A century car of parts meshed together - '26 roadster build

In reply to mke :

​​​​Aluminum would be great If you could find a source for the variable geometry stuff that bike manufacturers use.  The stuff that gets bigger diameter mid span but still has good wall thickness for joints.  

Round tube is better from a strength standpoint but there is something to be said for the ease of fabrication out of rectangular.  If your going super light and disregarding all regulations a frame made out of 2 or more Large diameter thin wall tube sections may be the best route.  You could do some riveted or bonded aluminum bulkheads and weld bolt flanges to the main chassis tubes.  Titanium may be a fun option to explore as well.  Lots of good options when you throw out needing to cary around 1-5/8 6+ point cages.

I'm excited to see how you solve the chassis, everything I've built has been mostly rules dictated.  It's neat to be in a position to ignore them.  

nocones said:

In reply to mke :

 

If your going super light and disregarding all regulations a frame made out of 2 or more Large diameter thin wall tube sections may be the best route. 

For sure that is about the easiest path, so good bet that is not where my mind is heading.    The model I posted has 144 tubes and I expect a front engine version to need a few more than that. 

The tubes go as far apart as possible making the entire thing a truss that just fits under the skin and nothing anywhere but trianagles (or shear plates).   This makes it extremely strong and rigid without needing  much weight to achieve it.   Right now the thought is it will be mostly 1"OD x .028" wall 4130 tubing, even that is probably overkill but I'll need to do some math and I will big around to see what is available for aluminum I like that thought.  There will be something bigger/thicker for what I call a main hoop becasue I'm fond of my head.  Also I'll need to see where the suspension stuff all ends up and where I need to mount anything off a strucutral hard point and on a tube requiring much stonger tubing member....that is the challenge with this type of frame, much like a monoque design you simply can't have a force at an unplanned location without bad things happening.

Cool project.  This was from a trip to the Auburn Cord Duesenberg museum a few years back:

In reply to Indy - Guy :

That is  kind of funny...I'm about certain that a '48 is a 292, or was when it left the factory.  The 305 came out in 42 for about a month or 2 before the war and again in 46 right after the war, but by late 46 is was back down to 292  and 125hp for reliability/rebuildability. The rear cylinders overheat and go out of round and at 305 they were thjinner so more prone to the issue and there was nothing left to bore out to fix it as I understand it.

The other problem is this is a 4 main bearing crank so it flexes. They increased the rod jounal sizes a couple times while it was a V12 and again in the last years of the ford straight 6 flathead to make the main bearing live.

There are lot of reasons not to use this engine on purpose I guess.......

In reply to mke :

Could be an error on that placard...  They mostly have ACD cars, but also a few others.  I'd trust the facts about the Auburns, Cords and Duesey's more than the Lincoln.

I Liked the Auburn v-12 down the isle and the displayed engine upstairs too:

Sorry for the distraction, I just find these early domestic V-12's fascinating.

In reply to Indy - Guy :

They are very cool to look at.

Here's something the maybe someone here can help with, here is what the connecting rods look like

7.25in center to center, 2.25" crank journal , angled end to fit through the tiny bore and really, REALLY scary spindly looking.  I would love to find something similar that is less scary looking but doesn't cost custom made rods money.

Anything come to anyone's mind? 

I'm going to need to hunt up a transaxle too....boxster 6spd maybe? Open to ideas, I would love something that supports paddle shift but that is extra weight and complexity so....

mke said:

7.25in center to center, 2.25" crank journal , angled end to fit through the tiny bore and really, REALLY scary spindly looking.  I would love to find something similar that is less scary looking but doesn't cost custom made rods money.

Anything come to anyone's mind? 

Odd thought, but I do kind of wonder how old a rod would have to be before someone could just weld a better one.

Mr_Asa said:

Odd thought, but I do kind of wonder how old a rod would have to be before someone could just weld a better one.

odd truth...I've done that. 

I ran an H-D roadrace bike 2 fully seasons with welded rods when the custom set I ordered took 8  months not the 8 week they told me and I had no interest in missing the season.  So yes, modifying something is on the list of things I'd try before I'd try running the stock rods

What about a track nose but with a roots blower running out the front like a 20's Bentley?  I have no idea on the rods or really anything useful to add.

pres589 (djronnebaum) said:

What about a track nose but with a roots blower running out the front like a 20's Bentley?  I have no idea on the rods or really anything useful to add.

You're talking about a Potvin blower, I believe.

