Lotus Elan

Chassis / subframe question

PostPost by: Andy8421 » Tue Sep 18, 2018 8:08 am

Its that time of year again, when I plan to start restoring the Sprint DHC in bought in 1984 in time for next summer.

This has been an annual event, each year I collect a few more parts, convincing myself I will spend the winter nights fiddling with old bits of Lotus. It has begun to occur to me I need to get moving on this, or I won't be around to enjoy the fruits of my labour.

The only major part I still need to figure out is the chassis.

The Sprint had a galvanised Lotus replacement chassis complete with LR number when I bought it, but it is a bit banged up. The vacuum tank shows the scars of careless jacking, the rear wishbone mounts are all bent - again from careless jacking, and I suspect the car has been crashed and has a new front (though that may have been the cause of the chassis replacement in the first place). An enthusiastic PO had the engine worked on, head modified and a big bore tubular exhaust of unknown parentage fitted and as a result chopped a lump out of the chassis to clear the manifold. Rather than start with a chassis of unknown provenance, it seemed best to start with a new chassis.

My questions are:

1. Do you agree I should replace the chassis?
2. If so, do I get a TTR 26R strengthened chassis, or stick with the standard chassis?

As they say in the best magazines, I intend to use the car for 'fast road use'.

Thank you for any advice.
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PostPost by: nmauduit » Tue Sep 18, 2018 9:42 am

Do you have photos of the damaged areas or dings (does the cross member hold vacuum), and did you get a chance to measure the LR chassis for straightness? if reasonably within specs and with only minor damages (fixable if need be) it can be reused - esp. if without corrosion...

Then depending on your acception of fast road : if that only stretches to occasionnal track day with no intent of winning actual races on super stiff suspensions and slick tires, then I would keep the standard chassis. You can even add a few reinforcements relatively easily (e.g. gussets on turrets, diff opening, engine and roll bar mount holes...) just in case you may change your mind and decide to push it more.
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PostPost by: ecamiel » Tue Sep 18, 2018 12:32 pm

It's definitely worth reinforcing or replacing the rear suspension pickups, as you can see. Also reinforce the motor mounts, rear torque rod pickups and the chassis "Y" over the tranny. Gusseting the turrets helps but also consider adding a removable member joining and triangulating the turrets.
Now would be a good time to add tow hooks front and rear - useful for a street car !

Finally, set up the chassis and TRUE IT UP. Having a true chassis (yes, even new ones can be way off) will make sorting the finished car much easier.

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PostPost by: alan.barker » Tue Sep 18, 2018 1:24 pm

I would first check and adjust carefully the Chassis into spec.
If the Cross Member has no leak leave as is and in the future use something between Jack and Cross Member when lifting (do pressure test).
Don't paint over the Galvanising it's pointless and will only peel off or trap water :shock: .
After, it depends if you want to use it on the road as Chapman intended with good roadholding and comfortable Suspension :? .
One thing is sure you will get a lot of different ideas. The most important is to enjoy your Lotus.

Some like me say Chapman got it spot on but others like to do their personal mods :shock:
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PostPost by: USA64 » Tue Sep 18, 2018 1:54 pm

The less you do the sooner you'll be driving it!
We are supposed to be having fun, are we not?
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PostPost by: Davidb » Tue Sep 18, 2018 3:45 pm

The so-called "26R mods" finish the chassis the way it should have been done in the first place. If money is not a concern get a new chassis-welding the old galvanized chassis is going to be time consuming-the galvanizing has to be removed for welding.
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PostPost by: alan.barker » Tue Sep 18, 2018 4:02 pm

Imho,
Galvanising is easily by far the best protection for a Chassis. If any Welding is needed you only need to remove in a very small area when using TIG or MIG.
If a Chassis is Powder Epoxy coated it looks nice when new BUT when the Chassis flexes it will crack the Powder Coating and water will go under with the capillary action and rust the Chassis quicker than not painted because it will stay wet.
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PostPost by: Frogelan » Wed Sep 19, 2018 5:30 am

I have the original chassis carefully preserved in my garage and I have opted for NOS 26R LR version for a number of reasons (although when I'm rich enough I plan to race). The LR and "TTR" chassis both come from the same place (Gartrac in Sussex).

Firstly, when you make the comparison, the standard chassis is missing a huge amount of very logical improvements. Even if I was not planning to race I would opt for it.

Secondly, the build quality is better IMHO.

Thirdly, although I have not checked my original factory chassis, the 26R version is surprisingly straight (or at least mine is).

I am carrying out my build in shared space and was able to compare my NOS LR chassis with the latest TTR offering, as mentioned from the same manufacturer. I was intrigued to note that I could easily pick up my NOS 26R LR chassis on my own...but had much more difficulty picking up the latest version, which has roughly 20% thicker gauge steel. At a guess it was 5kg heavier.

I suspect that TTR / Gartrac have probably opted for more strength in the last few years. The only other difference was strengthening around the resilient mountings for the diff. I am getting this detail amended on mine.

I hope this anorak information helps!
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PostPost by: alan.barker » Wed Sep 19, 2018 5:49 am

It seems strange that the replacement Chassis made by the same supplier as original "Gartrac" and i imagine the same methods and Jigs can be more acurate :?
I'm not so sure that Chapman would want to add 5 kgs :shock: :shock:
Like i said in my post many ideas and personal choices even on the colour of your Anorak :lol: :lol:
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PostPost by: Frogelan » Wed Sep 19, 2018 5:54 am

Alan

I was not able to weigh them...the LR chassis were apparently not made by the factory but by Gartrac.
[Gartrac do not advertise this on their website]. I'm just recounting the anecdotal "strewth mate" measurement which came from moving them about !
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PostPost by: alan.barker » Wed Sep 19, 2018 6:24 am

Yes,
i've always understood that most chassis were and still are made by Gartrac.
Sometimes things changed like with the Early Bourne Bodies. Or different suppliers for Cylinder Heads etc.
After all it was down to costs and making money to support the "F1 Team"
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PostPost by: Andy8421 » Sat Sep 22, 2018 5:09 am

Thank you everyone for your replies.

On balance, I think I will go with a new chassis - I plan a nut and bolt restoration and I would like to end up with as 'new' a car at the end of it as I can.

I am still unsure about which chassis to buy. if I had a choice, I think that I would opt for a standard chassis with a few of the modifications recommended to improve some of the weak spots, but not the full gusseted 26R solution.

I will speak with TTR and see if that is a option they offer.

I live a few miles from Gartrac who are just outside Chiddingfold in West Sussex. I am not sure they produced the chassis for Lotus when the Elan was in production, but I do believe they produce all the replacement chassis.
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PostPost by: Frogelan » Sat Sep 22, 2018 7:26 am

Andy, I own both chassis...a S2 26R and an original S2.

From what I can see there are quite a few justifications in favour of the 26R version as:

- it is stronger and probably safer
- none of the modifications change the basic fit of the body or change the suspension geometry
- there are no major visual changes or at least, you would need to be an "anorak" to spot them

Andrew

NB: I have no affiliation with Gartrac.
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PostPost by: alan.barker » Sat Sep 22, 2018 7:41 am

Andy,
if i was you i would phone Gartrac and see if you can take your galvanised Chassis to them to check it.
It's not too heavy to put on a Roof Rack.
You are very lucky to live near them to try this option :wink:
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PostPost by: William2 » Sat Sep 22, 2018 8:43 am

Try phoning Miles Wilkins who holds the manufacturing rights to the chassis as I understand it. As far as I know he is still trading on a parts only basis.
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