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Guy's I read a post a while ago about someone asking about the worth of various machine shop expenses. It seemed to be the consenses that they were all needed including align honing. Some, I believe said they would never build a motor without it.

I found this very interesting because in How To Build Horsepower Vol 3 by David Vixard page 37 he says " An option your machine shop may sugest is align honing the main bearings. My comment here is "forget it", it's an expense that returns little if anything..." He goes on to talk about the flexing the crank does under power and the align honing cannot help this.

I noticed in another post some actually knows David Vizard's phone number. I'd be interesting to hear what he has to say.
 

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I'd bet David Visard is talking about a block that doesn't have any significant core shift. I personally think it is necessary if the block has shifted and the main journals aren't already "lined up." Maybe he is saying don't do it looking for more HP. Some blocks can have so much core shift that they almost aren't worth even bothering with.

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68 Camaro, 383 small block with TH350 trans. 11.98's at 111mph and never trailered.
 

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Rick,
There are a bunch of factors that come into play when deciding if a block needs align honing.
1. What type of motor are you building ? Stock, Mild street, or a 800hp blown small block ? The more HP you are making, the more important it is that all tolerances are perfect, or as close to it as possible. One of the most important reasons for the align hone dimension to be correct is so that the bearings will be held in place properly. This is called the "crush"
2. What condition was the motor in when it was disassembled ? Particularly, how did the main bearings look ? If they were barely worn, or worn slightly and very evenly, chances are the align hone is fine. If the main bearings look at all suspicious, at least get it checked.
3. Are you replacing the main bolts with studs ? If so, align honing is almost mandantory.

These are just a few of the things that go into the decision. I personally have started insisting on align honing any type of performance engine. If you are spending 7k on a motor, the $130 to align hone is a minor part of the picture. On stock motors, I play it by ear, using some of the criteria I listed above. If you check all the clearances properly when you assemble the motor, any problems will show up anyway.

By the way, "core shift" has absolutely nothing to do with align honing.

Hope this helps,

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Bill Koustenis
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Waldorf Md
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He says if the crank spins OK, AND bearing crush is OK, you don't need to align hone the mains.
Your engine builder will usually tell you he needs to align bore it to establish a base for decking and boring the block.

Think of this, the engine builder spent a lot of money on that align bore machine. It isn't going to pay for itself unless he uses it.

On the other hand, if you refuse to align hone when he says it's needed, if you have a bearing spin later, he will have an excuse to blame it on you.
David

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Core shift. What is that? Is it the thing a ma chig on the bottom of the motor that spins being out of alignment with the holes above it that those other thing a ma chigs are connected too? LOL
Huh?

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Steve
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Discussion Starter #6
For the record David Vizard is talking about a motor with 700 HP and using a ragged junkyard block to start with.
 
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