A Little Help Please

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75Sport

75Sport

Grandpa
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This picture shows the width of thrust bearing recess on the # 3 main cap off my 360 LA. Do you agree that this width represents the 1974 and up supposedly wider thrust bearing being used? I say supposedly because my block was cast in October of 1972. Thanks in advance for the input.
Dan
 

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???
& With Respects Sir why exactly are You concerned about the O/D
of the Brng Insert or Yr of build...
Imho,
I see no 'fretting' on the 1 pic--- on #3.

Could I impose for another picture (with the same Mitutoyo)?
Across the machined thrust areas, front & rear #3 main cap ???

Thx!!!
 
mech1nxh said:
???
& With Respects Sir why exactly are You concerned about the O/D
of the Brng Insert or Yr of build...
Click to expand...


They made the "flange" on the thrust bearing larger in 74 and later engines.

However, I have seen that they incorporated the larger machining on it much earlier than 74.

So many of the pre 74 engines can still run the larger thrust bearing with the larger flange.

You can put the smaller flange main on all of the engines, but you can't put the large flange thrust bearing on one that doesn't have the deeper machining for it...

Always check the flange area of the thrust bearing with your bearing to make sure that they are compatible...

This was to help reduce wear on the thrust faces by providing more surface area to distribute the load....
 
A logical explanation to this, When Ma Mopar cast blocks they were done way in advance. I had a 6-6-71 340 block that was a cast crank motor and the year on the pan rail was showing it as a 3Bxxxxxx. The actual build date of the engine in fact backed this up on the drivers side front of the block. The larger thrust bearing was a 1974 release, but the block date code would be much earlier.
 
SGBARRACUDA said:
A logical explanation to this, When Ma Mopar cast blocks they were done way in advance. I had a 6-6-71 340 block that was a cast crank motor and the year on the pan rail was showing it as a 3Bxxxxxx. The actual build date of the engine in fact backed this up on the drivers side front of the block. The larger thrust bearing was a 1974 release, but the block date code would be much earlier.
Click to expand...


Chrycler made the change easier by implementing the new cut in the blocks way before the new bearing was available. That way they can purge out all of the early blocks with the smaller "scallop" for the bearing before the change...

Versus waiting until the new bearing was available, then trying to find any and all early blocks with the smaller scallop and running them out or scrapping them once the new bearing is released.

This way, when the new bearing is available, all blocks can use it and no need to sort or scrap blocks. It saves on scrap, rework, and special batch runs to use up the old blocks...
 
And I imagine just like the BB with the large thrust bearing cut, you can use the smaller flange bearing. Done that a few times
 
SGBARRACUDA said:
And I imagine just like the BB with the large thrust bearing cut, you can use the smaller flange bearing. Done that a few times
Click to expand...

Yes, as long as the block is cut for it and it fits with no interference...
 
krazykuda said:
Chrycler made the change easier by implementing the new cut in the blocks way before the new bearing was available. That way they can purge out all of the early blocks with the smaller "scallop" for the bearing before the change...

Versus waiting until the new bearing was available, then trying to find any and all early blocks with the smaller scallop and running them out or scrapping them once the new bearing is released.

This way, when the new bearing is available, all blocks can use it and no need to sort or scrap blocks. It saves on scrap, rework, and special batch runs to use up the old blocks...
Click to expand...
I'm glad I bumped this up. Thanks for all the confirming information. I should have known but I didn't. Thanks kuda! Dan
 
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