Topic: Honing

[Dave Voss]

Well, there are different methods of cylinder honing, and the one that most folks are talking about in this thread is flex-honing, the type that is typically performed by hand with a portable drill motor.  This leaves a cross hatch pattern on the cylinder walls, which serves two purposes.  One, to help new rings 'wear-in' with the cylinders, and two, to cause a small amount of oil to cling to the cylinders, which helps with lubrication and sealing to maintain a higher compression for a longer service life.

I would be concerned that after only 3000 miles that none of the previous cross hatch remains, as it is quite common for some amount of cross hatch to still be visible after ten times that mileage.  Is it possible that the flex-hone was too small (they require some compression to work effectively) or that it was used too quickly or lightly when this operation was performed?  Although you're not experiencing (or noticing) any compression or oil useage issues at this time, the cylinders may in fact be wearing faster than they should given the absence of any cross hatch after such a short time.

If you checked or sized the piston ring gaps when the engine was assembled (3000 miles ago), check them again now and compare, as it is possible that the rings are wearing too quickly and causing the cylinders to wear too quickly as well.  If the gaps are the same (or only differ by a thousandths or two) then the cross hatch was likely only very light and should probably be re-done.  If the gaps have grown, then I would replace the rings and perform a fresh flex-hone before reassembling the engine.  Also make sure the top ring wasn't inadvertently installed upside down, as this can also be the cause of accelerated wear on the cylinder walls.

[PeWe]

Very interesting thread!

[74750k4]

Indeed...

Rings are in properly (marks at top). Gaps are good, and spaced 120 apart. No signs of wear. Cylinder walls are smooth, all the way around, up, and down.
Those 3000 miles were extremely Hot, hard ridden miles, up/down steep winding canyon walls, at between 7-10K RPM right from day 1 of reassembly. I would think that scenario might equal a few thousand more than a typical "no more than 5000 RPM for the first 500 miles" type of break-in procedure. Sure, it seems it was a light honing, obviously it did it's job well. It's there now. Do we really need to repeat again, just to get back to where it already is now? Probably would not hurt anything. But the jury is still out...
Can anyone tell me specifically what difference there is in a fully assembled broken in Piston/Cylinder set, and one in the same condition, that gets disassembled, and re-assembled??? That would be the really determining factor in this decision.

[Dave Voss]

Can anyone tell me specifically what difference there is in a fully assembled broken in Piston/Cylinder set, and one in the same condition, that gets disassembled, and re-assembled??? That would be the really determining factor in this decision.

In theory, there should be no difference at all, but in practice there are opportunities for things to change due to the disassembly and reassembly process.  If great care is taken, and no damage occurs to the rings, then the engine will be the same afterward as before.  The critical area of concern is where there might be a lip at the end of the cylinder from ring wear, as this can cause damage to rings as they are scraped across the area of the cylinder wall that they normally never touch.

Of note in this instance, is that your 'before' is an engine with only 3000 miles and no cross hatch left on the cylinder walls, and so 'after' will be an engine that runs as it did before, but isn't in the overall condition that it should be in to ensure a long service life.  Assuming that full wear-in of the rings caused the elimination of the cross hatch, I would recommend applying a light cross hatch with a flex hone to restore what would normally remain after break-in.

[74750k4]

This is theory... or reality? Any hard proven facts on this to back it up? Would love to see them. Please provide a reference if you can.

Thanks!

[74750k4]

Lots of good information here, but never a mention of when it is essential to hone, or not!


http://www.brushresearch.com/pdf/GB.pdf

[KJ790]

The way I look at it is that I have seen more than one engine burn oil after someone tried to reuse the rings. I have also seen people do it successfully, but that tells me that it is not a guarantee that the engine will be just like before after reassembly.

I have built many many engines, always with fresh rings and fresh cross-hatch on the cylinder, and have never had one burn oil after assembly. Since a set of rings are fairly cheap and it takes 2 minutes to hone the cylinder, I don't see the benefit of taking the gamble. My time to pull the engine back out and tear it down again if a set of rings is not sealing is worth way more to me than the cost of a set of rings.

The fact that your cylinders do not have a visible cross-hatch is troubling. This tells me either they are glazed or they have worn excessively. What is your piston-cylinder clearance? The cross-hatch helps hold oil to lubricate your moving parts, it is not just for break-in.

Try taking some scotchbrite and warm soapy water and scrubbing the bores. If they are glazed then this will break the glaze and your original cross-hatch will become visible again. If there is still a cross-hatch hidden there the scotchbrite will not hurt it. If this does not bring a cross-hatch back to the cylinder then it is likely worn and you probably should address that issue.

If you really want to save the money on rings, then reassemble it with the old rings and maybe you will be one of the success stories I have seen.

[74750k4]

Maybe a set for ONE piston...   these are $33.33 for ONE piston. If you can find a "SET" of 4 cheaper than $133.32 , I might consider your suggestion. These are Riken OEM. I won't settle for less. Especially any unknown Brands, or Countries of Origin other than Japan.

http://www.partzilla.com/parts/detail/honda/HP-13011-392-004.html


Thanks!

