From the Reference Section:
- Buick Compound Carburetion
- Buick F-263 Head/Gasket Swaps, effects on compression
- Straight Eight Engine Specifications
-
263 Head X-Sections
    - Building a High Performance Straight Eight
- Buick Straight Eight Lifter Adjustment
- Straight Eight Intake Manifold X-Sections
- Straight Eight Oil Supply Update
Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: im new on block will crankshaft out of 1941 248 swap over 1950 248 1950 has rod brg

  1. #1
    Join Date
    Aug 2018
    Location
    pleasant g
    Posts
    5
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0

    im new on block will crankshaft out of 1941 248 swap over 1950 248 1950 has rod brg

    can i still use the 1950 rods are the front and rear seal interchanable

  2. #2
    Join Date
    Dec 2013
    Posts
    369
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0

    1941 to 1950 crankshaft

    Are you saying you want to use a 1941 crank in a 1950?

    Seals should be the same.

    Ben

  3. #3
    Join Date
    Aug 2018
    Location
    pleasant g
    Posts
    5
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0

    THANKS FOR THE HELP BEN swapping the cranks is my last straw IM hopeing to redill

    crankflange for standard flywheel

  4. #4
    Join Date
    Mar 2018
    Location
    Zimmerman,
    Posts
    29
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0
    The Hollander Interchange manual says crankshafts from 1939 to 1950 for stick shift Buicks of the model series 40 and 50 will interchange. 1951-53, cranks went from the 248s to the 263 and are are a lot different.
    So your 1941 248 Crank should fit the 1950 engine. Of course you will have to measure the journals to see if it has been reground, needing oversize bearings. Note each main bearing journal on the 248 crank is a different size. In 1951, they started making all the main bearing journals the same diameter.

    If your 1950 has a Dynaflow, the 1941 stick shift crank will not be compatible due to different flywheel mounting flange.
    Dave

  5. #5
    Join Date
    Feb 2018
    Location
    bothell, w
    Posts
    21
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0
    Quote Originally Posted by outbdnut View Post
    The Hollander Interchange manual says crankshafts from 1939 to 1950 for stick shift Buicks of the model series 40 and 50 will interchange. 1951-53, cranks went from the 248s to the 263 and are are a lot different.
    So your 1941 248 Crank should fit the 1950 engine. Of course you will have to measure the journals to see if it has been reground, needing oversize bearings. Note each main bearing journal on the 248 crank is a different size. In 1951, they started making all the main bearing journals the same diameter.

    If your 1950 has a Dynaflow, the 1941 stick shift crank will not be compatible due to different flywheel mounting flange.
    Dave
    Toss in my 2 cents worth here, the above is correct, 248 cranks interchange except dynaflow cranks and stick shift are different and can't be remachined to interchange or at least, with out great difficulty. The real trick here is, what rod are you going to use? The obvious rod to use is the 50 insert bearing rod, not the babbeted rod. Not so fast. The insert rod and the babbet rod are the same width. When Buick went to insert bearings they made a special wide bearing to fit. These bearings are no longer available. The only rod bearing you can get are rod bearings that fit other engines that just happen to fit the str8 rod, they are much narrower, like 7/8" vs. 1 1/4" about. This leaves a big gap on each side of the bearing. That's where the oil will squirt over to. Bearings are only as good as the oil supply. Two ways to solve. Rebuild the babbet rods and send off to Calico for Teflon coating the big end. A pain to do but with todays oil and a little zinc additive they will last for ever. Other option, if the original rod bearings are not in bad shape, like not run into the copper or pounded out or full of embedded grit, etc, send them off to Calico for coating. I've done this several times, works like a charm and its cheep insurance incase you loose a head gasket or such and get a load of antifreeze in the oil. Alleycat

  6. #6
    Join Date
    Mar 2018
    Location
    Zimmerman,
    Posts
    29
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0
    So are you saying these rod bearings won't fit his 1950 248? or they just won't fit his 248 when a 1941 Crank is used?


    https://www.kanter.com/productdetail...Router=Gallery

  7. #7
    Join Date
    Aug 2018
    Location
    pleasant g
    Posts
    5
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0

    Thumbs up Thanks for your help info i did not know ngmonty

    No after market suppyers made the wide rod brg insert ?