I'm never one to try and talk someone out of a turbo or three, but I wonder if a blower might be a better choice for this thing. It would certainly look more period correct. I just wonder about the necessary exhaust flow and excess heat... How high fast can one of these flatheads spin?

pres589 (djronnebaum) said:

What about a track nose but with a roots blower running out the front like a 20's Bentley?  I have no idea on the rods or really anything useful to add.

I like the sound of this!

mke said:

nocones said:

In reply to mke :

 

If your going super light and disregarding all regulations a frame made out of 2 or more Large diameter thin wall tube sections may be the best route. 

For sure that is about the easiest path, so good bet that is not where my mind is heading.    The model I posted has 144 tubes and I expect a front engine version to need a few more than that. 

The tubes go as far apart as possible making the entire thing a truss that just fits under the skin and nothing anywhere but trianagles (or shear plates).   This makes it extremely strong and rigid without needing  much weight to achieve it.   Right now the thought is it will be mostly 1"OD x .028" wall 4130 tubing, even that is probably overkill but I'll need to do some math and I will big around to see what is available for aluminum I like that thought.  There will be something bigger/thicker for what I call a main hoop becasue I'm fond of my head.  Also I'll need to see where the suspension stuff all ends up and where I need to mount anything off a strucutral hard point and on a tube requiring much stonger tubing member....that is the challenge with this type of frame, much like a monoque design you simply can't have a force at an unplanned location without bad things happening.

I can't comment about your design. Except to say Sounds like you're following the Birdcage Maserati thought as far  as design.  
      I should look up how thick 22 gauge is, I know most sheet metal is 20 gauge. 
     
   The ease of fabrication is only part of it.   The surface area available to  braze is so much greater. 
 For example the top rail goes across the inside rail at an angle forming 3 triangles. And the surface area  is probably over 12 inches.  That's just one tube. 
  The interesting thing was the first batch of frames for the 1954  DType  were aluminum.   The second batch were steel and they were both stronger and lighter. 
 Dumb me, I'm going to do mine in aluminum.   Polish them all up. My excuse is paint is heavy and polishing actually removes weight. 
      

pres589 (djronnebaum) said:

What about a track nose but with a roots blower running out the front like a 20's Bentley?  I have no idea on the rods or really anything useful to add.

That was my thoughts too!  
  With regard the rods, the cast iron 6 cylinder 4.2 Jaguar is 7.3  but no way is it 2.5  for the rod journal. I'll look in case I'm wrong. 

mke said:

nocones said:

In reply to mke :

 

If your going super light and disregarding all regulations a frame made out of 2 or more Large diameter thin wall tube sections may be the best route. 

For sure that is about the easiest path, so good bet that is not where my mind is heading.    The model I posted has 144 tubes and I expect a front engine version to need a few more than that. 

The tubes go as far apart as possible making the entire thing a truss that just fits under the skin and nothing anywhere but trianagles (or shear plates).   This makes it extremely strong and rigid without needing  much weight to achieve it.   Right now the thought is it will be mostly 1"OD x .028" wall 4130 tubing, even that is probably overkill but I'll need to do some math and I will big around to see what is available for aluminum I like that thought.  There will be something bigger/thicker for what I call a main hoop becasue I'm fond of my head.  Also I'll need to see where the suspension stuff all ends up and where I need to mount anything off a strucutral hard point and on a tube requiring much stonger tubing member....that is the challenge with this type of frame, much like a monoque design you simply can't have a force at an unplanned location without bad things happening.

Think about using your engine as a stressed member. You can then tie the frame to the engine and where  it connects mount the suspension link there too. Kind like the Cosworth era of Formula  1 in reverse.  Mount the radiator sub frame off the timing case  and that's the same place the front lower wishbone attaches. The rear lower wish bone attaches at the front of the engine. 
  You can use a splined hollow tube torsion  bar to connect to your wheel hub and pick it up  at the back of the engine. Speedway engineering's swaybars would be perfect for this.  

I wonder how much stress you really want to try and shove through a block that was clearly never meant to accept it.  I think this is a cool project and I am not knocking the choice of engine but these things don't seem to be all that sturdy... Designing the frame to do frame things and working the engine over so it's actually reliable(ish) might be a smarter path. 

