Ok LA Fans Explain this one to me......

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ply478

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The main caps are in order front to back. 1-2-3-4

Numbers 2 & 4 Main Caps have the windage tray main stud bolts.

Look at the block main on #3 The groove for the thrust bearing machined into the block.

Then look at the #4 Main cap. There is the other groove for the other half of the main thrust bearing.

What the heck? Has anyone ever seen this before?

PLY478

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The caps obviously got mixed up. A thrust cap doesn't work on a non thrust saddle. As far as the windage tray bolts. They are just bolts and can go wherever they are needed.
 
I get that... So your saying the Casting numbers are wrong? Like I said they are in order. Front to back by the casting number.
 
ply478 said:
I get that... So your saying the Casting numbers are wrong? Like I said they are in order. Front to back by the casting number.
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That part is strange. May be the caps were put in the wrong place and then the block machined. I wouldn't worry about the number mis match. Did the previous build have a thrust bearing upper in one position and a nother lower bearing in a different position? SO many questions! I would mate the correct thrust bearing cap with it's saddle and have your machine shop check the bores and the line bore. Just to be safe.
 
I wish I could answer some of your questions in post #4. I cant remember, as I tore this block apart 10 plus years ago. It was soaked with oil and shrink wrapped all these years until about a month ago. The project is now back in the garage.
 
ply478 said:
I wish I could answer some of your questions in post #4. I cant remember, as I tore this block apart 10 plus years ago. It was soaked with oil and shrink wrapped all these years until about a month ago. The project is now back in the garage.
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And the questions you are asking we can't answer, just speculate. You are going to need help from a machine shop.
 
JDMopar said:
Looks like a Monday morning or Friday afternoon machining job at the factory it was built in! :eek:
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Or Wednesday evening lunch break after the cafeteria vending machine got filled with Pabst, Stroh's, and Old Milwaukee...
 
It's at the machine shop now. They are on it. And if it needs to be line honed so be it. I was just posting how odd this is.
 
ply478 said:
It's at the machine shop now. They are on it. And if it needs to be line honed so be it. I was just posting how odd this is.
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They'll get it straightened out for you. Crazy things like this have happened before. The caps were probably matched up regardless of the numbers. You put the caps back on in number order some years ago not noticing the mismatch.
 
Leave the caps in order as they are numbered. The third cap saddles the only crank bearing that has sides for proper crank endplay. The rest of the main bearings have no issues on how they ride in the cap/ block….all is good.
 
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Dicer said:
Leave the caps in order as they are numbered. The rear cap saddles the only crank bearing that has sides for proper crank endplay. The rest of the main bearings have no issues on how they ride in the cap/ block….all is good.
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The thrust bearing is #3 saddle.

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Bolt position doesn’t matter. Block was machined with caps 3 and 4 backwards. Put for in 3 position and 3 in 4 position and re-mark them and move on. I’d bet there’s no need to align hone...
 
Dicer said:
Leave the caps in order as they are numbered. The third cap saddles the only crank bearing that has sides for proper crank endplay. The rest of the main bearings have no issues on how they ride in the cap/ block….all is good.
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U can’t do that as there is no room for the thrust bearing to fit between the crank counterweights. So the number 4 had to be in number 3 position even though it is numbered as such. Kim
 
Put the thrust bearing cap where it belongs, ignore the numbers on caps 3 and 4, and line hone it to be safe. It might not need the line hone, but if you have a competent machinist, i would.
An INcompetent machinist can just make it worse.
Btw, it could not have been assembled and ran with the caps in the numbered positions.
 
33IMP said:
Put the thrust bearing cap where it belongs, ignore the numbers on caps 3 and 4, and line hone it to be safe. It might not need the line hone, but if you have a competent machinist, i would.
An INcompetent machinist can just make it worse.
Btw, it could not have been assembled and ran with the caps in the numbered positions.
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That’s right. All those years ago u did t pay attention taking it apart. Then when u assembled it u were probably thinking this can’t be right but hey the numbers say so. Kim
 
Exactly. The thrust flange was machined when the original line hone was done, with the 3 & 4 caps mixed up. Just put it back so 4 is in the 3position and 3 is in the 4 position & check the main bores.
 
All is good. Main caps switched. Line bore was just checked and all came out well with no line bore needed. A Great machine shop!
 
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