Aluminum vs. Steel bellhousing

[Fman]

Could someone explain to me the pro's and con's to running Aluminum vs. Steel bellhousing?

I am looking at a Dart 427, approx 480 HP. From research I have done the aluminum bh is fine for this HP. I also have seen one build thread on someone having to trim down there steel housing because it was lower than the frame, apparently the aluminum bh does not require this. Would like to avoid grinding the bottom of my bh. The steel bh is also about $500 more over aluminum. I do not have a problem paying extra for the steel but want to make sure it is required or worth the extra cost for a street driver, I have no plans to race or track the car.

[edwardb]

Not $500 more. But agree steel, e.g. Quicktime, is definitely expensive. It's all about safety. Check the location of the flywheel and clutch and then your and your passengers body parts with these cars. Very close to say the least. The aluminum panel and carpet between you and there isn't going to stop much of anything. Will you blow it up with that HP and your planned driving? Likely not. But it's insurance I choose to use. Trimming what might be below the frame is a one-time thing, no big deal, and I wouldn't let that influence what is a long term decision. Ditto same discussion for a driveshaft loop.

[Higgybulin]

125622
This is a shot of a buddies clutch disc. Bellhousing was still attached on one side, clutch, everything else blew. No injuries but if the bellhousing was aluminum, who knows.

[Jim1855]

Fman,

I've run a McLeod scattershield, Ford aluminum and a QuickTime steel. Never a McLeod or Lakewood scattershield again. Currently have the QT, like it, well built and dimensionally accurate or at least way more accurate than the others. The Ford aluminum was the cleanest installation also the lightest and least expensive as you've found.

Many will say that you need the steel/scattershield for safety. No question it does provide a great level of extra security in case of a flywheel/clutch/pressure plate failure. At the same time I've yet to hear about a factory car with a scattershield installed from the factory and generally there are few failures on a "street" vehicle. It is possible that through improved manufacturing and metallurgy the likelihood of failure has been reduced.

Often the scattershields in particular the McLeod and Lakewoods, because of the manufacturing process, will need to be indexed in. This is potentially less likely with the QT or factory aluminum again due to manufacturing methods, but still possible and usually a good idea.

I've heard about cutting the bottom flange to reduce the protrusion below the frame. In a previous life and car, not a FFR, I did not do this. Not sure if I will or will need to for the current build. I know many advocate this and I do understand why. I would think that you'll need to install the engine/trans assembly to test fit and mark the required cut off. A band saw or other powered saw should be adequate for the task. A plasma cutter would make it a simple task. Cutting it will void the SFI rating but shouldn't be detrimental to the safety factor.

So now that I've added to the day's confusion, I wish you the best.

Thank you for the post, I think I'll drop my motor/trans in just to take a look-see. Curiosity changes my plans on a regular basis.

Jim

[NAZ]

Some people don't see a need for additional safety, even when they know better. I often see people here in AZ riding without helmets and the risk of injury from this practice cannot be argued.

Do an internet search of clutch explosions and see the potential for damage and injury. Start here:https://www.svtperformance.com/threads/my-clutch-exploded-today.823901/

I've had two driveshaft explosions and will submit to all reading this, they can do significant damage in a heartbeat so don't forget the driveshaft loop. You can google driveshaft explosions as well. And no, you don't have to have a race car to experience an explosion:https://youtu.be/wrxu4iySpSY

So only you can decide if running a scattershield AND driveshaft safety loop is worth the extra $$ for you and your passenger's safety.

[lgordon]

Choosing to use an aluminum bell housing doesn't necessarily assure you won't have the BH lip sitting below the frame tubes. I have a Coyote/TKO 600 in my MK4 and the lip of the bell housing does sit about 3/16" below the 4" frame tubes. While I've read about several builders trimming steel bell housings, so far I haven't heard of anyone trimming an aluminum bell housing.

If anyone has experience trimming the lip on a Ford aluminum bell housing I'd love to hear about it. It seems the only alternative is having a skid plate fabricated.

[Fman]

Appreciate the feedback, why would anyone run aluminum? Is it strictly a cost saving? less weight?

