Lotus Elan

Plan of attack, chassis issues

PostPost by: TomMull » Wed Nov 28, 2018 2:34 pm

I had hoped to be able to get the Plus 2 on the road as a driver, since it is intact and complete and not too badly worn, fitting with my other LBC drivers. However, on a little closer inspection I found the front wheel camber out of spec to say the least. Some of you I'm sure will know the reason already, cracks in the bottom of the spring towers.
There seems to be little evidence of rust and when tapping on the cracks with a hammer and punch everything seems solid. However, they most certainly have failed. The cracks were previously and very poorly welded. I have not noticed any other obvious chassis defects but of course not all will be obvious. Perhaps someone could suggest other problem areas.

I have read with interest several very interesting topics on chassis replacement and repairs along with the warnings about repairing the chassis.
Here is the issue, I think I have the tools and skill to make a reasonable and at least semi permanent repair once the body is off, but that part is what I'd like to avoid. If I do have to take the body off, (I've done body offs on other makes) then it would seem unproductive to put it back on an old repaired chassis although I suppose it could be done and probably has been. I would also like to avoid the "since it's all apart might as well do this and that and everything else" scenario.
So my questions: Anybody done body on chassis repairs? Any chassis available in the US? Finally, anyone else in the North East US looking for a chassis who might want to combine shipping expense from the UK, if that is feasible? (I won't be starting my repair or replacement until April 2019.)
All thoughts and advice appreciated.
Tom
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PostPost by: Mick6186 » Wed Nov 28, 2018 3:34 pm

Access to the chassis front towers with all the suspension removed is good and a competent welder could make a good permanent repair to the outside. The problems are :
1. Is the inner wall of the vacuum tank rotten. If so it would be a difficult repair, seemingly not possible without removing a large area of the tower to gain access.
2. Ensuring the chassis dimensions are correct before welding with the body on will be difficult.
Other areas to check are the engine and rear suspension mounts for cracks and the bottom of the backbone for rust,
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PostPost by: TomMull » Wed Nov 28, 2018 10:09 pm

Thanks Mick for the reply, and not quite as negative as I expected.
I'm not sure what you mean by the "inner wall" of the vacuum box section. All seems solid from what I can see on the outside.
Another challenge will be to remove the extra gussets and welds from the side that was repaired. Again, much easier and safer with the body off.
Cheers,
Tom
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PostPost by: pharriso » Wed Nov 28, 2018 10:31 pm

TomMull wrote:I'm not sure what you mean by the "inner wall" of the vacuum box section. All seems solid from what I can see on the outside.


I believe that he is referring to the 2 ends of the vacuum tank approx 45 degrees from the horizontal & vertical, in this picture of Gary Anderson's Sows Ear chassis you can see how they also rot away:

vacuumtankendplate.jpg and
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PostPost by: TomMull » Wed Nov 28, 2018 10:45 pm

Yes, thanks Phil, or the end caps for the tank which appear to be just inside the bigger holes on the outside in your picture. I'd need to cut a hole to see mine.

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PostPost by: mbell » Thu Nov 29, 2018 1:47 am

You could probably make some kind of a template(s) out of a sheet of plywood(s) to locate the right location for the suspension pick ups and therefor the towers. Thinking some kind of u shape positioned under the car and up into the wheel arches against the towers.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: TomMull » Thu Nov 29, 2018 1:31 pm

Yes thanks. I do have an old but stout trailer that doubles as a very crude chassis rack. I can clamp, bolt and weld to it and perhaps make a fixture for the Lotus chassis project.
Have you the original chassis in your Lotus?
Tom
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PostPost by: Gray » Thu Nov 29, 2018 6:07 pm

You need to be careful welding near the vacuum tank, there could be petrol vapour - which goes bang when ignited!
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PostPost by: TomMull » Thu Nov 29, 2018 6:24 pm

Gray wrote:You need to be careful welding near the vacuum tank, there could be petrol vapour - which goes bang when ignited!

