Interesting article about the control arm recall

[extrap]

Glad you like it. There is so much.

I am looking at doing a '05-'06 Ford GT design/engineering video series from start to finish. So many details and good stories from the program. This would include interviews with many of my FGT engineering teammates (technicians and all - everyone but Camilo! LOL KIDDING!!) and owners. Interviews with Camilo about breaking his heart multiple times including 86ing his deep dish wheels at the beginning and fender clearances.

I have done enough writing so this is my preference along with on-track footage new and old. What do you think?!

Yes please!

As time soldiers on, this will be part of your legacy. Prob good to record it as best you can, as soon as you can before memories fade ...

 

[sahlman]

As Fred and I got to be pretty good pals, he would tell me stories of him and Camilo butting heads on more than a few occasions. Guess it got pretty "interesting" when it came to fixed door glass issue. Those were the days buddy. Time of our lives.

Yep so much good stuff to include. I'll be visiting you in AZ and Rich Brooks, Denis, etc. Denis was devastated when Jeff Walsh and I destroyed CP4 in final testing...I had to assure him we were OK, but he didn't care. LOL He just had the 1000 foot stare in the general direction of the bent GT. His baby.

 

[Cobrar]

We were battling Boeing for sourcing every certified billet of 6061-T6 and then still ultra sounding and x-raying each billet before going to Roush and Multimatic. I can't recall if Wixom held these pieces before or after this testing step.

Have to appreciate, not only the difficulty in locating the 6061 material, but the requisite verification of the base material before the machine process began. Had to be subsequent rejection of unsuitable materials that didn’t meet your acceptance criteria. Just a guess - roughly 30% ??

 

[sahlman]

Have to appreciate, not only the difficulty in locating the 6061 material, but the requisite verification of the base material before the machine process began. Had to be subsequent rejection of unsuitable materials that didn’t meet your acceptance criteria. Just a guess - roughly 30% ??

Good guess. Just over 20% of the raw billet was scrapped. This was primarily because the edges (sides and ends) of the giant billet ingot (I don't recall for sure, but I believe in the 10' x 20' region) had laps/cracks from the manufacturing process. The huge ingot is cast and then rolled to final shape. The edges of these giant billet pieces end up with resultant laps and cracks as the rolls compress the material to the final flat size. As Huibert noted in the article, x-ray won't find closed shut laps/cracks due to the lack of density difference. So ultra sounding these was critical. But x-ray did also help us scrap some billet due to porosity.

We actually rejected or accepted billet specific to the layout of the arm in the big chunk of aluminum. Sometimes the defects would not be in the arm so we were able to use it rather than blindly scrapping useful pieces...very expensive pieces.

Further, it is far more accurate and easier to ultrasound and to some degree x-ray the flat pieces. Therefore, our raw billet pre-inspection process was very important for high confidence results and avoiding costly time and money that would have been spent on machined arms if we did ultra-sound and x-ray afterward.

 

[Specracer]

Boy hasn't this thread gotten good, thanks Scott!

 

[GT@50]

It's really cool hearing from you guys about the build process. More please. Thanks.

 

[sahlman]

Boy hasn't this thread gotten good, thanks Scott!

You are most welcome! So many details and stories

 

[sahlman]

It's really cool hearing from you guys about the build process. More please. Thanks.

Plenty more to come...as noted, I am working on getting a good FGT design video series going.

Is the following detail to mundane/technical?

We had to change the bushing and balljoint bore machining tolerances and process for these billet arms because the 6061-T6 aluminum has a lot more silicon (Si) content in it than the A356-T6 cast alum (closest cast to 6061-T6), which caused big trouble in control arm bushing press-in during this change since the friction of this billet aluminum was a lot higher than the cast material.

 

[Cobrar]

Good guess. Just over 20% of the raw billet was scrapped. This was primarily because the edges (sides and ends) of the giant billet ingot (I don't recall for sure, but I believe in the 10' x 20' region) had laps/cracks from the manufacturing process. The huge ingot is cast and then rolled to final shape. The edges of these giant billet pieces end up with resultant laps and cracks as the rolls compress the material to the final flat size. As Huibert noted in the article, x-ray won't find closed shut laps/cracks due to the lack of density difference. So ultra sounding these was critical. But x-ray did also help us scrap some billet due to porosity.

We actually rejected or accepted billet specific to the layout of the arm in the big chunk of aluminum. Sometimes the defects would not be in the arm so we were able to use it rather than blindly scrapping useful pieces...very expensive pieces.

Further, it is far more accurate and easier to ultrasound and to some degree x-ray the flat pieces. Therefore, our raw billet pre-inspection process was very important for high confidence results and avoiding costly time and money that would have been spent on machined arms if we did ultra-sound and x-ray afterward.

awesome! Thank you for sharing!!