[Ducky2009]

I blew a clutch at approx 8,000 RPM (and 90 MPH) racing a 69 Nova. Cut the bell housing in half, cracked the trans case down both sides, bent the and shifter.

Luckily everything went down instead of up. How are you going to drive? Don't say "I'll never race". It's RPMs not MPH that puts you at risk. Pull out and floor it.... How many RPMs are you turning.

[Derald Rice]

For a windsor block based motor, the Quicktime 6060 does not need to be trimmed at the bottom. However, the compromise is that this bell is not SFI approved, so if you were to take it to the drags, and run fast enough, the safety tech will not allow this bell.

I ran a aluminum for a long time, because a McLoud or a Lakewood was too big for my car, and when I swapped motors, I switched to the quicktime. The quicktime bells are actually smaller than the factory aluminum bells, so my "problem" was no longer an issue.

And, it doesn't happen often, but I have seen a new 2015+ , less than 1000 mile Mustang after the clutch exploded. It totalled the car. Driver was not injured at all, but there was very little of the floorpan left around his right foot. Most of the force went straight up into the base of the windshield.

[Fman]

I blew a clutch at approx 8,000 RPM (and 90 MPH) racing a 69 Nova. Cut the bell housing in half, split the trans case down both sides, bent the and shifter.

Luckily everything went down instead of up. How are you going to drive? Don't say "I'll never race". It's RPMs not MPH that puts you at risk. Pull out and floor it.... How many RPMs are you turning.

I don't plan on turning 8000 RPMs but regardless I will more than likely just go with the steel bh for the added safety benefit, along with a drive line hoop. There seems to be no good reason to run the aluminum bh other than saving a few bucks.

[GoDadGo]

I don't plan on turning 8000 RPMs but regardless I will more than likely just go with the steel bh for the added safety benefit, along with a drive line hoop. There seems to be no good reason to run the aluminum bh other than saving a few bucks.

Smart Move!

[boat737]

When I did the runout and dimension checks on the QuickTime, it was all within specs. (and those are some mighty small spec tolerances.). I would use the QT again just for that. I did have to "shave" the bottom after it drug on the ground a few times. I did it on the car with a little saber saw. A little hard on my back, but doable. Since then I haven't had any problems dragging the housing.

[AC Bill]

The aluminum one with a blanket, might be the answer. Save's around 30-35 lbs. and no worry about any mods needed.

https://www.jegs.com/i/Deist-Safety/303/81535.FORD/10002/-1

[Boydster]

The QT steel that is popular and requires no trimming is on sale now at Breeze. (https://www.breezeautomotive.com/shop/quick-time-steel-bellhousing-kit-302-351-to-t-5-tremec-tko/) Comes with the engine plate and all hardware. I used this one on my 427W and no alignment or trimming needed.

[TrevorP]

I would only get a steel bh if you drag race. These type of failures are from dumping a bunch of power with the tires being on a very sticky surface (drag race track). I think the driveshaft hoop is a requirement. The driveshafts are so short, binding is almost a given.

I have a race lightened billet steel flywheel, tilton triple disk 5.25" clutch with a magnesium bellhousing. Very light and strong also made for alignment with this type of clutch and flywheel.

You can always install a blanket that Bill posted if your that worried about it.

[NAZ]

Drag racing, or any type of racing can be hard on a clutch but it’s not sticky tires that causes a clutch or flywheel to explode, it’s RPM that creates the forces that can cause failure. The flywheel and clutch assembly is an energy storage device and the greater the RPM and assembly weight, the greater the energy. All flywheel / clutch assemblies have structural limits to the forces they can handle, lower quality materials have lower limits where a failure will occur. Choose wisely.

Track Car Clutch Explosion (https://www.youtube.com/watch?v=yQKePPM9cNQ)
Clutch Explosion Parked Car (https://www.youtube.com/watch?v=vYNTC9v7zWk)
Disc Explosion While Coasting (http://www.offroaders.com/cheap-tricks/avoid-the-exploding-clutch/)
Pressure Plates (https://ramclutches.com/critical-difference-part-3/)

[GTBradley]

Personally, I don’t see the need on a stock engine. I may be wrong, but I don’t think Ford uses steel bell housings on their Coyote engined cars and they are making 460hp and up. Now if I were to add a supercharger, sure, then I’d do a lot of things differently.

