Part spec sticky

Discussion in 'Big Block Cadillacs' started by Runnin L8, Oct 26, 2010.

  1. Runnin L8

    Runnin L8 New Member

    Joined:
    Jan 15, 2006
    Messages:
    667
    Likes Received:
    0
    Can we start a part / spec sticky? I know it is all in the site, but I find myself constantly having to go back and look up numbers or specs. I don't know much, but I'll start with the kind of thing I always end up looking for. Please fill in or correct where you know the answer and add anything you've had to go look for recently.

    500 Stock bore = 4.304
    Stock stroke = 4.304

    472 Stock bore = 4.304
    Stock stroke = 4.060

    Stock Rod length 472 / 500 = 6.750
    Big End Bore = 2.6243-.2.625"
    Small End Bore (pin diameter) = is .9997

    Crankshaft 500 part # last 3 digits 094 & 793
    Main =3.25" Bearing clearance .0003"-.0026"
    Rod =2.5". Bearing running clearance .0005"-.0028"
    Thrust spec = .0002"-.0012"
    Rec Rod Side clearance = .011~.021 looser isn't normally a problem here. Tighter is a problem.

    Crankshaft 472 part #1488424. Large N on second counter weight from front.
    Main = 3.25" Bearing clearance .0003"-.0026"
    Rod = 2.5". Bearing running clearance .0005"-.0028"
    Thrust spec =.0002"-.0012"
    Rec Rod Side clearance = .011~.021 looser isn't normally a problem here. Tighter is a problem.

    472 / 500 heads;

    493, 552 = 120cc comes stock with 2.00"/1.65" valves. Dave Brode - You can find Pontiac valves that are a little shorter or a little longer than the stock 120 valves. I prefer the longer Valve tip protrusion will be a little taller than stock [Assuming no huge top cut]. That's no problem IMO. Stock is 2.040"-2.050" iirc. [spring seat to tip]. You can snip a little off of the tip to lower it, but fwiw, I see no problem with 2.080 ish.

    76CC Port Volumes - Intake ports on stock heads are between 180.5cc and 186cc and exhausts are between 119cc and 124cc. A good ported head is 220-227 maybe more if you can weld up the pinch exhaust 130+

    Gives approx 13/1 with flat top pistons

    950, 902 , 250 = 76cc comes with ? valves. Can be replaced with ? / ? valves ? long
    Gives approx 8.5 / 1 with Peanut or Bathtub pistons (no clue if that's true)


    500 Pistons
    Compression height = 1.900
    (?) don't even know enough here to suggest needed specs :dunce:
    Bathtub dish volume =
    Peanut dish volume =

    472 Pistons
    Compression height = 2.020
    ?

    Stock pushrod length = ? not sure if it's different with each head

    Stock Rocker assembly = 1.65

    Max valve lift with stock guides = approx .490 lift

    Stock Spring height =
    Note - the "spec" on valve tip height, measured from the valve spring seat to the tip of the valve is 2.040" - 2.060". Varying the valve length will effect this, which can cause problems with valve geometry, spring installed height as well as lifter pre-load. ***This number is very important if you don't have an adjustable valvetrain.***

    Torque specs
    Main = 95 ft /lbs
    Rod = 40 lb/ft
    Head = 95 with bolts / 110 with studs using assembly lube
    Rocker T = 70 ft/lb

    Felpro Gasket install 0.043" compressed and a 4.357" bore

    Commonly used Rod / Piston combo
    7" Oldsmobile rods + ? pistons + stock stroke = 10.5 / 1 with 76cc heads
    ...........
    ...........

    Rough Draft
     
  2. dave brode

    dave brode Well-Known Member

    Joined:
    Oct 14, 2004
    Messages:
    14,871
    Likes Received:
    165
    Location:
    Frostburg, Maryland
    500 Stock bore = 4.300
    Stock stroke = 4.304"

    472 Stock bore = 4.300
    Stock stroke = 4.060"

    -------

    The following comes from a '74 Caddy factory manual. These specs are stock, NOT what most experts recommend:

    Stock Rod length 472 / 500 = 6.750"
    Big End Bore = 2.6243-.2.625"
    Pin diameter, .9994-.9999"
    Pin to piston clearance .0002"-.0004"

    Rod journal 2.5". Bearing running clearance .0005"-.0028"
    Main journal 3.25" Bearing clearance .0003"-.0026"

    Thrust spec = .0002"-.0012"
    Rod Side clearance = .011" -.0021"


    -------
     
  3. dave brode

    dave brode Well-Known Member

    Joined:
    Oct 14, 2004
    Messages:
    14,871
    Likes Received:
    165
    Location:
    Frostburg, Maryland
    Valves in early heads are *apx* 5.25" long.
    Valves in late heads are *apx* 5.00" long.

    11/32" stems

    There are several length Pontiac 2.11, 1.77 [and 1.66"] valves that have been used in both early and late head. Opinion varies on the effects of using a shorter valve or longer than stock valve. Note - the "spec" on valve tip hiegth, measured from the valve spring seat to the tip of the valve is 2.040" - 2.060". Varying the valve length will effect this, which can cause problems with valve geometry, spring installed hiegth as well as lifter pre-load.

    According to KB, the piston C.H. is 1.900 for 500s and 2.020" for 472 [and 425, afaik].
     
  4. dave brode

    dave brode Well-Known Member

    Joined:
    Oct 14, 2004
    Messages:
    14,871
    Likes Received:
    165
    Location:
    Frostburg, Maryland
    Pistons/rods/stroker crank info

    To figure piston needs for a different rod length [example];

    Stock 500 CH [compression hiegth, or distance {pin C/L to top of piston deck}] is 1.900, stock rod is 6.75". A 7" rod will need a piston that's .250" shorter. Etc, etc. Example: 7" rod needs 1.650" [1.900" - .250"].

