Technical Scatter Shields

Just make sure to run Synchromesh fluid in it.

 

As much as I want a stick this is one of those questions that makes me have second thoughts about it. There are so many options on scatter shields as well as their weight. Has anyone researched how much a standard transmission with clutch and scatter shield weighs vs an automatic?

 

Why is weight an issue? What are you planning?
Typically, a hydro-formed bellhousing is lighter than an oem cast iron bell. There are some cast steel units out there and they are not light. No doubt that an aluminum bell with a formed steel shield above it will be less weight than the iron cast pieces.
A piece of ¼" plate of the approximate size needed is about 10-12lbs (10.21 lbs/sf) and another 1 or 2 for mounting tabs and bolts.

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Street only except might run it at HAMB type drag events. I just want to keep my 57' Belair as light as I can for performance reasons but not locked in to either 4 speed or automatic yet. It will have a 327" tri-power, 350 cam and camel humps. Also looking into HP loss and weight of Positraction vs. 9" Ford. May not even use a scatter shield.

 

One of the reasons I am a techman for NHRA is because a techman saved me. Back in the mid to late 60's I raced on the street and at the local dragstrips. When I pulled the 427 out of my 63 Galaxie and put it into a 58 Ford, that moved me up to Modified Production. The techman at the local NHRA track would not let me race without a blowproof bellhousing. That meant spending money on something that did not improve performance or make my car look nicer. But I laid down cash for a new 2 piece RC blowproof bellhousing and was legal to race at the dragstrip. Six months later while street racing I went for third gear and exploded the flywheel. Nothing came inside the car at me but it took the back off the block, set the rear carb on fire, and blew out the right front tire. There were dents in both fenders from the inside out. I was able to get stopped without crashing but a lot of damage was done. The following year I got a job at the local track as a techman and the rest is history. The point of all this is to let everyone know that a clutch or flywheel can explode at the track or on the street. You spend a lot of money to have a quick ride. Spend some money on a blowproof bellhousing if you run a stick. You never know when you might decide to run up through the gears, quick shifting to chirp the tires. You might just save your feet and your nice paint job.

 

You can still find the old style, cast steel scatter-shields that are no longer SFI approved., although it says NHRA accepted on them; no longer legal for competition, they are still perfectly good for the street. Ansen, RC Industries, Wedge Engineering, COBRA, all made them. Some are one piece, some two piece, and some have side mounts for the Tri-Five Chevrolet cars. There is a rare and $$$ cast aluminum scattershield also. You will need to pay attention to the center hole, as trucks throwout bearing collars were usually larger in diameter; they make adapter rings to size up, and a lathe can be used to size down. Look at that auction site we all know and love. I am Butch/56sedandelivery.

 

If you go looking for one of these, be prepared for some SERIOUS sticker shock...No, this isn't mine, its an internet photo

 

I knew a guy in the early 70's that had the same thing happen to his tri-power 406.

 

We ran an injected BBC dragster in the late 70's to mid 70's. We ran the required blanket on the trans, which was a race glide. Scattered the trans once, nothing came outside the blanket. But, that was not a stick trans. I think if you run a manual trans and wanted to use a blanket you'd have to cut it for shifter and clutch, which would destroy the blanket integrity and marginalize the purpose of the blanket.

 

Friend had a COBRA scatter-shield in his 64, 289 powered, 4-speed Falcon Sprint. It was a former drag car with a fork lift battery in the trunk. Helped him change out the clutch, but had to leave before the job was finished. He placed the shift levers on the transmission "down", instead of "up". Transmission was a close ratio Borg Warner 4-speed, and he could't figure out why it would't shift right. This was in 1968 or so, and the car was painted "Competition Yellow"; it was BRIGHT! After he sold it, it wound up with a straight axle and a later model Olds 455 engine, and TH400 transmission. Someone made a mess out of a good car! I am Butch/56sedandelivery.

 

I have done a lot of road racing, from Lime Rock, to Laguna Seca, IMSA GTU to SCCA Pro Solo.

I have absolutely destroyed more clutches than I can count, and on the street, too.

