Honing a block with a Flex hone

Description of how to alternate rotational direction while using your flex hone and maintaining a steady medium RPM. One of the most important aspects of proper honing is using a light lubricating oil like transmission fluid not a time and just a little and get the tool moving fast enough to achieve the 45° hex marks.

[@outlawofga]

Great job on the block and video.. As a machinist I see many poor videos and lack of understanding of this process. Not only did you explain it well. But the reverse direction with a used hone says volumes ... This is oh soo true. Again great video buddy...You're a knowledgeable Man no doubt 💯👍😎

[@HeadFlowInc]

Thanks for watching and the feedback I appreciate it! I’m trying to share with like minded people building with what they have and can afford. Almost no one has heard of altering rotational direction to improve quality and make the tool last longer! I swear I learned it from Flexhone. Thanks again have a Happy New Year!!! JD

[@outlawofga]

@@HeadFlowInc you too my friend 👍

[@Swilling]

Great video, i used to hone my old dirtbike cylinders as a kid, but its funny, the more i learn and the older i get, the less i want to risk doin this on a real engine ha. You're videos are really great man, keep em coming

[@chrisrye9128]

Very informative. About to do this to my son's Bronco 6.6l/400. Great explanation of the process.

[@justinw523]

What part number Flex Hone was you using? I have a 5.3 I need to hone the cylinders

[@HeadFlowInc]

It’s the 240 grit 4.00” diameter we ordered off eBay. You could use a 320 grit or similar too

[@SidewaysInTraffic]

Thanks for the info bud. Only thing I question is the grit size, so I just went with a middle of the road 320.

[@TRyan-op2jo]

Thank you for sharing your knowledge in this excellent video. You are clearly very intelligent and a great teacher!

[@jameshawkins3312]

Great video "Microscopic roughness" haha that is definitely the correct terminology!

[@charlesdavid5137]

Great information on honing. Thank you for sharing. I've got a 1978 Ford 351M engine that is in good shape other than some rust that formed in cylinder 8. The engine would not turn over when I got it, but I slowly oiled and worked it free. It doesn't smoke, but low compression on cylinder 8. It looks like it's already got 0.040 over pistons from a recent rebuild. Do you think I can get away with honing or will I need to have it bored 0.060 over?

[@HeadFlowInc]

Charles David Was the ring possibly damaged during the process of freeing up? 1. It really depends on where and how bad the rust damaged the cylinder. 2. It’s possible you may be able to hone it and re-ring it. It’s hard to say without seeing it.

[@charlesdavid5137]

@@HeadFlowInc Yes, absolutely. I was very careful when I freed the engine, turning back and forward slowly. The cylinders had all been lubricated with WD-40 rust penatrant for several days, but when it finally came free I hear a metallic sound that I could liken to a ring breaking. I am going to remove the engine, completely disassemble it and measure and inspect the components and block.

[@turbot6592]

So for a 240 grit you would recommend iron rings. Would moly rings be the same grit to. How much more in price are the moly rings

[@HeadFlowInc]

Moly rings need a finer finish like 320-400 grit, I’ve even heard of some claiming 600 grit. We’ve generally used 240 for iron and 320 for moly mostly because they’re the more commonly available grits. Usually the moly rings cost a little more, but remember they’re tougher material on the face and sometimes are harder to set or seal to the cylinder. JD

[@jacekeeton9020]

I think my honing project came out alright.. I was curious, now that I am finished with the honing tool,,, what sort of cleaning should it recieve.? meaning the little dinkkleberries? lol. should it be a hot soapy bath also? the instuctions didnt mention that

[@HeadFlowInc]

jace keeton Definitely wash the bores until they wipe clean with a white lint free cloth. Scrub the bores with a nylon brush if you need to, the cleaner the better! 👍

[@jacekeeton9020]

HeadFlowInc thank you my friend... i will definately do that....now the tool itself? how and what do use to get the honer clean?

[@265chevy]

great stuff this video will help me out a lot thanks

[@G5Hohn]

A 30 deg crosshatch is generally preferable to 45 degrees.

[@Ever443]

Your never going to get accurate degrees doing it by hand, no matter how many you have done. Thats what honing machines are for. But thats not what vid is about

[@jacekeeton9020]

I was wondering ,,, if i will have to move my arm up and down faster,,,to obtain the 60 degree cross hatch pattern... that is a harley davidson spec. for my cylinder...i am glad you mentioned making the hone go clockwise and counter clockwise...

