Toddgoudeau

Great race Franklin speedster

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Hello all.   I have a 1923 10B that I bought a couple years ago and the body was just way too far gone to restore.  Soooo..... I am building it up as a dedicated Speedster with the hope/intent of running in the 2020 Great race.  For those of you who aren’t familiar..... it is a time/distance rally.   The highest assigned speed in the course is 50 mph.   95% of the time, the speeds are 25 to 40 mph.  Hard braking required occasionally.  My question goes out to any and all who have an opinion about the viability of my Franklin as a competitor and any and all suggestions/comments about the weak links in the chassis/brakes/engine, etc.....that would need to be addressed and/or beefed up.    The car/chassis  will be shortened 16” and an all new lightweight and aerodynamic wooden Boattail body constructed while keeping the original doghouse hood and firewall.  Most of my concerns are aimed at “can the engine/trans/differential survive at 50 or should I adapt an overdrive? Are the brakes sufficient?  U-joints robust enough? Overheating and valve sticking concerns? Likelihood of throwing a rod? Can an old Babbit job survive the torture? Etc.....   thanks in advance for any input.   Todd. 

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A series 10 is comfortable at 40mph. You can push it to 45 periodically, but running at 50 will destroy the engine rather quickly.

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Posted (edited)

Welcome Todd.

Yup!  Long distances at 50 mph is not good.

 

The Series 10 has a  "pulsed" oiling system. That means the oil pump only gives a squirt of oil to each bearing in turn as the pump gears rotate - not the constant oil flow like the later Franklin side draft engines, that can do 55-60 all day with the same type babbitt bearings.

 

The reason for the difference in cruising speeds is that the oil isn't just for lubrication, it's also part of the cooling system. Pulsed oil systems don't have as much oil flow volume to extract bearing heat as quickly and transfer it to the aluminum engine base and oil sump, where it is being cooled by incoming cooler air.  Push the system (speed-wise) beyond what it can shed heat with and the bearings can over heat and fail.  

 

Even if you put an overdrive on it, that just transfers more load to the engine with the loss of some of the mechanical advantage of the rear axle gearing, and at a slower engine speed for the cooling system - both air and oil. Then, not only does that gear ratio power loss have to be made up by increasing engine load, the increase in speed adds more air drag load on the engine - a double power whammy.  More power needed = more throttle opening = more heat output the engine will have to deal with, while the crankshaft mounted cooling fan, and the oil pump system. is now operating at a slower speeds and flow volume.

 

The "infernal combustion  engine " is  basically a "heat pump" designed to do "work". But if there's too much heat for what it was designed to handle, then it stops doing work.....often with a loud, BANG ! 

 

Paul

Edited by PFitz (see edit history)

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Well Poo!!   Not at all what I wanted to hear.  Lol.  But..... I have a ‘29 Hudson Roadster that’s up for the run.   Just really wanted to do it in the Franklin.   I’ll continue the build, but limit its use to Treks and Sunday dives for ice cream.  I just finished tearing down the bottom end last night and was ecstatic with the pristine condition of the crank journals, and Babbitt on all rods and main caps.  That quickly turned to horror when I rotated the crank and half of a broken in half upper main babbit insert came rotating out.  Ugh.   So..... after reading the Franklin FSS posts today I found out that its possible to find a used upper main insert and fit it? Or Have Tom/Oddessy make a babbited bronze insert?   Also.... the camshaft it badly pitted on 3 lobes.  Does anyone have a source for used camshaft and main upper insert that may fit my 23 10B?   NOS cam?   Any help is greatly appreciated 

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On 8/26/2019 at 4:01 PM, Toddgoudeau said:

Well Poo!!   Not at all what I wanted to hear.  Lol.  But..... I have a ‘29 Hudson Roadster that’s up for the run.   Just really wanted to do it in the Franklin.   I’ll continue the build, but limit its use to Treks and Sunday dives for ice cream.  I just finished tearing down the bottom end last night and was ecstatic with the pristine condition of the crank journals, and Babbitt on all rods and main caps.  That quickly turned to horror when I rotated the crank and half of a broken in half upper main babbit insert came rotating out.  Ugh.   So..... after reading the Franklin FSS posts today I found out that its possible to find a used upper main insert and fit it? Or Have Tom/Oddessy make a babbited bronze insert?   Also.... the camshaft it badly pitted on 3 lobes.  Does anyone have a source for used camshaft and main upper insert that may fit my 23 10B?   NOS cam?   Any help is greatly appreciated 

 

Todd - this sounds like exactly the scenario I found myself in a few months ago too on my 1926 Series 11A Sedan. Happy to find that the bearing clearances seemed good, and the condition of the journals was OK, and the caps, but when I rotated the crank, a top main shell turned out with it - but it was only half of the shell - broken across the oiling groove cut in it. I checked another one, and it came out in 3 pieces, with some missing too.

 

I have a spare engine that I'm going to pull apart and see what's in it, but it's looking like I'll have to have new main bearing shells poured and line bored to fix this.

 

Roger

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