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Clutch/flywheel explosions...let's hear some stories.

Discussion in 'The Hokey Ass Message Board' started by Kiwi Kev, May 28, 2007.

  1. fridaynitedrags
    Joined: Apr 17, 2009
    Posts: 402


    From the NHRA 2009 Rulebook, General Regulations, 2.10, FLYWHEEL SHIELD.....
    All front-wheel drive or transverse-mounted applications using a clutch and running 11.49 or quicker, for which an SFI Spec 6.1, 6.2, 6.3 or 9.1 flywheel shield is not commercially available, must be equipped with a flywheel shield made of 1/4 inch minimum thickness steel plate. Shield must surround the bellhousing completely except for area of bellhousing adjacent to differential and axle shaft. Shield may be multi-piece, with pieces bolted together using minimum 3/8 inch diameter Grade 5 or M10 class 8.8 bolts; may be attached to engine and/or bellhousing.

    Someone made a reference in an earlier post to using conveyor belting. I remember that from days gone by and in my opinion, once you get the shield made and mounted, it wouldn't be a real bad idea to mount some belting on the interior of the firewall. I'm talking about the belting that is used to convey rock, sand and gravel from one location to another at sand and gravel operations. I'll bet if you were to ask real nice, one of the companies would give you some for free.

    There's a turbocharged Honda that shows up nearly every Friday night at Firebird. The owner has fabricated a shield like that detailed above. He has also added an SFI 4.1 ballistic blanket over the fabricated steel shield. The 4.1 is actually designed for use around an automatic transmission on a RWD car, but he has used it on his transverse application and made it look nice. These 4.1 blankets are dated and must be replaced every two years, so I'll bet if you check around with some of the racers at the local drag strip, you could find someone with an outdated blanket that they would give to you. Just because it's out of date doesn't mean it won't add some degree of additional protection. This car I'm describing is teched to 8.50 in the quarter. It's a real nice car from a tech standpoint and the owner is obviously very safety conscious.
    Last edited: May 27, 2009
  2. Duntov
    Joined: Apr 15, 2009
    Posts: 60


    Referring to the above photo. Don Garlits blew his 2-speed transmission, not his clutch.

    In 1967-1968 Don Garlits started making and selling 2-speed transmissions for sling shot dragsters and he was using one in his AA/FD front engine dragster. Maverick Racing bought one from Garlits in 1968 and we put it in our SB Chevy powered Jr. Fuel dragster, with a Woody Gilmore front engine chassis. Our Ford based Garlits 2-speed transmission also blew in the second round at the 1969 NHRA Nationals at Pomona CA but the driver was not injured. That is because our Jr. Fuel dragster was not putting out the horsepower that Garlits AA/FD was producing. Unfortunately, Garlits lost most of his foot and thought of making a rear engine dragster while in his hospital bed.

    NHRA outlawed the Garlits transmissions next season because it was later determined by NHRA officials that they had welded gears in them. We went back to using our Fairbanks Clutch Flite transmission (based on a Chrysler Torque Flite transimssion) . The reason we purchased the Garlits 2-speed manual transmission was in a futile attempt to solve the lack of low-end torque that plagued many SB Chevys (355 CI) with the big Enderle injectors. We switched from 36" individual tubular headers to boat headers with a collector and that helped the low end torque somewhat. However, the smaller Enderle or Hilborn injectors would have improved the low end launches and I feel like it would have lowered the ET by 0.4 even though the smaller injectors would have slowed the dragster in the last 200 feet. We tried harder Goodyear tire compounds with unsatisfactory results. When using direct port injectors, launching at high RPM is needed to prevent bogging off the line. Many races are won or lost in the first 60 feet!

    High stall torque converters have replaced the old Clutch Flite transmissions when good lauches are required in full sized cars. Unfortunately, the nostalgia guys using front engine dragsters with direct port injectors don't have the space and cannot bear the enormous weight of a automatic transmission with a high stall converter.
    Last edited: May 27, 2009
  3. hugh m
    Joined: Jul 18, 2007
    Posts: 2,143

    hugh m
    from ct.