 

[extrap]

Plenty more to come...as noted, I am working on getting a good FGT design video series going.

Is the following detail to mundane/technical?

We had to change the bushing and balljoint bore machining tolerances and process for these billet arms because the 6061-T6 aluminum has a lot more silicon (Si) content in it than the A356-T6 cast alum (closest cast to 6061-T6), which caused big trouble in control arm bushing press-in during this change since the friction of this billet aluminum was a lot higher than the cast material.

Scott - No! I don't think you can get too mundane/technical for forum members. Great stuff, continue on!

I even want to know what "big trouble" you speak of Was the aluminum splitting?

 

[MTV8]

Great stuff. I would actually prioritize having the billet arms over some of the factory options.

 

[twobjshelbys]

So I think it was asked but I dont recall the answer. if a car with billets needs a replacement is it a new billett?

 

[PL510*Jeff]

"Is the following detail to mundane/technical?"

Absolutely Not. I, for one, learn from your (and others) posts. I may be able to use the technical knowledge in my next life.

As has been said before, we GT owners are lucky to have all of the "Ford techies" insure the cars we bought will perform as well today, as the did 16-17 years ago, when they were brand new.

 

[sahlman]

Scott - No! I don't think you can get too mundane/technical for forum members. Great stuff, continue on!

I even want to know what "big trouble" you speak of Was the aluminum splitting?

No, with the increased interface friction between the new billet arm and busing/balljoint housing the bushings were only pushing in halfway with the same machining dimensions, tolerances, process and forces as prior. So we had to adjust...quickly. Fortunately, ZF, the supplier for some of our suspension joints and the forged control arms knew what we had to adjust. This was significant.

 

[sahlman]

Scott - No! I don't think you can get too mundane/technical for forum members. Great stuff, continue on!

I even want to know what "big trouble" you speak of Was the aluminum splitting?

Alright! Will continue to ask.

 

[sahlman]

So I think it was asked but I dont recall the answer. if a car with billets needs a replacement is it a new billett?

Nope. The forged arm is the only OEM replacement. This is another area I may go after longer term with a few bushings replaced for multiple improvements.

We did ~1500 car sets of the billet arms until the forged arms were ready for production...12,000 arms.

 

[twobjshelbys]

Nope. The forged arm is the only OEM replacement. This is another area I may go after longer term with a few bushings replaced for multiple improvements.

We did ~1500 car sets of the billet arms until the forged arms were ready for production...12,000 arms.

Could billet parts be re-created? Either 3-D scanned to create the tooling files or maybe Ford would donate them (ha! Wishful thinking)

Let's say it was in warranty, if you lost a billet did you get all 4 replaced to keep style the same? I'm sure now it would be your own nickel.

I can see these parts from wrecked early cars being highly desirable

 

[PeteK]

Scott, no technical detail is too small. As these cars age, those of us who want to replace the bushings and keep the billet arms, or just continue to use the forged arms, versus paying $1000’s for new arms want to know these technical considerations. Yes, I know that getting the right amount of interference fit with new bushings is challenging, but at some point replacement arms will not be available. So everything we can record will help.

 

[sahlman]

Could billet parts be re-created? Either 3-D scanned to create the tooling files or maybe Ford would donate them (ha! Wishful thinking)

Let's say it was in warranty, if you lost a billet did you get all 4 replaced to keep style the same? I'm sure now it would be your own nickel.

I can see these parts from wrecked early cars being highly desirable

Yes they can be recreated. We are looking at this with some upgrades.

I am nearly certain there wasn’t any billet arms warrantied

 

[sahlman]

Scott, no technical detail is too small. As these cars age, those of us who want to replace the bushings and keep the billet arms, or just continue to use the forged arms, versus paying $1000’s for new arms want to know these technical considerations. Yes, I know that getting the right amount of interference fit with new bushings is challenging, but at some point replacement arms will not be available. So everything we can record will help.

Pete, understood on the details

Of note, there is an incredible amount of detail I won’t post to make this kind of replacement a high confidence robust solution for safety critical parts on a 200 mph supercar. In DFMEA speak every characteristic is a 9 or 10.

Those joints were pressed in without any other mechanical design elements to secure the joints. Pressing them out has a high liklihood of damaging the arm without confident ability to press new ones in. The bores would need to be oversized reducing badly needed material for strength and then new bushings.

It will require $1000’s for new arms. $12k for 8 billet arms complete would be a bargain. I have a beautiful high performance design in my head that may be less but not a lot as professional liability and product liability would be very high on these without many to amortize over