    Note: Rod choices have improved dramatically over the past several years. Prior to that, Forged 6.735" and 7" Olds rods were popular [olds and caddy use same rod bearing].

    7" work well with a 454 bbc piston in 120cc headed engines for around 8.8-1. The 7" rods were also used with dished 403 Olds pistons with 76cc heads, although those are way short at apx 1.615". Note that some clearance work on the notches at the pan rail on the block is req'd to clear the top of the rod bolts on the 7" olds rods with a 500 crank [not sure about the 6.735s]. The early non 5200 blocks do not have notches there, and will require more work.

    To figure piston needs for a "stroker";

    Piston hiegth needs change by 1/2 of the change in stroke length;

    Assuming no change in rod length, a .100" increase in stroke will require a .050" shorter piston. Etc, etc.

    Example: Theoretically possible +300" stroke increase using 6.8" long BBC rod:

    1.900" - .050" = 1.850" - .150" = 1.700" tall piston.

    --

    Dave
     
  5. dave brode

    dave brode Well-Known Member

    Joined:
    Oct 14, 2004
    Messages:
    14,871
    Likes Received:
    165
    Location:
    Frostburg, Maryland
    On clearances in the "hotrod" Caddy;

    Some of us have taken Terry's recommendations on clearance, with good results. That is, a thou per inch of journal. Note that there is nearly a thousandth spread in the spec on journals and rod and main bores. So, your parts can be within spec, and your clearances way to tight.

    In a nut shell, finishing the crank to the lower end of the spec [small], while sizing the main and rod bearing bores toward the high side of the spec [large] should result in proper clearance.

    On side clearance [rod to rod], opinion varies. Some like mid .02X, some like more. I have run .040" and bearings looked perfect. Fwiw, I would not run less than .026". A few passes on emory taped to glass will clean the rods up, and increase clearance a bit. You can also mill the surfaces. You can also CAREFULLY use a belt sander, but it is a bit tricky :eyepopping: Go slow, check 4 corners on the rod as you go.
    Dave
     
  6. Ted in Olympia

    Ted in Olympia Well-Known Member

    Joined:
    Oct 15, 2004
    Messages:
    5,267
    Likes Received:
    45
    Location:
    Olympia, WA
    Hi Dave,

    I could give you the job to put together a master book of Cadillac facts (kind of like the MTS guide but more complete) and I will stick this for all to see.

    Other than this I think the search engine is the way to go.

    TED
     
  7. pila78

    pila78 Well-Known Member

    Joined:
    Dec 1, 2009
    Messages:
    2,790
    Likes Received:
    94
    Location:
    Saginaw michigan area
    Not to muddy up this thread, but when I had a '76 Deville, I bought the factory manual for the car (& still have it) . Their spec for the rocker arm ratio is listed as 1.72:1, which is baloney from what I've read here and elsewhere, as actually being 1.65:1 That sound right? Of course there are a few typos in the manual elsewhere also, so no big surprise there.
     
  8. 76FleetBrougham

    76FleetBrougham Active Member

    Joined:
    Jul 13, 2005
    Messages:
    1,209
    Likes Received:
    2
    Location:
    VA / DC
    Parts not for the cadillac, but work fine:

    Oil pan studs: Moroso 38360. BBC kit but works fine and dandy for Cadillac.

    Header studs: ARP 100-1413 (normal hex head). 12 point head is 100-1403
     
  9. Ted in Olympia

    Ted in Olympia Well-Known Member

    Joined:
    Oct 15, 2004
    Messages:
    5,267
    Likes Received:
    45
    Location:
    Olympia, WA
    Removing the AC is easy and you can do this with any pulley set-up, all you need is a shorter belt to run you PS pump.

    The best and easiest way, (but not the cheapest), to remove the air pump, AC and or PS, is to buy the pulleys from MTS new. They have them for both the early double belts and later single belts.

    http://www.mtscadparts.net/servlet/the- ... num/Detail

    As far as I know there are three type of non-air pump pulleys set up;

    The 1970 engine had a double belt system and is the best way for 68-73 cars. These were tin pulleys and used a damper.
    Some 1975-1976 cars came without the air pump. These were cast iron and did not use the damper.
    Some 1977-1979 cars came without the air pump. These were tin pulleys and did not use the damper.

    The problem with all three of these options is that you should find a compete set of; crank pulley, water pump pulley and timing tab. If you use you stock water pump pulley is will be smaller and you will over drive you water pump. The other problem is that it has been 30 to 40 years since they have been made and they are getting rarer everyday. If I had a set of any of the three I would demand at least $100 for a complete set. You should also get he alternator bracket but it is not really necessary; they are the same but the air pump bracket is longer to hold the air pump. But this can be cut off to clean it up.

    I tried to move my alternator in (directly the head) and run it on one belt back. But this system works but it will over drive your water pump.

    Don't know what else to tell you.

    TED
     
    Roy Heisenberg likes this.
  10. Roy Heisenberg

    Roy Heisenberg The 472 Crank is stronger due to overlap

    Joined:
    Dec 26, 2018
    Messages:
    212
    Likes Received:
    23
    Location:
    Folsom, California
    What vehicle(s) do you drive?:
    472 Caddy in a ‘75 Jeep J-20 TH-400 Dana-60 100LL
    8B14C2E2-03C6-474A-9E33-83E918CD6A41.png 35A52E42-25BC-49F6-A2DD-721B0A1260A4.png Here are 3 cams that can make some power, but mostly just idle like a top fuel dragster....

    The Big Mutha Thumper seems just about right for a 472?

    Enjoy these in your 472 or 500,
    Roy
     

Share This Page