    Had one fly past my head one time, and knew what it was instantly because of the yellow timing tape. Never even thought about it coming apart til it did.
  4. redsdad
    Joined: Oct 5, 2009
    Posts: 252


  5. Buzzard II
    Joined: Aug 27, 2009
    Posts: 354

    Buzzard II

    Little Wing,
    Cast iron bell housings are not blow proof. Lakewood scattershields with block savers are the only way to go!:)
  6. terrarodder
    Joined: Sep 9, 2005
    Posts: 1,101

    from EASTERN PA

    Oh so young and dumb, back in the early 50s I ran an model A with an 50 Olds. The scattershield was a piece of tire tread held on with pipe strapping bolted to the frame. I guess you couldn't wind a stock Olds. too tight anyway. As that was not bad enuff the roll bar had 2" pipe with 2" pipe elbows the corners.
  7. Chevy55
    Joined: Nov 6, 2008
    Posts: 409

    from Nebraska

    I just went through this thread all the way from the first post and I will think I will order a new flywheel for my car tomorrow. I have a Lakewood bell with block plate picked up at a swap for $75. The guy was tired of tripping over it. I just hope I never have to find out if it works. Really scary stuff on this post.
  8. I have seen enough flywheel explosions that now I buy scatter shields for anything that revvs above 4K. The first one was a super modified at Portland speedway, cut the driver's leg off, bad deal, he was using a home made shield, I think it was made from a truck wheel. At some sand drags a clutch came out of a jeep, nipped the pedals off under the drivers feet, lucky guy. and went out the side of the cowell. Lost a flywheel on the stock car, had a Anson scatter shield, looked like it was beat up with a jackhammer but it contained most of it, one piece got out and injured a spectator in the stands. It goes on and on from there. I worked on heavy trucks and have seen damage from flywheels, clutches and crankshafts breaking, containment systems at any price are worth the money.
  9. RatRoy
    Joined: Jul 9, 2008
    Posts: 372


    I drag raced a Super Street 67 Camaro (10:90 index) for several years and experienced a transmission explosion at Sears Point. The high gear drum exploded at the finish line at about 7400 rpm and took the entire top off the transmission. I had a TCI Transmission Shield and Flex plate shield on the car so nothing came inside. Something else that can go wrong when using a trans-brake is exploding the tourqe converter. The good ones had an anti-balooning plate installed on the converter to prevent explosions but anything can happen under racing stress.:)
  10. GuyW
    Joined: Feb 23, 2007
    Posts: 573


    That's only good for grocery-getters - if you "race" at all - get a new (steel) flywheel.

    ...never seen a non-steel "scattershield"....and bellhousings ain't scattershields...

  11. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 9,582

    Johnny Gee
    from Downey, Ca

    Sorry, no happy it hasn't happened to me. Thats why I got a scatter shield!
    Joined: Aug 27, 2005
    Posts: 770


    My Box of parts:D

    What can I say it was working fine , then I thought a weekend at the drag strip was in order. Sixth pass , 6000 Side Step and Boom!

    Best money I ever spent was on that Can!!!!!!!

    No problems , but still saving pop cans to put her back together:D


    Attached Files:

  13. BCR
    Joined: Dec 11, 2005
    Posts: 1,262


    Guess I will ask a dumb question. Did not hear it discussed yet.

    Running an automatic on the street, I would think a trans blanket would build a lot of heat in the trans. Would it be best to build a shield out of 1/4" steel for the trans so air can still get around it? Would this help as shrapnel would still proably bounce up from the ground. Just wondering out loud.
  14. yoyodyne
    Joined: Nov 26, 2008
    Posts: 856


    Here's one in a parking lot. Sorry about the OT car.