Thanks, will purge with air and fill with shielding gas.I will also check the tank for leaks. Of course I have not ruled out a new chassis and have requested shipping estimates. In the mean time I'm still crawling around underneath.
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PostPost by: mbell » Thu Nov 29, 2018 7:22 pm

TomMull wrote:Yes thanks. I do have an old but stout trailer that doubles as a very crude chassis rack. I can clamp, bolt and weld to it and perhaps make a fixture for the Lotus chassis project.


To be more specific (now I am not reply from my phone) I was think more of transfer the chassis measurements from the chassis drawings so the pickup point where in exactly the right locations on the the board and then shaping it so it could be placed up against or fasten to the chassis with body in place. This would allow you to get the towers in the exact correct positions for the repair.

I can see with your trailer (aka crude chassis rack) you could easily fix the tower back in their current positions but might be harder to get them into the correct positions.

TomMull wrote:Have you the original chassis in your Lotus?


Yes, somehow the original survived ~20 years in the UK but it does have repaired towers, engine mount brackets and some other issues. I've actually a NOS Sypder space frame on the garage wall waiting for my life to get to the point I can fit it (or the car to force my hand into it...). Then I plan to restore fix/restore the original to be refitted again at some point.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: gus » Sat Dec 01, 2018 4:38 pm

You cannot repair the chassis in any permanent fashion, with any expectation of longevity from the outside

period

your camber is out of spec, that means the towers have drifted in to a point that, well, you do not know.

The closing plates at the bottom of the towers ARE perforated, that is why the towers have moved

Take a cardboard box all taped up. pretty rigid right?

Cut the bottom of it out, how does it feel now?

IF you were in New Mexico, and your chassis failed as described, and you needed to get home to New York, yeah, a hydraulic jack and a MIG welder will get you home

The chassis needs to come out

IF you wanted to fix it, the towers need to come off and new closing plates welded in and new towers fabricated

I have done it, it got me a decade and 50k miles or so, which is probably more than the factory chassis got before a spiral of bad repairs.

Then I bought a new chassis

You can repair the front, properly, but how do your lower diff mounts look? And your rear towers?

Unless this is Jim Clark's car or somesuch, there is precisely zero advantage to having an original chassis over a new one.


I am sure this is more the answer you expected, and it is the truth

If you want to do this job over and over, and wonder why your car doesn't drive properly, try to fix it in the car.
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PostPost by: TomMull » Sat Dec 01, 2018 6:39 pm

Certainly not as encouraging as some of the earlier replies but thanks anyway, Gus. Still gathering advice and information at this point. A new chassis has always been an option.
Cheers,
Tom
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PostPost by: Bigbaldybloke » Sat Dec 01, 2018 9:05 pm

Years ago my Plus 2 chassis was heading that way, at that time Spyder offered a reconditioned and improved sheet steel chassis, basically the front crossmember and uprights were completely replaced using a round tubular section for the vacuum tank and the uprights closed at the top to prevent ingress of water and muck causing the same problem again. Also two lengths of 1? square tube were welded in the full length of the chassis underneath front to back which strengthened and reinforced the lower diff mountings. They also fitted mounting points for their rear suspension system and made the front wishbone pivot spindles replaceable. A few other minor mods were included, a removable cross member under the engine and some additional strengthening at the rear. I don?t think they do this now but gives you an idea of what can be done.
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PostPost by: TomMull » Sat Dec 01, 2018 10:42 pm

Looks like there was an earlier topic describing a similar chassis.
http://www.lotuselan.net/forums/elan-mods-f31/modified-early-spyder-chassis-t24494-15.html
Spyder seems to be going with their "Space Frame" chassis now with pretty good reviews.

Edit: OOPS, It looks like the carry the improved standard chassis too.
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PostPost by: gus » Sun Dec 02, 2018 1:03 pm

They have been making the space frame since the 80's

Oh, and you are going to need sills too

Mine came out in handfuls
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