[Dave Voss]

This is theory... or reality? Any hard proven facts on this to back it up? Would love to see them. Please provide a reference if you can.

My experience in engine building and failure diagnosis is the basis of my 'facts', although I'm sure that I'm just one of thousands of folks that would likely provide the same recommendation given the information that you offered.  It is very well established that cross hatch on cylinder walls is necessary for rings to wear-in properly, and it is equally well established that cross hatch after ring wear-in is important for oil retention to prevent premature wear of the cylinder walls.

Since the cylinder walls and piston rings make metal-to-metal contact, some oil retention on the cylinder walls is necessary, and its the cross hatch that facilitates this.  Ideally, there should be sufficient cross hatch remaining after the rings wear-in to cause a bit more oil than is necessary for proper lubrication to cling to the cylinder walls, so that the oil scraper ring can reduce the amount to only what's necessary on the downward stroke, collecting it to partially redeposit a small amount of oil on the upward stroke.  If the cylinder walls are completely smooth, the necessary oil to prevent accelerated wear will be lacking, and the service life of the engine will be shortened.

High rpm, high load break-in procedures require a deeper cross hatch, with an angle matched to the type of piston rings used (cast, chrome, etc.) in order for it to outlast the wear-in period of the rings.  In your case, I would suspect that the cross hatch applied 3000 miles ago simply wasn't enough to last through break-in.

For supporting references, just google 'cylinder wall cross hatch' or something similar, and you'll find more information than you could ever find time to read.

[74750k4]

But if you scroll up, there seem to be just as many folks who say all the break in is done, you're there, so why care??? !
Following the logic then, we should all be tearing down our engines to see if there are any hone marks left. Not too practical...
I have seen many engines with, and without traces of hone marks. If I look closely, there may be some traces left. I'll have to look closer.

Gentlemen, start tearing down your engines

[Dave Voss]

But if you scroll up, there seem to be just as many folks who say all the break in is done, you're there, so why care??? !

I would agree that the break-in probably is done, but the rest of the life of this engine still lies ahead, and so the point that I would make is that *now* is your convenient opportunity, while the engine is at least partially dismantled, to do something that would increase your odds of achieving a long service life.  Based on your observations of there being little-to-no cross hatch on the cylinder walls after so few miles of use, the odds are that this engine may very well experience premature ring and cylinder wall wear before it should.

Following the logic then, we should all be tearing down our engines to see if there are any hone marks left. Not too practical...

Of course that's not practical, and most folks wouldn't do this anyway.  However, once disassembled (for other reasons), it would be prudent to take a look and decide whether or not re-ringing and/or flex-honing might be a good idea to help improve its condition and extend its life.

I have seen many engines with, and without traces of hone marks. If I look closely, there may be some traces left. I'll have to look closer.

It is normal for the cross hatch to continue to wear throughout the life of the engine, and so there will always be a variance as to how much may be visible between used engines.  If I understand your situation correctly, this was a fairly recent rebuild with only 3000 miles of use, and at that point in the engine's life there should be an obvious amount of distinct cross hatch visible on the cylinder walls.

Nothing (and no one) says you have to have fresh cross hatch, I'm sure the engine will run fine as it did before, but my recommendation is to restore the cross hatch to improve the longevity of the engine.

[lucky]

Just run a hone through the cylinders and you will sleep at night.
Do you want to have to take it all back apart again to stop it from smoking?

I know from actual experience what I am talking about.

If the OP does not hone the cylinder walls and it DOES smoke, do you think he will report back that he should have done it. Of course not.

[lucky]

For new rings, yes.  For old rings I don't see a reason  - but I believe ring rotates on pistons 

If you pull the cylinders and then try to reuse the rings then your chance of them not sealing properly goes up quite a bit. There are people that have gotten lucky doing this, but there are many that have tried only to have one or two cylinders burning oil. Rings are way cheaper than my time, so to me it is not worth the risk of them not sealing again.

If you pull the piston from the bore and put it right back in what has changed to cause it to no longer seal?

The position of the rings.

[dave500]

theyve already broken in to those bores,just reassemble it for #$%*s sake,it goes without saying to be sure they all go back into their original postions,rings might rotate a little in the grooves,they can go back and forth,they can hang up in one spot,space them evenly during assembly,with lots of oil not dry.

[Powderman]

For new rings, yes.  For old rings I don't see a reason  - but I believe ring rotates on pistons 

If you pull the cylinders and then try to reuse the rings then your chance of them not sealing properly goes up quite a bit. There are people that have gotten lucky doing this, but there are many that have tried only to have one or two cylinders burning oil. Rings are way cheaper than my time, so to me it is not worth the risk of them not sealing again.

If you pull the piston from the bore and put it right back in what has changed to cause it to no longer seal?

The position of the rings.

