[lambertius]

So this is the current plan for the lower arm, it should be less than half the cost of the OEM arm to manufacture. It uses the same tie rods that the arms come with, or that you can buy from formula dynamics. The idea being that it you can save a bit of money reusing parts.

The trade off is that it will be a bit more of a pita for the wheel alignment, and the rose joints won't last as long long as a sealed ball joints but since they cost ~$16USD each I can stand to replace them more often.

 

[damichi]

At first glance I do have a question. Did you run an FEM Analysis for this version?
My fear is that the lower control arm may not be able to hold the shearing force induced by the brake momentum.

Cheers,
Michael

 

[lambertius]

At first glance I do have a question. Did you run an FEM Analysis for this version?
My fear is that the lower control arm may not be able to hold the shearing force induced by the brake momentum.

Cheers,
Michael

Yes I did, I haven't had as much spare time as I wanted recently so I've just been working on getting this done so I can order the parts and finally get it fitted.

This is pretty similar to how you would design control arms for racing, in particular drifting, with tie rods and rose joints, so it is a well tested way of handling the abuse.

The real reason I've had to look at doing things this way however is that there are issues with sourcing a replacement ball joint that is suitable due to a weird design choice witht he original part using a spacer that was pressed on to ensure alignment. That said, I may have just solved that problem today, so I'm bouncing the idea off a colleague for a sanity check and then I'll be drawing the part again.

I'll need a lot of pictures to properly explain the issue!

 

[damichi]

I know the pressed on spacer you are talking about. Maserati did a hell of an effort to make this part being refurbished. Great to see your progress.
I was just wondering about this, because i could not find one with two parallel beams and without a diagonal brace.

 

[lambertius]

I know the pressed on spacer you are talking about. Maserati did a hell of an effort to make this part being refurbished. Great to see your progress.
I was just wondering about this, because i could not find one with two parallel beams and without a diagonal brace.

Yeah it would be braced... I was just lazy in the modelling... And yes, they did a lot of things that just make me wonder why? There is a group who claim they can rebuild the arms - but the more I've looked into remaking this the more doubtful I am that they can be rebuilt fully.

 

[twinspark]

Yeah it would be braced... I was just lazy in the modelling... And yes, they did a lot of things that just make me wonder why? There is a group who claim they can rebuild the arms - but the more I've looked into remaking this the more doubtful I am that they can be rebuilt fully.

If its that company (I forgot their name) somewhere in East Europe, nobody has actually sent a 3200/4200 set there. IIRC they have good reviews from some Lambo owners and did make custom control arms for certain obscure classics.

 

[lambertius]

If its that company (I forgot their name) somewhere in East Europe, nobody has actually sent a 3200/4200 set there. IIRC they have good reviews from some Lambo owners and did make custom control arms for certain obscure classics.

Yeah we're thinking of the same one. They clearly have a good reputation. I emailed them to ask for some input on their process but they were pretty cagey in their response (but they were polite and helpful). The more I've pulled at how this arm was designed the less confident I am that the methods they've used to rebuild other arms would be suitable for the Maserati without actually seeing a completed result to convince me. I'd like to send a spare arm out there to get built and review it (I did ask) but I just can't throw money at everything.

I think I've finally found a suitable ball joint to finish my control arm project. This has been super difficult because I've really struggled to find catalogues with technical specifications of the ball joints. I think this is because searching for anything related to ball joint drowns your results in online shops. I contacted a fair few manufacturers, none are willing to give out dimensions. I've had to go down the route of purchasing ball joints, measuring them up and assessing their suitability. The solutions I've found have required a few smaller parts to also be manufactured which drive up costs. However, I reminded myself today why I'm doing this.From the quotes I've gotten so far, the lower control arm (that larger of the two by a lot) should cost roughly $1000USD per arm completed. They currently retail for over $1800USD. The upper arm is a staggering $3600USD, so to fix my car I'm out $10800USD or $15000AUD... I'll be able to complete these for less than 1/3rd that price.

Anyway, I'm off to purchase another ball joint tomorrow and then finish both the upper and lower CAD models and send them off for a final quote and manufacturing.

 

[Driven_Garage]

So I started this a while ago, got 90% of the way there and then got distracted by other things. I'm realistically a few days of work from ordering it, but you know, who has a few days of solid time to work on their hobby?


