VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 216 conrods

I am having a 48 motor rebuilt with slipper bearings. In the process the machine shop decided that one conrod was no good so he used a 38 conrod.He noticed that it was too wide on the bigend so he machined it down. My mechanic is now assembling the motor and finds that the piston is protruding slightly from the block. I note that the conrods for 48 differ in number from 1938. Does anyone know if there is a difference in the length of the conrods?
I gather that I cannot put the 38 head on the 48 block because the compression ration will drop badly.

I didn't hear anything in your post about weighing the rods/pistons. Sounds like a disaster in the making. Does the mechanic have any credentials?

I think I would stop the operation and get things straightened out.

1948 connecting rods are different from 1938 connecting rods. 1937-1947 connecting rods are the same. I agree with Ray. Stop now with the reassembly of the 1948 engine and get it figured out before it is too late.

I also agree! Sounds like your machine shop lacks the experience to do the job correctly. Stop now before you waste a ton of money! :eek: :( :( :(

The 1937-47 conn. rods are wider than the 1948-53 - but the length is the same.The piston height is another problem. :confused:

216 and 235 use the same rods for a give year.

What is the number on the strange rod???

The rod bearings on 37-48 are babbit lined and are bonded to the rod and cap, and shims are to be used to get the proper adjustment, is it possible it is over-shimmed?
Why have you chosen slipper bearings? I agree with the others, stop now.
Good luck, Walt

If you are rebuilding a 48 block, with a 48 crankshaft in it you CANNOT use any rods before 1948!!! The 48 crank pins are not as wide as the crank pins on a 47 and earlier 216. I know first hand, as I am in the process of rebuilding a 47 216, and have many NOS 48 parts that just wont fit!! If you are interested I have a complete set of 1950 insert type rods, with a complete set of NOS rod bearings .020 under size that would work great in a 48 block, and are just sitting on my shelf!! I also agree with the others, that I would consider changing machine shops!! You are at a critical stage in rebuilding! I would stop and regroup before you regret it!!!
Drop me line: vintagesarge@sbcglobal.net

Yikes Terry, this situation does NOT sound good. Actually sounds very bad! It's unfortunate; but sounds best to STOP even tho in process.

Bill.

I tend to agree with all of you.I am reviewing the situation. The mechanic is good and the machine shop has a good reputation. Unfortunately he went and did the 38 rod without asking me to check out the situation beforehand.
I asked a lot of people about the 48 motor and of course they said "they're all the same!".We now know that they are not.
Why did I use slipper bearings? (1)There are very few people in Sydney who can pour bearings and they are (a) Expensive (B) Questionable (3) Snowed under with work. Slipper bearings were supposedly the answer to all problems.
Thank you for your advice and offers of parts. I will stop the work and consider the next step.

I gather Terry refers to "Inserted" rod bearings as "slipper bearings", I have heard the term before here from some of the older mechanics. There aren't many places anymore that pour or spin babbit bearings for rods. Maybe it is because the old babbit rods are so durable and work forever with proper care and lubrication, or there just ain't very many around.

I've been hearing "they're all the same" for 50
years. And, the uninformed mean from '29 to '53.
Some refer to the 216's as the same....

There aren't many people babbitting thes 216 rods because they require a very thin layer of babbitt. There are many doing babbitting for other motors like the FQrd flatheads. When you convert the rods to inserts, you get to use a modern bearing material which should be more durable.