Duesenberg Straight Eight rebuild

[Hemi Joel]

Tom, I have noted the seeming lack of attention to performance on the intake side as well. I have a theory, but obviously no way to verify it. The theory is that they wanted to lug the motor at extremely low rpm in high gear without bucking or stalling. You can't do that with multiple carbs, because the low air velocity in the carbs will not create enough pressure drop to pull fuel into the venturie.

I read in some old literature that people who bought Duesenbergs new often specified a deep rear end gear, especially if they lived in the city. Not so that they could peel out of the hole, but so they didn't have to downshift unless they stopped. So they'd get it in high gear, and lug it down to 5 mph if need be. Don't bother to double clutch, match the gear speeds and drop a gear. I think this was a big selling point of the car. You could go from 5 mph to 100+ in high gear. (I know that Cadillac used that in their sales pitch for their 452 cid V-16 that was introduced in 1930)

In 1932, they made a supercharger available with a single carb, rated at 320 BHP. Then a dual carb set up at 400 BHP.

5.5 to 1 compression was due the low octane gas at the time. Could they have gone higher? Probably. But I suppose there would be trade offs. Like maybe risk multiple occurrences of engine damage from crap gas in a higher compression engine ruining their reputation. And they already had the field more than covered in power, so why risk it? I'm just speculating here.

[Huskinhano]

Joel, I believe you have a good point. I'm probably looking at it in terms of present day thinking and not of the period and customer base of the time. That's the reason why it was common for luxury cars to have 12 and 16 cylinders for smoothness. The 320 and 400 hp ratings clearly show the potential. I'll be willing to bet with a few modern touches such as a 4V, EFI, what ever along with a little boost, 500 hp would probably be very easy. Thanks again for showing this unique engine! It's just something you definitely don't see every day.

[Huskinhano]

You could go from 5 mph to 100+ in high gear. (I know that Cadillac used that in their sales pitch for their 452 cid V-16 that was introduced in 1930)

Probably the closest thing to automatic transmission back then.

[BOSSMAN]

I picked up the head from Cedar Machine today. This is the only Duesenberg head he worked on this week.
We had new guides custom made on a cnc lathe from manganese bronze.


Also we had new stainless intake valves custom made by Rev.



Ron at Cedar Machine ground the seats to a 3 angle valve job. We chose to grind them rather than cut them in the Serdi machine because it removes less material, and I am trying to remove as little as possible. He said that the seats were so hard, that he had to dress each stone 32 times to maintain accuracy.

Ron did a nice job for you! Smart thing to do while trying to maintain stem height. Replacing guides tend to move things around more than one thinks, looks like a job well done.

[Hemi Joel]

Hey Bossman, nice to hear from you!

I'm making progress, but I only have time for a quickie update. I got the pistons and rods in. They had to go in from the crank case side, because the rod big ends don't fit through the bores. I had to carefully position the rods, so that when we dropped the crank in, the rod journals that were pointed down nested right into the rods. I didn't want to push the rod/piston assembly down too far, or the rings would have cleared the deck and expanded. By using wadded up paper towels to position the rods, we got it in on the 1st try. And that's a good thing when 2 guys are manually dropping in a 140 pound crankshaft.

[Hemi Joel]

THe front of the motor is starting to come together..

[DanStokes]

Joel, that crank takes my breath away. It's absolutely beautiful. The skill and craftsmanship in the engine continues to be breathtaking. The method of assembly is interesting, too. I wonder how they did it at the factory, given that paper towels hadn't been invented yet.

Dan

[Hemi Joel]

I wonder how they did it at the factory, given that paper towels hadn't been invented yet.

Dan

[Deaf Bob]

Maybe install rods on the crank and drop it all in at once?
Sure is mechanically beautiful!
Light years ahead of their time!

[Huskinhano]

Hey Bob, how well do you think this engine would hold up derby car?

[SuperBuickGuy]

I wonder how they determined that 4 sprockets were required....

[DanStokes]

Knowing how they did stuff, they (I think that would have been Leo Goosen) calculated that 2 were sufficient. Therefore, a 100% margin of safety.

Dan

[Hemi Joel]

What I want to know is would this motor fit into the vintage OHV inliner class at Bonneville? If I recall, (from reading, not from witnessing!) Ab Jenkins drove the supercharged Duesenberg Special roadster over 165 mph. What would that motor (with some modern technology applied) do in a lakster or a 'liner? 200 club?

[Hemi Joel]

I wonder how they determined that 4 sprockets were required....

You mean the width? It does seem that that chain is overkill to run the water pump, generator and cams.

My thought is that he was planning ahead for the supercharger. The supercharged model, introduced in 1932, was no doubt under development from the start. The blower runs off the passenger side accessory shaft, so the chain is transferring the 60-100 horse that it takes to spool the impeller up to 18000 rpm.

Fred was experimenting with blowers as far back as WWI. His first Indy 500 victory in 1924 was the first Indy win by a supercharged racecar.

[Hemi Joel]

Now that I've got sidetracked on Duesenberg history....

Here is their 4 cylinder, 16 valve racing engine from about 1918. This was their most highly developed 4, just before he sold off all his 4 cylinder patents, tooling and licensing rights so he could focus on eights.
It has a cam on each side, running the long rocker arms up to the valves, and was known for the best power to weight ratio of any motor at the time, as well as being extremely durable. They nicknamed it the "walking beam" motor. The original walking beam, an 8 valve, was probably first built in their St. Paul, MN facility. It was used initially in race cars, but eventually found its way into passenger cars, airplanes, and watercraft.