The position of the rings are constantly moving under use. So how does manually changing the position keep them from sealing? Makes no sense to me.

[Dave Voss]

The position of the rings are constantly moving under use. So how does manually changing the position keep them from sealing? Makes no sense to me.

The reason is because neither the rings nor the cylinder walls are perfectly round following break-in.  When new rings are installed in freshly honed cylinders, there are many 'high' points of contact that get worn down during wear-in, until the contact between the rings and the cylinders becomes fairly uniform all around.  This process results in the rings and the cylinders being distorted somewhat from a theoretically perfect circle, but since they become matched to each other, this minor distortion is complimentary and therefore irrelevent.

If the rings are rotated to a different position and then reinstalled in the cylinders, it upsets the 'matching' that occurred previously, resulting in a new set of 'high' points as two not-perfectly-round-but-otherwsie-matched circles are rotated in relation to each other, leaving very minor gaps that reduce the effective sealing.  In the real world, the rings and cylinders will wear-in a bit more to correct the mis-match, and in a young otherwise healthy engine it probably won't have a noticeable impact, but in an older more worn engine, it could result in a noticeable drop in compression as the rings no longer seal as well.

As to rings spinning around the pistons by themselves in normal service, my experience tells me that it just doesn't happen that much.  When I build engines, I always orient the top ring gap along the piston wrist pin centerline, facing the Cyl #1 side of the engine.  Second ring gap is oriented 120 degrees clockwise as viewed from the top of the piston, and the third ring is oriented 120 degrees counter clockwise.  I've dismantled more than a few engines that I've assembled, and in each case the piston rings rotated away from their original orientation by only a few degrees, probably during the initial wear-in.  As explained above, rotation causes a slight compression, which requires forces that aren't really present, so the orientation of the rings tends to remain fairly static in operation.

[754]

So there you have it..dont move or spin the rings, while the piston is out of the motor..

 Some may remember when some folks used scouring powder to rejuvenate engines, seems to have been done a lot with industrial diesels..  So...I surmised that if for a few minutes while tuning, you ran without aircleaners.. That you may actually be re seating the assembly.. Shorter less harsh version..

[crazypj]

I'm way more interested in WHY it was taken apart after 3,000 miles?
 As for the rest of it...........................
 Rings rotate, get over it.
Just put the damn thing back together -DRY- with a spot of oil on piston skirts only.
Wash the cylinders with brake cleaner or similar
Slathering oil up and down bore and all over the rings causes glazing and that, combined with excess piston to cylinder clearance (allowing piston to tilt ever so slightly) gives smoky engines
The old school myths don't need to be perpetrated any longer
Even 'mirror finish' cylinders will eventually bed in rings, it may take 10,000 miles, (or more) but, they will bed in

[74750k4]

The main reason for disassembly was a so-called street stock piston compatible camshaft was installed. Here it is...

http://dynoman.net/zencart/index.php?main_page=product_info&cPath=36_38_44&products_id=59

I may still use this cam in an 849cc CycleX piston build.  It is definitely not good for stock pistons. No compression with the large overlap, and huge duration makes idling below 2000 RPM extremely difficult, and inconvenient for a street ridden machine. It's astounding above 5000 RPM to ??K RPM.  I'm going to the Web Cam 41 / CycleX CX2 in this engine instead.

[KJ790]

The main reason for disassembly was a so-called street stock piston compatible camshaft was installed. Here it is...

http://dynoman.net/zencart/index.php?main_page=product_info&cPath=36_38_44&products_id=59

I may still use this cam in an 849cc CycleX piston build.  It is definitely not good for stock pistons. No compression with the large overlap, and huge duration makes idling below 2000 RPM extremely difficult, and inconvenient for a street ridden machine. It's astounding above 5000 RPM to ??K RPM.  I'm going to the Web Cam 41 / CycleX CX2 in this engine instead.

What are the specs on that cam, their website doesn't give any useful information. What lobe centers did you degree the cam to when you installed it? It is odd that a cam advertised for street touring would perform that poorly at low RPMs. It may simply be too retarded at the moment, causing poor low RPM operation.

[74750k4]

Look here...

http://forums.sohc4.net/index.php?action=dlattach;topic=123458.0;attach=224875


19-103 is the Kenny Harmon "D" grind, which is exactly what DP is selling. Megacyle has specs on it as well if you go to their site. It is set up per the specs. A beautiful square lobed HP cam. (not suggested for street use with stock pistons, and confirmed by Ken at CycleX)

[74750k4]

oh, and here...


http://dynoman.net/engine/cams/timing-cards/cam-card-DPKHD.pdf

[KJ790]

Yeah, that is a lot of overlap for a street cam! No wonder it idles poorly, that cam would kill your dynamic compression ratio!

[thirsty 1]

Does anyone think that it's odd that the cross hatch is gone in just 3k miles?

[lucky]

Does anyone think that it's odd that the cross hatch is gone in just 3k miles?

From my experience that is normal.