  15. Mechaniac
    Joined: Dec 17, 2009
    Posts: 13


    In 74 my brother in law sat in his 55 Chevy Bel Air wrapping it up to high heavens and the flywheel let go. The idiot only lost the tip of his right cowboy boot and had a small piece imbedded in his lower left jaw. Pretty much ended the life of the 55, though.
  16. jakedmoe
    Joined: Aug 2, 2008
    Posts: 177

    from California

    WOW!! some wild stuff
  17. t-rod
    Joined: Feb 7, 2009
    Posts: 423


    My story is pretty tame compared to most of these but here goes. When I was 16 in '86 I worked at a full service gas station/2 bay repair shop. One guy had come in on his day off to use the lift to replace the clutch in his '69 Camaro. Didn't take too long and when he was done he did the obligitory burnout across the parking lot. He didn't go far before "BANG" "POP" "BOING-BOIng-boing". We pushed the car back to the shop and and discovered many clutch pieces and a broken alnminum bellhousing. We spent the rest of the day wondering how he didn't lose his feet.
  18. In some ways I am surprised by some responses and in other ways I am not. must be the younger guys out there that are so ' surprised' at these pics.
    You guys want to 'live in the old days' do ahead. a lot of people died or were permantely injured because of running that old junk.
    There are reasons for SFI tags and good parts made today. That is why this crap doesn't happen anymore, unless you are trying to reinvent the wheel.
    So many here want their rides to look like death traps and they accomplish just that. it's your life.
    If you are all so scared at seeing vintage pics of clutch explosions, try looking at some old wreck pics of cars without shoulder belts, absorbing columns, disc brakes, etc, etc.

    There are reasons why things changed and got better, safety wise. I like old stuff as much as anyone but, don't be stupid with safety. That includes the safety of others, not just your hind end.
    Ignorance is bliss. Wake up! The 'good old days' were not always good.

    Does anyone here know how Mike Sorokin died at OCIR?

    No problem making your stuff 'look' old and dangerous but, build it safe and enjoy it longer.
    Old cast iron flywheels have no business in a hot rod. it is better to avoid an explosion than to contain it. If you can do both, great but, use a SFI flywheel and have a bit more confidence in your wide.
    This is why there is SFI.

    Front motor fuel cars are much safer today because of SFI rated clutch cans and clutches. They are expensive and require recerts often but, it did solve the problem. None of these cars has has a clutch explosion with related driver/chassis damage in the modern era 9 after the late 80s when they became popular again).
    I know about those costs because I own one of them. Play it smart guys. Perhaps other safety related thread need to be started so the 'kids' can be schooled on the problems of running old junk.

    Last edited: Jan 3, 2010
  19. Anderhart Speed
    Joined: Nov 8, 2009
    Posts: 356

    Anderhart Speed

    This is actually kinda of a sad story-or ironically humorous if you have that kind of sense of humor. My High Performance suspensions teacher in college told us this one when explaining flywheel metallurgy. There was a IHRA meet at a dragstrip, and they offered free admission to all the kids at a local childrens hospital that could make it out on a friday. One of those kids was 10 years old, and was recovering from kidney replacement surgery. Both of his kidneys failed and his older brother donated him one of his own. The surgery was successful and he was expected to make a full recovery. A guy in a 27 T altered rolled up on the line running a wild small chev and a gray iron flywheel (oem stuff). Needless to say, when he dropped the clutch the flywheel shattered, and a large piece entered the 10 year olds new (and only) kidney. He later died from those injuries. Bet ya that guy started using the right flywheel and a scatter shield from then on.
  20. snap too
    Joined: Dec 13, 2005
    Posts: 259

    snap too
    from lost wages

    I guess I'm getting in on the tailend of this but I've seen it and my partner damn near lost a foot and a young spectator got hurt , it's no BS ,even with the autos , torqueflite sprague failure spins the drum 3 times engine RPM , yeah right Boom! One of the reasons NHRA dropped the clutchflite.Red 57 chevy 210 (Bob Wiseman as I recall) boiling the tires out of the Round Up Drive in in Vegas showing what a bad ass ride he had , missed 2nd gear , again Kaboom! Cast iron flywheels, crappy fasteners, no shield and lack of judgement.I shudder at some of the "stuff" guys used to do and I still see it.
  21. Anderhart Speed
    Joined: Nov 8, 2009
    Posts: 356

