Packard Forum Index » Pre-War (1899-1942)

Looking for the mechanical advance specs for this 1954 model year distributor. They are normally in the "Owners Manual" and list the degrees advance with the corresponding distributor RPM's. Trying to find out how they match up with the 1940 Auto-Lite model IGT 4201 distributor. For some reason, someone previously installed a 5402E distributor in my 1940 356 engine! Any suggestions where I might look to find these specs if they are not in the 1954 manual?

There was usually one issue of a service letter or service counselor either right before or right after introduction devoted to upcoming model specs. 54 mechanical specs appears to be a bit later than usual but are in April 54 Vol 28#4. If something changed after introduction then there was usually a follow up article or if significant, a tech bulletin.

Here is the 54 dist portion from that service counselor but believe same info in in a supplement in 51-54 service manual.

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Bill, look at my reply to your posting in the Post-war section.

(o{}o)

Thanks to everyone for the information in both the Pre and Post War forums, it was very informative. Took some time to try and compare the Motors Manual, which is great which I use it often for my 1940 Packard,and the Packard information. Some what challenging to compare, as not only are the reference points often different between Motor's and Packard but the reference points with in each is different for the 40 and 54 years as well. However, here's the jest of it, the 1940 distributor centrifugal advance starts sooner and goes higher than the 1954 (11.5 compared to 8 max). Would this be because the compression was lower in 1940 (more time needed for complete fuel burn) and because of lower octane fuels? The max vacuum advance of the 40 is 5.5 compared to 5.0 degrees of the 54. So, since the 1954 distributor has just been rebuilt and the vacuum advance is in the shop for a new diaphragm, should I just see how the Packard runs through acceleration with the 1954 distributor? Fuel economy may also go down (less advance) by using the 54 distributor? The other alternative, other than trying to find a 1940 distributor, is to shave the head to bring the compression ratio up?

I would not shave the head because you don't know what might have been done over the years. The valves have minimal clearance even with an untouched head so you run the risk of valves hitting if it has already been milled before.

Packard did issue a service counselor article in the 48-50 period on swapping heads for different ratios and what compression ratio might be obtained with different heads. I don't remember if the 356 was included in their combinations but the counselor is on site if you want to find and download it.

Your thoughts on shaving the head are well appreciated. That's what started this entire rebuilding process. Had a leaking head gasket. So, while I was at it, had a small warp taken out or the head, .013" shaved. This resulted in a bent exhaust valve. On that note, did a complete ring and valve job plus rod bearings. Found a replacement head, (same part #). You could actually see the deeper combustion chamber. That illustrated how much the original head had been shaved. On the original head .030 was faintly stamped on the under side. That should have alerted me but as this is my first engine rebuilding experience I didn't realize what I was looking at. The original head may also explain the reason for the 54 distributor, which as I understand it, has the centrifugal weights and springs for the higher 1954 compression. This may have also explained what I thought was the exceptional up hill power of this engine. If I had it to do over again would probably of had the already installed hardened valve seats cut .030" ground the valve stems and put the old head back on.Does that sound like it would have worked?
Will stay on the look-out for a 1940 Auto-Lite distributor.