You can read the original thread here Making My Own Control Arms For anyone who doesn't know yet, I can't follow it up there anyway after I was banned on that forum after I complained about SopranoStu. Matt Yates, the owner, used this to leverage Stu for money he was owed then banned me. If you care about that sort of thing I still have all the conversations saved and am happy to share so you can make up your own mind. It isn't really a loss though, I don't have to argue with conaero and Zep showing up and disparaging me as being unsafe and going on about insurance and what not for a part I had no intention to sell. A bit rich from a couple of guys selling counterfeit AP racing rotors which are "insured" by a company they can't disclose because they have a "NDA"... Right... Moving on.

Catching y'all up:

I used some worn arms which I got from the always helpful New Model Wreckers, in Sydney Australia (they'll ship internationally) as dimensional references. I sent these to an engineering firm that had a CMM (Co-ordinate Measuring Machine) so I could copy the geometry exactly.

View attachment 135504
View attachment 135505
View attachment 135506
View attachment 135508

I then sent a sample of an arm off to a lab so I could work out exactly which alloy the arms were made from so I could use these properties to complete FEA (Finite Element Analysis). The alloy is 4343, and using this I can economically outperform the OEM arms using 6061.

View attachment 135507
View attachment 135510
View attachment 135511
View attachment 135509

I think broke a bone in my foot. It seemed like a good idea at the time.
View attachment 135512

I moved onto the bushings where I made accurate models of the OEM parts so that I could explore more cost-effective options.

186494

186496

I did a bit of research into far more cost effective bushings since I can control the dimensions of the bushings in my own part.

After that I just kind of started filming DIY videos DIY Videos and chilling out a bit and lost interest in this. After the success of the brake kit Why I'm Making My Own Brakes, the exhaust and the clutch I figured it was time to revisit this. A few people have asked me about it (thanks for the support, especially those of you who have been on sportsmaserati for a while) and then this post popped up and I felt motivated to finish the project Bushings & Polyurethane Bushings

It was a bit demoralising getting setup and bullied by Matt Yates, he had the audacity to pressure the mods here to edit my posts and comments (and I suspect he wanted me banned here as well) which was pretty exhausting. Motivation has returned now though, so I figure I'll finish this. I may even make them available to others just to upset him further since pettiness is tremendously motivating.

In case you're wondering why this is necessary - the captured ball joint has a 100% failure rate, and the only solution is to replace the whole arm. How much are the arms you ask?

The lower arms are 1364.90GBP and the upper are 2639.39GBP, each. That's right, it would cost you 8008.58GBP to replace the control arms on your car, if you source the parts yourself and don't pay any labour. Right now, the arms I designed will cost less than half that and have a replaceable ball joint so that this issue never happens again.

So I started this a while ago, got 90% of the way there and then got distracted by other things. I'm realistically a few days of work from ordering it, but you know, who has a few days of solid time to work on their hobby?


You can read the original thread here Making My Own Control Arms For anyone who doesn't know yet, I can't follow it up there anyway after I was banned on that forum after I complained about SopranoStu. Matt Yates, the owner, used this to leverage Stu for money he was owed then banned me. If you care about that sort of thing I still have all the conversations saved and am happy to share so you can make up your own mind. It isn't really a loss though, I don't have to argue with conaero and Zep showing up and disparaging me as being unsafe and going on about insurance and what not for a part I had no intention to sell. A bit rich from a couple of guys selling counterfeit AP racing rotors which are "insured" by a company they can't disclose because they have a "NDA"... Right... Moving on.

Catching y'all up:

I used some worn arms which I got from the always helpful New Model Wreckers, in Sydney Australia (they'll ship internationally) as dimensional references. I sent these to an engineering firm that had a CMM (Co-ordinate Measuring Machine) so I could copy the geometry exactly.

View attachment 135504
View attachment 135505
View attachment 135506
View attachment 135508

I then sent a sample of an arm off to a lab so I could work out exactly which alloy the arms were made from so I could use these properties to complete FEA (Finite Element Analysis). The alloy is 4343, and using this I can economically outperform the OEM arms using 6061.

View attachment 135507
View attachment 135510
View attachment 135511
View attachment 135509

I think broke a bone in my foot. It seemed like a good idea at the time.
View attachment 135512

I moved onto the bushings where I made accurate models of the OEM parts so that I could explore more cost-effective options.

