Elan S2 Chassis - "Now that's not right, is it?"

[bilcoh]

Hi all:

Last weekend, I pulled the frame from under my 66 Elan S2, since I'd basically removed everything over the previous years and I figured it'd be much easier to build up the chassis/running gear and drop the body on later. Ran it off to the blaster and now it's bright and clean. And then I noticed something .....

Note lower rear pickup mount.

Same but worse on this one.

This car has been in my family since 1974, and we've never had any shunts, but there were 8 years with DPO's, so maybe?

Three questions:

1. All the upper pickups are in line with each other, basically perpendicular to the front cross-member. If it safe to assume that the these seemingly bent pickups should be in line with the others?
2. What's the preferred method for straightening, assuming we're on a frame table with critical points locked down? Heat? Pressure from a large lever of sorts? Other?
2. At some point on this site, I found very readable scanned images of a frame diagram with all needed dimensions. I thought "Wow, how great for anyone who needs it." Little did I know that would be me. Anyone able to provide or point me back to it? I'm striking out.

Thanks for the help. BTW, next step is to add strengthening mods to frame, and straighten as needed, then paint before starting rebuild. Actually, another question. Metal for the frame mods.....is steel just steel, as long as it's the right gauge, or is there a particular alloy or type I should be sourcing? And though I expect a welder (don't have one yet) to know what system to use, what do we like? Mig, Tig, other? I'm embarrassingly ignorant on this topic. Help me not let the welder find out.


Cheers,

[Elanintheforest]

Hi Dave
Have you studied the workshop manual, chassis section?

Not good news. It says.....

'Even when no damage is apparent to the mounting pins, if the wishbones have been damaged, it is strongly advised that a new chassis is fitted. Should the mounting pins be damaged or bent (however slightly) A NEW CHASSIS MUST BE FITTED.'

It looks like your car has hit a kerb heavily, maybe a few times. It seems that the chassis can suffer from micro cracks after such an event, which could lead to suspension failure.

The chassis really is designed to be a 'disposable' item after even a small accident. I know this only too well having replaced a chassis, and the next week hitting a kerb at little more than parking speed. I bent the pins, and the chassis was condemned at the Lotus shop....another was fitted the following weekend.

Sorry for the bad news, but it's your neck on the line here!

Mark

[ardee_selby]

Have you studied the workshop manual, chassis section?

Not good news. It says.....

'Even when no damage is apparent to the mounting pins, if the wishbones have been damaged, it is strongly advised that a new chassis is fitted. Should the mounting pins be damaged or bent (however slightly) A NEW CHASSIS MUST BE FITTED.'

Mark,

The above quote appears in section A3 of my edition of the manual, but what do you make of section A5 "Additional Information" (where the use of a Cookes hole cutter is described)?

"However slightly" has been toned down a bit to "PROVIDED that no excessive damage" etc

Cheers - Richard

[bilcoh]

I shall conclude, from your responses, that the rear lower pickups should *indeed* be in line with the front pickups, and that they are truly bent.

Regarding strength and trustworthiness of the frame, here's the thing....

Having driven the car aggressively for 12 years (both Dad and I before it went into the proverbial mothballs), and knowing it never contacted anything, it's hard to imagine that the frame suddenly poses a tremendous safety risk now that I've discovered this. I'm presuming that perhaps this fault has existed for quite some time.

Now, it certainly begs the question that we might have lived with the horrible handling that surely resulted, and been lunkheads for not realizing it. But in the wisdom of this group, is there really no reasonable way to straighten such an item on the frame, and do so with some degree of confidence?

Thanks in advance for any suggestions,

[europatek]

I'm of the opinion that this can be successfully repaired buy one of two
Methods;
1. Straighten the pins cold ie; no heat. Wind a nut over the thread
And use a hammer or lever. Check and watch as you go.
2. Carefully grind off the welds and remove the pin. Replace with
A new pin made to the same dims. MIG in place.
If you are worried about cracks buy a crack test kit with powder
And dye to check relevant areas of the frame. If you find any prepare
And weldup the crack. Dress smooth afterwards.
For your frame mods mild steel of the same gauge should
Be fine. Either MIG or TIG should be fine.

[Yum-yum]

It's hard to see how the arms could even swing with the misalignment apparent in the lower picture. I would think this should be repairable confidently with welding. Are the original pins one piece per side? If not, then replacing with such would at least ensure concentricity from front to back.

