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[42merc]

Originally Posted by Mart

I wouldn't delete the plate. It acts as an anti stress raiser for the cast iron flywheel. I would consider using an alternative bolt from another motor that has a washer face built in and less overall height. If they were available I would then consider deleting the plate, but would possibly stake the dowel holes so the dowels can't come out (Unlikely, I guess).

I saw a flywheel explode on a test cell, due to the use of Allen bolts instead of regular bolts holding it on. The smaller head of the allen bolt created too much stress and the flywheel exploded. There was a big dent in the roof girder from the shrapnel.

This is why I would leave the flat plate in place, unless using washered bolts.

Mart.

We are dealing with a 3000 max rpm motor. Henry probably drives about 50 mph tops, at what 2000rpm?
There are about a zillion small block Chevys with cast iron flywheels & non washered bolts on the road at any given time.
Don't over think it.

[Frank Miller]

Allow me to throw another wrench into the works. As far as clutch chatter, is the flywheel running true to the block? The transmission is being rebuilt and I think I have heard of worn bearings being a factor. Then again just having the disc rubbing against the bolts during engagement could have been an issue. It would be interesting to measure your flywheel against a known good one or one not resurfaced. I don't have a ton of experience but this seems like an unusual issue as a flywheel will not be resurfaced many times like a brake drum.

[A bones]

Originally Posted by Ross F-1

8BAs aren't safety-wired, I wonder if their bolts are enough shorter to gain what you need? Sure, the flywheel is near end-of life, but it's a big deal to replace and driving season is coming up quickly (although that's a year-round season for you!)

Please help me understand why. Nuts and bolts, The chatter will be gone.

[Mart]

^^ I think purely because flywheel replacement means pan removal and may also mean engine out. Other than that, as you say, just nuts and bolts like everything else. Compared to just putting a new clutch disc is, it's a much bigger job.

Mart.

[V8 Bob]

JFYI, I am using flywheel bolts from ARP that have a shorter head for more disc spring clearance on an 8BA. The part number is P10AP.750-1 and are 7/16" x 20 x .750", 3/4 hex, .250 shank, .250 head.

[Old Henry]

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Originally Posted by V8 Bob

JFYI, I am using flywheel bolts from ARP that have a shorter head for more disc spring clearance on an 8BA. The part number is P10AP.750-1 and are 7/16" x 20 x .750", 3/4 hex, .250 shank, .250 head.

Great! I just ordered 5. No matter what else I do, I will replace the bolts with those. Look better than grinding the heads down on mine (for all of the myriad eyes that would behold such).

[Old Henry]

Originally Posted by Frank Miller

Allow me to throw another wrench into the works. As far as clutch chatter, is the flywheel running true to the block? The transmission is being rebuilt and I think I have heard of worn bearings being a factor. Then again just having the disc rubbing against the bolts during engagement could have been an issue. It would be interesting to measure your flywheel against a known good one or one not resurfaced. I don't have a ton of experience but this seems like an unusual issue as a flywheel will not be resurfaced many times like a brake drum.

Originally Posted by A bones

Please help me understand why. Nuts and bolts, The chatter will be gone.

I never had clutch chatter in this car when I drove it in high school in the 60's. After the car sat for 31 years and I got it going again it had no chatter until the first replacement of the clutch and resurfacing of the flywheel. No matter what I've done since it has not eliminated the clutch chatter, even right out of the chute with new clutch and resurfaced flywheel, way before any springs rubbed on any bolts. I even replaced the crankshaft to get rid of a measly .002 runnout with no benefit. So, replacing all now is no guarantee.

[Old Henry]

Originally Posted by Mart

^^ I think purely because flywheel replacement means pan removal and may also mean engine out. Other than that, as you say, just nuts and bolts like everything else. Compared to just putting a new clutch disc is, it's a much bigger job.

Mart.

And, NAPA doesn't just have those flywheels piled up on their shelf. Mac VanPelt is checking to see if he has one any better than mine. They do not appear to be readily available, certainly not new from the usual suppliers that I have checked. Repops on ebay are upwards of $400.

[V8 Bob]

Originally Posted by Old Henry

Great! I just ordered 5. No matter what else I do, I will replace the bolts with those. Look better than grinding the heads down on mine (for all of the myriad eyes that would behold such).

When I bought my bolts, I was told to very lightly chamfer the flywheel bolt holes because the bolts have a small radius under the heads, and you want the heads to be flat against the surface. Also, torque values were:
70 ft/lbs with moly
75 ft/lbs with locktight
85 ft/lbs with oil.
I did not use the dowel retainer just to gain another .050" or so.
I'm using a steel Centerforce flywheel that cost well below $400, but that was a few years ago.

