# Cylinder honing: DIY, or better left for professionals?



## NTRabbit (Mar 28, 2001)

I need to have a block cleaned and honed, and I was wondering how hard/easy it is to just buy a honing tool and do it yourself. I would just like to have the tool, and have the ability to do it in the future. Do you guys think it is ok for the average DIY guy to hone cylinders, or should it be left to the machine shops?


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## yellowslc (Aug 29, 2000)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

I purchased a blueberry style hone for the sole purpose of cleaning a block quickly to allow the bore gauge tool to be used. Unless you are just slapping something together and not building a HP engine this may suffice with some practice. 
I'd leave this one to a pro.
R


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## vwpieces (Apr 20, 2002)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

Definitely a professional job. The machines used are regulated with rpm & the in & out speed is relative to rpm, to assure you get the proper angle on the cross hatching. 
It is too easy to over spin a hone, especially with a variable speed drill. One quick pull of the trigger can make the bore too far out of spec. 
Another tip is to make darn sure the clean all the honing grit out of the bore when you get it back.


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## NTRabbit (Mar 28, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (vwpieces)*

Ok, thanks for the advice. A couple of people I know told me that honing could easily be done at home. It just didn't seem like a good idea to me though. You can definitly see a very neat cross hatch pattern after they are honed. So I guess that would make sense. Thanks.


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## The Quinner (Dec 10, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

Do a Google search for "brush research" or "flex hone"...they have some good info on their site (what to use for lube, feed/speeds, etc.).
Cleaning and final prepping an iron block (or sleeve) with a ball hone is not a difficult job. It's not a job for the ham-fisted, but neither is changing spark plugs...if you can handle one, you can handle the other.
It's nice to have a scrap cylinder to practice with...to get the timing down. But...it's also fine to run the flex-hone for a few seconds...check your work...adjust accordingly...and, finish the flex-honing.
You want approximately 45 degrees between the cross-hatches...NOT 45 degrees from an imaginary "straight" line (which would give 90 degrees between the cross-hatches...WAY too much). If the hatching is too close, increase the speed of the in-and-out cycles or decrease the speed of the drill...if the hatching is to far apart, increase the speed of the drill or decrease the in-and-out speed.
I use my 3/8" VSR drill and generally run the flex-hone clockwise for about 8-12 seconds...then, I reverse the direction and go counter-clockwise for the remainder (another 8-12 seconds).
Don't forget to use some sort of honing lube/fluid...I use plain old WD-40 for my iron sleeved motorcycle cylinders. And...as someone else said, CLEAN the block well after any sort of honing or machining...a clean rag should stay clean when you're done. Lightly oil the cylinder surfaces (and other machined surfaces) if the block will sit for any period of time before use (also put it in a sturdy plastic bag...unless you want to go through the whole cleaning process again).



_Modified by The Quinner at 10:59 AM 12-24-2005_


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## mechsoldier (Aug 14, 2004)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

You can definitely hone an engine on your own and I AM a professional mechanic telling you this


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## NTRabbit (Mar 28, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (mechsoldier)*

Sounds good. Looks like I may take this on after all. http://www.brushresearch.com
Also, why would you recommend the brush type hone instead of a stone hone? I found a craftsman version of the stone hone for $22. http://www.sears.com/sr/javasr...33000




_Modified by NTRabbit at 11:16 AM 12-27-2005_


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## mechsoldier (Aug 14, 2004)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

I don't think there's anything wrong with a stone hone...


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## The Quinner (Dec 10, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_I don't think there's anything wrong with a stone hone...

