Technical are scatter shields necessary?

Clutch cans (bell housings) have come a long way since the 60's, I straddled this aluminum one back in the 80's for a few runs. It did have an 1/8" steel liner.

 

I saw all that bull shit on 1320 and some face book posts too . I say even if you did everything wrong that bell housing should not have unraveled and opened up like that, I bought a QuickTime before and liked the fact it was more compact than a Lakewood and easier to build floors around but after seeing this I’m thinking NO more..

QuickTime seemed quick to point the finger too , it tore right at the weld which seems like a bit of a production failure on their end if you ask me

 

Any time the purchaser drills or modifys the "can" as is, it voids the SFI cert, Proper Tech inspection would have caught it. This is a Browell can of similar design with access hole properly in place. The piece removed from the can is welded to the inspection cover so that it is smooth inside and nothing to grab on to.

 

A question was asked on how they are tested--- a cast flywheel is cut in 6 sections down to the bolt flange and then bolted to a hub mounted to an electric motor spin fixture, the can gets bolted to the face plate of the fixture and a 2" thick ballistic drum gets bolted to the faceplate. The drum is so heavy that its wheeled over on guided tracks. The motor spins going up in RPM till the flywheel fails and the RPM is recorded. The shrapnel must be retained (small amounts may exit the clutch fork area) and deformation and dents only, any cracks or tears is subject to failure. Flywheel explosions have been so great that the ballistic drum lifts off the tracks

 

The Ansen scatter shields were made of cast aluminum and they quit making them because they couldn’t contain a blown clutch or flywheel coming apart. I knew a guy who had one on a small block Chevy with a balanced rotating assembly. When clutch came apart broke Ansen shield in six pieces. No intrusion inside car but lots of deformation of trans tunnel, holes through cowl and headers, took of input shaft of trans and corner of block. Only safe option is stamped or hydro formed steel

 

Thank you, @dreracecar, for the description and explanation.

 

The missing block plate would have added a lot of strength if it had been used. It has bolts all around it that helps keep the front of the can from ballooning open like yours did. Kind of reminds me of someone using shoulder straps but omitting the lap belt. Just isn't near as strong and at some point you are coming out of the seat in a most violent manner!

 

That one was cast steel I have the hernia to prove it.

The only reason I would run an Ansen would be if I wanted a car to be 100% period correct with limited track time.
If I was building a car to do full on racing I would run a Lakewood.

 

Lucky, Indeed!!!! I am happy he was not seriously lnjured. In 1965, a high school friend of mine wound his 55 Chevy 265 to tight, Clutch/Flywheel came straight up through Dash/Windshield. Luckily he wasn’t hurt. Stock Chevy Bellhousing/3-sp. on the floor.

 

I bought a used Ansen in the late 1980's must have been made sometime in the 1970's, that was a hydro-formed gold irridite plated steel bell just like a Lakewood with the only difference being the bell was a 3-piece design....the bell had a block plate, the major portion of the bell, and the bottom 1/3 "half moon" which could be unbolted with the rest of the bell and block plate left in place, to service the clutch. Ran it for a couple of years before local track tech got snooty about it because there was no way to get a re-cert on it(after letting me use it for two years already with no-cert WTF? Ansen was out of business)). I resold it to a street runner. It was a bit thicker than the Lakewood, wish now I'd have kept it.

 

I found a nice used Lakewood to put behind the hemi with a clutchflite. Hard to believe how difficult it was to get one of these. Not sure if anyone makes a new bell that is comparable for my application. (Using a sbm bell)

 

I to have a. Vintage RC Industries Bellhousing on Sbc. In my 57 Chevy,It also has the bottom bolt on dust cover with it (generally missing). While no longer legal for Dragstrip use, I feel it was a good addition to my build and T-10 for street use. At 71yrs.old, I doubt I will be doing any Clutch popping or 6000/8000 rpm shifts. Peace of Mind , I guess.

 

I used a Lakewood this winter when I put the TKO in my 55. I have a small block that will rarely see 7000 rpm. I wanted a new bell housing anyway and figured it wasn’t that much more money than a 621, and it gives me confidence that I shouldn’t have problems.

 

Lakewood......

 

Personally I think the root cause of the explosion may have been cracks in the aluminum pressure ring near the base of lift lugs. It's pretty common to see cracks there, as the aluminum rings flex and fatigue. I think one of the cracks in the pressure ring let go, and the wide openings in the Long cover let a broken section of the aluminum pressure ring escape and wedge between the spinning cover and the opening in the bell. That caused the PP cover/bolts to be ripped apart which in turn caused the can opener effect on the bell.

Here's a pic of the crack location (highlighted in yellow) i'm talking about...



I'd be real curious to see if the pressure ring has similar cracks like those above.

Grant

 

An 1/8-inch scattershield might more rightly be called an adapter.

About 60 years ago, when clutch/flywheel protection was mandated for "competition" cars, some strips required 180º (top half) 1/4-inch steel shields. We had one on our roadster. When the clutch/flywheel let go, it cut the "foam aluminum" transmission adapter out, dropped the engine down with the headers resting on the draglink, heading the car off the strip at Fontana. Fortunately no harm done.

Earlier that year I was peppered with the shrapnel from a small-block Chevy gasser at Riverside. I guess crowd protection came in second place.