[Old Henry]

What is chamfer?

[V8 Bob]

Originally Posted by Old Henry

What is chamfer?

A very light countersink.

[40 Deluxe]

Originally Posted by Old Henry

What is chamfer?

I think he means a slight countersink on the flywheel bolt holes so the radius under the bolt head doesn't contact the edge of the bolt hole.

Also, try setting up a dial indicator on the bell housing to measure any runout on the flywheel face. I once ran into a flywheel that was not true. Apparently the guy who resurfaced it was careless somehow so that the flywheel was not flat in his machine and was cut crooked.

[V8COOPMAN]

Originally Posted by Old Henry

What is chamfer?

In this situation, chamfering a hole is similar to barely touching the top of the hole with a counter sink. The main reason is to make a relief space at that SHARP 90 degree angle when a hole is drilled. The space is necessary because MOST bolts have a radius of material just below the head, where it transitions into the shank. Without the chamfer, the bolt HEAD would not actually sit flush with the FLAT surface. DD

[rotorwrench]

I wonder what kind of machine was used to resurface that flywheel? There were some really good machines that were dedicated just for flywheels but there are other ways that don't leave quite as nice a finish and possibly not as accurate a surface thickness/concentricity depending on machine and/or operator.

[JM 35 Sedan]

Originally Posted by V8 Bob

When I bought my bolts, I was told to very lightly chamfer the flywheel threads because the bolts have a small radius under the heads, and you want the heads to be flat against the surface. Also, torque values were:
70 ft/lbs with moly
75 ft/lbs with locktight
85 ft/lbs with oil.
I did not use the dowel retainer just to gain another .050" or so.
I'm using a steel Centerforce flywheel that cost well below $400, but that was a few years ago.

Bob, did you mean the flywheel bolt threads on the crankshaft flange? The through holes on the flywheel, for the flywheel bolts, also need to be lightly chamfered. I would definitely check the flywheel mounting surface on the crankshaft flange and the mating surface on the back of the flywheel for flatness, etc., to make sure there is a flush mounting of the flywheel to the crankshaft.

[V8 Bob]

Originally Posted by JM 35 Sedan

Bob, did you mean the flywheel bolt threads on the crankshaft flange? The through holes on the flywheel, for the flywheel bolts, also need to be lightly chamfered. I would definitely check the flywheel mounting surface on the crankshaft flange and the mating surface on the back of the flywheel for flatness, etc., to make sure there is a flush mounting of the flywheel to the crankshaft.

Correct John, the 4 flywheel bolt threads on the crank flange.

I caused some confusion by stating "flywheel bolt threads" on an earlier thread, but should have said "flywheel bolt holes" which has been corrected. The 4 flywheel bolt mounting holes need to be chamfered.

[flatheadmurre]

If the shatter started after the flywheel was resurfaced there´s a chance the machine/machinist did a less good job and the surface ain´t running true to the crank now.
I´ve seen so many flywheels come into the shop that´s been freshly machined by lathes or grinders but way off in the surface...
Next source would be soft engine mounts and when the new clutch got a better grip it managed to move the engine more then the old one ?

[AnthonyG]

wonder what kind of machine was used to resurface that flywheel? There were some really good machines that were dedicated just for flywheels but there are other ways that don't leave quite as nice a finish and possibly not as accurate a surface thickness/concentricity depending on machine and/or operator.

Almost looks like someone set up a lathe with an electric hand grinder mounted to the compound and used the side of the grinding wheel feeding it like a cutting tool across the face of the flywheel.

Prof., I think I have a re-surfaced flywheel that originally I tried to use with a10.5" or 11" clutch but someone had tried to re-drill / tap for larger clutch on a flywheel originally used for a 9" clutch and drilled the holes almost .100" out of concentric. The 9" pattern is good. I'll get some pic's of it and check the size of the bolt circle too make sure and I'll PM you.

[V8COOPMAN]

Originally Posted by AnthonyG

Prof., I think I have a re-surfaced flywheel that originally I tried to use......... .

Anthony.........If that flywheel is for your 8BA, it won't work on Craig's early block. Just sayin'! DD

[AnthonyG]

DD, thx, my knowledge only goes as far as my vehicle and what I learned / read on the Barn with regard to the Early Fords. If it wasn't for your help and others here I'd of been up the creek quite a few times while building my '35 with as you indicate a '49 8BA. I do bow to the more experienced guys on the site who have much more breadth of knowledge than I. Turned out I remembered wrong, memory not what it used to be, LOL. Checked my records and forgot Jerry Livingston, United Engines who built my motor took back the flywheel I thought I still had and sent me another. I gave the Prof. a heads up in a PM.