OzVMX Forum
Clubroom => Tech Talk => Topic started by: mx250 on November 05, 2007, 06:28:00 pm
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Bought a three prong cylinder honer today - any tips how to use, what to be careful of etc etce
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Check the stones are tight before each job ;) Lost one once and the spring tensioned arm sort of left a very nasty ........... but was sort of lucky as it was the free loading neighbours Victa 160 ::). Now whether too spin hone fast or slow and what sort of cross hatching is best , how much lube/liquid assistance ,should bore be warmed or cooled ,etc etc, that is a real turd full of maggots to caress, so over to the suitably qualified engineering technicians to sort elbows from arses.. Cheers Tim754 :D
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It's not one of the Super Cheap Autos cylinder hone tools is it Graeme? I have been considering a purchase myself and would like some experience with them. They are a medium grade stone...whatever medium means.
Havent honed a bore for over 20 years smyself o would like some recent expert advice also.
I recall I used to use kerosene as a lubricant and put the hone on the end of an electric drill. Move the hone up and down fairly quickly. You want the cross hatch effect - about 45 degrees. Take it carefully and only hone enough to remove the glazed appearance and establish the cross hatch effect for the rings to bed into.
Over to the gurus......
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Someone who'se opinion I trusted told me that it's very easy to stuff the bore up with the typical three prong supercheap style stone hone. Something about it being easy to get the bore out of taper and round if your not careful. He suggested using the brush style ( I think they might be silicon carbide tipped, but I really don't know) hones that are dearer. The ones that look like overgrown bottle scrubbers.
I helped him hone the liners out of a V12 MTU diesel and (1800 shaft horsepower and 52 liters displacement) and the trick seemed to be keep the hone moving always, never in the same spot and lots of kero.
Oh, and he also had a pic of his good self standing INSIDE the cylinder of some monster ship engine using a angle grinder to do the very same task.... ;D ;D
Charlie, wonder if he's still alive. He could fix anything, after a fashion.
FBC
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I would think that very sound advice FBC, but you only really hone to size after a rebore.Even then it is done with diamond blades preferably with something like a Sunnen brand hone. Some 800/1200 wet and dry can restore cross hatching/remove glazing without the fear of making the bore oval.
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I'm with Lozza, I've always used fine wet and dry and to remove glazing from bores. Obviously with a 125/80 it can be a little tricky but small hands help in this instance..get your Mrs. to do these! :D
Seriously, it doesn't take much at all to remove the glazing by hand and costs about 20cents for a scrap of wet and dry sandpaper which is all you'll need..oh..and some water...lots of water ;)
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You can use a cordless drill on slow speed and move it up and down resonably fast, make sure you have plenty of lube, normaly kerosene as previously stated, and it shouldn't take too long to get the 60 deg cross hatch required. As long as all you want to do to remove the glazing and put the cross hatch back in, a 3 prong hone should be fine. All up it should only take you a few minutes. I would not be concerned about damaging the bore as you will be removing minimal material, less than 0.001"
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Oh, and he also had a pic of his good self standing INSIDE the cylinder of some monster ship engine using a angle grinder to do the very same task.... ;D ;D
what you are doing on the top of a ships liner is "blending"' the step that the old rings have left behind at the top of their stroke so the new new rings don't get contracted as they pass over that area, its the cycles of contraction that break the rings which is quite common on marine 2 strokes. I have seen liners that never wore significantly after 25 years of service (made in Japan) and others that lasted 2 years, made elsewhere is Asia.
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Bought a three prong cylinder honer today - any tips how to use, what to be careful of etc etce
From the little that I know these are bad news if used on a 2 stroke bore due to the ports causing the stones to "jump"
The correct hone to use is the one in the attached photo.
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100% correct lc4 ;D
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Educate me some.....what sort of hone is that called ??? ???? 2 stones or 4? I cant tell from the photo. Cheers
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Educate me some.....what sort of hone is that called ??? ???? 2 stones or 4? I cant tell from the photo. Cheers
Search for "Sunnen Hones",basicly this hone will maintain even pressure through the whole bore length and not be affected by the ports.
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All of the above makes a whole lot of sense.
For my money, and not having enough demand for a quality hone - take the jug to an expert and I bet it will cost you next to nothing for a top job.
