Flywheel Housing Check

[jharrellh]

Good day all! My '29 roadster has had some pretty severe clutch chatter in 1st and reverse and a slight vibration since I have owned it. Ordered a long feeler gauge to check the finger adjustment, but planning for worst-case to pull the rear end and transmission to inspect things and replace the clutch...car was restored in the early 80's and I have heard some repro parts at the time were of dubious quality? While I am in there, I am wondering if it is possible/accurate to do a quick check of the clutch housing alignment with the engine in the car? Plan would be to have a helper turn the crankshaft with the starting crank while applying inward pressure to take up the endplay while checking runout at 9-12-3. I realize any shimming is a different ballgame, and I would pull the engine for that, but is it possible to measure in this fashion to hopefully rule out the housing as part of the problem? FYI, I have checked motor mounts and adjustments and replaced the front springs with good quailty.

Very new to A's, so please forgive me if I am overlooking something obvious!

[Russ/40]

I would think the possibility of reliable numbers would greatly depend on the condition of the main bearings. I would not feel comfortable with the crank line being horizontal. I'm thinking the crank centerline needs to be vertical. I'd like to hear others opinions on this though.

[Patrick L.]

Setting the fingers in the vehicle with a thin long feeler strip is a good thing to try and see what happens.

I know no way to set or check the housing without splitting the two. Some would prefer to remove the engine. I remove the transmitter, but, the older I get the less I like crawling around under these monsters.

Once either the engine or transmission is out then setting the pressure plate fingers, flywheel run-out is easier and more accurate.

[redmodelt]

He is asking about checking the flywheel housing, to see if it is within specks. I don't know how well that could be done with engine installed in the car.
Personally I think that; it is nice to start out with everything setup, but as soon as the engine is installed in the car between the frame flex and forces applied by radius rod ball and bolting up the bell housing/transmission, that will change anyway.

[BRENT in 10-uh-C]

Originally Posted by redmodelt

He is asking about checking the flywheel housing, to see if it is within specks. I don't know how well that could be done with engine installed in the car.
Personally I think that; it is nice to start out with everything setup, but as soon as the engine is installed in the car between the frame flex and forces applied by radius rod ball and bolting up the bell housing/transmission, that will change anyway.

You are correct Mark. Using shims is a bandaid at best. Ford only used two shims on the flywheel which were the same thickness as a compressed flywheel housing gasket.

[Patrick L.]

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To check the housing while in the vehicle I set up a dial indicator to the crank flange and measure the run out to the housing. Just keep forward pressure on the crank. The spec if I remember correctly is .009".

[BRENT in 10-uh-C]

Originally Posted by Patrick L.

To check the housing while in the vehicle I set up a dial indicator to the crank flange and measure the run out to the housing. Just keep forward pressure on the crank. The spec if I remember correctly is .009".

So how do you keep the crankshaft forward when the engine is sitting in the car slanted rearward. Unless the engine is pointing nose downward, you will never get an accurate reading from my experiences. Gravity only needs to be what keeps the thrust equal. Also, checking flywheel flange runout cannot be done unless the nose of the crank is also pointing downward.

[40-A Twins]

An original solid clutch plate can also cause chattering.
The later v8 style clutch plates are less prone to chattering than original type is.

[Patrick L.]

Originally Posted by BRENT in 10-uh-C

So how do you keep the crankshaft forward when the engine is sitting in the car slanted rearward. Unless the engine is pointing nose downward, you will never get an accurate reading from my experiences. Gravity only needs to be what keeps the thrust equal. Also, checking flywheel flange runout cannot be done unless the nose of the crank is also pointing downward.

Ssshhh, don't let my car know that !

[Dan Partain]

I haven't tried it this way with the engine in the car, but I don't see why it wouldn't work. I've done it this way with the engine sitting in one of those wooden engine cradles made out of 2x6's. Yes, it's a little tedious to squeeze with channel locks every time you turn the crankshaft, but it worked great for me on a few engines. By the way, this is a large set of channel locks!

