main caps and bearings size

[er82]

I have a good 6 bolt block that didn't come with main caps. So I plan to use main caps from another block that was not good. So the main bores need to be align honed? If the overall diameter is increased what size bearings are available? The bearings I've seen online only have sizes for the crank since that's the wear surface. Is there like a master catalog with all sizes?

 

[BogusSVO]

The caps are cut and the finished housing bore after the align bore/hone will be the same as factory.

You will not need oversized OD bearings,

 

[er82]

The caps are cut and the finished housing bore after the align bore/hone will be the same as factory.

You will not need oversized OD bearings,

Thanks, that would work! I will make sure the machine shop knows about that.

 

[bastarddsm]

Bogus, do they cut the block too?

 

[1990TSIAWDTALON]

Bastarddsm, they basically grind down the main caps mating surface to make them "shorter", fractionally, then bolt them back on and align hone. Dale please correct me if I am wrong but I'm pretty sure its the same way that you resize a rod after spinning a bearing.

 

[BogusSVO]

Yes the block gets cut too.

On average the cap will be cut .005-.010,

Then to true up the housing bore, most will try to just cut .001-.002 from the block side and the rest out of the cap.

 

[BogusSVO]

Bastarddsm, they basically grind down the main caps mating surface to make them "shorter", fractionally, then bolt them back on and align hone. Dale please correct me if I am wrong but I'm pretty sure its the same way that you resize a rod after spinning a bearing.

For the most part you are correct, Depending on how bad the rod spun, both the cap and the rod will be cut the honed back to size.

 

[1990TSIAWDTALON]

^^ From the man that knows for sure!

 

[bastarddsm]

Dale,

What machine cuts the block?

 

[BogusSVO]

I should correct myself,

A line bore machine can be set up to cut a minimal amount from the block.

http://www.ebay.com/itm/A-M-C-L2500...121?pt=LH_DefaultDomain_0&hash=item2a448bc929

Now a line hone will remove appox the same amount of material from both the block and cap.

http://www.ebay.com/itm/G-A-M-Line-Hone-/221760895823?hash=item33a1fabb4f&item=221760895823&vxp=mtr

A line bore can be set up to "off set cut" where a line hone can not.

The best in a perfect world would be a line bore, then finish with a line hone.

 

[bastarddsm]

I meant like cutting the block and cap mating surface on the block side.

 

[BogusSVO]

If tit is needed to cut the block mating surface, I would have to say a fly cutter on a vertical mill would do.

 

[bastarddsm]

Ok, I didn't know if there was a special machine for that or what.