 

I've always been of the opinion that, you can't put a price on "piece of mind." That being said, I think a scatter shield is worth every red cent! I have always run one on all of my junk, from mild to wild, just to be on the safe side. We all get a little goofy sometimes with our ride's and, personally, for a few measly bucks, I feel a lot better knowing that the clutch and flywheel will stay contained to it's proper region as opposed to dropping in unexpectedly in the cockpit with me where it is COMPLETELY UNWANTED! I try to think of it like an unexpected visit from the in law's, AVOID IT AT ALL COST!

 

Someone mentioned not being concerned because he was running an automatic trans. A few years ago I had to repair a floor pan and lower firewall section that was damaged when the auto trans exploded. Even though it was wrapped with a trans blanket that contained most of the flying debris, the blanket expanded enough to open up the factory weld seam between the floor pan and the firewall to a gap of about 6"! Had the trans blanket not been there, the explosion would have caused just as much damage as an exploding clutch would have caused. The guy carried pictures of the inside of the trans blanket and the pile if broken stuff it contained. The blanket did its job, but the car still needed some metal work to fix. Gene

 

I read this also but wouldn't it be more accurate to add the torsional load of an engine under power twisting the transmission bolts as the explosion occurs? These things don't explode sitting at idle.

Let me post a picture of the 'missing block plate' if you needed to hide behind one - now - it is correct that I didn't put the bolts in the bottom. My incorrect thinking was "parts can only escape" not "parts are going to be rotating and beating on everything"

Gotta do this with my phone - hang on

Also take note of the bolt holes available on the bottom of the steel block saver plate.

 

Yes that’s where it came apart. I’ve been on the phone with RAM clutch all week and they are making a different design for this area. Stronger right here. Pat called me at the track Sunday morning and I sent him over 100 pictures to study. Great folks.

 

Tony, just glad that you're OK! Hope you didn't swallow your cigar, but I see that the crew chief has the matters well in hand. Hope to make a race this year, Carp.

 

When I first saw the photos on Facebook I noticed that you have a Chevy bellhousing adapted to the hemi. Do you plan to put a direct mount Chrysler pattern housing in the car now? Alternatively you could use the same style of studs as used in the fuel cars where a countersunk head will stop the stud from being pulled out of the adapter. You would need to cut the engine side off the stud (where it did not clear the hemi block) and make provisions to thread it into the adapter. Another option would be to simply use countersunk bolts threaded into the adapter from the block side. Besides the fact that is is relatively easy for a big impact to pull threaded studs out of the aluminum plate the most commonly used studs are generally a relatively low grade and prone to shearing in this sort of situation.

Roo

 

[QUOTE

I read this also but wouldn't it be more accurate to add the torsional load of an engine under power twisting the transmission bolts as the explosion occurs? These things don't explode sitting at idle.
/QUOTE]

There are 100's of situations that they can test for, but testing each and every one is time consuming and expensive that no business can recover from spending $2500+ a test with reports. The only test they can do and the only thing they need to be concerned with is containment of an reciprocating explosion also it was found during testing that Allen socket bolts were too brittle and quite often broke during the test and that Grade 5 bolts bent and stretched, but did not break, with the junk grade 5 bolts one can get these days, the grade 8's are just better. Improper mods to a clutch can is like pulling a pin on a hand grenade and scotch taping the handle down, it will hold for now, but sooner or later, the tape will release the handle--- and BOOM.
Before the new SFI Powerglide case came in, a stock case with a shield was used over the planetary section. Racers would drill a 1/4" hole to hold the dipstick tube and tech would/could call you on it because it was not there from the manuf as silly as it sounds, but those are the rules. That gross mod to the can should have been caught during any proper tech inspection.
Techniqley , the can was never tested with the aluminum adapter and thus voided the SFI by not using the steel blockoff plate for which the assembly was tested with and certed for. By the grace of a higher being, that the only thing hurt was your wallet, improper installation and mods to the unit would make you the responsable party. Done correctly and the Manuf product liability covers it

 

I see the Sharpie marks on the top of your trans say 2.93 1st, which says to me that your clutch is going to need to slip a little longer than the guys using 3.17 or 3.25.

I'm personally not a fan of aluminum flywheels or pressure rings. Not only do they flex more than nod iron, but I also feel the 2pc design can't absorb enough energy fast enough which compromises the amount of effective slipping that the clutch can do without damage. When the clutch is slipping properly, the added weight of steel/iron over aluminum won't hurt your performance. It's only when the clutch is hitting hard enough to knock the tires loose that you will see a dragstrip advantage from aluminum flywheel/pressure ring.

Grant
clutchtamer.com​

 

For most of the people reading this thread a tin can is not necessary at all. For the precious few that one is necessary they are really necessary.

 

Every safety rule/spec is written in somebodies blood

 

That's an unfortunate truth!

 

Automatic's don't explode ?? Been there-done this.

 

First, I am glad you are OK Tony. Many of us have learned or reinforced a good lesson at your expense. I run a lakewood bell and engine plate on my street 1955 Chevy. A forged steel flywheel also. I had a friend back in the 1960's explode one in his 1957 Chevy with a 270 hp small block. Seeing what it did to the dash and floors was a lesson I didn't forget.

 

Mother MOPAR started this adapter idea - probably to be able to swap the starter side to side. There's no place to put a starter without and adapter. Here's the 1957 factory part.