Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: BryanM on August 12, 2024, 08:43:30 PM

Title: 1947 Cadillac tuneup specs
Post by: BryanM on August 12, 2024, 08:43:30 PM
Wondering if anyone could help me with tuneup specs on a 1947 Cadillac flathead. I don't have a shop manual handy. Looking for spark plug gap, timing info etc.. thanks
Bryan
Title: Re: 1947 Cadillac tuneup specs
Post by: Warren Rauch #4286 on August 13, 2024, 08:56:20 AM
 from 42-48 shop manuals 

     Plugs .028-.033 use wire type gauge,not feeler gauge
     Points .0125- .0175 ( .013-.018 in 48 book)
     Timing points start to open 5 degrees before top dead center
     dwell 31 degrees +/- 2 degrees
     Dist advance Manual  20 degrees
                  Automatic 21-24 Degrees
                  Vacuum  18 degrees
From Carter Carb

   Float 9/64
   Idle Adjustment 1/2 to 1 1/2 turns open

Warren
Title: Re: 1947 Cadillac tuneup specs
Post by: Jeff Rosansky CLC #28373 on August 13, 2024, 08:58:24 AM
Quote from: Warren Rauch #4286 on August 13, 2024, 08:56:20 AMfrom 42-48 shop manuals 

     Plugs .028-.033 use wire type gauge,not feeler gauge
     Points .0125- .0175 ( .013-.018 in 48 book)
     Timing points start to open 5 degrees before top dead center
     dwell 31 degrees +/- 2 degrees
     Dist advance Manual  20 degrees
                  Automatic 21-24 Degrees
                  Vacuum  18 degrees
From Carter Carb

   Float 9/64
   Idle Adjustment 1/2 to 1 1/2 turns open

Warren

Ok, gotta ask. Why a wire feeler gauge for the plugs?
Any idea?
Thanks
Title: Re: 1947 Cadillac tuneup specs
Post by: Big Fins on August 13, 2024, 12:24:54 PM
Wire type gives the more accurate gap setting. Look at the negative electrode on a spark plug. The very end tip has a slight hook on the side where the spark would be. A flat feeler gauge would give you a slightly wider gap, where dragging the wire through, it falls off of the center electrode before totally clearing the gap setting.