So...
I want to drive my 1950 88 around the world in various historic car endurance rallies. They are regularity trials rather than races (with some exceptions!), a couple of the legs, particularly the long drive along the Old Silk Road from Beijing toEurope, are on pretty rough terrain where the car will be spending day in day out for days or weeks at a time on rough roads/tracks and as one commentator put it “Toughness is vital, speed is useful”. Among the mods recommended for the endurance types of rallies which are the primary focus is strengthening the chassis, and I’m working through a choice on this issue.

Also, after mid 2019 when (hopefully) the car will complete its world lap in Paris I have vague thoughts of using it in more traditional historic performance events such as the Goodwood Revival,Pikes Peak, possibly Bonneville – those sort of fun things – where speed is a bit more than useful and a reasonable performance chassis would be very helpful. The engine Tony Lombardi is building for me will also be significantly more powerful than the stock unit (say >300bhp and 400ftlb)and I’m keen to not only make the frame tougher but to reduce flex in hardtarmac driving.

The most obvious solution is to strengthen the existing frame by boxing it, adding gussets etc, but figuring out where to add metal is going to be a bit of a guess and I’m nervous of my ability to work out whether or not those things and increased section sway bars etc are going to simply shift and possibly concentrate the forces and stresses leading to increased rather than reduced vulnerability to stress cracking.

In my research I discovered that the main frame C-section rails for the ’50 convertible 88 were made of stronger steel than for the full bodied cars and the convertible’s X-member was significantlystronger being made up of I-beams rather than C-section. The Olds engineers who had to work out the best way of improving the frame to compensate for the convertible body knew their business way better than I ever could so itoccurred to me that I might be better off starting with a swapped-inconvertible frame rather than the sedan frame.

It looks like I may have a very kind offer to source a convertible frame but before committing to that approach I’d like to try and be as sure as possible that it makes sense in practice as well as on paper, so I'm looking for the benefit of people's colective wisdom on a few questions around the idea.

· As far as anyone knows, would the convertible frame be identical in dimensions other than the strength things I mentioned so that itwould be a genuine and simple ‘bolt in’ replacement without having to work outthings like new mounting points, different steering geometry etc etc? Basically is it an easy or hard swap do you think?

· Does anyone have any idea of the weights of the two types of frame? – somewhere there is a point where the weight/strength tradeoff doesn’t make sense. Depending on exactly which source I look at it seems the convertible was about 250 to 300lbs heavier than my Club Coupe Delux but how much of that is frame and how much other stiffening (or not!) I have no idea. Any thoughts anyone?

· I'm interested in any thoughts as to the real benefitof the proposed swap? The two issues I’m thinking about are toughness/integrity and flex. I’ve seen commentary on the web to the effect that the standard '50 88 frame is pretty flexy and that isn’t great when pushing the car from time to time. I would think that the convertible frame would be likely to improve that aspect reasonably effectively. The toughness aspect is more difficult for me to get my head around; the car will be being bounced around for weeks on end and frame cracking issues seem to be far from uncommon on the Peking to Paris. The 88 will probably weigh north of 4500lbs fully laden with people, fuel and spares and the stock engine I understand is around700lbs (though Tony’s engine will be lighter) bouncing around on the mounts and frame. I have been told that there is a weakness in the ’50 88 frame just in front of the cowl and obviously the suspension and steering pickup points are going to be taking a fair hammering. I don't see boxing it adding as much weight (basically the weight of two new strips of steel the length of the frame plus whatever is added to the X-member) and I wonder if a boxed closed body frame would be even stronger than the convertible frame.

· Fully boxing does create a consequential issue with finding well protected routes for the fuel & brake lines unless I try step-boxing which adds work and possible quality issues.

Thanks anyone for your thoughts - or to put it another way "HELP"

Cheers

Erik

 

Erik,

The custom frame designers are an option as well. You could send your convertible frame for them to pick up the mounting and interference points. They design frames with software that the 1950's engineers would have loved.

I have a friend with a 1956 Pontiac Safari wagon who had a custom frame made by Morrison. The result was a car that felt much more stable --it didn't dance over the bumps. That's probably what you are looking for.

There are a number of other custom frame designers...

• Schwartz
• Auto Weld
• Chris Alston
• Progressive
• Roadster Shop

Cal them and discuss your project to see if this fits your objectives.