[UAB807F]

Although the Lotus manual does say "scrap", I think I'd be tempted to have a go repairing it first. After all, you have been driving it for years in that state so I doubt you'll make matters worse by straightening it. I'd also check the arms to see if they've deformed to accommodate the bent pin because if not I can't see how you could bolt up the front trunnions without noticing something.

I'd probably try to warm the pin before bending so as to bend the pin and not surrounding chassis, assuming it looks like only the pin has moved. But remember the front chassis section is normally used for the vac. reserve tank and might well have petrol fumes condensed in there.

However you repair it I would certainly take the suggestion about testing afterwards, dye penetrant kits are easy to use and good enough to show cracks. In fact if you don't clean the area well enough before testing, you'll probably scare yourself to death !

Brian

[elanman999]

Dave ,
If you look in the +2 manual Section A page 9 "Additional Information" it does tell you how to replace a "fulcrum Pin" as Lotus call it.
A new pin is PN 026 A 0218 and the cup washer is 026 A 0219.
It says the fulcrum pin is EN16T steel so I would not straighten a bent one.
Cheers
John

[gherlt]

I would also suggest that in 40 years some progress in repair and welding techniques have been achieved, a welding specialist can do miracles ...

[robertverhey]

Would it be sacrilige to suggest getting a piece of pipe that fits snugly over the pin and just bend it back? No heat, just apply force in the opposite direction to the force that bent it. Just steel, after all, has a certain amount of flexibility

[Elanintheforest]

Well guys, you can certainly straighten it all out so that it looks good, but if the metal around the pin is now fatigued, how will you know that it can perform as well as it should under harsh conditions, in an accident or even hitting a pothole?

Lotus had a reputation for building the cars near the edge of tolerance when they were new, to make everything do two or three jobs and to be as light as possible. If they said to replace it, I for one wouldn?t argue, and indeed didn?t argue when my 1 week old chassis sustained the same sort of damage.

Spyder used to provide a service where they would cut the front off the chassis and replace it with a new one, for just such an eventuality, and of course to fix the rusty front turrets / cross-member. It may be worth investigating if anybody in the US does this, although again, I doubt that it has much financial advantage over buying a new chassis.

At this stage with the car stripped right down, it seems crazy to me to even consider mending something like that when a new chassis is, relatively speaking, so cheap.

[StressCraxx]

Hello Dave,

I am pretty sure that can be fixed and the area reinforced to prevent fatigue. In addition there are the 26R chassis mods that can be done to your chassis by a competent race shop fabricator. They usually understand what you are trying to do and they take a lot of pride in producing good work. I believe there a a couple of vintage race restoration shops. (J&L in Puyallup comes to mind)

Regards,
Dan Wise

[bill308]

I'm not sure fatigue of this member is a big issue for a road car. A quick look shows EN16 has a good resistance to shock with excellent ductility. The deformation shown is not likely from fatigue but rather impact. Straightening may in fact work harden the stud where it was subject to yield. Fatigue is caused by cyclic loading, lots of it. If the cyclic loading remains low enough (steet tires-non competition use), I would consider bending them straight cold and then crack checking (magnaflux). If there are no cracks, you should be good to go. There will be residual stresses, but a single bend should be tolerable. Absent stress relieving by someone who knows what they are doing and a method to do so, I would not heat this member. Heating enough to soften the steel would likely affect the metallurgy in an adverse manner.

Bill

[bilcoh]

Thanks to all for the replies thus far. For those urging caution and frame replacement, I'm afraid there isn't $3,000 in the budget to deliver a new frame to me here in Seattle. Thus, I greatly appreciate information that might suggest possible repair. I've got reasonably priced access to fabrication and welding, so it would take a while to justify a new frame if this one can be fixed.

Looking more closely at the offending items, I'm wondering just how the lower front pickups are fabricated and mounted? John (elanman999), you noted the part numbers for the pin and cup washer. Anyone have anything showing how these parts are welded up to the crossmember?

Thanks,

Dave

[elanman999]

Dave,
As Richard and I have indicated the instructions for this repair are in the later versions (1974) of the workshop manual. What to do is very clear in these instructions. I doubt that you will be able to buy the parts now but the look easy to make. It even tells you what material to make them from.
I'd even make them for you but the postage would be more than the parts.

I don't have time at the moment but this evening I'll scan the couple of pages in and post them, that's unless anyone else has done it before me.
Cheers
John