Cam and main bearing question

[MikeH686]

Im rebuilding my 302 and was looking online at rod and main bearings and cam bearings and all what not but one thing has me for a whirl is that the bearings have three different sizes that i can pick from .001,.010,.030 i would like some education on what size i should get as best to my knowledge the owner before me has not done anything other then boreing the block .030. if someone could help this would be greatly appreciated

 

[RangerJoe]

You will have to measure the mains on your crank. Does the crank need to be turned? Your crank should be something like 2.49" stock. You would have to measure what you have, subtract it from 2.49" and determine which beairings you need. As the crank wears, the mains get worn. If they wear too much, the crank needs to be reground, which would further reduce its size. In relation to the amount you grind away, you would buy oversized bearings: such as the .010 or .030 over bearings you mentioned in order to take up the slack.

Joe

 

[Rick 91GT]

Stock 302 main is 2.249", the other sizes are oversizes to either add or make up clearance, or make up for the area from turning the crank. .010" rod or main

Cam bearings are a standard size for a stock 302, race blocks vary

If you need standard sizes I recommend King Engine Bearings, best brand bearing out IMO and all I use now days.

CAM Bearings CS514BB (tcam bearings require special tools for installation)
MAIN Bearings MB529SI
ROD Bearings CR804SI

 

[rd]

The main and rod bearings work the same way, as the crank wears, it is ground undersize to provide a good finish on the main and rod journals.

New bearings with the matching undersize are then installed. Actually, the crank journals get smaller .010, .020, etc, and the bearing insert is thicker to make up the difference.

Cam bearings are usually fine and may not need to be changed. If changed, they are usually the original (standard size) in anticipation of a new cam. Note that the cam bearing ods are different from front to back on a small Ford, and installing them is usually left to the machine shop. I have rebuilt engines with and without changing them with good results.

 

[RangerJoe]

Stock 302 main is 2.249", the other sizes are oversizes to either add or make up clearance, or make up for the area from turning the crank. .010" rod or main

Cam bearings are a standard size for a stock 302, race blocks vary

If you need standard sizes I recommend King Engine Bearings, best brand bearing out IMO and all I use now days.

CAM Bearings CS514BB (tcam bearings require special tools for installation)
MAIN Bearings MB529SI
ROD Bearings CR804SI

Sorry for giving you the wrong size. Its been a little while since I messed with one.

Joe