Well...there's nothing wrong with them...but, it depends on your needs. There are basically three processes that can be done: boring, honing, and surface prep. *Generally*, when folks talk about 'cleaning and honing,' they are talking about surface prep...
*Boring* is the process of removing material to restore a straight and round bore...boring will require new/different pistons to make up for the additional diameter of the bore.
*Honing* is the final step in a bore job...generally done with a three stone hone, it will continue to remove material, but will leave a better surface for the rings than a boring bar will leave.
*Finish honing / surface prep* is the final prep...Brush Research has way more info than I could ever give...but, the Flex-hone has properties that allow it to 'plateau' the microscopic finish of the cylinder. 
Think of it as the difference between a snow plow (3-stone hone) and a rake (flex-hone). The plow shoves everything along...removing a layer and leaving a smooth surface. The rake, as opposed to removing material, *displaces* material...leaving a grooved surface where some areas have been raised and some lowered. Flex honing does that at a microscopic level...leaving a prepared surface (essentially a double cut file that halps the rings break in)...withOUT removing any material (if it's used properly).
So...bottom line is: you can use a 3-stone hone to prep a block, but be aware that you are constantly removing material while the stone is moving. The Flex hone is really the proper tool and is MUCH easier for a beginner to use.


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## NTRabbit (Mar 28, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (The Quinner)*

Thanks for explaining all of that. It all makes MUCH more sense now after reading through websites about honing and boring. 
So the block I am getting is from a friend who says it is old, and he is removing it because he is getting lots of ring blow by and burning a lot of oil. With an old block like that, can the pistons actually wear out the cylinders and bore them out a little? If so, do you have to measure the diameter of the cylinders at different points, and possibly have it bored?


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## jamesb (Mar 14, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

Its not the pistons that usually wear down the bore its the rings will wear down the bore. What you need to do is check the bore once you have the block stripped down, if its outside of stock specs then you would have to overbore. In most cases the rings give out before the bore it out of spec. 
As for honing if you can get your hands on a drill where you can set the speed limit (my milwalkee has that feature) then you can ensure a slow rpm for the hone. If this all seems too foreign to you, and if you lack all the tools and gauges needed then I would suggest having a reputable shop do the work.


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## NTRabbit (Mar 28, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (jamesb)*


_Quote, originally posted by *jamesb* »_
Its not the pistons that usually wear down the bore its the rings will wear down the bore. 

Little typo. Yeah, I know its the rings not the pistons.

_Quote, originally posted by *jamesb* »_
If this all seems too foreign to you, and if you lack all the tools and gauges needed then I would suggest having a reputable shop do the work.

This stuff doesn't really seem foreign to me, I've just never done it before. I've just become a DIY freak in the past few years, haha. You have to start somewhere right? Ultimately, I probably will have a shop refinish the cylinders because its not that pricey. But... I don't want to send a block to the machine shop for refinishing if the cylinders are out of spec. So once I get the block stripped down, I want to measure the cylinders to make sure they are good. I don't want to have to buy new oversized pistons. Can someone recommend an affordable bore gauge?


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## The Quinner (Dec 10, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

Well...it sort of depends on your ultimate goal...but, there are some cheater methods for "measuring" the bores...
First, it's good to realize that they generally don't wear out evenly...that is, the bore won't simply turn into a bigger cylinder as it wears. Instead, it will taper and ovalize...the areas near TDC and BDC tend to wear more than the middle of the cylinder (taper)...and, the surfaces perpendicular to the wrist pin will wear more than the surfaces that are inline with the wrist pins...
Next, realize that there are areas of the bore where there should be NO appreciable wear...the area below the piston travel (or, ring travel).
So...keeping those things in mind, you can use an old ring to check the bore...
First, we can check taper with the ring. Put the ring near the top of the ring travel and square it with a depth gauge or a piston so that it is dead square in the bore. Use a feeler gauge to check the ring gap...record the results. Now, move the "check ring" to the middle of the wear area...square the ring and check the gap...record it. Finally, move to the bottom of the ring travel...square the ring and check the gap. Okay...so, now we have some data that will tell us how much the circumference of the bore changes from top to bottom...dividing the results by Pi (3.14) will tell us how much taper there is in the DIAMETER of the bore. It's probably worth it to take five to seven readings, as opposed to just three...but, you get the idea.
Next...put the ring in the area where there is no appreciable wear...square the ring and measure the end gap. Divide by Pi and compare the results to the numbers you got above...this will tell you approximately how much the cylinder has worn.
It might sound hokey, but it works very well and is very easy for a beginner to do.
Also, make sure that everything is settled at room temperature...that means that the measuring tools and the items to be measured must sit in a relatively constant temp for at least 24 hours. If you don't do that, then your body temp will affect the readings...the ring will expand as you handle it, etc. This is critical for any type of accurate measuring...whether using micrometers and inside bore gauges or the ring and feeler gauge method.


