I had a couple of people at work ask me if I could check whether or not they needed an align bore/hone on their used block. So I told them how to check it themselves, rather cheaply. Here goes, if i miss something, ya'll let me know, it's been a while since I worked in a real machine shop....

1) You need a machinist's straight edge (24 in). Can be had for around 40-50 bucks, good tool to have, it'll let you check your block/head decks for straightness also.

2) standard feeler guage. The fold out fan lookin ones.

3) Bolt your main caps on, and torque to spec. Make sure to use the fasteners that you will be using when you assemble the shortblock.

4) lay the straight edge on the block side of the main bore, down the entire length of the block, but don't lay it on top of the rear main seal area.

5) while holding the straightedge still, try to slide the feeler guage underneath it. You shouldn't be able to silde anything thicker than .001 (1 thousanth of an inch) underneath it.

6)flip the block over (right side up). You can check the main caps this way also.

7) Align bore or hone? Which to do? When installing new caps, i prefer to align bore. It will remove most of the material from the caps, and keep you crank centerline where it's supposed to be. This process is independent of the original crankshaft centerline. It can also be used to correct core shift in the block that moved the crank centerline from perpendicular to the deck surface (shifted left to right).

8) Align Hone: removes roughly equal amounts from the block and caps, usually good to correct minor misalignment. This process uses the existing crankshaft centerline as the basis for alignment, and can move your crankshaft centerline closer to the camshaft centerline if much material is removed.

 

Lot's of good info.

I've always left this up to my shop to decide, but my only concern is if the block needs align honing/boring, due to out of roundness of the caps...which a straight edge won't tell you.

Maybe it dosn't come up too often, but is worth consideration.

 

Out of roundness check: Using an inside bore micrometer or dial calipers and standard micrometer, check each main bore, like this: up and down ( | ) then diagonally ( / and \ ).

 

Ya, I agree, but now were into 50 bucks for a straight edge. Another 75 for an import dialbore gauge set, that the average Joe will only use once every 15 years...

What's it cost for the shop to check it once they have the block? maybe 5 minutes of work and almost no price?

I guess what I'm saying is if it needs to be done the shop will tell ya.

Ofcourse if you're out "block shopping" and have the tools, then it's a wash I guess if you find a block that oesn;t need to be Aligned honed/bored.

You agree?

I mean even if you have one on the stand that needes it, it's not like you can do it yourself

 

BTW, just for FYI, I have all the tools to do it...I'm just trying to convey to the average guy it's best left up to the shop they trust to deterime what needs to be done.

 

Like I said, at least the straight edge is good to have. Like when you blow a head gasket, why not check the deck when you have the head off? I have changed at least two headgaskets on other cars, and when i checked them they were warped, and if i put them back together, it probably would have blown again. again, you are correct, the "average joe" will not have these tools, but if you have them, why not check it yourself? I know of a couple of machine shops that will go ahead and do the work if you ask, and not even check and see if it needs to be done. Of course, many people on this board have done more than a few motors, in which case it may be kind of safe to assume they have a few engine building tools around the shop.

 

I agree...don't take me wrong, I'm not discounting aynthing you say. In fact the more I think about it, the better off you are checking what's been dnoe.

I've had more than my share of shop work come back at substandard levels.

Hope there's no misunderstanding.

 

Oh, no misunderstanding. I understood you point too. I was just tryin to say that an average guy can check this kind of stuff, assuming he has a few engine building tools. The mic set is kinda good to have too, if building a hi po motor. I know i wouldn't trust the bearing clearances on my new 406 to some plastiguage, which i have found to be innaccurate is some cases, mostly because it is somewhat error prone, as a slight slip may change the reading just enough to make it seem like it's ok...

 

i have a 36" precission straight edge, dial bore gage, mics, indicators and all the other tools and consider my self just "average guy" at home. don't run a shop or anything. i always like being able to check something and having some sort of idea what i had before i took it to a shop. my shop is what i guess you'd call full service. if i take a block in to be cleaned they normally put in oil plugs, freeze plugs, cam bearings, and hone it long as it doesn't need bored. they'll check it and let you know it's out of spec. it's not that i don't trust them but i just like knowing and there are times when i don't take something to the shop, like rods and i can check and know what i have.

 

Usaually a block doesent need to be align bored unless somthing munched.

 

or if you install new/aftermarket main caps, or if you need/want to correct the crankshaft centerline.