1936 Bugatti 57S

[George K]

I believe you are confusing ownership and engineering. Duesenberg’s sold to Cord 1926. Cord engaged the Duesenberg’s to use their racing/ engineering to produce through Lycoming the J engine. Attached is an excerpt from Duerksen’s “ Great American Classics”

[Rusty_OToole]

What is wrong with Duesenberg con rods?

[JV Puleo]

Made of Lynite, the earliest aluminum developed for purposes like that. I believe Franklin also used them but it was over stressed in the Model J engine. I have also heard that it didn't age well - on that I have no opinion as to whether its oft repeated "lore" or has been scientifically assessed.

[edinmass]

24 minutes ago, JV Puleo said:

Made of Lynite, the earliest aluminum developed for purposes like that. I believe Franklin also used them but it was over stressed in the Model J engine. I have also heard that it didn't age well - on that I have no opinion as to whether its oft repeated "lore" or has been scientifically assessed.

 

Our recent barn find had the original rods it it. You can see them crack before they fail. The pistons in our car were original also. The material failed after we started it for the first time in 50 years. The invar strut came lose from the casting and the skirt cracked. So, yes.......you replace all original Duesenberg J pistons and rods ASAP. 

[JV Puleo]

Right after WWI, Alcoa hired Laurence Pomeroy to come to the US and work on Aluminum alloys for use in automobiles. Pomeroy was a big exponent of reducing reciprocating weight in engines and wrote several papers at the time that were published by the SAE. Lynite was an Alcoa alloy and was used for both rods and pistons.

 

And, if you are wondering how I know about this, I spent quite a bit of time researching the proper alloy for the aluminum connecting rods I'm planning to make. Of course, Lynite is no longer available but I was able to compare its strength specifications to more modern alloys...the alloy I've chosen, 7075, is about twice as strong as Lynite while the stresses in my engine may be less than a Franklin and certainly are less than a Model J.

[1937hd45]

It is nice to know that new connecting rods can be made and broken cars can run again. I fished #8 rod out of this Type 59 Bugatti back in the 1970's.

[edinmass]

Here are what new Duesenberg rods, pistons, wrist pins, etc. look like. In the past we used a famous racing piston.......and they are having issues now. This set is a new to us company that don’t have their head up their arse. 

 

 

 

Photos disappeared........sorry.

 

 

 

Edited July 31, 2021 by edinmass (see edit history)

[Rusty_OToole]

Have heard that aluminum is much more prone to metal fatigue and weakening with age than steel. Some cheap alloys crumble to pieces after 50 or 60 years even if not stressed. I can see where rods and pistons would fail under stress. Is there a formula to tell how fast aluminum loses strength?

[Rusty_OToole]

I heard Dodge had aluminum rods before anybody. It was seeing them that inspired Pomeroy to remark "if you can make aluminium connecting rods you can make an aluminium motor" and that led to the experimental cars for Alcoa and Pierce.

[edinmass]

My guess is modern aluminum is much more stable, and probably ten time stronger. Metallurgy has come a long way. 

[JV Puleo]

I prepared a chart on this...I'll see if I can find it when I get home. If I remember correctly, 7075 aluminum is close to mild steel. I do not have figures on deterioration over time but, as Ed says, metallurgy has made huge advances in the last 100 years. If those RR aluminum heads had been made from one of the alloys available today they would never have been a problem. A friend of mine recently told me this story; In the course of restoring one of the Mercedes or Auto Union racers of the late 30s, Mercedes sent an aluminum head to their metallurgy lab to analyze. The lab reported "we make lawn chairs out of this stuff today."

[edinmass]

Chinesium is the correct name for the modern alloy that contains almost no quality control.

[wayne sheldon]

The history of aluminum is almost hard to believe. It is one of the most common elements on Earth! It can be found almost anywhere there is land. Although it has been known of for hundreds of years, it wasn't until the middle of the 1800s that any practical way to refine or process the metal was discovered. It wasn't until near the late 1800s that aluminum began being used in significant quantities.