I have been known to rip hubs out of clutches on downshifts, on cars that I did not own, and could never afford.

I have yet to have a piece of one exit. Maybe I am just lucky.

 

Hello,
Here is an excerpt from a story I wrote for the WDIFL web site. It is about our 40 Willys destruction in the finals of a C/Gas race at Lions in 1960 which ended our drag racing involvement. My brother was at least two car lengths ahead of the class champion when the clutch let go and the flying pieces went everywhere. They went everywhere, even into the legal, approved Moon fuel tank bolted to the floor in front of the passenger seat.
"...The following Sunday, Atts Ono and I went back to Lions to see what happened to our 40 Willys. The car was a burned out hulk. The fire did a complete burn and melting of the interior. The seats were just wire and metal, the moon tank was gone, survived by a couple of nuts and bolts in the floor, the glove box door was half gone into a melting mess, etc. The worst thing we noticed was that there were metal chunks wedged into the top of the dash, near where our tachometer used to be mounted. The doors also had metal pieces wedged into the window sills. There was a huge hole in the floorboard where the scattershield just flew out somewhere. We never knew where it went. It was a scary sight to see such destruction in the bright sunlight..."
The best thing to come out of this destruction was the new rule that went into effect moving all interior Moon gas tanks outside. No Moon tank inside, no fire, just flying clutch and scattershield pieces wedged into almost every nook and cranny from a stick shift unit. This was late 1960 and the landslide from this ruling moved a lot of racers into the B&M, C&O, or Cal Hydro camp.
If we had continued racing with a new build, we were going to a B&M or C&O stick hydro. The only reason we put in a C&O in our 58 Impala was the initial conversion cost was less at Gino's C&O shop. (B&M at the time did not do stick to auto conversions) The stick hydros tend not to blow up under a 671 SBC horsepower.
Jnaki

 

Hello,
The Drag News of the day in August 13, 1960 had some reporting errors, but this portion showed the ruling that forever moved the Moon tanks out of the cab and to a safer place in the front or rear of any race car. We applauded this decision, but it was a little too late. Stronger scattershield builds and rules should have been implemented sooner. Ours was a top and bottom unit approved by the racing rules. By the end of the following year, there were companies making full coverage bell housing scattershields. But, sometimes in big motors, even these let go...
"from Rich Fox: I would buy a Lakewood or other SFI approved blowshield and if they didn't make one for my engine of choice, I would adapt it."
Safety over cost is always a great idea. Live to tell another story is simple and preferred...
Jnaki
Blame us for all of those moon tanks showing up on the outside of cars...but you are still safer for it...

 

Well, you are putting a lot of thought into something that may never happen, absent any real stupidity. However, since you brought a couple things up, a blanket on a street car is sure to retain a bunch of heat. That will cause excess wear within the trans and eventually make it hurt itself when the urge for hi-powered sillyness hits. Your trans is an integral bell design, yes? Can't just swap it out for a steel scatter can without some considerable machine work and tear down. I didn't get what it's bolted to, but let's assume it's a Chevy. So, what's used on an automatic trans? There's a couple versions, one that's a full bell shield and others that are steel with tabs, bolt it on, done. In your case you might have to lose a little off the bottom near the cluch fork/slave area, but it would still provide some flywheel limit should it ever come apart. Check these:
https://www.summitracing.com/parts/...Be-UAb-cSRF4lC3d_1NvRf63baBi5ZymqSRoCzALw_wcB

http://www.jegs.com/i/TCI/890/97000...Yufh2cX4GiEhM8VbszFRKP8alGeQVOfx3fhoCqKbw_wcB

Are these NHRA/IHRA approved for an NV3500? Who cares, it's for you, not them. I dunno, maybe this is too easy? Your trans is like big automatic with a shifter poking out the top. You're concern in the flywheel. Have fun, explore the options. I found those with a google image search "turbo 400 flywheel shield"

 

I happen to have one it's in pretty good shape

 

I put a pressure plate through the floor of my 65 Mustang back in 1973 at the local dragstrip. Missed my passengers left foot by two inches, sliced the firewall all the way up to the hood, severed the brake line, and knocked the lower two ears off the block, quite a ride. I have used scattershields ever since.

