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Good day all! I have a 54 convertible that I’m looking to have the engine overhauled. At this point it is suspected/assumed that the aluminum head on the engine has been over-milled. This assumption is due to the fact that the correct spark plugs had multiple compression washers on them. Installing new plugs resulted in the gap being closed on each after the engine was cranked. Since aluminum heads appear to be as scarce as hen’s teeth, I was considering use of a 288AT head that I have assuming it is in spec/useable. I’ve read the different threads from years passed and, quite honestly, remain confused on whether that would be my best course of action if I cannot find a useable aluminum head. Seems the “AT” was for cars with Ultramatics (?). Assuming it COULD be as a viable alternative, can it be used on a car with standard 3-on-the-tree w/overdrive tranny?

Thanks for any clarification or insight that anyone may we willing to offer! Since some threads on this subject are a number of years old, I’m hoping there might be some progress in resolving this situation for those of us trying to preserve these fine automobiles!!!!!

As an alternate approach, I believe there is a shorter plug that I could use, but if the head has been over-milled, does it present other issues?

You can take a look at this excel sheet that shows compression ratios with mixing various blocks and heads:

packardinfo.com/xoops/html/modules/archive/content.php?ContentID=533

Last I checked, Kanter had aluminum heads for for a very high price. That said, any of the cast iron heads of the era will fit but I recall seeing in the Service Counselor something about which one was recommended as a field replacement but I cannot locate it now.

Are you sure someone didn't use a extended tip spark plug(OK for most overhead valve V8's)? When they mill a head they only take off the flat sealing surface.

Quote:

I don't remember a service article on a suggested replacement but a few years ago Ross did post a reply to another posters question on the same subject. He did have a couple of recommendations as well as one or two definite NO's. On the do not use heads the pinging caused by the increased compression ratio that resulted could not be compensated for via timing, fuel or any other work. If anyone remembers or can find that post it might be beneficial.

If the head had been milled so much that the spark plugs have issues, then it is so thin that the valves will hit the head. Probably the plugs themselves are the wrong ones. Speaking of plugs, the head on my 1954 Patrician has had Heli-Coil inserts installed many decades ago so little worry of stripping the threads.

Yes, agree, first confirm the spark plugs are correct.

No, stacking washers under the plug is a VERY BAD THING !! The extra washers impede heat transfer, effectively making it a much hotter plug; increasing the liklihood of pinging.

No, do not change to an iron head unless the aluminum head is declared unserviceable by a knowledgeable Packard expert. Packard Engineering went to the aluminum head because it was necessary for your engine.

jack vines

Good day!

Thank you for all your insight. I checked with Kanter and all they have are cast iron heads. I’ve reached out to Max Merritt, but they have not responded.

In comparing the spark plugs, the multi-washer plugs have a longer center electrode, so have installed same temp-rated plugs, but with shorter center electrode. Now no gap issue when the engine cranked.

I completely understand that the aluminum head is the preferred head, but was interested in your combined experiences and knowledge IF there was no alternative should it be unserviceable.

So, if I may, the engine in the car is not the original. When I purchased the convertible, it was not running and the owner could not tell me the last time it had nor provide any information on condition when it did run. Through an acquaintance knowledgeable about Packards, I found a 54 Patrician that was being sold in an estate sale. The engine had been recently overhauled, but it had a 288AT head on it. I bought it and had the engines swapped out. The aluminum head that was on the convertible engine was installed on the Pat’s. engine and then installed in the convertible. The engine has, in my opinion, never run properly and I have found out this week that it has compression issues in a couple of cylinders. SO, I’m seriously considering going back to the original engine for the convertible. Since I have no history on the original engine, are there any basic checks I can do on the engine to determine if the block is sound and worth taking the next steps toward overhaul? The odometer on the convertible said the car had 55,501 miles on it, so I’m thinking it would not need a complete overhaul. But it makes a whole lot of sense to go all the way. I can rotate the motor with a socket wrench, so know it isn’t frozen/siezed. Guess I’m probably naively trying to save a few bucks on what I fear will be an expensive endeavor.

Mark

Hi BigKev,

Can you tell me the correct part # for a 1954 359 aluminum head? My head clearly has #446913 on it however upon looking at part reference numbers including your list and my parts book, I do not see #446913 / 8.7 to 1 CR anywhere. I see #446974 / 8.5 to 1 CR and #455140 / 8.0 to 1 CR. Your help is greatly appreciated. TC

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Good Morning...Just a suggestion...send a private message to Ross Miller and ask him what to do. He will know what is best. Ernie in Atizona