    Anderhart Speed

    This is what we learned in college-and this is straight from Dave Morgan, who is a drag racing suspension and driveline guru-any engine that we commonly deal with has a very high likelyhood of shattering any type of OEM flywheel above 350 torque. There are two main types of OEM flywheels, cast iron and Gray iron (i believe, I may be incorrect on that, going from memory here). If you're pushing more than that than an aftermarket peice is a VERY smart idea. Whether its steel or aluminum is based on application, both are relatively safe. Steel is better for street/drag apps because they hit the tires harder, think inertia. Aluminum is popular in dirt applications and non turbo road race cars. honestly aluminum really is going to hurt performance in most of the stuff we deal with, and they're more expensive, but theres more to that theory than I care to write about right now, just rule of thumb stuff. We were taught to always use a scattersheild in addition the an aftermarket flywheel if the car was going to be run hard (and seriously, whos gonna build a badass car just to look at it? haha). OEM bellhousings will not offer any considerable protection. They do absorb some of the energy, but not enough to really do anything. Thats what I learned in school. My car has an OE Gray iron flywheel (i'm only pushing 320hp) gray iron being the only choice if you're forced to run an OEM flywheel. I'm running an OEM mustang aluminum bell housing, and I fab'd a .250" steel scattersheild for the top 180 degrees. Not what I would choose if I had the money to afford good stuff, but enough to keep my legs on and shrapnel out of bystanders.
  22. ricardo_rocha
    Joined: Nov 29, 2008
    Posts: 765

    from Brazil

  23. jughead2
    Joined: Mar 24, 2010
    Posts: 67

    from tenn.

    saw a 66 chevie blow one in 1967. cleaned the firewall as if with a giant meat cleaver. piece of flywheel put a big dent over competing drivers head in the roof. no one hurt but from then on helmets required no exception.
  24. HenryJGuy
    Joined: Mar 8, 2007
    Posts: 234

    from Dayton, TN

    Time to revive this thread. My dad told me a story about his friend's Henry J drag car, which was built in the '70s. It had a MAJOR engine setback, which put the front of the engine where the firewall should be. To drive it, you sat in the original Henry J back seat....yikes. Anyway, the guy was an excellent engine builder, and mainly dealt with small block Chevys. His engines would be capable of 9-10 grand with no problem, and he always ran a four-speed transmission.

    Not sure which track he was at, but I'm thinking it was Brainerd Optimist Drag Strip. My dad was standing behind the car as it launched, and toward the end of the track, the flywheel let go with the engine at about 10 grand. My dad said it looked like the entire car exploded from his vantage point. Lots of smoke, oil everywhere, chunks of stuff flying through the air, awful sounds. Luckily, his seating position saved his feet, but he was definitely shook up from it. The flywheel blew through the engine/trans enclosure, the boxed (2x3-inch) frame rail and another piece shot through the roof of the car.

    My only experience with a clutch/flywheel explosion happened last summer at I-40 Dragway. The event is called Dragstalgia, and the car had a Y-block and manual transmission. The car wasn't particularly fast, but the pressure plate let go at about 500 feet down the eighth mile track. I heard the pop, quickly looked at the car and saw that it was bouncing, as if it had come off the ground. Parts went everywhere, and one of the big chunks exploded the master cylinder, which meant no brakes. He got it stopped though. Here's a picture of the carnage.

  25. So-cal Tex
    Joined: Aug 24, 2005
    Posts: 1,379

    So-cal Tex

    Not to discount the the reasoning for a scattershield......but do you notice the theme here??

    I read all the stories from page 1 to here and it seems Back in the day most of these clutch/flywheel and pressure plate failures were related to old used cast flywheels and stock clutches/riveted pressure plates that lets loose at high RPM .

    These stock parts were not engienering or rated for 8,000 rpm shifts and hard launches.

    I just converted my '55 chevy to a 4spd car and I did upgrade the fly wheel to a Billet steel version with a SFI-1.1 rating even though I had 3 cast ones I could have used.

