Duesenberg Straight Eight rebuild

[Hemi Joel]

About 3 years ago I pulled the oil pan off of the 29 Duesenberg, mostly out of curiosity. I found that the original aluminum rods were losing some of the poured in place babbit bearing material, thus I have seldom driven the car since. Well, it has been announced that there will be a Duesenberg Drag Race this coming Labor day weekend, and they are trying to set a new record for Duesenberg attendance. That motivated me to get busy on this car so I can make the event. So now I am trying to finish my 31 Plymouth hot rod for Drag Week 2015, and simultaneously rebuilding the mighty 420 inch Straight Eight. That doesn't leave me much time to play on the web, but I find this project so intriguing, I want to share it with my fellow Bangshifters.

Here is a shot of the car, and the engine prior to the start of the project:





I did all the usual disconnecting type stuff, but spend WAY more time and care than usual documenting, to aide in proper re-assembly. I removed the head, trans, clutch and flywheel prior to pulling this big beast.

Cam covers and intake removed:


I beefed up my cherry picker a bit before pulling:



There was a lot of rusty sludge under the water jacket covers, so I put the covers back on and soaked it with evaporust, which eliminated the rust, but is not acidic.

[Hemi Joel]

I have a really beefy engine stand made for truck engines, but I didn't want to hang this 4 foot long, irreplaceable block by one end, so I built a cradle that I mounted on the engine stand, that supports both the front and rear of the block. Plus I had to extend the length of its legs. I tested its strength with disaster protection by a sling hung from the cherry picker

[JOES66FURY]

what a monster....thanks for taing the time to post this....not every day we get to see something like this.

[Hemi Joel]

Timing chain system for the dual overhead cams: The drivers side sprocket drives an accessory shaft for the generator, oil pump, fuel pump and brain box. The pass side sprocket drives the water pump. The tensioner is spring loaded, but the spring does not carry the chain slop, it tightens the tensioner to the next notch in a vernier pin type mechanical holding system. The big sprocket at the top drives a separate sprocket and chain up to the cams.

[Hemi Joel]

The crankshaft is forged steel with a 4.75 stroke. It weighs 142 pounds and is over 4 feet long. Each rod journal is hollow, and the oil flows though the hollow area which acts as a centrifuge to collect solids from the oil. Each has a removable plug on the side that has to be removed to clean out the sludge.

[Hemi Joel]

Here you can see the babbit bearing material flaking off the aluminum rods. it starts right around the oil hole. That hole goes all the way up to oil the piston pin. You can also see that the big end of the rods do not fit thru the bores, so the pistons have to be removed and installed from the crankcase. Also, you will notice a screw head in the main bearing. In the block, there is a removable steel bearing shell that has the babbit poured into it and machined. On the caps, there is no shell, the babbit is poured right onto the cap. The big steel tube is the main oil galley.

[Hemi Joel]

I checked out the bores, and figured it would clean up at +.010.

[Hemi Joel]

I stripped off all the paint and got it all cleaned up with Berrymans C12, and my roof ice steamer. I chased all the threads, then hauled to over to Cedar Machine to hone it .010 over.



After loading it into the truck, I shrink wrapped it to keep it clean.

[Hemi Joel]

It barely fit into the hone:



ROn at Cedar Machine did a great job of taking only what was necessary to clean it up, saving precious iron for the future.

[Hemi Joel]

Before ordering the new pistons from Arias, I checked the combustion chamber CC, so I could specify a piston dome to bump the compression up a bit. Due to the low octane gas in 1929, the original compression ratio was only 5.5 to 1. I will bump it up to 8.5 to 1. No, I still don't have a fancy burette, I still use a cheap plastic syringe from the farm store.

[Hemi Joel]

32 valve head in 1929....




That's all I have for now. More as the project progresses and time permits, I hope you enjoy it!

[Barry Donovan]

5 mains, 180 throws.
that is beautiful.
That design gave them confidence in not only sending a real channel to a piston pin, they found a way to capture debris.
I drew up a 90 degree v8, also with 180 throws. Very similar...just compacted.

that is a very nice engine. Had my daydreams before never seeing one...
I can see why they are among the best eternally.

[squirrel]

Beautiful! thanks for posting

[STINEY]

This is really cool, thanks for sharing.

My '65 Ducati has that crankshaft sludge collection design as well. Interesting to see it in a way different application.

Only thing I have with Babbitt is my windmill. No machining though, just pour and run. Old manuals are great reading.

[SuperBuickGuy]

way cool, they did build them beefy. I had the same weight concerns when I was working with the Buick Straight eights... though the Duesenburg wins because more valves