186494

186496

I did a bit of research into far more cost effective bushings since I can control the dimensions of the bushings in my own part.

After that I just kind of started filming DIY videos DIY Videos and chilling out a bit and lost interest in this. After the success of the brake kit Why I'm Making My Own Brakes, the exhaust and the clutch I figured it was time to revisit this. A few people have asked me about it (thanks for the support, especially those of you who have been on sportsmaserati for a while) and then this post popped up and I felt motivated to finish the project Bushings & Polyurethane Bushings

It was a bit demoralising getting setup and bullied by Matt Yates, he had the audacity to pressure the mods here to edit my posts and comments (and I suspect he wanted me banned here as well) which was pretty exhausting. Motivation has returned now though, so I figure I'll finish this. I may even make them available to others just to upset him further since pettiness is tremendously motivating.

In case you're wondering why this is necessary - the captured ball joint has a 100% failure rate, and the only solution is to replace the whole arm. How much are the arms you ask?

The lower arms are 1364.90GBP and the upper are 2639.39GBP, each. That's right, it would cost you 8008.58GBP to replace the control arms on your car, if you source the parts yourself and don't pay any labour. Right now, the arms I designed will cost less than half that and have a replaceable ball joint so that this issue never happens again.

CAN I ORDER SOME!?!?!?

 

[lambertius]

CAN I ORDER SOME!?!?!?

Not just yet - but soon. I started making progress again and then I had to move and am doing a fair bit of overtime at work. I'll be back on it by the new year!

 

[MRQP]

Awesome work!

 

[lambertius]

Well after a long stall on this, it is time to get this rolling again.

The short version is that I got hung up on trying to find a suitable off the shelf ball joint and I just couldn't implement anything with any sort of convenience because of the unusual design features of the control arm. Between getting stuck on catalogues, a huge amount of overtime at work and moving house I just kind of left this to fall by the wayside.

Today I sent off for a quote for the parts. I'm now only held up by the distribution of parts.

My original intent was to redesign the part using conveniently available off the shelf components so that the parts would be sustainable for the long term. It turned out much harder to achieve than I wanted, so instead I'll be making exact copies of the existing arm that will take a custom user replaceable ball joint. The ball joint will be available off the shelf from the manufacturer making the part sustainable in the long term, unlike the OEM part.

The ball joint will use a threaded body like below and will make life a lot easier for everyone. If you're like me an track your car, this will be more sustainable in the long term because the ball joints will blow out. The ball joints will be around the $200AUD mark.

 

[Cdn17Sport6MT]

Are u using FEA for the design, and if so how have u figured what suspension stresses should be used to load the arm in your FEA? Now, if you reverse engineer the part, knowing the alloy details including the heat treating it's undergone, it seems to me that that'd work too. Can u infer what the heat treat condition is, knowing the alloy's chemistry + it's hardness?

 

[lambertius]

Are u using FEA for the design, and if so how have u figured what suspension stresses should be used to load the arm in your FEA? Now, if you reverse engineer the part, knowing the alloy details including the heat treating it's undergone, it seems to me that that'd work too. Can u infer what the heat treat condition is, knowing the alloy's chemistry + it's hardness?

When I started this I sent a sample off to a metrology lab and to a chemistry lab to identify the alloy. I'm making mine out of billet 6061-T6 which is stronger than the factory cast 4343.

Rather than analyse the suspension loads, I set an arbitary load in FEA and analysed the factory part to get a point of reference for the failure condition. I then applied FEA to my part to ensure that the part exceeds the original part.

All that said, I also just copied the original part nearly exactly using a stronger alloy and made the walls around the bushings slightly thicker to address known issues with the arms fracturing so it will be stronger all around.

 

[Cdn17Sport6MT]

Ah, that makes sense... and well done, btw 😊. No, I'm not a "plant" haha...

 

[Cdn17Sport6MT]

Just thinking, re the fatigue resistance of 6061T6, is it materially different to that of the 4343, meaning of course that yes, with some local thickening of your part, the stresses in operation would be less than the OEM part... but if your (6061T6) lower endurance (stress) level (a fatigue resistance parameter) is less than than that of 4343, it might still be problematic.

Now one caveat, here, and I note that my metallurgy classes at uni were about 40+ years ago... I almost seem to recall that aluminum, unlike steel, actually does not have a lower endurance (stress) level... so mebe my question is daft...

