Flywheel question

[JohnMD]

I am rebuilding my first N tractor. I have done several car engines but this is the first N. It is a 1950 8N side mount. I took the engine apart and took all appropiate parts to a machine shop. The surface on the flywheel where the clutch friction disc rubs had two pits where it looked like some thing had got in between the flywheel and disc and worn small pits. I asked that the flywheel be resurfaced. When I picked it up the entire flywheel surface had been ground flat. When I asked about why the raised friction disc surface had been ground flat I was told that is how it was supposed to be. The shop guy called a another guy who I believe is the owner. He said he had just rebuilt his 8N and reground the flywheel flat and that was the way it was supposed to be. I think they messed up my flywheel and now don't want to make things right. Does anyone have a picture of a flywheel with dimensions showing a raised area for the friction disc and/or spec on how to reface an 8 N flywheel? Man am I pi$$ed.

 

[Dunk]

All I have ever seen were ground flat, the whole face surface, mine is/was.

 

[Dunk]

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Pressure Plate[/b:654c4848f0] - 9in. single, flat flywheel. For Models: 1800, 2130, 2N, 8N,
9N, NAA, NAB, 600, 700, 800, 900 w single clutch. <font size="-2">(Part No:
8N7563)<font face="Verdana" size="-2">$74.04</font> </font></font>

 

[JohnMD]

I just found this in the Ford 8n,9N 2N online Service manual, page 16."Reface Flywheel" "Remove just enough material from the clutch friction surface to obtain a smooth flat surface parallel with the flywheel mounting flange. The same amount of material must also be removed from that portion of the flywheel to which the clutch pressure plate is attached." If a flat flywheel works then this must not be critical but it just does not seem right to grind off a raised area.

 

[Mike OH]

John, All the Ford 8N's and Jubilee flywheels I've even seen (and that has been a few) have been flat across the entire face. I believe the machine shop was telling you the truth. Perhaps someone did some incorrect machining in the past.

Put her together, adjust for 3/4" free pedal movement and you should be good to go.

 

[Dan]

Mine have all been done like that - no problems yet.

Dan

 

[JMOR]

(quoted from post at 13:05:33 02/21/08) I am rebuilding my first N tractor. I have done several car engines but this is the first N. It is a 1950 8N side mount. I took the engine apart and took all appropiate parts to a machine shop. The surface on the flywheel where the clutch friction disc rubs had two pits where it looked like some thing had got in between the flywheel and disc and worn small pits. I asked that the flywheel be resurfaced. When I picked it up the entire flywheel surface had been ground flat. When I asked about why the raised friction disc surface had been ground flat I was told that is how it was supposed to be. The shop guy called a another guy who I believe is the owner. He said he had just rebuilt his 8N and reground the flywheel flat and that was the way it was supposed to be. I think they messed up my flywheel and now don't want to make things right. Does anyone have a picture of a flywheel with dimensions showing a raised area for the friction disc and/or spec on how to reface an 8 N flywheel? Man am I pi$$ed.

Well, there are two distinct areas on Sean (TX)'s flywheel. Whether they are different elevations or not, I can't tell. Maybe Sean will see this &amp; tell us.

 

[Dan]

Usually, as was the case on my recent 1939 9N flywheel I just got resurfaced, the area where the clutch friction disk rides will be resessed from wear. I'll bet this is what we are seeing here.

Dan

 

[Mike OH]

Looks to me to be typical wear pattern from friction disk, but surface should have started off as being machined flat.

 

[Hobo,NC]

A nice'in will have a step on the inside,,, but not on the out side,,, i spec you will b ok,,, their is a minimum spec,,, .905 standard,,, .855 discard,,, i would not worry about it but would make damm sure the clutch cover bolts did not bottom out fer they tighten the cover to the flywheel,,, if they look like it may B a problem add a extra lock washer under the head of each cover bolt....

