I just recently bought a 74 360 la block .060" overbore, i know it has been built at least a couple times and curious how many times it can be align honed before it is unusable. thanks for any responses

 

Do you mean cylinder overbore, or are you actually referring to "align bored" which is the process of boring through the main journals to correct crankshaft misalignment.

I'd say that if an engine needs to be align bored more than once, it's probably done.

Every time you do this, you move the crank centerline up into the block, which makes the cam drive situation worse, and you need to mill the ends of the main caps (or use aftermarket) to make them shorter (smaller) so that you can take material out.

CYLINDER overbore just depends on the block. Some engines will go .125 oversize, others are lucky to make it to .060

 

[QUOTE=birkey;80658 can you get oversized bearings for the mains just like you would if the rod journals were taken down.[/QUOTE]

You can get UNDERsized mains just like the rods, but this has nothing to do with 'line boring.'

Whenever you buy a ground crank, it will be expressed as 010-010, or 010-020, etc, which amounts to the sizes it was ground to.

(Sorry, for the life of me I cannot remember which size is first, rod or mains, but you need to find this out, as they are often NOT the same undersize)

 

if you align bore then your bearing cleareances will change, right? hints bigger bearings?

 

NO, line boring, and I thought I made that clear, is to correct crank misalignment, or damaged bearing saddles. What you do is, you mill the ends off the caps which of course makes them shorter, or you use aftermarket caps, which must be bored to the engine on which they will be used. So aftermarket caps are purposely undersized.

You bore the block and caps, and the only way to clean up the upper (block) side of the saddles, is to move the tool center UP towards the camshaft. So when you are done, the crank centerline is not UP further into the block, the bearing saddles are the same OUTER size as originals, and everything should be square, plumb, ready for new bearings.

One article:

http://www.enginebuildermag.com/Arti...g_subject.aspx

 

My 440 block just came out of the shop. Both the mains and rods were honed to correct bearing clearances.

 

so i should consider buying a tensioner for the timing chain

 

Nope

 

440 Roadrunner, dont you mean that the crank centerline is NOW up further into the block after align boring, no matter which caps you use? You wrote that the crank centerline is NOT up further into the block.