440 #1 main bearing

[mopar367]

I am assembling a 440 and while installing the main bearings the Chrysler chassis manual I have from 1976 says- "The No. 1 upper main bearing IS NOT INTERCHANGEABLE AND IS CHAMFERED on the tab side for timing chain oiling and can be identified by a red marking on the edge of the bearing."

The bearings I have do not have one that is marked in red. How do I
identify the "chamfered" bearing, and/or is this important? All the upper
main bearings fit each 1, 2, 4, and 5 upper bearing supports (3 is the
thrust bearing and is obviously different). Are all upper mains the same
today? Do they all have the necessary chamfer to oil the timing chain?

The bearings I have are sealed power 4924. Has anybody come across this problem?

​

 

[lewtot184]

i'm going to go out on a limb here, but i haven't seen a "red" #1 bearing in ages. i don't think they're made anymore. i have a set of those bearings with 2-02 dates and no sign of the "red/chamfered" #1 bearing.

 

[mopar367]

Ya there could be a chance they don't make the bearings like that anymore. Since you have the same bearings was there a difference in the #1 upper? Book says it doesn't interchange. All the bearing uppers look the same to me.

 

[lewtot184]

no difference.

 

[Cranky]

I don't recall seeing a different bearing....ever.

 

[67 B-body]

I don't think I've ever seen a different bearing in any kit I've purchased....

 

[lewtot184]

i vaguely remember the red stripe but that was decades ago.

 

[mopar367]

Thanks guys, I looked the bearings over quite thoroughly. I couldn't tell any difference either. I think because my book is so dated they might have made the bearings differently back then. All mine have a chamfered edge on them. I think back in the day they might have had a 90 degree edge with no chamfer. Anyways I got the crank in and all is good. But now I have to remove it and grind where weight was added for the balance.

 

[Meep-Meep]

Thanks guys, I looked the bearings over quite thoroughly. I couldn't tell any difference either. I think because my book is so dated they might have made the bearings differently back then. All mine have a chamfered edge on them. I think back in the day they might have had a 90 degree edge with no chamfer. Anyways I got the crank in and all is good. But now I have to remove it and grind where weight was added for the balance.

Yeah, not sure about the special bearing either, but I bet that info was superseded.

I hope you mean you will clearance the block and NOT grind on the crank!

 

[bluefury]

Chamfered upper bearing shell

I am assembling a 440 and while installing the main bearings the Chrysler chassis manual I have from 1976 says- "The No. 1 upper main bearing IS NOT INTERCHANGEABLE AND IS CHAMFERED on the tab side for timing chain oiling and can be identified by a red marking on the edge of the bearing."

I remember there being an issue with #1 upper main bearing failures due to overtightening of belts. Not just on Mopars either. I wonder if the chamfering of the bearing was to allow extra lubrication in an effort to avoid the problem....?????

It could be that they went on to chamfer all the bearings to avoid confusion and potental for improper installation.

 

[Cranky]

I am assembling a 440 and while installing the main bearings the Chrysler chassis manual I have from 1976 says- "The No. 1 upper main bearing IS NOT INTERCHANGEABLE AND IS CHAMFERED on the tab side for timing chain oiling and can be identified by a red marking on the edge of the bearing."

I remember there being an issue with #1 upper main bearing failures due to overtightening of belts. Not just on Mopars either. I wonder if the chamfering of the bearing was to allow extra lubrication in an effort to avoid the problem....?????

It could be that they went on to chamfer all the bearings to avoid confusion and potental for improper installation.

Man, a sleeve bearing takes all kinds of loading and I would think the pounding of the pistons would knock out the bottom bearing before overtightened belts would take out the upper.....just saying....

 

[bluefury]

bearing loads

Man, a sleeve bearing takes all kinds of loading and I would think the pounding of the pistons would knock out the bottom bearing before overtightened belts would take out the upper.....just saying....


I'm not speculating, this used to be a REAL issue. Chevy 409 engines were especially prone to #1 engine bearing falure because of overtight belts.

Here is a link that might help explain.


http://www.brakeandfrontend.com/Article/46777/Tech_Featu.aspx