Driveline safety? Scatter shields & drive shaft loops

[narly1]

With the thought of the driveline in these vehicles being close to my feet and legs I'm wondering what safety precautions us builders have taken in terms of scatter shields and driveshaft loops.

Also what was the HP/torque/RPM/usage case scenario that made you decide to take (or not take) these precautions?

[NAZ]

Torque places a load on the flywheel, clutch, and driveshaft and dumping the clutch imparts a shock load on these components. But the speed of these components also places a load on them as any imbalance is increased exponentially with RPM. So I don't look at HP or torque as the ONLY criteria, how fast these components turn and any expected shock loads are also considerations. And the condition of these parts will play a large role in their potential for catastrophic failure.

My first driveshaft explosion was in a 1966 Mustang GT with a little 289 and caused by a shock load from me dumping the clutch at an intersection. Those diminutive little engines are low powered by today's standards and the driveshaft RPMs were also very low as I was starting from a stop and only got maybe 20' before the failure. Still the damage was impressive. The second explosion was at 6500 RPM as I remember and that was like an explosive charge was detonated under my seat.

My car has an NHRA accepted safety loop in front and at the rear of the cockpit and a ballistic shield over the driveshaft running the length of the cockpit. I also have a flywheel shield and a transmission shield which is mandated by NHRA and have to be replaced every two-years. Having experienced driveshaft explosions and seen many more, I understand the risks and work to mitigate them. You don't have to own a race car to be at risk.

[narly1]

Thanks for your insight. Does the same hold true for automatic transmissions?

In my case I'm looking at~ 350 HP into an AOD transmission.

Also what was the fitment like? is there enough room in the FFR trans tunnel design to accommodate a shield?

[NAZ]

Yes, flex plates and gear sets can and have exited the housing at ballistic speeds and can cut through steel tubing like a hot knife through butter. I run a Powerglide trans.

[Mike N]

There were a couple of old threads on the other forum showing pictures of the carnage from a driveshaft failure. The pictures are no longer available. A driveshaft safety hoop is so cheap that it makes sense to do it anyway. A common cause of driveshaft failure is binding of the universal joints when used with a solid rear axle. IRS cars should not have this problem. The binding is compounded by how short the driveshaft is on these cars. Using a combination of bump stops and travel limit straps on the rear end is important to prevent binding. Binding will cause failure.

Clutch explosions are rare on relatively stock engine combinations assuming that the flywheel and clutch was assembled correctly. If you are replacing the clutch and flywheel as a part of your build then using SFI rated pieces and new hardware is a smart move. This is what I did. Investing another $600 to $700 on an SFI rated scattershield would be a smart move if you are planning any sort of drag racing or open track use where consistent high rpm and high rpm shifts are likely.

For an auto consider a trans blanket. Typically not much more than $100.

[mike223]

The pictures are no longer available.

Here's one:

97456

[narly1]

I've found a couple of shields for the AOD online. I'm at the point now where the only thing that would stop me from using one would be the ability to fit it into the trans tunnel space available. They're only a couple of hundred USD.

[Fman]

Per recommendation of the forum I went with this Metco. Bolts on, easy install.

https://www.metcomotorsports.com/proddetail.asp?prod=MDL2500

[narly1]

Per recommendation of the forum I went with this Metco. Bolts on, easy install.

https://www.metcomotorsports.com/proddetail.asp?prod=MDL2500

I wonder if that would work with the hotrod?

[Joel Hauser]

After reading these posts, and looking at the pictures, I too just ordered the driveshaft loop from Metco. Thanks for posting this thread. This was very useful information.