[boat737]

Personally, I don’t see the need on a stock engine. I may be wrong, but I don’t think Ford uses steel bell housings on their Coyote engined cars and they are making 460hp and up. Now if I were to add a supercharger, sure, then I’d do a lot of things differently.

True enough, but are you sitting practically on top of the trans and bell in a stock Ford? In these cars, there isn't much between you and the moving parts. Just thinking worst case scenario is all.

[Bobby Doug]

Just remember there is only .040 aluminum between the bell housing and your legs. My legs are worth a lot more than a few hundred dollars and the time it takes to trim the bottom should it be lower than the frame. I can’t believe that some would argue against a steel bell housing.
Doug

[GTBradley]

No disrespect to anyone who uses one and I totally get that this thing gives piece of mind. And I’m definitely not arguing against them, or even advocating that someone else do what I did in using the standard bell housing. It’s just that the excessive risk logic of it doesn’t add up for me if the only difference between my car and a Ford Mustang is the tunnel/floor pan thickness. If there are verifiable stats of mustangs blowing their clutches I’d be the first to say my thinking is wrong and buy a blanket for more protection.

[TMartinLVNV]

No disrespect to anyone who uses one and I totally get that this thing gives piece of mind. And I’m definitely not arguing against them, or even advocating that someone else do what I did in using the standard bell housing. It’s just that the excessive risk logic of it doesn’t add up for me if the only difference between my car and a Ford Mustang is the tunnel/floor pan thickness. If there are verifiable stats of mustangs blowing their clutches I’d be the first to say my thinking is wrong and buy a blanket for more protection.

Bradley, I completely agree with you. The only reason I got the Quicktime bellhousing is in case I ever have the opportunity to get the car on a track and it is a requirement. The risk of a catastrophic failure causing injury from this part for our street cars has to be incredibly small (it is certainly not zero). Of course we don't have the stats, but I bet it would increase "safety" more than a steel bell housing and reduce the overall risk of injury for us to wear helmets in the car while driving, to have larger rear view mirrors, to have anti lock brakes, to have traction control, to have more side impact protection, and to drive on all season tires.

How many of us have tiny mirrors (maybe none on passenger side), track tires or dry weather only tires, manual everything and are driving it on the street? I rode a motorcycle for 13 years and fortunately never went down. I had a blast on it. I feel that this car is basically a 4 wheel motorcycle with a trunk and just slightly safer because it is touching the road in 4 places rather than two.

There are a whole lotta Coyote motors out there doing just fine with the aluminum bell housing. Everyone makes their own decision and that is the beauty of these cars. They are creations of the owners/builders. I'm a lot more worried about other things than a clutch exploding. I'm not arguing against the Quicktime (heck I have it), but there are a lot of other things that can be done with a greater increase of "safety" than a Quicktime bell housing for the majority of our collective use of these cars.

[rich grsc]

Bradley, I completely agree with you. The only reason I got the Quicktime bellhousing is in case I ever have the opportunity to get the car on a track and it is a requirement. The risk of a catastrophic failure causing injury from this part for our street cars has to be incredibly small (it is certainly not zero). Of course we don't have the stats, but I bet it would increase "safety" more than a steel bell housing and reduce the overall risk of injury for us to wear helmets in the car while driving, to have larger rear view mirrors, to have anti lock brakes, to have traction control, to have more side impact protection, and to drive on all season tires.

How many of us have tiny mirrors (maybe none on passenger side), track tires or dry weather only tires, manual everything and are driving it on the street? I rode a motorcycle for 13 years and fortunately never went down. I had a blast on it. I feel that this car is basically a 4 wheel motorcycle with a trunk and just slightly safer because it is touching the road in 4 places rather than two.