    I also upgraded the pressure plate bolts to grade 8 from the stock grade 5 crap, and I am running a SFI-1.1 RAM clutch and pressure plate rated for higher RPM.

    The rev limiter is set at 6K so I should be alright if I miss a gear.

    Has Anybody had a clutch/Pressure plate/ Flywheel explosions with SFI rated quality parts?
  26. cooljunk
    Joined: Dec 18, 2007
    Posts: 423


    Not a big crash but the bell housing of my TH350 broke and the trans turned over in the car.
    I thought it was a fluke until I cracked another one.
    Cut off the bell housing and installed an Ultra Bell.
    No problems now.
  27. Any more stories out there?
  28. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    Member Emeritus

    Bremerton Raceway in Washington State used to have a "display board" of broken parts; it was used to show the carnage, and importance of safety equipment. Most of the parts and pieces were from clutch/flywheel explosions. I saw a 67 or 68 Camaro street cat at Bremerton Raceway explode the clutch using stock components. Completely cut off the header collector on one side of the car, ripped up the floorboard/firewall/dash/windshield, and left the guy limping around the track the rest of the day. I was the starter one year for a nostalgia event. I believe it was the Wayne Harry 40's Willys Coupe car in the right lane about to make a single pass. I was standing just to the left rear of the car, and decided to move back just a little bit more. No sooner did I do that, I threw the start switch, and most of the Torqueflite exploded onto the track. At SIR one year, I looked at an early 70's Chevelle sitting on a trailer; broken windshield, messed up cowl, messed up floorboards and dash, all from a clutch explosion. I did't see it happen, but it sure messed up that Chevelle. At another nostalgia event, was a Jr. Fuel type dragster with an injected SBC and Torqueflite trans. Or what was left of a Torqueflite trans; it too had exploded, but was mostly contained in a trans blanket. There used to be a small speed shop in downtown Everett, Evergreen Speed ran by Al Van Dyke. He had a permanent limp, the result of a clutch explosion in a 55 Chevy at Arlington Drag Strip. He even had pictures of the car and carnage posted on the bench his cash register sat on. As I was sitting here reading this old thread, I got an PM from another HAMBER asking if I'd care to sell one of my old R.C. Industries scatter shields. I have one that's "aluminum", although another poster has said they're made of a manganese alloy. The rest are made of cast STEEL, not cast iron; that's why they're so much heavier than a cast iron bell housing. I have never seen one of those come apart, but they went out of favor when the hydroformed units became available, and the SEMA/SFI specs came along. They are no longer legal for NHRA/IHRA/(AHRA), but for the street, a whole lot better than cast iron or aluminum. I still have my transmission blanket, left over from my FED I sold in 85; always thought I'd use it for backup for something one day. I have never had a clutch/flywheel let go, but have had a couple/few clutch discs throw the lining. Butch/56sedandelivery.
  29. Back in the 80's at Great Lakes Dragaway (Da Grove). I took my mild performance 69 Nova with a street diaphragm clutch and stock housing down the strip. The car was doing 14's all night, so I didn't think it was all that crazy in performance. But, the clutch went about 3/4 of the track down in third gear. All I heard was Bam! and the first thought (as I was a stupid 20 something at the time) was I blew the motor, but all gauges told me everything was fine.
    Only when I down shifted, that's when I knew what happened. It was fun trying to slow down with unassisted drum brakes.
    So, actually the car still moved on its own and only in 3rd gear. When I got back from the return road, I told my friend about it and he said he would tow me back to Milwaukee. I said, lets see if I can drive her home and you follow me.
    Sure enough, I made it.
    The next day I took the tranny out and found; I blew some small holes through the floor, a bigger hole in the housing and only 2 pads left on the deformed diaphragm clutch. It's amazing it made it back.
    Yup, the next week I got a shield and a sturdier Borg and Beck clutch.
  30. R W Ohio
    Joined: Dec 24, 2011
    Posts: 494

    R W Ohio
    from Ohio


    Not a clutch, but pretty messy.

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