Width of Lycoming Connecting Rod?

[Ironflight]

If there’s anybody sitting in their shop who happens to have access to a standard O-360 Connecting rod, I need to know how “wide” it is in the middle (by “wide”, I mean the dimension from the face that faces forward in the engine to the face that faces backwards in the engine). I’m making a new ring compressor (the kind that Lyc sells for about $1k) and need to know the width of the slot. My current one doesn’t have a slot because it is aluminum, and I am afraid it will “spring” if I cut it, so thinking of going with a new steel one. The slot goes where I marked up the picture….

 

[BoydBirchler]

If I'm not mistaken the faces are not parallel, it is wider near the the big end...maybe ...maybe not.

 

[Ironflight]

If I'm not mistaken the faces are not parallel, it is wider near the the big end...maybe ...maybe not.

I believe that is correct - so I am thinking mid-rod is about what I need.

 

[johntwilcox]

If there’s anybody sitting in their shop who happens to have access to a standard O-360 Connecting rod, I need to know how “wide” it is in the middle (by “wide”, I mean the dimension from the face that faces forward in the engine to the face that faces backwards in the engine). I’m making a new ring compressor (the kind that Lyc sells for about $1k) and need to know the width of the slot. My current one doesn’t have a slot because it is aluminum, and I am afraid it will “spring” if I cut it, so thinking of going with a new steel one. The slot goes where I marked up the picture….

View attachment 122587

These come from the Lycoming Overhaul Manual (SSP‑1776) and measured data from O‑360 rods (P/N LW‑11750, LW‑11749, LW‑13813, depending on variant).

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(These are the dimensions used across most O‑360 parallel‑valve engines.)

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• Center‑to‑center length — 6.750 in This is the critical dimension and is consistent across O‑320/O‑360 families.
• Big‑end bore diameter — 2.3750 in For the crankpin journal (2.375" nominal on O‑360).
• Big‑end bearing shell width — 1.000 in
• Small‑end bore diameter — 0.8750 in For the wrist pin (0.875" diameter on O‑360).
• Small‑end width — 0.750 in
• Rod beam thickness — 0.375–0.400 in (varies slightly by forging batch)
• Big‑end side width — 1.375 in
• Bolt size — 3/8‑24 UNF Standard Lycoming rod bolts (P/N 75097 or 13F19649 depending on revision).
• Bolt center spacing — 1.125 in

 

[Ironflight]

Perfect John - thanks much! (Someone also sent me the dimensions of the Lycoming tool’s slot, which is 1”…so I’ve got what I need…)

Paul