BTW once you mate the engine to the trans,,, install a few bolts,,,,install the left floor board and check clutch for releasing,,, make sure you install the left floor board first its the pedal stop both ways,,,, top of travel and bottom of travel

<a href="http://www.hobos8ns.com/">
<img border="0" src="http://www.hobos8ns.com/Graphics/Hobo-logo-avatar.gif" width="242" height="72"></a>

 

[JohnMD]

Thanks for the tip HOBO. Mine had the step on the inside and the machine shop ground it off flat. The online manual also indicates that there should be a step as I read it. From what everyone else has said I should not have a problem but still seems like a poor job. This tractor will only plow a small garden, cut grass and push snow so I guess the stress on the clutch will be minimum. I hate to be lied to by some one I am paying to do work. If the machine shop had told me what they planned to do and why I would have at least had a chance to say yea or nea. As it was they acted like I was stupid and did not know what it looked like when I brought it in. I am still mad but looks like not much I can do about it.

 

[Tom N MS]

Installed two new clutch kits in 2 different 2Ns and had them resurfaced. Both were machined flat. I see no reason that any area would be raised. You have no problem.

 

[Hobo,NC]

Well,,, you can take it back and ask that the inside step B ground back into it,,, It has no function,,, don't help or hurt,,, has nothing 2 do with the clutch set up,,,, nuttin 2 b mad at,,, machine shop man did his job,,, got his kill,,, more than likely you will B alright,,, check them bolts and make sure the shoulder on the bolt does not bottom out fer it nails the cover 2 the flywheel....

 

[Sean (TX)]

I was just seeing what it looked like after a little sanding. I had a machine shop do it. Didnt get a good pic of the finished product. But is flat and all one surface. Best move I ever made. That clutch works great and I have the left brake adjusted just right. Clutch engages and I push farther and I can lock up the left brake. Works great...I think the ring in the first pic is from the disk. That ring is the outside edge of the disk.

Here is a rough pic of it after the machine shop finished it..Scratched it up a bit putting the ring gear on. Tip: replace ring gear before resurfacing the flywheel...

(quoted from post at 15:06:04 02/21/08)

(quoted from post at 13:05:33 02/21/08) I am rebuilding my first N tractor. I have done several car engines but this is the first N. It is a 1950 8N side mount. I took the engine apart and took all appropiate parts to a machine shop. The surface on the flywheel where the clutch friction disc rubs had two pits where it looked like some thing had got in between the flywheel and disc and worn small pits. I asked that the flywheel be resurfaced. When I picked it up the entire flywheel surface had been ground flat. When I asked about why the raised friction disc surface had been ground flat I was told that is how it was supposed to be. The shop guy called a another guy who I believe is the owner. He said he had just rebuilt his 8N and reground the flywheel flat and that was the way it was supposed to be. I think they messed up my flywheel and now don't want to make things right. Does anyone have a picture of a flywheel with dimensions showing a raised area for the friction disc and/or spec on how to reface an 8 N flywheel? Man am I pi$$ed.

Well, there are two distinct areas on Sean (TX)'s flywheel. Whether they are different elevations or not, I can't tell. Maybe Sean will see this &amp; tell us.

/b]

 

[Dunk]

Hobo, I am reasonably sure, and I wouldn't even post this if I wasn't that the holes in my flywheel for the pressure plate bolts go all the way thru the flywheel, and are counter sunk a bit on the threads, for the shoulder.

I wrung about 3 of mine off when I was last in there (those 3 wrung off with very little torque, and I know the torque specs on 'em), they were easier to screw all the way on thru and fall out on the floor, than they were to back up.

I replaced them with old model Chevy valve cover bolts.

 

[Dunk]

They may have been old briggs and stratton engine cover bolts.

"Ell they worked, and have been working for 2 years.

