bearing clearance too tight

[ace1]

I am getting to small clearances on my bearings. All new parts. Crank mic's on spec, 2.45 mains, 2.1 rods. I torqued caps and used dial bore gauge. I get .001 clearance on mains and rods. Will using the .001 bearings give enough clearance. Are they available for the rods? I thought there would be more clearance than this on new parts. Whats my options.

[Lizardracing]

Assuming the crank and rods are machined to the middle spec everything should work out fine but in reality that doesn't usually happen. Consider Tolerance Stack Up and that's not an unusual problem to have. +.001 bearings are available for rods and mains for King and Clevitte (ACL's are a little bit more limited) will get you the additional room you need. So will polishing a crank .0005 but I don't like that idea personally. Although you may have to do both to get additional .0015 to reach your .0025 goals.

[fastford]

I didn't realize any one made a + .001 bearing, usually there the other way which would defeat the purpose and take clearance away. ive polished clearance a lot of times and never had a problem. im gone check on those bearings lizard, thanks for the tip......

[powerslide]

What kind/brand of dial bore gage?

[RCJ]

Is the crank on the high side off tolerance?

[ace1]

Enco gage. Crank is right on 2.45 mains. About 2.0992 - 2.0998 on rods. Set gage with good starrett mic. I'm going to start all over and mic everything again. Even going to use some plastigage for a comparison. I just don't believe its right. I don't see getting only .001 on both main and rods. But may be.

[powerslide]

I agree double check with the plastic gauge. How does it feel when you spin it? If its leaving a mark in the bearing you are getting a false reading. Sunnen is the best for bearings.

[ace1]

I miced the crank again. I'm confident its right. Checked one main with bore gauge and still get .001. Tried plastigage and got just a little under .002. I didn't check the rods again. Its going to the machine shop to get check out. Thanks for the suggestions.

[fastford]

plastigage if very finiky, its got to be less than 3 months old , and should be used in a 70 degree controlled environment where every thing your checking is the same temp as the room or it will give a false reading. I also use a starrett dial bore gage. this is the only way to get a true reading but it has to be calibrated to the journal properly . I made a stand to hold my mic so I could set my dial bore gage to "0" a lot easier. I would trust my bore gage if I were you.....

[RCJ]

I have a set of king bearings that gave me to much clearance. I 'LL mail them to you to try if you would like.What brand of bearing are you using now?

[ace1]

I had a set of king before I got the bore gauge. I damaged them so picked up a set of sealed power at local parts store to see what happened. Your set might be worth a try. Might save me some machine work.

[RCJ]

Oops, found the bearing.They were .010.I've run in to clearance problems a lot.I would run the rods down to .0019 ,mains .0022.Crankshaft spec is 2.4481 to 2.4490 .does sound like your crank is big

[ace1]

This one is 2.448-2.449 also. Rods are 2.0993-2.099. Its going to my motor man. He'll get it going.

[HINKSON AUTO]

Enco gage. Crank is right on 2.45 mains. About 2.0992 - 2.0998 on rods. Set gage with good starrett mic. I'm going to start all over and mic everything again. Even going to use some plastigage for a comparison. I just don't believe its right. I don't see getting only .001 on both main and rods. But may be.

Don't use cheap bore gauges to check bearing clearances. Look this thread over http://www.performanceboats.com/gn7-...learances.html

[ace1]

I hope its that simple as a cheap gauge.

[TBRE]

I agree Hinkson...........