Video - in line Boring - but is it correct

[pad4]

Just mooching around on youtube and come across this very nice video of a snazzy machine inline boring a block.

Not being the engineer type really - is it right there taking material from the surface of the bearing housing on the actual block its self, and not just from the caps

Surely this would move the crank centre further into the block - or is it made up with the bearings ?

http://www.youtube.com/watch?v=UZBmSjVH_XU

Pad

[Chalkie]

Its just lining all the main's up so the crank can run true

you make up what you lose with +0.010 bearings (may have size wrong)
after market caps won't match your block nore will 2 a series engines side by side match down to who machined them.

[mk1]

You do take the merest scrape of material off the block when line boring a block. This is usually just a few thou & is far to little to effect anything adversely.

M

[Smiffy]

I'd expect thats the modern equivalent using some sort of cad system. Ok when it's all brand new but she it's slightly worn then you'll have lots of fun with it.
This is proper Line Boring:
http://www.youtube.com/watch?v=IXPEKlGBGLo

[251 ENG]

The block being line bored is a 1275 midget or marina block so no problems with drop gear mesh if you move the crank centre line . BUT it will effect timing chain fit .

They seam to be taking quite a lot out of the block , block does not appear to have been machined down on sump / bearing cap face so this may just be a scrap block being machine for show or it is being opened out to use a different bearing with a bigger housing size .

The tolerance on the main bearing housings on an A series block is 0.0005" , or but it another way , cut a human hair in to 8 equal bits .

[pad4]

So really on a miniblock its best not to remove anymetal from the block itself

pad

[Spider]

251 ENG is spot on here.

So really on a miniblock its best not to remove anymetal from the block itself

pad

Yes if it can be avoided.

I have done them without line boring, but you need to be 100% sure that the tunnels in the block are perfect, or it'll be a wasted effort.

[251 ENG]

Yes , it takes some real skill to line bore a block with steel caps as the cutter wants to " push off " the tough steel and cut the soft iron . Just what you don,t want . Line honing is much better for taking out small amounts of metal .