.

The initial design of the flywheel housing (Part #A-6395) was revised 8 times during the 4 years of production. I believe the exterior was identical for the first 7 revisions, and each revision added more material to the inside hidden area in an attempt to make the housing stronger. The 8th revision on Oct 26, 1931, added external ribs at the bell housing bolt hole locations. This 8th revision was used on very late 1931 vehicles, was an over-the-counter part that was available at Ford parts counters. The 8th revision didn't solve the basic strength problem.

The basic problem is that the housing is too thin where the 4 attachment bolts are. All 8 revisions were 1/2-inch thick. The new housing is 7/8-inch thick and based on the 7th revision.

Flywheel housing loads come from the front axle wishbone. The wishbone is in compression during acceleration, braking, and when hitting a pothole or curb. This compression is transferred to the bellhousing and then the flywheel housing, causing it to crack at the 2 lower bolt holes.

The lower part of the housing, located below the two lower attachment bolts, is a cantilever beam.

The cantilever beam formula for strength is based on width x height cubed.

For simplicity, imagine a 1 x 4 piece of wood as a cantilever beam. If placed with the 4-inch side down, the strength is 4 x 1 x 1 x 1 = 4. If placed with the 1-inch side down, the strength is 1 x 4 x 4 x 4 = 64.

The new flywheel housing is 7/8-inch thick, and the thick area is 3 times wider at the lower attachment bolts than a stock housing. Doing the math, the original housing is 1 x 1/2 x 1/2 x 1/2 = 0.13, and the new housing is 3 x 7/8 x 7/8 x 7/8 = 2.01.

The new housing is 2.01/0.13 = 15.46 times stronger.

All of our parts have the appearance and interfaces as original Ford parts.

An O-ring is supplied to seal the rear camshaft, so a gasket and upper shims are not required unless you are building a "points" car for judging.

[alexiskai]

Originally Posted by Terry Burtz, Calif

The basic problem is that the housing is too thin where the 4 attachment bolts are. All 8 revisions were 1/2-inch thick. The new housing is 7/8-inch thick and based on the 7th revision.

Just to be super-clear, you are talking about the two bolts on each side that attach to the rear motor mount?