Lotus Elan

Front suspension arm gusset

PostPost by: gjz30075 » Thu Aug 18, 2011 10:49 pm

The picture shows the arm on the left, which is coming off my '72 Sprint, having a gusset wrapping around the bushing pivot. The arm on the right does not have this. I'm assuming this is a factory strengthening of sorts, as I know it was not done by me in the last 35 years and doubtful it was done by POs. So if factory, when was this change applied?

The part numbers on both arms are the same.

Learning something new every day!

Greg Z
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PostPost by: Famous Frank » Fri Aug 19, 2011 5:12 am

Greg,

Learning when this change over took place is an interesting question. But I'd like to know if the change was made because of a weekness in the arm itself? Do the earlier arms have history of failing? And if so, how? Has anyone had their arms fail? Did they fail during normal street driving? What does the failure look like? And where exactly on the arm was the failure?

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PostPost by: UAB807F » Fri Aug 19, 2011 6:03 am

I wonder if it was done to improve resistance to kerbing damage ? It's mentioned in the Robinshaw & Ross book on the Elan but I don't recall them giving a date of the upgrade. The ones on my 1968 car are reinforced and AFAIK are the original ones, so presumably some time in the mid 60s ?
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PostPost by: bilcoh » Fri Aug 19, 2011 6:21 am

The suspension bits on my 66 S2 (built in 65, actually) are not reinforced, so perhaps we've got it narrowed down to 66 or 67?

Interesting aside....I was lucky enough to be a 16-18 year old in Southern California, building a Europa and then the Elan I still have. This all happened at our family shop just miles from Dave Vegher's business while he was campaigning his Elan to 3 consecutive SCCA national championships. Somehow I connected with him, and wound up at some of the local races as crew support. You can probably see that influence resulting in how my car looks in my avatar photo.

Anyway, I clearly remember his front suspension members having that reinforcement wrapping, though I thought he'd done that mod himself as he'd also modified the outboard end to take a Heim joint and give him fully adjustable suspension. Don't know if that really adds to the conversation except to say that it met the ultimate racing challenge and held up.

Given that I'm currently dealing with a frame where the front suspension pins took a bending, ostensibly from some kerbing or other abuse, having really strong suspension members begs the question of what will give (and what do you want to give) if the car suffers some abuse. Suspension members are cheaper/easier to replace than a frame. However, I think this mod is really designed more to eliminate stress cracking than bending as the result of an impact. Anyone agree or disagree with that?

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PostPost by: cliveyboy » Sun Aug 21, 2011 8:54 am

Dave
You are right about strengthening up the weld.
The original design is quite a good example of the type of welded joint you should try to avoid if the component will see lots of force.
As for making the suspension arm too stiff. The extra plate does not extend down the arm far enough to make a massive difference.
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PostPost by: rgh0 » Mon Aug 22, 2011 11:08 am

Agree the change occured around 1967 sometime. I have not seen enough orginal cars to know if it was required but clearly Lotus thought it was required as it added cost and Lotus never added cost without a very strong reason

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PostPost by: Gray » Tue Aug 23, 2011 12:47 pm

Hi

The suspension arms usually crack around the outer end damper and trunnion holes. Possibly more so on the +2 with longer arms in my experience. The outer holes can also get elongated. Dealers used to do a good turnover on wishbones in the seventies. I've changed quite a few over the years. My current Elan has Spyder wishbones, which appear much better made. Plus with a Spyder chassis there is the advantage of replaceable fornt pivot pins.

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PostPost by: Elan45 » Tue Aug 23, 2011 12:52 pm

My S3 Super Safety does not have the reinforcement. That was made pretty late in 1967.

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PostPost by: saildrive2001 » Thu Aug 25, 2011 1:29 am

My 69 S4 doesn't have the reinforcements.
Got to cut the reply short major thunderstorm happening.
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