[Synchro909]

Originally Posted by Dan Partain

I haven't tried it this way with the engine in the car, but I don't see why it wouldn't work. I've done it this way with the engine sitting in one of those wooden engine cradles made out of 2x6's. Yes, it's a little tedious to squeeze with channel locks every time you turn the crankshaft, but it worked great for me on a few engines. By the way, this is a large set of channel locks!

That's one way of doing it. Another might be to put some forward pressure on the crank at the front pulley before taking a measurement.

[jharrellh]

Thanks everyone! Some great food for thought. I will definitely be checking the pressure plate adjustment and go from there. Hopefully it's just the fingers. I do like the channel locks approach, and I have a giant pair. Guess it can't hurt to try, I will report any progress or lack thereof.

[BRENT in 10-uh-C]

Originally Posted by jharrellh

Thanks everyone! Some great food for thought. I will definitely be checking the pressure plate adjustment and go from there. Hopefully it's just the fingers. I do like the channel locks approach, and I have a giant pair. Guess it can't hurt to try, I will report any progress or lack thereof.

I guess it is all in what your expectations are. While I have not tried this method with the slip pliers, I feel very confident that I could squeeze the pliers by varying amounts to create 0.003 - 0.004 inches of deflection on the flange, -and maybe even more. If I can create that much difference in measurements, then your findings really won't be accurate IMO.


With regard to clutch chatter, I have read many times on social media sites about pressure plate finger adjustments being the cause of chatter however the majority of what you read on those sites is grossly incorrect IMHO. For the finger adjustments to be the issue, the pressure plate would likely slip too.

It has always been my experience that it is one (-or more) issues that causes 'chatter'. The root problem is always related to alignment ...beginning with the centerline of the crankshaft, -then thru the transmission Main Drive Gear (input shaft), and on thru the Main Shaft of the transmission. The end of the crankshaft has a pilot bearing that must be concentric to the crankshaft main journals. This concentricity can be off due to improper crankshaft set-up in the grinder prior to grinding. This inconsistency is typically found more prevalent in crankshafts that were ground in machines that used chucks instead of centers. We can discuss this at a later time however just know that if the pilot bearing is not concentric to the crankshaft centerline, there will always be a disc centering (i.e.: 'chatter') issue.

So once the concentricity of the bearing has been established, the fit of the nose of the Main Drive Gear inside of the pilot bearing must be less than 0.001 (-e.g.: ½-thousandth per side) clearance. This is a tight slip fit without any detectible slop or lateral movement. If there is any excess clearance in this area, it allows the Main Drive Gear shaft to deflect out of the exact centerline of the crankshaft, and when the clutch disc is engaged to the flywheel surface, the disc will wobble or vibrate briefly out of the centerline until it can self-center. This non-concentric wobble is what you are feeling as 'clutch chatter'.

FWIW, there are other issues that can exacerbate the wobble such as a Pressure Plate that is not centered correctly onto the flywheel. This very common on flywheels that have been converted to a V8 style pressure plate. If there is not any alignment pins or pilot-shoulderd fasteners to index the pressure plate to the flywheel, then this can be the source of the 'chatter'. Also, it can be a flywheel housing that is not centered on the cylinder case block, -or it can be warped causing the transmission to not be in that exact centerline of the crankshaft, -and these can create a centerline issue. The other issue can be a worn Main Drive Gear bearing in the transmission case that is worn, ...again causing the Main Drive gear shaft to fall out of centerline alignment. If you are thinking that I am overthinking this, then take a moment to to think about all the places in these connections where these housings are piloted to one another either thru pilot pins or indexing counterbores before the fasteners are installed/tightened.

While on the topic of Flywheel Housings, it has been my experience that most flywheel housings are warped and need to be restored (-remachined). This is because this housing is what all of the movement of the vehicle is channeled thru, -and these constant forces is what causes this housing to flex or even crack over time. Contrary to what some will try to convince you, there is no reason for anyone to need to shim the flywheel housing to create perpendicularity to the crankshaft centerline. If so, something is incorrect. It can be the crankshaft is not parallel with the centerline of the engine case (-poor quality lineboring set-up), or the crankshaft machining was done incorrectly. As I stated above, it can also be the flywheel housing. Just understand that Ford did not 'indicate" the flywheel housing during assembly and then use shims to make corrections. The Flywheel Housing Shims sole purpose was to fill the void at the top 2 tabs that was created by the Flywheel Housing gasket thickness. It was never used to preload the housing to make it's mounting for the Clutch Housing perpendicular to the crankshaft centerline.

