Camshaft journal size

[Denalibro76]

Does anyone know when the split between 2003 and 2004 blocks happened? I understand that the journal sizes are different between the two years? My LQ4 is a 2003 with a casting of G13 on the front passenger side. Do these digits correlate to anything? In a nutshell I’m asking which cam bearings to get? Can anyone help me out with brands and part numbers that will work with what I have?

 

[Donal]

You may need to supply the vehicle VIN to get the correct bearing for your application. Looks like position 1 and 5 are different diameters.
First design: Position 1 and 5 Diameter 2.3260/ 2.3280 inches. Clevite num. SH1814S

Second design: Position 1 and 5 dia. 2.3460/2.3480 inches. Clevite num. SH2125S

You may PM the VIN if you want further asistance.

 

[Denalibro76]

You may need to supply the vehicle VIN to get the correct bearing for your application. Looks like position 1 and 5 are different diameters.
First design: Position 1 and 5 Diameter 2.3260/ 2.3280 inches. Clevite num. SH1814S

Second design: Position 1 and 5 dia. 2.3460/2.3480 inches. Clevite num. SH2125S

You may PM the VIN if you want further asistance.

Thanks!! Yeah I have the first design. The oiling holes are the smaller holes. The 2nd design have larger ones. Just getting ready to knock the old ones out and clean those journals. The rest of the block is ready for assembly. Just have to chase the head bolt threads.

 

[swathdiver]

Thanks!! Yeah I have the first design. The oiling holes are the smaller holes. The 2nd design have larger ones. Just getting ready to knock the old ones out and clean those journals. The rest of the block is ready for assembly. Just have to chase the head bolt threads.

Unless I am confusing something, I thought that the new bearings can be used in the older blocks as they are wider. Contact Brian Nutter at Summit Racing or wherever he is these days to make sure.

 

[Denalibro76]

Unless I am confusing something, I thought that the new bearings can be used in the older blocks as they are wider. Contact Brian Nutter at Summit Racing or wherever he is these days to make sure.

Do you have any ideas as to why they made the OD of the bore different in position 1/5? The journals of the cam are always the same are they not? Why the need to make the bearing thicker or thinner depending on the location? Seems silly to me but I’m by no means an expert on the situation.

 

[swathdiver]

Do you have any ideas as to why they made the OD of the bore different in position 1/5? The journals of the cam are always the same are they not? Why the need to make the bearing thicker or thinner depending on the location? Seems silly to me but I’m by no means an expert on the situation.

Your question is starting to jar my memory. The information wasn't in an online file I keep, it might be in a book on my shelf. Let me check...

 

[Donal]

Do you have any ideas as to why they made the OD of the bore different in position 1/5? The journals of the cam are always the same are they not? Why the need to make the bearing thicker or thinner depending on the location? Seems silly to me but I’m by no means an expert on the situation.

Many features and dimensions of engine blocks are to enable/allow machining operations to be performed. The orginals SBC cam bearings were location specific well.

 

[swathdiver]

Your question is starting to jar my memory. The information wasn't in an online file I keep, it might be in a book on my shelf. Let me check...

Can't find any of the books, someone moved them! Pretty sure that info was in How to Build and Modify GM LS-Series Engines by Joseph Potak. Ask Nutter, he'll probably know off the top of his head.

 

[Denalibro76]

Many features and dimensions of engine blocks are to enable/allow machining operations to be performed. The orginals SBC cam bearings were location specific well.

Yeah I guess that makes sense

 

[Denalibro76]

Can't find any of the books, someone moved them! Pretty sure that info was in How to Build and Modify GM LS-Series Engines by Joseph Potak. Ask Nutter, he'll probably know off the top of his head.

On a side note/question…you happen to know what the GM specs for main and rod bearing clearance? I got them all measured out and I’m ready to order bearings. I have .0015 on the mains and .0020 on the rods