 

[Hobo,NC]

The threads in the flywheel are counter sunk,,, the OEM bolts have a shoulder that goes into the countersunk hole,,, well all is find and dandy cuzz the countersunk hole izz made for the OEM bolt with a shoulder figger'in the thickness of the clutch cover and a lock washer,,, when you grind the flywheel it will allow the OEM bolt shoulder to go deeper into the countersunk hole in the flywheel and the shoulder will bottom out fer the head of the bolt will tighten again the cover,,, bolts with no shoulder or a very short shoulder will not affect the original design,,, consider yer self lucky that only clutch cover bolts have a long shoulder and yer BS cover bolts werked,,, I have a lot more to say about grinding flywheels and the flywheel grinder,,, the flywheel grinding man,,, flywheel bolts,,, its a,a,a,a not as simple as it sounds,,, Long day gonna cut it short

 

[Paul in MN]

John,

I have to agree with the other guys. The clutch face surface is meant to be machined flat. Anything is possible in the 60 year life these things have already gone through. If yours did have a raised area that the friction plate made contact on, I'd bet that some home brew machinist did that to make up for wear on the plate portion of the pressure plate. I have had both the flywheel and pressure plate surfaces machined flat and then the clutch guy resets the pressure plate release fingers accordingly so the throwout bearing moves in exactly the correct original positions. But that is being much more picky than any 8N clutch job needs to be.

While you are in there, replace the throwout bearing and the pilot bearing. I have found the pilot bearing usually in worse shape from clutch dust drying out the one time lube in that bearing.

I think you owe your flywheel guy an apology.

When the service manuals refer to the step in the flywheel, they are referring to the groove that the ring gear sits down into. You will be able to see this step when you replace the ring gear, but do that only if there is damage to the teeth from engagement with the starter bendix gear.

Paul in MN

 

[Randy(PA)]

The drawing shows a flat surface that is .880 to .890 away from the surface the mounting palm of the crankshaft mates with. It also, however allows an area inside 9.25 diameter to be recessed from 0 to .005" to true the surface to meet the squareness requirement of that surface to the 4.00" mounting palm pilot diameter: 'This surface must be square .... within .005" '. This probably made sense with the production machines available in the factory, but the shops of today probably can achieve this squareness, and better, by working the whole surface. They do flywheels for many different clutch sizes, so they don't have special tools just to do 9" clutch faces flywheels. I would be concerned with too much being taken off for: (a)the loss of mass to the flywheel, how that affects cold starting and overall smoothness of running, (b)the possibility that balancing holes are cut off and need rebalancing, and (c)any position changes that affect releasing, etc (clutch operation). You probably don't have any of these problems to be concerned about unless there was something like 1/4" taken off. Oh, yes, the holes tapped for bolting fast the pressure plate assembly are drilled .88 deep, tapped 5/16-18 NC 3 .64 deep and counterbored .3130/.3145 .26 deep. This should give you some nominal new flywheel dimensions to check against, if you want.

 

[Dunk]

(quoted from post at 00:12:15 02/22/08) The threads in the flywheel are counter sunk,,, the OEM bolts have a shoulder that goes into the countersunk hole,,, well all is find and dandy cuzz the countersunk hole izz made for the OEM bolt with a shoulder figger'in the thickness of the clutch cover and a lock washer,,,

Me and you, know you are right!! (the others too)

Hang in there Buddy.

I'm with ya, not against ya.

I am about to slide on my rocker though, the Ole Lady done let me run slap outa beer, an a good night, and I have had to go to straight whiskey.

 

[JohnMD]

Thanks for all the comments. It looks like I will not have a problem. I just don't understand why the manual gives the instructions about resurfacing if it is not necessary. The flywheel did have a raised area for the friction disc surface before I took it to the machine shop. I did not measure it to see how high it was. I have a 1949 N to rebuild next. I don't think it has been worked on much over it's life. I put rings in it 20 years ago and it looked original. I can't wait to pull the flywheel on it to see what it looks like. I'll take a picture the next time and measure the raised area if there is one.