[@HeadFlowInc]

jace keeton Experiment until you get the results you need. I’d say it would be pretty fast to end up with a 60 degree hex. Thanks for the feedback I appreciate it! JD

[@jacekeeton9020]

thank you much,,, for responding back so fast

[@jacekeeton9020]

i thought you might have a good answer for another wonderment... my cylinders measure a true 4.o" across...but my shop manual calls the finished bore 3.7500... that is miles of space .. i almost get the impression that spec. pertains to ring space to the walls? and i know my cylinders arent that worn.... or did my shop manual mean it in another area,,, that i am not seeing the obvious.. i havent even got to the piston and rings buyathon yet...and i am hopefully not having to go to a true bore situation

[@HeadFlowInc]

jace keeton I’m not sure where they recommend measuring a motorcycle bore, but it sounds like you have a larger bore jug setup over factory. 🤔 There normally won’t be more than a .0015” to .007” difference between the size of the piston skirt size and finished bore size. The piston to wall clearance is dependent on the piston material. cast/hyper pistons will have a tight clearance and a Forged piston requires more clearance due to expansion. I’d recommend doing some more research on the engine.👍

[@HeadFlowInc]

jace keeton What size engine do you have?

[@justingeraldi2304]

I was always told to never remove the hone from the cylinder as you go up and down!!!!# Also it's imperative to clean all the stone sand and metal grit out of the engine. And transmission fluid is the best rust prevention out there,,use it before during and after so it doesn't rust

[@HeadFlowInc]

Justin Geraldi I used ATF in this video and yes the block should be washed after honing I agree. The hone should never stop or start turning while in the bore, this can cause horizontal scratches. The hone should be turning as you enter and exit. I can see what you might me saying about allowing the hone to peek out at the top of the cylinder it might slightly chamfer the edge. Thanks for watching and the feedback I appreciate it! I hope you subscribed JD

[@roberthallstrom9238]

Excellent video!

[@HeadFlowInc]

I used ATF as lubricant, a lot of people miss it. Thanks for the feedback! JD

[@newwavepressure6478]

Did you have to get a bigger size piston

[@HeadFlowInc]

JT 1200 Stock OEM Standard bore pistons, 1995 rotating assembly w/powdered metal rods. On the next rebuild this engine would probably need bored to a larger piston. Thanks for watching! JD

[@efijemuehphilip542]

Hi sir, where can I buy this flex hone because I can't find it in aliexpress

[@HeadFlowInc]

We usually ordered on eBay to find a deal. You can also get flexhone brand from tool trucks but at a much higher price. Also, check with companies like Grainger, Fastenall, or ask your parts stores if they can get them. Thanks for watching and the feedback I appreciate it! JD

[@mannymix1274]

Wondering if I can send you some photos of my lq4 6.0l block there is some rust in two of the cylinder walls (person I got it from didnt know what he was doing) I’m not sure on grit to use

[@HeadFlowInc]

Manny Mix If any of the rust is pitted in the top 2 1/2” of the bore it’ll need bored. The rings live and seal in a relatively small section at the top of the cylinder. Final hone should be 320-400 grit, I’ve used 240 grit but I think it can lead to poor ring seal and oil consumption. I’ve got a 6.0 block that needs bored which sucks. You could email pictures to [e-mail]

[@mannymix1274]

HeadFlowInc photos sent thanks

[@jpcallan97225]

I didn't see you apply oil to the Flex-Hone as they recommend in their automotive instructional video

[@HeadFlowInc]

John P. Callan Pay better attention next time I used transmission fluid. 👍😎

[@jpcallan97225]

​@@HeadFlowInc I noticed you did mention ATF at one point, but didn't see you apply lubrication. Other less patient viewers might just jump right in and try your technique dry. It does differ from the Brush Research recommendation - see +1:35 into kzbin.info/www/bejne/oJinhq2Frcxlg7c& for the factory take on hone lubrication. By the way, an FYI.. I think the term of art is "hatch marks" (instead of hex marks) or "crosshatching" to describe the pattern on the cylinders walls, at least that is what my machinist has been calling them. en.wikipedia.org/wiki/Hatch_mark www.thefreedictionary.com/crosshatching Thank you for the effort you made bringing us this video and sharing some of the subtleties of bore honing.

[@Califormula]

Thank you Sir 👍🏾

[@buchanansleeve7427]

Great job bud!

[@Rycoda]

can i use coffee filters instead of a lint free cloth?

