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Flywheel Stress Cracks

VANDAN

VANDAN

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I had a failure in my driveline Friday night going to a Cruise. The pressure plate gave up, as one of the finger cast arms snapped, and that was all she wrote ! Ended up tearing things up a bit, so need to replace it all. After pulling it apart, I see there are stress cracks all around the circumference of the flywheel, and they are deep enough to feel the edge on them ? Is this a product of age, heat, or is it just time to replace it ? The car gave no indication of trouble, and it's not a high output design, just a 383 stock type build, and it really doesn't get beat on. Can the F/W be turned and re-used safely, or is a boat anchor ? Thanks for any input on this..
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I've never seen the fingers of a pressure plate worn of like that. Either the clutch wasn't releasing fully or someone has been riding the clutch

Heat makes the flywheels crack. I would replace it.
 
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Heat cracks are normal where the clutch has been generating some heat and they start at the surface and work into the flywheel... I agree with the clutch breakage too. That looks abnormal to me.
It can be turned, but you want to make sure none of the cracks remain. I've done that several times before with the engines being beaten pretty hard. So if there are any signs of cracks remaining after it's turned, get a new one.
I would also dial indicate and center the bellhousing too. That may be causing some issues.
 
I'd scrap the flywheel, it's not worth the risk if it's a hot rod. And you have some issues.
 
If you can afford another one then get one but I have had small cracks after turning one on a stock build with no problems. JMO
 
They may machine out - just depends how deep they go. You might take it to a qualified machine shop that surfaces flywheels and get their opinion before spending money on it. Also you may want to measure the thickness of the flywheel as it may have been turned once or twice already and could be on the thin side.

Did you have any free play at the top of your clutch pedal adjusted in?
 
Yes, the pedal was adjusted, as all the driving I've done recently seemed normal, and the car drove just fine. Before the breakage, we were driving a country road, 45mph, coming up to a corner, down shift, rotational noise starts as we slow, gets worse, round corner, and pull into lot, clutch it, no longer disengaging, still running, shut down & show over. Parked it and went to pick up trailer for ride home...
 
I would think the throwout bearing froze up. Wouldn't take long to chew up the fingers like that
 
Get machine shop to check if flywheel is worth turning. Many times the normal small surface heat cracks you see can be cleaned up with resurfacing. If you can get a fingernail into any of the larger cracks they will not turn out. Looks like no toe play causing throw out bearing to run on pressure plate fingers all the time until throw out bearing finally failed. See a lot of this failure in autos and commercial trucks with push type clutches.
 
Sonny says; clean & resurface it up and sell it...call Brewers get the good stuff!

JMVHO
 
Fingers wore as a result of no clearance to the throw out bearing. The bearing then turns constantly, something it's not designed to do. Is the face of the T/O bearing blue? What does the front bearing retainer look like where the bearing rides? More pictures would be helpful. I agree that I'd let the machine shop dictate the suitability of using that flywheel. For non high performance use, a new stock flywheel, clutch and pressure plate is all that's needed. Don't forget the pilot bushing and T/O bearing as well.
 
If you go with a new flywheel, which would come with a new starter ring installed, I suggest checking into the one "440 Source" sells. low priced and probably manufactured off shore. I got one and was very impressed with it, but would not recommend for racing....................MO
 
I agree, throw out bearing failure or improper adjustment. Call Brewers, get the right stuff including the release fork. (the ends look a little boogered up) Take the flywheel to a machine shop. They will know if it can be saved. Hopefully they can grind it and not turn it on a lathe. Grinding gives it a better non-directional finish. I had a new clutch fail like that from improper adjustment. I adjusted the free play and not the gap between the t/o bearing and the pressure plate fingers. Since then, I adjust the gap and have had no failures. 1/8" works.
 
I have a 71 440 in my 70 V-code Roadrunner. It came that way. 6 bbl intake, 292* .509 Purple Stripe cam. The 2 pictures are of my harmonic balancer. It has the eccentric, which I'm told means externally balanced. I am sure it is a 71 block, I checked the date code. I have read and been told that 70 & 71 440x6bbl and 440x4bbl motors had steel cranks and "heavy" rods (I assume that means "6pak" rods). The picture of the flywheel by the O.P. looks like mine. I have never noticed in the couple of times I have held my flywheel in my hands any signs of balancing.
I am installing the a855 Passon 5 speed and I would like a new steel flywheel. Mine is 130 tooth and I use the 10.5" McCleod clutch disc and 3 finger HD pressure plate. Where can I get one? Part # would be great.
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You might want to see which clutch you have. It should be the 10.95" clutch, not the more common 10.5" version that all non-6bbl or Hemi engines got.
 
biomedtechguy said:
I have a 71 440 in my 70 V-code Roadrunner. It came that way. 6 bbl intake, 292* .509 Purple Stripe cam. The 2 pictures are of my harmonic balancer. It has the eccentric, which I'm told means externally balanced. I am sure it is a 71 block, I checked the date code. I have read and been told that 70 & 71 440x6bbl and 440x4bbl motors had steel cranks and "heavy" rods (I assume that means "6pak" rods). The picture of the flywheel by the O.P. looks like mine. I have never noticed in the couple of times I have held my flywheel in my hands any signs of balancing.
I am installing the a855 Passon 5 speed and I would like a new steel flywheel. Mine is 130 tooth and I use the 10.5" McCleod clutch disc and 3 finger HD pressure plate. Where can I get one? Part # would be great.
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Since I've been shopping for new parts for my repair, Brewer's seems to have a good selection of "Name Brand" items, and I think they had McLeods Brand. I pretty much went with everything I could replace between the Crank Bushing, to the Gasket & Seal on the face of the Transmission. Just waiting for some longer ARP Flywheel bolts, as the ones I ordered were to short for the new Flywheel, thicker mounting surface on it. Hope to have it back up & running this W/E...
 
While I'm on this again, I'm questioning whether the seal on the tranny input shaft housing was correctly installed, as I seemed to have a good amount of heavy oil on the backside face of the assembly. Looking at it, I think it was in there backwards ? If anyone has a pic, or schematic of the 833 in detail, I'd appreciate that info...Thanks
 
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