B

 

I'll just leave this here

 

That's a classic photo, use a Scatter shield.

 

If your going to race it make sure it will do the job. Back in the late 50's I decided to race my 34 Ford 5 window (B altered) with a full race olds engine. I built my own and thank the lord it worked as on my 2nd run the clutch blew, parts all over the drag strip. One weld broke jamming the throttle at wide open. I was near the end of the quarter mile doing over 100 mph and when I hit the kill button the tach was crossing 6000 rpm which was redline for my cam. Fortunately nothing got into the cab and I was fine but the engine, adapter and trans were toast which ended my hot rodding for over 50 years.

 

I agree that a cast flywheel is a bomb looking for a place to blow. So is the cast iron pressure plate. If you can't find a scatter sheild for your application, at least get an SFI approved billet flywheel and clutch. They are available for anything, and will reduce the chance of an explosion to almost never .

 

My brother came home with a basket full of clutch and bellhousing parts one night in the late 60's. Street racing a mid 50's Ford with a 289 that would wind 6000 RPM easily. The pressure plate exploded, and that turned the aluminum bellhousing into unrecognizable bits. It broke a couple of ears off the transmission case and put some pieces through the hood (nearly new paint job). The car went back together with a new scattershield and high performance clutch. It was never a problem again, but a friend had the same thing happen to him in a 57 Chevy a short time later. The cast iron bellhousing contained everything but he put it back together with a scattershield as well. Better to be safe than footloose.

 

I can name 3 examples of when a scattershield would have helped save things and one example of when a scattershield did help. In 1978 I changed a motor in a Chevy pickup with a camper on the back.
I told the owner the flywheel had some cracks and he needed to change it. He dsid I never turn the motor very high and it will be fine . A week later he was leaving to go deer hunting and was going about 10 mph pulling out of parking lot when the flywheel came apart. Breaking the bell housing shearing the input shaft ,ruining the new clutch and pressure plate and his deer hunting trip.
I got to say I told you so and lay in the snow and fix it as it was too high to fit in my shop.
In 1969 my buddy bought a brand new Z-28 . He took it to Motor City to see what it would do. On his second pass the flywheel came apart and destroyed that Camaro .The dash pad was touching the inside rear view mirror. Luckily he retained both feet. The insurance company refused to cover the damage because he was at the track.
In 1970 we were running a hobby stock 57 Chevy dirt track car and coming off the turn the flywheel exploded and the cast iron bellhousing did not contain the flywheel. A piece hit the gas pedal breaking 4 toes on the right foot of the driver.

 

The last example is when my brothers big block vette exploded a flywheel with a Lakewood shield and it still took out the back of the block and the input shaft and knocked the starter off. He feels lucky to have had a shield on the car and it still hangs on the wall of his shop.

 

A cast flywheel is shaky in any kind of performance application but even with a good billet flywheel I would put something between me and the destruction even if it's home made and not approved by any sanctioning body.
Years back a friend of mine had a '56 Chevy with a high dollar 292" sbc and a 4 spd. He was leaning over the fender revving it up in his garage when the flywheel exploded. He had a cast Ansen scattershield with the removable bottom not installed. It blew off of the block, wrecked the block, trans, distributor, headers, and tore up the floor/firewall. There was a blast mark on the garage floor the shape of the scattershield and holes in the garage wall. He was lucky not to be hurt and I learned a big lesson at his expense.

 

When dirt track racing back in the 70s we were running a 57 Chevy with the stock bell housing. We fabricated a shield from deck plate and bolted it to the bell housing bolts. One night a track developed a deep hole during the race. Our driver hit it, the rear wheels came off the ground. When it landed, we could see the pressure plate come out from under the car and the driver coasted into the pits. The tattletale tach indicator was pegged at 10,000 rpm. The engine lived. The fabricated shield made a huge bulge in the floor but it kept the pieces outside.

When we got to the car in the pit, I happened to notice something moving. A tire came down about 8 feet away and bounced up higher than the light poles in the pits and headed into a marsh. Somebody else hit the hole and lost a wheel. Fun night.