And agreed that I was thinking about a Potvin blower drive but I wasn't sure if everyone else would know what I was talking about. Probably have to custom fab all of it anyway.  Something like a 4-71 perhaps. 

https://youtu.be/868DSi85odQ

Perhaps a theme song?

pres589 (djronnebaum) said:

I wonder how much stress you really want to try and shove through a block that was clearly never meant to accept it.  I think this is a cool project and I am not knocking the choice of engine but these things don't seem to be all that sturdy... Designing the frame to do frame things and working the engine over so it's actually reliable(ish) might be a smarter path. 

And agreed that I was thinking about a Potvin blower drive but I wasn't sure if everyone else would know what I was talking about. Probably have to custom fab all of it anyway.  Something like a 4-71 perhaps. 

There are easy ways to confirm the strength of an engine.   I used all the race cars I built as stressed members including a designed in WW2 Cast iron 6 cylinder.  
      Figure out what stress you feel acceptable bolt plates to opposite ends and set weights according to your tolerance.   Then compare that to the stress level you'll allow on chassis. 
   The reason all engines aren't stress mounted  is because of noise and vibrations transmitted.   Hot rods aren't high on concerns about noise and vibration. In fact that's part of the appeal. 

frenchyd said:

      I should look up how thick 22 gauge is, I know most sheet metal is 20 gauge.        

22 gauge is 0.030", the tubing I'll be using for most of the frame is 0.028, just over 23g which is 0.027".  20g is right out at 0.036".  It will be welded not brazed so surface area is of little concern.

barefootcyborg5000 said:

I'm never one to try and talk someone out of a turbo or three, but I wonder if a blower might be a better choice for this thing. It would certainly look more period correct. I just wonder about the necessary exhaust flow and excess heat... How high fast can one of these flatheads spin?

A blower was the original plan and still may endup the choice and yes, exhaust heat is the concern with turbo(s).  My concern with a blower is packaging, I talked a bit about it here before starting this thread but look at the height of this...it ain't fitting under the hood.

And hitting the 250hp hp goal would be a struggle as the blower is really only good for 5-7psi. 

Now, I could use a more modern end inlet blower but then the how to fuel it becomes the question as modern blowers want to be run dry and trying to flow fuel sideways is a fool errand anyway.  So EFI,  which is why this came up in the EFI thread.  This engine only have 8 intake (and exhaust) ports making port injection a challenge as its hard to know which cylinder gets the fuel.  I has 3/4 talked myself into Direct Injection, the heads couldn't be simpler to convert but I'm told the tuning is a real bugger so back to port injection.  It is possible to get the injectors into the V, its been done

But where I'm leaning is what I put in the 1st post, an intake like a modern V8

but try to leave room the get the injectors to the inside

it would be no shorter than the blower on top but give me tuned length runners and a bit more freedom with the injectors....and allows an intercooler.  That got me to turbos being easier to package.....but a blower is still an option. 

I need to collect a body and transaxle and see what makes sense space wise.  Because I'm planning a space frame  integral to the body not a ladder frame under it I will have less room then most hotrods....this will be about what I can package neatly.

This engine was a spinner back in the day making its 125 peak hp at 3800rpm.  I will probably bump that to 4500-5000 unless I can't find a solution to the scary connecting rods.

frenchyd said:

 With regard the rods, the cast iron 6 cylinder 4.2 Jaguar is 7.3  but no way is it 2.5  for the rod journal. I'll look in case I'm wrong. 

Crank rod journal of 2.0-2.25" I could live with but the issue is the 2.875" bore size.....the big end of the rod must be angled and it doesn't look like the jag rods are.  Often diesel rods are the right design, a 5.9 cummings rod is close but has a 2.875 big end

Finding dimensions is the issue....this case rod LOOKS great but no idea what size it is other than it says the beam width is .875"

edit 2 - fond it, 2.75" journal size 

Someone on here was building one of the little Toyota Hemi V8s, from memory it has the angle split rods too. Not so much so they fit down the bore, but so you can actually do up the cap bolts.

Alfa-sud flat fours also have angle split rods, might be a bit on the short side for you though?

http://www.alfasud-parts.co.uk/catalog/images/IMG_5199-a080e-1024x820.JPG

The Mercedes V6 diesel in this thread also has them:

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/they-said-it-cant-be-fixed-journey-inside-mercedes/142999/page13/

In reply to Gammaboy :

I can't find the journal size for the alpha but the Mercedes is 2.5" so too big

This one might do it with some rework, a Deutz 511

Wouldn't be the first time Deutz parts have gone into a hot rod.