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1956 cylinder heads

Started by Charlie Hillegass, September 10, 2009, 09:28:49 PM

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Charlie Hillegass

     Dear Caddy fans.
     Does anyone out there have intimate knowlege of why Cadillac produced a 2nd design 365 cylinder head?  Hollander Interchange lists a 1st design head cast #{last digits 982 right head and 406 left head.
     2nd design they list the same casting numbers, which I think is incorrect, because I have a 56 engine with head cast #1465431-2 which some sources say was used in 1957. I have also the original heads from my car that have cast #1465406-7 on them with casting dates of 5n24 and 6n1. My car's engine unit number is4x77186 produced before my car's production date of  June 1955. Using Hollanders unit number break-off point of4x22787, my car was way after the design change point, if I understand this information correctly. My real question is: can anyone produce info from a cadillac source as to why this change was necessary ?  And the date of the changes?  I know 56 365's had a 2nd design camshaft with
later valve timing. My parts book says valves in both heads are the same, but valve springs and valve seats
for the valve keepers were different also.  Also Could any other owners check their head numbers on heads lying around for the cast # and date?  Please don't take any cars apart! I'm trying to increase the number of running 56 Caddys on the planet'

       Thank you all for your indulgence, Charlie #14462

Warren Rauch

 I couldn't find the information you wanted.
I did find that the head change was at the same time as the camshaft change. The the following is the change made to valve springs at the same time. Since you could not add the (1 1/2-1 9/32= 7/32) 7/32 " of added compressed spring by just changing the spring seat( keeper holder) they must have sunk the springs into the head deeper.
From Sealed Power Cat.  valve springs.
 
    year        part#      OD        freelength     Comp. length       spring test #
   55-56     vs-454     1 7/32     1 63/64        1 9/32                 152-162
   56-60     vs-485     1 7/32     2 1/4            1 1/2                  155-165

But why they did it???? Warren

charlie Hillegass

     Dear Mr. Rauch,
     Thank You for your reply. You have validated my theory on what they changed. I offer a cylinder head 
     where one of the spring retainers has a peice missing therefore letting the valve spring cock at bad
     angle. I never heard this engine run, but i'm sure you would hear lots of valve train noise. I was hoping
     that perhaps a seasoned Cadillac technician could remember service bulletins etc. on the topic. Is there
     a chance that the factory never recorded the release date of the changes? What changes did Cadillac
     do to the 365 in 1957? Compression or valve sizes for example. Cadillac was a "hot car in '57.
     Does a 1957 Caddy 365 block still have the water outlet for the transmission cooler like a 56 block does?
             I ask because I may have easier access to a 57 or 58 block, if they work. So far every 56 365 I
     have found is so stuck you have to break pistons to get them apart.
                             Thank you again for responding , Chas

CEC #20099

CEC  #20099
56 Cad heads cracked. Compared to 55`s, the ports were larger, the compression was higher, & they did it on the cheap.
Cracks were in the exhaust area, & between the valves. Cadillac had record sales in 55, & they were god.
If you are working on 56 heads, both versions, a pressure crack inspection is highly advised.
The Dual Coupling 56 hydramatic is another disaster. I had a 56, and prefer my 55.   CEC.

Ccharlie Hillegass

       
     Dear CLC members,

      Thank you for your reply CEC.  In my limited travels I also have heard sentiments such as yours about prefering  1955 Cadillac running gear over the troublesome 56 version.  About 10 years ago a friend of mine had a beautiful 56 62 series coupe, light green over kelly green and only 37,000 miles. We soon learned why he got it so cheaply.  It took a veteran Cadillac dealer trans man 4 tries to get the Hydramatic to quit skipping gears.  But when it was finally right it drove like a dream, and I became hooked.
      Disreguarding all reason, I bought my #16 gray fleetwood 60 special because I like it's style , some would call it more of a parts car than a restorable automobile. It came to me with a seized engine and a
1969 state inspection sticker, so it is quite a project. It will never be like my buddies low mileage coupe,
  since I am not wealthy enough to restore it properly. But I like a challange, and I have resusitated a
  1962 sedan deville, a 1963 sedan deville, a 1956 super 88 olds, and a 1955 Pontiac Cheiftain. I usually start with a car that others have given up on, and eventually even drive them.
     My Dad and Grandfather drove Cadillacs, and I continue the tradition with my daily driver, a 1997
Northstar Eldorado.  I Really like this message board and its contributors because It is apparent to me that
we all do try to help each other and promote the Cadillac brand.
      Again, I thank you for allowing me to ramble , and I appreciate your contribution.
                                                  Sincerely , Chas

     

Doug Houston

I have my second '56 Cadillac now, and have had it since November, 1987. I've driven it no more than 50 miles, then put it in storage. So, I really don't know a lot about it. It runs good; the transmission shifts nicely, and that's about all I can say for sure. the odometer says 27K, or so, and the car looks like it's correct.

