Re: Ken's 1937 120 Touring Sedan

Posted by Ken_P On 2020/8/11 14:45:50

Got all of the pistons pulled today. Everything seemed pretty tidy, lots of carbon, but I didn't see any broken rings or obvious problems.

Rod bearing clearance was uniformly 0.002 to 0.0025, so definitely room for improvement there, since the spec is 0.0005 to 0.0015. My connecting rod journals mic'ed out at 2.0940 to 2.0945, and I'm confident that a few ten thousandths of that is attributable to operator error! So I plan to replace the rod bearings with stock size, vice 0.001 undersized.

Now that I have all the pistons out, the next steps are re-checking cylinder taper in all holes, cleaning and inspecting the pistons, and ordering parts.

Are piston expanders available if I find that the pistons are more than 0.006" in diameter under the point of maximum cylinder wear? (Referencing the 41-48 Engine Manual, paragraph 4 on Piston Inspection).

I don't have the tools to verify connecting rod alignment (Connecting Rod Aligning Jig J-874-PA), so I'll visually check for straightness, etc.

I'm also going to check the piston pins for obvious looseness, misalignment, etc. Hoping to avoid replacing anything here because I don't have the machine tools to ream things myself and my shop is SLOW, but I'll replace if I need to.

A few pictures will follow when I get back to them.