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## NTRabbit (Mar 28, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (The Quinner)*

Sounds like a pretty good method. Maybe I will just try that.


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## punk rock kiel (Aug 27, 2003)

*Re: Cylinder honing: DIY, or better left for professionals? (NTRabbit)*

being an automotive machinist and driving the beauty i own, i know home hone jobs blow. 
someone thought they would hone the block in my car before i owned it and i dont wanna check the compression cause its gonna be sad. 
for a machine shop to toss a block in the honing machine and doin the job takes next to nothing. 
if the block is tight at the top or the bottom, it can be fixed easily.
plus they used 3 or maybe 4 different grit stones to hone it so it turns out smooth. 
constant pressure on the stones at all times. 
and u know its done right. 
u also need a dial bore gage that measures out to .0001 increments. 
go ahead and try it urself and see how good u get it done.


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## G60syncro (Feb 7, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (punk rock kiel)*

I used my dad's old trick back when he was building street rods... He has an old Black&Decker 1/2" drill that was just the right weight fir the setup he rigged. Basically it was 4 springs from those arm exrecisers everyone seems to have lying around in the basement junk somewhere... He just suspended the drill from the ceiling with those. You need enough tension to barely hold the weight of the drill and hone. That way, you only need a light shove downward, then let it come back up by itself in order to get the right motion going. It makes it very easy to keep the rythm and have an even crosshatch everytime.
If the block needs to be bored, you can always practice on it to get the hang of it... Then get it bored out to spec afterwards.


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## The Quinner (Dec 10, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (punk rock kiel)*


_Quote, originally posted by *punk rock kiel* »_being an automotive machinist and driving the beauty i own, i know home hone jobs blow. 
someone thought they would hone the block in my car before i owned it and i dont wanna check the compression cause its gonna be sad. 
for a machine shop to toss a block in the honing machine and doin the job takes next to nothing. 
if the block is tight at the top or the bottom, it can be fixed easily.
plus they used 3 or maybe 4 different grit stones to hone it so it turns out smooth. 
constant pressure on the stones at all times. 
and u know its done right. 
u also need a dial bore gage that measures out to .0001 increments. 
go ahead and try it urself and see how good u get it done. 

If there are dimensional problems (taper, ovality, etc.)...then HONING is not the proper thing to do. Honing is a finishing process...it prepares the surface to break in new rings. If there are dimensional problems, BORING should be done (followed by honing). 
If a shop were to tell me they were going to correct dimensional problems with a 3-stone or ball hone, I'd take my business elsewhere...quickly.
SO...*if the block measures within tolerance and simply needs a surface prep...HONE*...this can easily be done at home...you are simply putting a finish on an already round cylinder. You have to be pretty ham-fisted to screw up a good cylinder with a ball hone.
*If there is too much taper or ovality...BORE.* _Honing is NOT an alternative to boring._ If you try to hone a bad cylinder, you'll have a bad cylinder with a nice cross-hatch...which is still a bad cylinder.


