I have not had a good look at this yet but it would appear that the front chassis upright box section is open at the top and closed at the bottom i.e. no drain holes?
The chassis is an old but unused Lotus type and therefore would it not be sensible to provide a drain hole so that all the moisture/crud could drain away?
Any comments concerning reduced strength and or size of holes that could be drilled would be very helpful…
There should be a small approx 1/4 inch hole at the lowest point. These generally become plugged up with paint/undercoating/debris/flotsam/jetsam etc. Probe about and you should find them.
I would have a good look for the original holes before drilling. Last time I cleaned mine it took a bit of scraping and poking to locate them (amazing in such a small area). Mine are less a “hole” and more like some of the steel has been “relieved” prior to welding - on and above the seam of the weld with the horizontal frame member.
rgds,
Or you could do what I have done and fill the uprights with expanding foam (available from any D-I-Y store) after suitable preparation,stops them filling up with crud etc…
John I used the expanding foam method for a landscape job where we used 2" dia bamboo canes used as vertical posts, we then had to fill the void back to the nearest knot to avoid them acting as water buckets.
A year later we found the foam had been acting as a sponge so removed them and replaced with a filler, I think from this experience I would be concerned they would hold moisture or have you not found this?
One is to clean out the entire upright, fill it with a primer to coat the inside (though catch it all as it comes out of the drain hole!), then fill it with something like Waxoyl to give outer protection, then seal the drain hole and fit a closing plate to the top of the turret.
Or more simply, drill out the drain hole to make it larger. Most I have seen have been in the shape of a half moon, so that those larger pieces of crud that would otherwise tend to block the hole can be forced out.
I think I’m moving toward extending the size of the hole, then at least it is a maintenance job one has some control over - i’m imagining it is similar to the drain hole of the rear spring housing which from experience only needs a flint to block the hole before the dirt and crud start to block the hole.
Probably a well directed blast from an air gun will then do the job…
I cleaned mine out using a hoover (90% of the crud seemed to be sand so I am guessing that the previous owner live either near the sea or has sandy loam as a top soil and lives down a dirt track!)
then plastered the inside with waxoil underseal. best done using you hand (in a rubber glove).
This “should” protect it for a fair while!!
Tim
Regarding expanding foam, I’m pretty sure that I heard that it comes in closed cell and open cell varieties. If this is the case, a closed call type would be the only one to use. Otherwise, it’s the sponge event.
I’d be really reluctant to do anything like welding to the top of the upright or using expanding foam.
The key to preventing rust is ventilation. Enclosed box sections are bad news as they encourage condensation, that’s why modern cars avoid them and even go to the trouble of ducting air into doors and other cavities. It’s the same reason you shouldn’t use car covers in damp environments or put a wet car in a garage, it just traps moisture. Of course, the inside of the uprights need to be kept scrupulously clean and the drain holes must be clear, so hoovers are a good idea and I even ues a hose pipe to flush them out if it’s a nice day. As regards waxoil, only use it sparingly and allow any excess to drain. If it gets too thick, it will set and then trap moisture behind it (no matter what it says on the tin).
The Spyder stressed-skin chassis in my car has the uprights welded as a closed box structure. I’ve always understood that this and a few other strengthening changes from the original Lotus design is what made the Spyder chassis so much better.
And, of course, forced Lotus to stop Spyder making that chassis.
Thank’s to all for their posts and the variety of methods.
I’ve now got the chassis onto a twirler and have enlarged the drain holes by roughly 50% using an air powered dremel with some very effective small ‘bits’ that I use for grinding down welds.
I’ve shot blast the inside and will apply a couple of coats POR 15, have made a card board template from which to form a simple metal cover which I will attach by a couple of quarter inch bolts (through to a nut welded on outside of the opposing solid side) and spacers welded to the cover so the inside can be accessed at will.
The cover will not be air tight as will sit proud on the edge of the weld, the POR 15 should provide a strong enough protective finish to stop any rusting where the cover and weld adjoin.
When I fitted a new chassis to my 1968 S3 in about 1978, I bought a Lotus replacement. I couldn’t afford the galvanised one so opted for a primer finish. The previous chassis had succumbed when a front tower collapsed due to rust. The whole arrangement of the tower, the open top, the drain holes etc, just struck me as ridiculous and a very flawed piece of design: a ticking time bomb as you know it’ll rust through one day, and until it does you’ll worry about it.
Consequently I closed up the towers on the new chassis by Sifbronzing closing plates over the apertures and closed up the drain holes with more Sifbronze. Sifbronze (Nickel Bronze welding) is brilliant for this kind of thing. I painted the chassis with Hammerite. I removed the chassis last year and treated myself to a Spyder chassis. The original (modified)chassis front end was perfect after 30 years. I just could never see the benefits of having those towers open to the weather.
Tony Taunton
Before people start talking about flawed design I think it’s necessary to ask what criteria were applied at the design stage. Do people really expect that a car chassis designed by a commercial motor manufacturer should have been designed to last forever?
My understanding was, the Elan was actually intended to last about 10 years or 100,000 miles. If thats the case, my car which is still on it’s originally chassis after 35 years, really demonstrates the chassis is about 3 times over engineered
Of course, it’s now common place for comsumer products, including cars, to be designed for a finite service life, but back in the sixties this idea would have been fairly uncommon. The people who would have understood the principle very well, however, would have been those, like Lotus, who applied racing car/Formular 1 principles to their road cars (Out of interest, I wonder how well built contemporary Ferrari’s were as far as longevity was concerned).
For me, the beauty of Lotus is that you have a car that’s based on contemporary Formular 1 racing technology. If you really want somthing that good and tough, and will survive with minimun maintainance, get a Austin Healy 3000. That’s based on lorry technology.
Are you suggesting that the Chassis designers deliberately left the towers open so that they would rust…so that rust would kill the lightweight chassis design before it sucommed to fatigue failure?
If so, how did they expect the corrosion rate to be controlled (too many variables including type of mud/dirt, days dry/wet, salinity.