Early Cadillac Driveability

[Guest littlegto64]

OK, I'll fess up. I bought the 1926 Touring intending to rod it. As I've indicated in a prior post, it had been converted to a tow truck probably around WWII. Now, after close examination and an inventory of everything with it, I'm having second thoughts. (It would probably run with fresh gas and a rebuilt carb.) I also have a good friend who is a Model A fanatic who is encouraging me to at least get it running and see if I like it before "ruining" it.

So, I would like to know a little bit about the driveability of these old Cadillacs. I'm leery about an 80 horsepower motor and mechanical brakes in a 4,500 pound car. This probably comes from having previously owned a stock 1929 Model A. While the car would do 50 - 55 mph, (65 downhill with a tailwind), stopping was an interesting proposition and required signficant advance planning.

I live in a small town 60 miles south of Tucson. Speed limit is 75 mph. Traffic flows 80 plus. To enjoy an older car, in my opinion, its pretty much necessary that the car be able to run highway speeds (at least 65 mph) along with being able to stop reasonably and hopefully not break down. So, can these old Cadillacs be made to run reliably with current traffic with the original drivetrain? What about with an overdrive, such as the Mitchell unit that is sold for the Model A's.

Thanks for the input

Chuck Kendall

[Ivan Saxton]

If you measure the total area of brake lining of 1923-27 Cadillacs, you will find it exceeds that of any other car, old or modern. You need to have the mecanical components in good order and properly adjusted, because mechanical brakes do not have the inherent equalisation of hydraulics. in practice this is not a problem.

The brake drums are steel, which is thin compared to cast iron, and it does not have such good braking characteristics. I have rebuilt a lot of brake drums using Metco coating Spraysteel LS. "LS" stands for "low shrink", and it is a work-hardening carbon steel with about 7% molybdenum content. The coating as sprayed has slight porosity, which is sealed with an air-hardening phenolic sealer, to prevent moisture getting in. The braking characteristics ar very close to cast iron. And you can use modern lining material. I rebuild drums for a 1926 Buick and an A Ford belonging to a brake service owner here in Warragul years ago; so I can get material definitions for you. He does long distance outback tours in these cars. If front drums are worn there is less material to absorb and radiate the heat; so they will expand and fade much more. That is another good reason to put material back.

Footbrake at the rear is external contracting, as you will have observed. When it rains you need to quickly expell water from between lining and drum, so it does not lubricate the brake. If you cut a series of diagonal grooves in the linings so the water is expelled towards the centre of the car, the wheels will not need cleaning as often. Some people with lesser cars with the same internal expanding handbrake/external contracting footbrake at the rear make a coupling of the two so the squeeze the drum similar to disc brake action.

Those Cadillac carburettors work well if you follow the instructions. You may need to make a new cork float and seal it with shellac or suitable modern material. One owner of a new sedan in Melbourne kept careful records which showed it averaged 16mpg over 65,000 miles. Sedans had 5 to 1 axle ratio.

The phaeton I owned had 4 1/2 to one axle ratio, and never needed first to start on the level. Overdrive would be nice if you really want to send it along. I used to move with the traffic when I had it, and Ken Moss would not let people pass him in the car while he was still around to drive it.

The engine has fork-and-blade conrods. Bob Craddock's phaeton has done over 500,000 miles. The bearings must be in good order, and you crack-test the conrods when the engine is apart, and use new top-grade bolts. If you fit aluminium pistons, fit an air cleaner; which will exercise your ingenuity. And make sure they do not eceed standard skit length, or the crankcase ventilation will not work as intended.

You will have much more satisfaction if you restore your car as it was. There are too few of them left. Phil Irving designed the champion Repco Brabham Formula 1 engines out of a Buick block.

One pearl of wisdom I heard from him in response to someone's question, was: "You can expend a lot of effort and money changing things; and you will eventually discover that the designer was right in the first place".

Ivan Saxton

[Guest littlegto64]

Any parts sources? I.E. Carb rebuild kits or engine kits?

[Ivan Saxton]

cause the carb is not diecast, the only age-sensitive parts are the cork float and the leather strip secured by a brass ring on which the airvalve seats. You may be able to resurrect the latter with repeated saturation with a good leather dressing. The air flap should seat nicely so you cannot see light through from a small bulb moved around the inside edge. I had a lot of trouble with this at the time because I pulled it out, thinking it would be easy to cut and fit a new one, but I did not have the material, resourcefulness, or manual dexterity I would use today. One Saturday morning as I was driving home from town the car suddenly took off with an impatience it never had before or since. The throttle was closed, yet it still wanted to bolt; and the only way I could control it was to keep switching the ignition on and off. My less than perfect leather seat had partly unravelled, otherwise I could see nothing else different. You will probably need to make a new cork float, starting with a cork block and a hole saw, and finishing with shellac or suitable modern sealer resistant to fuel.

Otherwise there are only two types of carburettor trouble. There is Dirt trouble, and there is Spanner trouble. The most likely point of wear due to abrasion is the needle valve and seat. Making new ones is pretty routine Lathe work, using brass stock for the seat, and monel for the needle. I doubt whether the orifice in the single jet would be significantly worn. It is a pretty big hole, and you adjust the mixture with the click-action screw which varies the tension on the little air-valve spring. Make new gaskets so you dont have leaks. The double bi-metallic strip thermostatic control unit under the cover on the side should not be a problem unless someone has interfered with it. You have all the information you need to check in the Radco data I put up for you. Just be very gentle and respectful of the little springs, The one on the air-valve, and the little rotational action one on the "automatic throttle" shaft.

There must be better authority than me on these cars, because I parted with the one I rebuilt and drove in 1966 as part trade for a Mercer. I have two good restoreable chassis which I wont tackle for a while, so I have not even started to make corebox and pattern for pistons for them yet. You should be able to get Egge or Jahns. You can probably get head gaskets off the shelf, where I would have to get these made to sample. I got photocopy of engine section of the workshop manual from GMHolden in 1961, so you should be able to access the same from Cadillac now. I let this go to Ken Moss with the car; and when someone had a worn complete manual for $40 thirty years ago I could not find the cash at the time. My chassis are what you blokes would probably classify as "parts cars", but what you can achieve is different.

All the best. I am happy to encourage and answer questions. I"ll try to get that contact for you over the weekend. Ivan Saxton