There are a whole lotta Coyote motors out there doing just fine with the aluminum bell housing. Everyone makes their own decision and that is the beauty of these cars. They are creations of the owners/builders. I'm a lot more worried about other things than a clutch exploding. I'm not arguing against the Quicktime (heck I have it), but there are a lot of other things that can be done with a greater increase of "safety" than a Quicktime bell housing for the majority of our collective use of these cars.

Exactly, the risk of having an accident with severe injury is much greater than a catastrophe clutch failure.

[mike forte]

Hi FMan,
The weight difference between an aluminum bellhousing @ 14.5 lbs with blockplate and Quick Time RM-6065 SFI bellhousing @ 31.5 is only 17 lbs. That's not much. The cost difference of the aluminum @ $275.00 or QT @ $756.00 is $481.00. That's a lot of money but safety has a price and most sanctioned racing requires safety components.
I know you said no racing, but if you want to legally exercise the power in your car I recommend safety bellhousing.
Call me if you're looking for specials... We are open and trying to sell parts...

[bobl]

Some food for thought. Let’s suppose you have a 302 with a decent set of heads, cam and 4 bbl carb. Mayber 375 HP. Pretty much a minimal build in our cars. It will easily pull well past 6000 rpm. You go out for a joy ride and decide to run it through the gears. Somewhere near the top of second gear you have a driveline failure, or miss a gear, etc. You’ve got all this spinning mass that all of a sudden has no load. It can easily spin well past 7000 rpm, even with a rev limiter it can exceed it. Assuming you have a stock flywheel and clutch it could very realistically come apart. No scattershield, it could be in your lap. Ask me how I know this! Fortunately it was in an early Mustang and the clutch was ahead of your feet. So it just totaled the car. I’ve always run a scattershield since then, even on a mild build. That was 50 years ago but I haven’t forgotten. It was like a bomb went off. Stuff happens. Be safe my friends.

Bob

[TrevorP]

It's tough for me to think that way and be the devil's advocate on every possible failure that can cause harm. Think about riding a motorcycle... I whole bunch of rotating parts are right under the foam and plastic seat.

I'm sure you will be fine with an aluminum or steel bell housing.

[ckrueger]

Drag racing, or any type of racing can be hard on a clutch but it’s not sticky tires that causes a clutch or flywheel to explode, it’s RPM that creates the forces that can cause failure. The flywheel and clutch assembly is an energy storage device and the greater the RPM and assembly weight, the greater the energy. All flywheel / clutch assemblies have structural limits to the forces they can handle, lower quality materials have lower limits where a failure will occur. Choose wisely.

Track Car Clutch Explosion (https://www.youtube.com/watch?v=yQKePPM9cNQ)
Clutch Explosion Parked Car (https://www.youtube.com/watch?v=vYNTC9v7zWk)
Disc Explosion While Coasting (http://www.offroaders.com/cheap-tricks/avoid-the-exploding-clutch/)
Pressure Plates (https://ramclutches.com/critical-difference-part-3/)

This is almost exactly what I did on my QT bell housing. I am running a Coyote with a TKO. A little trimming and you are good to go.

[Avalanche325]

125622
This is a shot of a buddies clutch disc. Bellhousing was still attached on one side, clutch, everything else blew. No injuries but if the bellhousing was aluminum, who knows.

Nice feature. You can check your clutch wear without even getting out of the car.

I think that picture says all that needs to be said about aluminum bellhousings.

[mike223]

I think that picture says all that needs to be said about aluminum bellhousings.


It says a lot, but I'm actually more afraid of the flywheel itself.

That's why I spent extra for a steel flywheel (rather than cast iron) + QT bellhousing too.

That's all simply spinning too fast and too close to my knees for comfort.



Exactly, the risk of having an accident with severe injury is much greater than a catastrophe clutch failure.

This is also absolutely true.


But they both fit in the category of mistakes you'll likely only get to make once in this sort of car.

[cv2065]

Whatever gives you peace of mind. If I focused on everything that could go wrong while driving one of these cars, I probably would have never built one in the first place. There are no guarantees regardless of what safety features you install.