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## elRey (May 15, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (The Quinner)*

Great info in here!.
If I may, is it possible to finish/prep (hone) with the block in car.
Only having head and pan removed (and rods/pistons obviously).
MK4
Rey


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## mechsoldier (Aug 14, 2004)

*Re: Cylinder honing: DIY, or better left for professionals? (elRey)*

yes, you just gotta make sure you clean it out good before you put it back together (like you would if it was out)


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## Bora Lab (Nov 12, 2002)

*Re: Cylinder honing: DIY, or better left for professionals? (The Quinner)*


_Quote, originally posted by *The Quinner* »_
If there are dimensional problems (taper, ovality, etc.)...then HONING is not the proper thing to do. Honing is a finishing process...it prepares the surface to break in new rings. If there are dimensional problems, BORING should be done (followed by honing). 
If a shop were to tell me they were going to correct dimensional problems with a 3-stone or ball hone, I'd take my business elsewhere...quickly.
SO...*if the block measures within tolerance and simply needs a surface prep...HONE*...this can easily be done at home...you are simply putting a finish on an already round cylinder. You have to be pretty ham-fisted to screw up a good cylinder with a ball hone.
*If there is too much taper or ovality...BORE.* _Honing is NOT an alternative to boring._ If you try to hone a bad cylinder, you'll have a bad cylinder with a nice cross-hatch...which is still a bad cylinder.

This isnt exactly true. I am also an ASE machinist and the newer machines that are using the diamond stones can and will correct an out of round cylinder. This system is usually refered to as plateau honing because the final step, which most people dont do, is running a carbon brush through to knock the points off of the cross-hatch. This will save your rings from having to "break them in".
A rough diamond is used first and can take out .030" from a cast iron block in a matter of minutes. Pressure can be watched and measured by a series of dots on a sceen that indicated more or less pressure from top to bottom. Therefore, you can determine where you have a tight or loose spot. From there, a smoother set of diamonds is used depending on what type of rings are being used. After that, the carbon brushes are used. The only time we use the boring bar at our shop is to intall a sleeve or to take out huge amounts of metal at a time.
Ive been using a Rottler HP6A for about 3 years now and have been very impressed with the way that it can take a beat up cylinder and create a perfectly round hole within .0001" from top to bottom. 

I do agree with the statement of taking a block to a shop to have it dingleberry honed. The problem with these is that there is never a consistent pressure and you stand a good chance of ballooning the cylinder. 

_Modified by Bora Lab at 7:47 PM 1-21-2006_


_Modified by Bora Lab at 7:48 PM 1-21-2006_


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## The Quinner (Dec 10, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (Bora Lab)*

I think we have it down to semantics at this point...
If the cylinder is within spec...the *cleaning and honing* can be done at home. This implies a ball hone or a 3-stone finishing hone. The ball hone is an easy way for a home mechanic to plateau the rough surface left by a boring process...or, to clean a glaze and plateau the surface of a dirty, but useable block.
If there are dimensional problems, then something other than a finishing hone must be used...whether we call it a honing machine, boring machine, or whatever.
The problem with using a honing machine (Sunnen, etc) is the finished product. Sure...an out of round cylinder can be made round again...but, the only choice is to widen the whole hole (heh heh







) to (or slightly larger than) the widest area. How will your pistons fit then? What about the ring gaps? These are not trivial matters and are precisely why there have been oversized pistons available for decades. That is, when it's time to remove material, it must be done to match the oversized pistons and rings...not just until a round bore is (re)achieved.
Traditionally, you bore to an oversize...and, hone to prep the surface. Whatever you want to call it, though, the concepts are the same...a good cylinder just requires surface prep...a bad cylinder must have material removed (to restore the straightness and roundness of the bore) and then a surface prep. Simply prepping a bad hole...still leaves you with a bad hole.


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## NTRabbit (Mar 28, 2001)

*Re: Cylinder honing: DIY, or better left for professionals? (The Quinner)*

Well, I decided to go the safe route and just have my cylinders bored and fit larger pistons. I went from 82.5mm pistons to 83.5mm, and they should be in today. My machinist is going to measure them and then bore the cylinders appropriately. I'm happy now because I know that my cylinders are going to be perfect, and the pistons will fit just right. And I'm getting an extra 50cc's out of it. 
Thanks for all the advice,.. this thread really turned into a good informational tek. Hopefully other people will be able to use it in the future. 
-Nick


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