WHY ............does anybody know the answer

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trudysduster

trudysduster

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Ok, I am into a total rebuild on a 1966 Valiant. The engine is a slant 6. I bought some main bearings for it. STD. I bought Michigan brand because I have used them before no problem. The last /6 I used these bearings and that engine runs fine. Didnt pay any attention to this. This engine, I opened up the box and started to put the thrust bearing in and it wouldnt fit. Found out that they slipped a cast crank bearing in the box. so I started looking at the rest of the boxes. The box says : consists of 1 pair 7376T, 1 pair of 7377T and 2 pair of 7378 T. The 7377 T is the thrust bearing. so, why do they have 2 different numbers for the other 3 journals. Arent the other 3 journals the same. I checked the bearings and there is no difference in them. they all fit good and look the same. But I am stumped as to why there are 2 pairs with 1 number and 1 pair with a different number. I have checked other sets of main bearings and they have 1 thrust bearing and 3 sets of regular bearings. So, does anybody know why. I am kinda leary now about using these. What kind of bearings do you use on a forged crank for '66. I need to buy a couple of sets as I have another '66 engine after this one.

DSC04053.JPG
 
Oil hole in different location......comes to mind...........
 
trudysduster said:
Ok, I am into a total rebuild on a 1966 Valiant. The engine is a slant 6. I bought some main bearings for it. STD. I bought Michigan brand because I have used them before no problem. The last /6 I used these bearings and that engine runs fine. Didnt pay any attention to this. This engine, I opened up the box and started to put the thrust bearing in and it wouldnt fit. Found out that they slipped a cast crank bearing in the box. so I started looking at the rest of the boxes. The box says : consists of 1 pair 7376T, 1 pair of 7377T and 2 pair of 7378 T. The 7377 T is the thrust bearing. so, why do they have 2 different numbers for the other 3 journals. Arent the other 3 journals the same. I checked the bearings and there is no difference in them. they all fit good and look the same. But I am stumped as to why there are 2 pairs with 1 number and 1 pair with a different number. I have checked other sets of main bearings and they have 1 thrust bearing and 3 sets of regular bearings. So, does anybody know why. I am kinda leary now about using these. What kind of bearings do you use on a forged crank for '66. I need to buy a couple of sets as I have another '66 engine after this one.

View attachment 1716190704
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This might not be an issue but I would have a hard time believing what's inside a bearing box if the original part number has been crossed out. Just sayin'
 
toolmanmike said:
This might not be an issue but I would have a hard time believing what's inside a bearing box if the original part number has been crossed out. Just sayin'
Click to expand...
I just found this on ebay. this I can buy. same Michigan part # 1092T buy look at the parts it says are inside. 1-7377 and 3-7376. That is different from the other box. same seller, same brand

DSC04055.JPG
 
The number 1 main bearing is supposed to have a champher on the upper shell. It is for timing chain lubrication. Except for the champhor the bearing is the same as the #2 and #4
Many if not most of the after market sets do not have the champhor. If I get a set like that I file the champhor on the edge of the bearing shell. I don't know about the aftermarket bearings, but the factory replacement bearing have that marked with a red paint mark.
PS: the factory service manual refers to this.
 
Charrlie_S said:
The number 1 main bearing is supposed to have a champher on the upper shell. It is for timing chain lubrication. Except for the champhor the bearing is the same as the #2 and #4
Many if not most of the after market sets do not have the champhor. If I get a set like that I file the champhor on the edge of the bearing shell. I don't know about the aftermarket bearings, but the factory replacement bearing have that marked with a red paint mark.
PS: the factory service manual refers to this.
Click to expand...
thanks Charlie
 
trudysduster said:
thanks Charlie
Click to expand...
The picture isn't mine but I swiped it and modified it to show you where to put the chamfer. Just knock the inside square edge off with a file where the red mark is from the oil groove all the way out to the front of that upper front bearing shell. I don't do that anymore, I just remove the front oil gallery plug behind the camshaft sprocket and drill about a .040" hole in it and put it back. That puts a pressurized stream of oil right on the back of the camshaft sprocket and soaks the timing set. Either way will work fine.

SLANT 6 OIL CHAMFER.jpg
 
RustyRatRod said:
The picture isn't mine but I swiped it and modified it to show you where to put the chamfer. Just knock the inside square edge off with a file where the red mark is from the oil groove all the way out to the front of that upper front bearing shell. I don't do that anymore, I just remove the front oil gallery plug behind the camshaft sprocket and drill about a .040" hole in it and put it back. That puts a pressurized stream of oil right on the back of the camshaft sprocket and soaks the timing set. Either way will work fine.

View attachment 1716190887
Click to expand...
Perfect picture of what to do. Thanks RRR
 
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