Block Honing

[Larry Hill]

A profilometer is a must to get the desired finish on the cylinder walls. Jeff Taylor’s shop does a good job of hitting the numbers. New Sunnen SV 10 with the screen.

To get the best work possible have a set of old mains installed and torqued to keep the block bores from getting dinged. Have an old set of head gaskets the correct thickness and make to go under the torque plates, yes one on each side if possible. It probably makes no difference but I assign bolt and or stud placement. Over the years I have my own torque plates.

Another great shop is BES in Indiana.

[Alan Roehrich]

They're pretty far away from you, but we use Day Enterprises, just north of Nashville TN. Chris Amos does our work, and Day Enterprises has the new Sunnen CNC hone.

[nhramnl]

I myself prefer a dingle hone (available at Auto-Zone) powered by a Black and Decker hand drill. Though other drills will do the job, I have found the B&D to be the gold standard for true, record-setting power. Email me for more speed secrets.

[Larry Hill]

The block doesn’t care how it gets straight, round and the desired size.

[Frank Castros]

Originally Posted by Larry Hill

A profilometer is a must to get the desired finish on the cylinder walls. Jeff Taylor’s shop does a good job of hitting the numbers. New Sunnen SV 10 with the screen.

To get the best work possible have a set of old mains installed and torqued to keep the block bores from getting dinged. Have an old set of head gaskets the correct thickness and make to go under the torque plates, yes one on each side if possible. It probably makes no difference but I assign bolt and or stud placement. Over the years I have my own torque plates.

Another great shop is BES in Indiana.

Bill Ceralli in Paterson NJ performed this procedure in the mid-nineties

[Robert Simpson]

Thank you guys for the reply. Please continue with suggestions.

Robert

[Larry Hill]

If you’re going to bore the block before honing have them register the bores off of crankshaft thrust surface. If block will be filled give it time to cure before machining. Don’t forget to check the back of the block to be 90* to crankshaft center line. Also check your trans pump housing bore or bellhousing bore for being on crank center line and perpendicular. That way if the car doesn’t perform as you think it should you can look elsewhere. You know the cylinders are located, straight, round, and perpendicular to the crankshaft.

Sometimes straight, round, and perpendicular takes a while but I think worth the effort. Do what you can, within the rules, to keep the block from twisting.

Just some early morning thoughts.

[Alan Roehrich]

The tall man is correct here on all points.


If you're starting with a new aftermarket block, then your path is short and straight, you just need to set your deck height and bore size, then it's off to the hone.


If this is a production block, then it's a whole different ball of wax. Assume that it's already been thoroughly cleaned, to the point where the water jacket has been acid washed, and the usual checks have been performed for wear and damage.


The first step is a thorough sonic test. Once the block passes that, I always pour next.I use regular stock head bolts and cheap gaskets, for this. I bolt one head on, and then pour the first side, immediately bolt the head on over it. This I let cure in at least 60 degree F ambient temp, for 24-48 hours. Then I pour the other side. This time, it sits for at least two weeks.


After that, if you can find someone trustworthy, who has a CNC program for your block, you're fortunate, you can get your block trued up, as Mr. Hill describes. Next best choice is someone with the necessary Block-Tru, Bore-Tru, and other fixtures by BHJ to true up your block. Your first step is to get the crank bore perpendicular to the bellhousing flange and indexed to the block dowel pins. Now, if you have the means, you can also verify that the cam bore is parallel to the crank bore, here. Then it's off to properly size the main bores. Hopefully, an align hone will do that. I finish my crank bores in the second step because everything else indexes from there. My next step is to Block-Tru the deck surface to the main bore. Then Bore-Tru, here you correctly locate all 8 cylinders (if you have that many). And you bore to size, leaving the requisite hone stock to finish the bores.


Since we're concerned about honing here I'm just going to make this note about lifter boresafter you deal with honing your block, if it isn't a new aftermarket block, you're going to want to bush the lefter bores with a Lifter-Tru setup, and even if it is an aftermarket block, bushings may be required for your lifters).



And now we come to honing. Can you get the "perfect bore" with a CV 616 or similar hone? Pretty close, assuming you have a skilled operator, with the necessary patience and the requisite measuring tools. And there's the sticking point. Most shops that don't have a CNC hone, also don't have a PAT gauge, and a regular dial bore gauge cannot actually measure whether a bore is round. Never mind straight. That's where the CNC machine becomes a necessity for approaching perfection. It can measure its work in ways that a human cannot measure his.


If you go look on youtube, you'll find about a dozen videos posted by the guys at Total Seal on just this subject. Do yourself a big favor, and watch them all. It tells you about the CNC machines, the older equipment, and the profilometer. All priceless information.


Hope this helps you, good luck.

[Larry Hill]

My thoughts differ slightly from a lot of folks. I will check an aftermarket block just as closely as I will an OEM block. The best surprise is no surprise.

[dragracerray]

Originally Posted by Alan Roehrich

The tall man is correct here on all points.


If you're starting with a new aftermarket block, then your path is short and straight, you just need to set your deck height and bore size, then it's off to the hone.


If this is a production block, then it's a whole different ball of wax. Assume that it's already been thoroughly cleaned, to the point where the water jacket has been acid washed, and the usual checks have been performed for wear and damage.


The first step is a thorough sonic test. Once the block passes that, I always pour next.I use regular stock head bolts and cheap gaskets, for this. I bolt one head on, and then pour the first side, immediately bolt the head on over it. This I let cure in at least 60 degree F ambient temp, for 24-48 hours. Then I pour the other side. This time, it sits for at least two weeks.


After that, if you can find someone trustworthy, who has a CNC program for your block, you're fortunate, you can get your block trued up, as Mr. Hill describes. Next best choice is someone with the necessary Block-Tru, Bore-Tru, and other fixtures by BHJ to true up your block. Your first step is to get the crank bore perpendicular to the bellhousing flange and indexed to the block dowel pins. Now, if you have the means, you can also verify that the cam bore is parallel to the crank bore, here. Then it's off to properly size the main bores. Hopefully, an align hone will do that. I finish my crank bores in the second step because everything else indexes from there. My next step is to Block-Tru the deck surface to the main bore. Then Bore-Tru, here you correctly locate all 8 cylinders (if you have that many). And you bore to size, leaving the requisite hone stock to finish the bores.


Since we're concerned about honing here I'm just going to make this note about lifter boresafter you deal with honing your block, if it isn't a new aftermarket block, you're going to want to bush the lefter bores with a Lifter-Tru setup, and even if it is an aftermarket block, bushings may be required for your lifters).



And now we come to honing. Can you get the "perfect bore" with a CV 616 or similar hone? Pretty close, assuming you have a skilled operator, with the necessary patience and the requisite measuring tools. And there's the sticking point. Most shops that don't have a CNC hone, also don't have a PAT gauge, and a regular dial bore gauge cannot actually measure whether a bore is round. Never mind straight. That's where the CNC machine becomes a necessity for approaching perfection. It can measure its work in ways that a human cannot measure his.


If you go look on youtube, you'll find about a dozen videos posted by the guys at Total Seal on just this subject. Do yourself a big favor, and watch them all. It tells you about the CNC machines, the older equipment, and the profilometer. All priceless information.


Hope this helps you, good luck.

Alan what is a PAT gage?
Ray