[@HeadFlowInc]

Raphael Nava I’m not sure, if the filter material can absorb the honing fluid and not shed maybe? I’ve never used coffee filters but you never know. You can use old cotton t-shirts, those Blue shop paper towels low lint at Walmart, parts stores etc. Since you’re going to need to wash the block thoroughly with soapy water you’ll have a chance to clean up the cylinders. JD

[@Rycoda]

@@HeadFlowInc oh okay ill use the blue shop towels and then soap and air spray

[@glenlarson5373]

It's called cross hatch, not hex marks.

[@h2bbuilt]

I thought you need to lubricate it with at least oil before honing. did the manufacturer said otherwise?

[@HeadFlowInc]

h2bbuilt It's hard to see in the cylinders, I squirted transmission fluid inside all cylinders before I started the video. At the beginning you'll here me say coated the cylinders with ATF Thanks for asking, hopefully this helps clarify. JD

[@207garage3]

Good video

[@Iamdavidroark]

Where’s your oil for the cylinders while your honeing

[@HeadFlowInc]

If you go back in the video you’ll hear I used transmission fluid on the flexhone/cylinder. JD

[@black85chevy]

do you hone the lifter bores too?

[@HeadFlowInc]

No honing needed the lifter bores were in great shape. JD

[@josecastellanos4538]

What grit ur using?

[@HeadFlowInc]

Jose Castellanos I want to say 240 grit, I hope I’m right. JD

[@xESPplayer500x]

This is not a true honing device. It's really just a light glaze breaker

[@Moparmaga-1]

He answered all the questions you idiots asked.

[@LovelyMoose98]

Sweet.

[@HeadFlowInc]

MikayLa Singletary Thank you! 👍

[@pratapaher4132]

why cutting fluid is not there

[@HeadFlowInc]

Swapnil Wakale All cylinders are coated with ATF, Automatic Transmission Fluid, plus the hone is already wet with ATF. I mention it in the video. I have a small bottle of ATF I pour around the top circumference of the bore that runs down. JD

[@pratapaher4132]

HeadFlowinc Thanx for this informative video

[@HeadFlowInc]

Swapnil Wakale Thank you, I appreciate the feedback!

[@georgekolotouros230]

Pratap Aher cause he used a medium stone. Doesn't remove material.

[@tonykelly5141]

Dingle berry hones are great if you're running egg shaped pistons. Only a motorcycle mechanic would use one of those on a car motor. 😆🤣😂

[@HeadFlowInc]

You’re so funny thanks for the laugh! Yeah the 1500+ Hp engines we’ve built by honing stock bores must be a miracle. lol

[@tonykelly5141]

@@HeadFlowInc were those 2 stroke Hondas or 4?

[@robertduran1945]

In and out cheeseburger boom boom boom

[@CanadianCharlie64]

What grit size is your hone????

[@HeadFlowInc]

CanadianCharlie64 Iirc it's 240 grit. Try to match the recommended grit to the ring manufacturers recommendation.

[@James7796ify]

Dry?

[@HeadFlowInc]

It's hard to see but I already lubed the cylinders with ATF before I started recording and the hone is already soaked with ATF. I use a small plastic bottle like you use for ketchup or something but an oil can would do the same thing. Re-apply the ATF before each honing session. JD

[@HeadFlowInc]

Thanks for the feedback, I added an annotation to help explain better. If you look in the cylinder after I start honing you can see the lubricant and the metal dust being removed build up in the cylinders. I try not to use to much lubricant so it doesn't make a huge mess on the floor.

[@daveponder2754]

Use a slower drill (DUH!). Flex "hones" are not hones to begin with. A hone is a settable set of stones, such as the Lisle 16000/15000. No manufacturer or top engine builders use these ball style deglazers. The only thing worse than a Flex Hone is the spring loaded style deglazer. For a re-ring job the Ball type deglazer is superior to the spring loaded types. Speed reducers can be had that will lower the RPMs. For moly or chrome use the finest grit available. For some moly or chrome rings the manufacturer recommends a 30 degree cross hatch, instead of 45 degrees. Most blow by is due to the gasses flowing behind the ring/cylinder face through worn ring grooves. Always check the pistons for bell mouthed or worn out ring grooves. If too many pistons have to be replaced, bore out the cylinders for new +size pistons, and have the machine shop plateau hone all of the cylinders. Do not use the ball deglazer, or spring type where a fresh rebore with a machine plateau honed finish has been done. Oil fouled plugs, and an oil smoky exhaust is usually the valve guides and seals.

[@HeadFlowInc]

Thanks for watching and the feedback! JD