Franklin Drivers

[1:1 Scale]

It just goes to show that the institutional knowledge on these Franklins is just not there. I think they are a good engine but have a lot of issues by incorrect maintenance.

I have the same belief. I have two engines- one that is 0 SMOH that's waiting if I need it, and one that I installed when it was time to put an engine on the plane during my rebuild, and I hadn't gotten the one back from O/H yet. The one that's currently on my plane has 1975 hours on it SNEW, and has never even had a cylinder removed I feel like I'm sitting on a unicorn. I'm planning to fire it up for the first time in about 20 years this weekend, and depending on how it runs, oil pressure, compression, etc., I plan to continue running it. If it displays any bad behavior, I'll swap engines.

[Mog]

Anyone want to speculate why Maules setup is different than the Stinson setup.

[1:1 Scale]

Which setup? It's been a while since I've had my Stinson, but if you referring to the oil line routing, my best guess would be that the engine cases are entirely different, but I don't know if they changed the basic oil routing between the 150/165 and the 180/220 cases.

[Mog]

Yes, referring to the oil plumbing. Best I can tell is that all the engines are the same. It seems the Maule method may be a bit more passive in changing oil flow where the Stinson setup may be a bit more of a positive swap between paths. But I haven’t drawn both out to wrap my head around it.

[Mog]

Maybe the vernatherm blocks changed at some point. Seems the Stinson block uses one extra hose. But I think the Maule block is the same and the extra port is just plugged.

[1:1 Scale]

I remember the vernatherm on my Stinson being an integral part of the oil cooler, and it's not on my Maule....