 

[lambertius]

Just thinking, re the fatigue resistance of 6061T6, is it materially different to that of the 4343, meaning of course that yes, with some local thickening of your part, the stresses in operation would be less than the OEM part... but if your (6061T6) lower endurance (stress) level (a fatigue resistance parameter) is less than than that of 4343, it might still be problematic.

Now one caveat, here, and I note that my metallurgy classes at uni were about 40+ years ago... I almost seem to recall that aluminum, unlike steel, actually does not have a lower endurance (stress) level... so mebe my question is daft...

You're not wrong - aluminium has all kinds of technical issues with longevity, which is why they x-ray airframes and why steel body cars will outlast aluminium bodies. Aluminium has no endurance limit, not matter how over engineered the part is it will eventually fail, even from regular use. I suspect it is the reason why the OEM arms fail around the casting seam for the bushings. It is another reason why this is worth doing, it will make it possible to replace the arms going forward not just the ball joints. I did think about doing them out of steel, but honestly I'm not going to live 100 more years so it isn't a problem I have to deal with!

I've made some nice pictures.

At this point I'm waiting on the exact measurements of the ball joint so I can finalise a few details and order the arms. I've had both the upper and lower arm quoted for manufacturing and it should be around $300USD for the upper and $600USD for the lower. The ball joint should be about $150USD and then the bushings on top of it.

 

[MC2012]

At this point I'm waiting on the exact measurements of the ball joint so I can finalise a few details and order the arms. I've had both the upper and lower arm quoted for manufacturing and it should be around $300USD for the upper and $600USD for the lower. The ball joint should be about $150USD and then the bushings on top of it.

I'm pleasantly surprised by the relatively low cost of manufacturing these, and I can see your control arms indirectly affecting the general value of these cars in a positive way. I've heard of services entailing machining the old joints out and fitting the arms with new joints, but that's a scarce practice and has separate drawbacks. I think the control arms are the biggest caveat of these cars (far more so than the clutch), and so I'm sure the market will respond very well to this. I'm sure these arms will be a great selling point for any 4200 or GranSport, somewhat similar to how a new / hardly worn clutch is. Thanks for sharing your work and taking the extra step of having these manufactured for the rest of the community to enjoy.

 

[lambertius]

I'm pleasantly surprised by the relatively low cost of manufacturing these, and I can see your control arms indirectly affecting the general value of these cars in a positive way. I've heard of services entailing machining the old joints out and fitting the arms with new joints, but that's a scarce practice and has separate drawbacks. I think the control arms are the biggest caveat of these cars (far more so than the clutch), and so I'm sure the market will respond very well to this. I'm sure these arms will be a great selling point for any 4200 or GranSport, somewhat similar to how a new / hardly worn clutch is. Thanks for sharing your work and taking the extra step of having these manufactured for the rest of the community to enjoy.

I appreciate the support.

The final push to get this going was that I found out the upper arm is now NLA. If I don't do finish this project then there will be no user serviceable options.

I absolutely think this a bigger deal than the clutch. They're far more costly, NLA and unique to only our vehicles.

 

[MC2012]

I appreciate the support.

The final push to get this going was that I found out the upper arm is now NLA. If I don't do finish this project then there will be no user serviceable options.

I absolutely think this a bigger deal than the clutch. They're far more costly, NLA and unique to only our vehicles.

Yes, I agree it's a much bigger deal than the clutch. (AFAIK, the clutches and ancillary components are still widely available, correct?). It really is the time for a superior aftermarket solution. Hard to imagine a car like this being kept off the road, over ball joints.

Side note: someone may have already asked this, but I'm forgetting... what are the specifics on the availability of OEM components for the front upper & lower arms? I understand that one of the two has user-replaceable joints, while the other has the same drawback as the rears. And, regarding the set that are replaceable, I'm curious to know if the replacement joints themselves are scarce.

 

[lambertius]

The issues with the front arms is the same. I haven't done anything with them because they're:

a) Still available
b) I wasn't doing this for any commercial intent, I literally just needed some new arms for my car. People's interest in buying these is more of a positive feedback type thing.

A lot of people have asked me about the front arms as well - and if enough people buy the rear arms to justify the cost of registering a business and the liability and warranty insurance, then I'll look at doing the front arms as well.