But, I know on the best authority, that the optimum transmission for a '56 is a '58 Cadillac transmission, with a '56 tail assembly. I will do that on this car.

Now, on the other '56 I had,  the car had been owned by Cadillac Motor Division before the owner I got it from owned it. The heads were '57 heads, but we never knew why. It was some sort of an upgrade, but we only knew that '57 heads were better. Looks like this is coming out in some of the above mesages.

I pulled the engine around 110K miles, though I shouldn't have needed to. I bought everything new, except rods, pistons, crankshaft, and valve train. When I ordered the camshaft from Cadillac Detroit, I had to give them my engine unit number, in order to get the correct camshaft. When I took out the distributor, I left the high tension wires in it, and set it aside.

Engine assembled, and ignition connected, the engine backfired, and wouldn't run at all. Distributor was in correctly.Wires in their original locations. A complete timing sequence check was necessary, and I found that I had to change some of the plug wires, to make it run. I didn't check, but it almost seemed that the firing order had changed with the new camshaft (I've never heard of that before).  Once that was settled, it ran beautifully.

There was a really significant change in those engines during the model year, and I have no idea why. From the engine unit number, it had been a '56 engine. It looked to me (and still does), that the camshaft had been changed before Cadillac sold the car to the first owner. I acquired the car in Spring 1958. What a glorious barge to tool around in!

It might have been a test bed for engine changes; I dunno.

Then, the other weird one. I called Tom Bucklen, at Cadillac parts, to get the invoice data on the car. (This was around 1960) He read it off to me on the phone, and told me tht the interior was green and white. No, Tom, it's red and white. Nope, green and white. Well,OK, if that's what the invoice says!.

A few years later, I had the dash pad off for some reason, and looking down at one of the trim anchor strips......they were green. The interior HAD been changed while Cadillac  owned it!

The one I have now (also a convertible) has a solid red interior. I'm not about to make any profound statements about ANYTHING. The VIN is earlier than the one on my first '56.



38-6019S
38-9039
39-9057B
41-6227D
41-6019SF
41-6229D
41-6267D
56-6267
70-DeV Conv
41-Chev 41-1167
41 Olds 41-3929

TonyZappone #2624

You better believe the previous heads cracked.  Out of the five 56's I have owned ,  (two Derham 75's, one Eldorado Biarritz, and one S&S wagon),  two of them had cracked heads.  Indeed there was a demand for the new heads, I got the last two heads from the warehouse in the 80's.  I really loved the 56's I had, but between the new slim jim transmission, and the head problems, these cars were kind of a pain.
Tony Zappone, #2624
1936 Pierce-Arrow conv sed
1947 Cadillac Conv cpe
1958 Cadillac conv
2016 Cadillac CT6 Platinum
2022 Chrysler Pacifica Pinnacle

Charlie Hillegass


        Dear Cadillac freinds,

        First, Mr. Houston and Mr. Zappone thank you for your responses. 
        I know from listening to my dad who was a GM dealer technician in the fifties, that cars from the
        factory did not always get built according to invoice, and it was up to the dealers to make them
        right before delivery.  More than once dad had to change interiors to correct mistakes. He often
        told the story of a 1957 Pontiac that came to him minus the rear crankshaft seal in the engine,
        a big-time leak right off the truck.
              In the early sixties dad used to buy a car for $100 bucks, fix it, and sell it for a couple hundred
        more in profit. One was a 57 deville convertible, which took a valve job to fix. As a 10 year old, I was
        the chief gopher and "helped two steps behind him."  Probably more of an annoyance than help.
        This Caddy ragtop turned out to be probably the worst car he ever had, because every time we went
        cruising, we all walked back. Of course , the car became my favorite,because of this excitement.
        Needless to say, Dad sold it quick.  Check out Ebay Item270454853383 ending 9/17/09. It is a twin.