For several years, the company that used more aluminum than anybody else in the world was the H. H. Franklin Manufacturing Company, the company that became Franklin motorcars! In the late 1890s, they were casting hundreds of products and selling all over the world. 

The alloys, and casting processes, were still in their infancy at the turn of 1900. And H. H.  Franklin was leading the way. Only a few years later, many automobiles were using cast aluminum in engines and automobiles. As the processes improved, and the ubiquitous metal remained relatively cheap as well as easy to work with, aluminum was used for so much more than crankcases. Floorboards for many cars were being cast by 1905. And, eventually, several cars including Pierce Arrow were casting most of the whole body of the car!

Casting was tricky in those days. If the metal isn't hot enough, it won't flow into the mold properly, and the metal will have to be recycled. If the metal is a bit too hot? The casting may look fine, but the result be porous and/or brittle.

A longtime good friend has a Simplex that he got a good deal on about thirty years ago because the original transmission case was porous and brittle. It was a very nice high quality restoration, however, the transmission case had been broken and welded numerous times, and was broken again. He had consulted with a few other owners of mid 1910s Simplex automobiles, and found that nearly all of them had brittle transmission cases and been welded several times. It cost almost $30,000 (not exaggerating!) to have patterns made, new housing and covers cast, and machined for the car! The car is incredible, and he has said it was worth the cost to fix it.

It wasn't until the 1920s that enough advances in alloys and casting methods had improved enough to even consider making rods out of aluminum. World War two R&D advanced the technology even further.

Edited July 31, 2021 by wayne sheldon
Additional thought. (see edit history)

[Graham Man]

They were a little slow to the table but wonderful looking and sounding car... 1936 Bentley 4.25L Drop Head Coupe, what a great name

 

[George K]

Hal and Bill Ullrich worked for D. Cameron Peck. I knew both. Hal told me that his Duesenberg powered car didn’t pull right. Then he dumped the updraft and built a new manifold and put four down draft carb. Hal said it finally woke up. Great use of a junkyard engine in a hot rod. 

[1937hd45]

^^^^^^^^^^ I think that Ford Roadster did some SCCA racing in the early 1950's, may have been on one of Jay Leno's Garage shows. Bob 

[George K]

Hal raced often. I contacted Hal when I was working on a race car that he had driven at Bridgehampton . That was when they raced on town roads.

[JV Puleo]

Here are the aluminum figures I compiled... 25ST is the strongest alloy sown in the 1926 (I think that was the date) Alcoa handbook.

SAE 1035 was the steel recommended for connecting rods in the SAE handbook of about the same year.

 

Edited August 2, 2021 by JV Puleo (see edit history)

[George K]

I believe the SAE 1035 would have been forged for grain flow. Lynite I have encountered is alloyed with either zinc or copper. Bad stuff either way. Modern aluminum alloys are produced to such purity and control that there is no comparison. Metal has grain but I understand the extrusion process for aluminum positions the grain in such away that further forging is not necessary. What type of bearings are you going to use with your rods? I knew an old drag racer who made his Model A rod inserts out of aluminum. Never had a problem.

[JV Puleo]

I'm probably going to make bronze inserts and Babbitt them but that is a way down the line so I can't say for certain yet. I'm skeptical of modern inserts because the Babbitt layer is only a few thousandths thick...the bronze shells & Babbitt are a lot of work but I've so much time into this already that a little more hardly makes a difference.

 

And yes, I'm sure the 1035 was forged since by the time the SAE handbook was publisher (1926 or 27?) virtually all con rods were made that way. Only on the better quality cars were they were then machined all over...

Edited August 2, 2021 by JV Puleo (see edit history)

[George K]

I remember reading that Duesenberg’s had trouble with con rods when they began building eight cylinder race engines. They built a single cylinder test engine and came to conclusion the bearing shells held the heat and caused the failure. They built tubular finned con rods without shells and babbitted directly on the steel. That fixed the problem. Again they led the way to modern engineering by always racing to find and analyze failures.