    Quote Originally Posted by alleycatoo View Post
    toss in my 2 cents worth here, the above is correct, 248 cranks interchange except dynaflow cranks and stick shift are different and can't be remachined to interchange or at least, with out great difficulty. The real trick here is, what rod are you going to use? The obvious rod to use is the 50 insert bearing rod, not the babbeted rod. Not so fast. The insert rod and the babbet rod are the same width. When buick went to insert bearings they made a special wide bearing to fit. These bearings are no longer available. The only rod bearing you can get are rod bearings that fit other engines that just happen to fit the str8 rod, they are much narrower, like 7/8" vs. 1 1/4" about. This leaves a big gap on each side of the bearing. That's where the oil will squirt over to. Bearings are only as good as the oil supply. Two ways to solve. Rebuild the babbet rods and send off to calico for teflon coating the big end. A pain to do but with todays oil and a little zinc additive they will last for ever. Other option, if the original rod bearings are not in bad shape, like not run into the copper or pounded out or full of embedded grit, etc, send them off to calico for coating. I've done this several times, works like a charm and its cheep insurance incase you loose a head gasket or such and get a load of antifreeze in the oil. Alleycat

  8. #8
    Join Date
    Feb 2018
    Location
    bothell, w
    Posts
    21
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0
    Yes and no. All the 248 cranks will interchange. The very early ones may not because possiably the mains were poured babbet as well which is different thing and exactly when the change over happened I'm not sure. But the journals for the babbet or insert bearing rods stayed the same. So the problem is with the insert bearings that are available for the insert rods. The rod bearings that suppliers have are bearings that are actually for other engines that just happen to fit the str8 rod. And they are narrower. The originals are much wider, nobody makes 'em. I'll just bet the guys selling them don't even know the difference. So what you end up with is a rod bearing with reduced load carrying capacity due to increased side clearance. The oil pump has a limited amount of capacity and pressure. Makes me nervious. So, it looks like to me that if you want a bullitproof engine the babbeted rods are the way to go. Is it a pain in the behind to rebuild these babys? Yup. But if you're rolling down the road to a show or something and about 60 miles into the trip and a rod bearing goes away and they go fast...Going to be a unhappy day. I like the insert type rods but if ya can't get the right bearing for it, kinda moot point. Alleycat

  9. #9
    Join Date
    Aug 2018
    Location
    pleasant g
    Posts
    5
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0

    Im new on the block rear main oil seals

    On a 248motor has any body had good luck with the new rubber seal instead of the rope seal?

  10. #10
    Join Date
    Feb 2018
    Location
    bothell, w
    Posts
    21
    My Feedback

    (0% Positive Feedback)
    Rep Power
    0
    yes indeed! And, I like 'em! The problem with the rope seal is that in order to get a good leak free seal, you got to really pack that seal in there. It then takes about 30-40 foot pounds of torque to turn the engine! The rubber seal takes about 5! That means that torque goes into power output not frictional losses. I haven't run the pudding out of 'em over a long period of time but so far...not bad! Alleycat

Similar Threads

  1. Ngmonty new on the block 1950 sp sedanette need help switching dyn to standard
    By ngmonty in forum Nailhead: 264, 322, 364, 401, 425
    Replies: 0
    Last Post: 08-01-2018, 05:07 PM
  2. 1950 Buick Bullet Fuse Block Connector
    By rsvp4sean in forum Straight Eights!
    Replies: 11
    Last Post: 01-29-2012, 04:03 PM
  3. 1950 Buick Engine Swap Help
    By ssk875 in forum Engine and Transmission Swaps
    Replies: 4
    Last Post: 06-27-2011, 10:57 PM
  4. Transplant 1950 into 1941?
    By wickedgoodracing in forum Transmissions and Drivelines...
    Replies: 3
    Last Post: 10-28-2007, 07:02 PM
  5. 1950 chassis swap wanted
    By pat50 in forum Tools, Shops, and Garages
    Replies: 0
    Last Post: 01-13-2006, 04:58 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Featured Items

TeamBuick.com Privacy Policy