I do all my own engine work EXCEPT boring and honing - I have a good machinist in Port Macquarie of all places who is an ex toolmaker like me and his work is EXCEPTIONAL and fairly priced.
For LIGHT honing Flex-Hones are the go 600/800 grit for light refinishing 35 - 45 degrees in a bucket of diesel (wear protective gloves)
Self honing without the right gear AND KNOWLEDGE = :'(
For what it's worth
Dave Mac
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A few comments based on 25 years of boring and Honing, but keep in mind I'm now way out of date :-\.
No luck with the cheap three stone hones, especially on 2 strokes. Extremely difficult to maintain accuracy and the stone to wall pressure is so light it often produces a finish which is more like polishing than honing. Marginally OK on soft bores or with kero or diesel as honing fluid.
Tried brush hones when they first became available and found that unless you are careful with the driven speed and the honing fluid they tend to bounce in the bore. Again, kero or similar instead of a proper honing fluid ( eg Castrol ) can help. Generally the finish left on the cylinder was prickly, the cross hatch is there but the surface if examined closely looks like wet and dry paper. Piston skirts after a short run were a mass of fine scores, anal cleaning of the bore after brush honing seems to be essential and even then I think the lousy surface finish in the bore can lead to early piston damage. We gave up on them pronto, but they are brilliant for producing an oil retentive finish in plain bushes and valve guides providing they get the anal cleaning to remove all traces of abrasive.
I reckon the trick for a re ring is to deglaze by hand with about 180 wet and dry and engine oil , as others have suggested or if the bore needs truing up pay a Pro. 45 degree cross hatch. Easy to control and make adjustments to finish etc as you go. If 180 wet and dry too aggressive ( depends on the cylinder material ) draw it slowly across the corner of a piece of angle iron a couple of times ( with pressure ) to take the starch out of it.
For a rebore, track down someone with the best equipment and the best attitood you can find and spend the money, cheaper in the long run.
Plenty of controversy over how to clean the cylinder after honing, but we settled on a rough wash with petrol or solvent, and then endless mopping with clean LINT FREE cotton rag and engine oil. Keep selecting a clean area on the rag, wet with fresh oil, and go around the whole bore and up into ports over and over until the rag with fresh oil comes out Clean. Apply pressure when mopping and follow the cross hatch, first one way and then the other. It's scary how much grit comes off on the oily rag. Cheers. :)
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i have been told to hone using kerosine as cutting lubricant,then wash with kerro THEN wash thoroughly with detergent and water or soap and water to prevent premature wear.immediately after the last wash take steps to prevent rust with oily rag or wd40.cheers wally.
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Biggest cause of premature wear (on 2T) is incorrect dressing of the port windows.The hot soap wash works very well and definantly removes fine grit leftover from the stones. I normaly just smear with oil after this.
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lozza i must point out that that your by-line makes an incorrect claim! quote from King James Bible."THE LORD RODE FORTH [not fourth] ON HIS TRIUMPH"! four strokes rule since biblical times! cheers wally.
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Not being an eclesiastical expert Wally but I think the next line says "BEFORE HE BROKETH DOWN,AND CAUGHT FIRE" ;D
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A cylinder hone has four stones and a micrometer adjustment. Your three stone "hone" is a glaze breaker,
used to break the oilf glaze from the cylinder wall. Your hone will just follow your cylinder's out of round bore and will only make it worse. Use a honing oil not kerosene.
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Always took to a pro to hone to size( I thought that given the small increases for oversizes on most of our old 2 strokes that a boring bar was not always used).
Unless you have a large fleet of machines, it makes no cost sense to not use a pro IMO. I have carefully used a ball hone to cross hatch for re-ring-very slow speed-and I always clean in solvent tank thoroughy, wash with hot soapy water, spray with WD-40-blow dry, spray with WD-40-and do the clean towel procedure described above. I think next time, I'll try the wet and dry paper , but wrap it on a "soft block"-autobody sanding block for color sanding with fine grits, so as to not get finger gouges.
BTW a few years back had a bloke come to store looking for a hone for chrome bore on a late CR 2 stroke. On chrome bores, I always just cleaned it and reassembled-also no real "break -in" prcedure on these. As soon as the coated 2stroke oil burned off clean-ready to run. Maybe not right, but I had no problems .
James