Have a question about an engine that i was given the other day, the engine was bored and honed at a machine shop they put new pistons, bearings, reconditioned the crank and rods, i have this guy that was interested in buying it, but he mentioned that the engine was not line bored, do you guys know what that is, also is this required for a simple build..thanks just forgot to add, it was not line bore it was align boring which he mentioned, isnt that process done after making the bore bigger then isnt it honed.

Line boring ( I think it's called line honing now as the equipment has changed over the years) is an operation that is done to the saddles and caps that the crankshaft and it's bearings are installed. The ends of the caps are machined down, the caps re-installed and torqued, and then the bores are honed on a dedicated machine untill the correct size is established. If the engine was done at a reputable shop, they would have checked the saddles with a straight edge and the bores with a gauge to see if line honing was necessary. It's usually always done if your 'blueprinting' an engine, but mostly done on an 'as-needed' basis otherwise. Sounds like he might be trying to beat you up on price. Call the machine shop and ask if they check for that as part of their rebuilds, I bet they do.

Unless we are installing new caps we line bore and on rebuilds we only line hone as it takes the guess work out later.

Every block that goes through our shop is line honed.

Line boring/honing is EXACTLY the same thing done to the crankshaft bores as is done to the cylinders. You ONLY want to have it line honed if at all possible. The crank bores have to be really misaligned before it needs to be line bored. IF, AND I MEAN IF, the crank bores are not aligned, usually a hone will true up the bores.
I've been buildiing engines for 40+yrs, and I've only run across 2-3 blocks that need line honing. I always have my machinist check the crank bores, and if they are OK, I DO NOT allow him to hone the bores.
SOME machine shops do line honing as a standard procedure to a block. I don't want it done if not needed. Also, I DO NOT allow my machinist to surface the cylinder decks if not needed (again, in 40+yrs of building engines, I've only had 2-3 blockes surfaced). It is critical NOT to surface a block if you need to preserve the original numbers!!!!!!!! In 99.9% of cases, a good head gasket will seal any slight imperfection. :thumbsup:

Line boring/honing is EXACTLY the same thing done to the crankshaft bores as is done to the cylinders. You ONLY want to have it line honed if at all possible. The crank bores have to be really misaligned before it needs to be line bored. IF, AND I MEAN IF, the crank bores are not aligned, usually a hone will true up the bores.
I've been buildiing engines for 40+yrs, and I've only run across 2-3 blocks that need line honing. I always have my machinist check the crank bores, and if they are OK, I DO NOT allow him to hone the bores.
SOME machine shops do line honing as a standard procedure to a block. I don't want it done if not needed. Also, I DO NOT allow my machinist to surface the cylinder decks if not needed (again, in 40+yrs of building engines, I've only had 2-3 blockes surfaced). It is critical NOT to surface a block if you need to preserve the original numbers!!!!!!!! In 99.9% of cases, a good head gasket will seal any slight imperfection. :thumbsup:

TOM

We line hone all are blocks as find alot alignment issues with the blocks that go through our performance shop but there again we do all performance work and we only line bore if installing caps.

I hope your not boring the blocks off an unsquared decks as most shops bore of the decks and not having them squared first is not the correct way to get the cylinder bores true to the main line.

At our shop we bore a few blocks where the numbers have to be preserved as we are set up to bore of the main line and not the decks.

We have had some blocks in the shop where guys have bored off from an unsquared deck and tried to correct them to find out they won't clean up from .030 to .040 and at .060 most of the time they won't pass the sonic test.

Well i think he was trying to do just that, this guys running a shop called Custom-Mania down here in chino,ca, he has a 70 nova that he sort of fixed up from the ground up, looks very good, came to me saying that he needed an engine for it since the one he had, had low compression, i beleive he had the car listed on ebay for 15k only one bid, had to cancel bid since his engine was not ready...thanks guys...

Line boring/honing is EXACTLY the same thing done to the crankshaft bores as is done to the cylinders. You ONLY want to have it line honed if at all possible. The crank bores have to be really misaligned before it needs to be line bored. IF, AND I MEAN IF, the crank bores are not aligned, usually a hone will true up the bores.
I've been buildiing engines for 40+yrs, and I've only run across 2-3 blocks that need line honing. I always have my machinist check the crank bores, and if they are OK, I DO NOT allow him to hone the bores.
SOME machine shops do line honing as a standard procedure to a block. I don't want it done if not needed. Also, I DO NOT allow my machinist to surface the cylinder decks if not needed (again, in 40+yrs of building engines, I've only had 2-3 blockes surfaced). It is critical NOT to surface a block if you need to preserve the original numbers!!!!!!!! In 99.9% of cases, a good head gasket will seal any slight imperfection. :thumbsup:
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Tom,
While I respect your opinon I do not completly agree with this if you are building a performance engine
I do a lot of blocks & I deck 99% of them unless specificly asked not to as they can be horrible.
I do not build a performance engine unless I square the deck

I did three blocks recently that are a great example
Two were 400 small blocks & one was a BB
The nominal deck height for a SB is 9.025 & for a BB 9.800 for the standard deck
The two 400's
Worst one was 9.011 on one corner, 9.031 on the opposite end of the other side.
Sweeping this block from intake to exhaust was over .010 from a 45° using the cam as a datum.
The other was better, 9.019-9.027
The 454 was 9.797 to 9.815

Now the question becomes,,,, which hole, side or corner do you want to use as your deck height :D

This is why I don't build performance engines without decking the block square from the mains to whatever piston height I require.
Usually zero to .005 down.
The only exception would be a numbers matching block for a restoration
But just for info, I can deck a block & leave the numbers ;)

This is also why almost all common combinations have a c/h of pistons that come out less then the nominal deck of the block.
It is a hell of a lot easier to adjust the block than to adjust the pistons,,

Now on line boring / honing , I do measure the bores & if they are correct do not line hone in some cases but it is very rare I find a block that is not well over the hi limit.
This is why most GM engines come with select fit bearings that are .0002-.0004 under in the mains.
These bearings are not available in the field but this is how GM sets clearance during assembly.

Tom,
Decked 2 small blocks today, a late model 350 and an older 400. The 400 was off .015" from side to side, but pretty square from end to end. The 350 was "twisted" almost .016"
from the front right to the rear left corner. They are absolutely terrible from the factory :(

Tom,
Decked 2 small blocks today, a late model 350 and an older 400. The 400 was off .015" from side to side, but pretty square from end to end. The 350 was "twisted" almost .016"
from the front right to the rear left corner. They are absolutely terrible from the factory :(

Bill are they that bad as they come from the factory, or have the moved somewhat through several years of heat/cool cycles?

Bill are they that bad as they come from the factory, or have the moved somewhat through several years of heat/cool cycles?
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Jim,
Not Bill but,,,
They may move a little but this has nothing to do with how bad they can be machined right from the factory & the older blocks are usually worse.
They can be anywhere from right on to stupid bad. :D

I'd imagine if the factory put in the precision, you, Bill, Carl & others do the cars would cost a couple hundred $$$ more.;):D