So the bottom line in all of this is measuring run-out with dial indicator and adjusting finger heights likely has little to do with correcting the clutch chatter. I'm thinking your issue is more likely to be in one of the areas I described above.

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[jharrellh]

Thank you Brent for your detailed reply, certainly seems to make sense. Hopefully I just have some clutch or transmission issues and not something more foundational such as crank misalignment.

[Jack Shaft]

Flywheel housing alignment is critical with multidisc heavy truck clutches powering 3 shaft transmissions. Not for chatter but to insure a free running mainshaft. It can be used with a model a to check for block/flywheel housing alignment but that deviation, if there is any is slight.

One area that can cause chatter is based on design. the clutch pedal cross shaft is attached to the transmission housing. In a car with loose or worn engine mounts when you 'load' the engine engaging the clutch the cross shaft moves as the engine takes load, creating a chain reaction against the pressure your putting on the clutch pedal. Engine mounts are key in minimizing this, often using after market float a motor rear mounts and the stock A front mount causes this effect.

Ford battled chatter for years, with the V8's they used an 'anti chatter' rod, a stiffener from the bellhousing to the frame..in reality an engineering bandaid..

[jharrellh]

Hello all! Just thought I would update this thread with the results for future reference. I think I had a couple of issues. A couple of the pressure plate fingers were WAY out of adjustment for starters. There were no shims under the upper ears, and using Dan's advice to push the crank forward with giant channel locks, I was able to verify that the housing was far out of alignment. I was able to shim the top bolts to get the housing to what I believe was well in spec...obviously, not as good of a job as nose-down on an engine stand, but the readings were very consistent so I believe it is much better than when I started. Ron's Machine Shop in Shandon, OH did an awesome job of reconditioning and balancing my flywheel and provided a new pressure plate and disk as well as the laminated shims for the flywheel housing. I also checked out the transmission and found everything to be in excellent shape, and verified the roller bearings were good quality.

The result...no more chatter, smooth as silk!! Thanks everyone for taking the time to respond, looking forward to some long trips this fall!

[nkaminar]

I wonder if a nose down configuration for the engine in the car could be obtained by putting the car nose down. Maybe jacking up the rear end enough to get the crank to be always toward the front of the engine. All done with safety in mind, of course. Just a thought.

[700rpm]

Originally Posted by redmodelt

He is asking about checking the flywheel housing, to see if it is within specks. I don't know how well that could be done with engine installed in the car.
Personally I think that; it is nice to start out with everything setup, but as soon as the engine is installed in the car between the frame flex and forces applied by radius rod ball and bolting up the bell housing/transmission, that will change anyway.

Excellent comment. I admit to being careless about this the last time I installed an engine. Consequently, reverse is pretty chatterly. At my age and the approximate miles and years I have left to drive my A’s, I can live with it.

[nkaminar]

Brent had some good comments about how everything needs to be in alignment. The ford engineers were pretty smart in this respect. Cast iron is fairly good in this respect as it tends not to distort (granite is better but not a good material for a bell housing). The Ford engineers no doubt learned a valuable lesson about how stamped steel can distort with the combination engine and transmission pan on the Model T. The engineering for the Model A continues to impress me. For a late 20's early 30's design it was really advanced. The car is simple but sophisticated at the same time.

[Patrick L.]

Originally Posted by nkaminar

I wonder if a nose down configuration for the engine in the car could be obtained by putting the car nose down. Maybe jacking up the rear end enough to get the crank to be always toward the front of the engine. All done with safety in mind, of course. Just a thought.

The rear end is jacked fairly high to jerk the rear axle out from under it. Plus I need room to be able to sit up while under there. Its kinda nice under there, people can't seem to find me.