Joker, around 400 grit and do all of the bore. Remember that all I am doing here is to give a new surface for the rings to 'grip' to to help them bed in.
Glazing in diesel engines isn't what you're describing though. That is literally a byproduct of the combustion process left on the surface and giving it a golden appearance. See I disagree with you here. A polished surface is EXACTLY what you want for proper lubrication of moving parts. If the surface is nice and polished and bedded in - the moving part will lubricate well and last a lot longer. I believe people do it, but very few people understand why. They do it because "it is done". I think strategies have changed over the years as technologies have changed, materials have evolved into alloys and all that sort of stuff... there are a lot of old wives tales that creep in through 'old school' word of mouth sort of processes that are probably not necessary anymore, and I think if a pedantic Japanese engineer didn't list the process as specifically required in his instructions for an engine overhaul in the late 80's it's likely he didn't think it was necessary. The Japanese hate fixing things, that's true... but when they fix things they do it perfectly and are extremely fussy about it. Just my view though. All up I'll give it a rub with some sandpaper I suppose, see how it goes.
Sorry...but you are wrong on each count...none of this is "hearsay" or "old wives tales"... it is Automotive Engineering Fact....just because it hasn't been mentioned by the "copy writer" who did the manual doesn't mean a thing....I have seen dozens of high performance, race and production engines...brand new...old and being freshened up and each and every one was honed....i have read dozens of technical text books on performance engines....etc etc...and each and every one stresses the impeortance of honing the bores before re-assembly... Believe what you want... but glazing in a diesel engine means it needs rebuilding... it blows smoke, uses oil and lacks compression...because the bore is too smooth...because fuel washed away lubrication. Highly polished surfaces do NOT retain any lubricant and as such will not be lubricated...much the same way as using too low a viscosity oil will be harmful... very low surface tension. People do this because it is a required step in the engineering process....they know exactly why they do it....it is a process that is done on every single internal combustion engine manufactured... (apart from Wankel Rotaries)......it is even done on current F1 engines.... I disagree with you on the Japanese being pedantic and meticulous in repairs...there are a multitude of little things that Professional engine builders do that are not mentioned in the Service Manuals...The manual describes disassembly and reassembly... not refurbishing...they show you the valve angles but not how to cut them or lap them in... Yes... material composition is far superior these days but that doesn't mean that proven production techniques based on solid engineering practice no longer applies... Also... your engine is a standard design with Aluminium cylinders with grey cast iron liners....alloy pistons and cast iron piston rings...maybe...the compression rings have a coating to protect against premature wear on initial start up... but it is certainly not what you would class as a "modern" engine in terms of materials or design... With all my training and hands on experience over a 45 year period I would NOT just give the bore a rub with Sandpaper... when for $20 you can get a flex iPhone from Bunnings... but hey... its not my engine and just mine and hundreds of thousands of engineers views over theirs right...
my 2 bobs worth-if you have piston slap the bore can give the appearance of a cross hatch hone marks. if you bore a 2 stroke and do not hone it the chrome rings will polish the bore. a fine hone gives a micro gfroove to hold oil as the rings bed in. this gives a better seal.
The whole deal with the de-glazing/honing is to get a fine crosshatching of the bore surface to hold a minute amount of oil film to help the rings seal to the bore surface. Too shiney and there will be no oil and will get metal to metal contact = lots of wear. Side story; I once worked with a home mechanic who rebuilt a Perkins 4 cyl diesel of a harvester and the bore glazed after the first day. When I arrived the second morning he had the engine at full revs with the aircleaner off and sprinkling Ajax powder into the engine intake. It worked, as that engine had more power and never used oil again.
@Andych if you get the chance, head to Japan and spend some time in one of their "wreckers" or repair shops (if they let you). If they are not the most meticulous, pedantic, careful, committed bunch of mechanics you have ever met - I'd be very surprised. I still work with the Japanese in business and they are painful because of how ridiculous they are about everything. And one more favour... please don't pass your opinion off with comments like "hundreds and thousands of engineers views" as fact to an engineer asking for engineering evidence... opinions are a dime a dozen but those backed up by fact are a lot harder to come by so thanks for your input but I'll just continue to question things until I get what I am looking for. So getting back to the build... found an old translation I did which came in handy. Interestingly it doesn't mention the ring thickness, ie which should be the top and/or bottom. The chinese set came with a black and a silver ring... will measure the gap to see if I can tell which is which. The top/bottom of the ring isn't marked either so this will be fun.
Chrome/silver ring is the top. The rings I got were marked AHL and installed with the lettering facing up. Oil control rings were not marked.
Ah Ok thanks. Mine are from AHL but are only marked "HL". Bit hard to tell which is the rounded/flat side though.
Oh and browsing around I found this... Crux of it is at 4:26. I get that they call it deglazing and what it does but not convinced with his explanation why - and this seems like a class. I suppose I should just shut up about it now because honestly you're probably all sick of reading my rants about it. For me I'll grab the 400 grit and do what murdo suggested... see what happens.
What makes you think ONLY the Japanese are meticulous, pedantic, careful and committed?? If you think that way then you obviously have not worked with any other Nationalities... Just taking Automotive World Championships into account... Germans rule the roost in F1, WEC, WRC and in WSB you have BMW, Ducati, Aprillia all in the top 10... as well as Kawasaki and Honda. MotoGP Ducati is right up there... so please take off your rose coloured glasses... Far from "just" my opinion... but hey.. your are only going to continue questioning until you find someone who agrees with you... good luck on that... For a well written Technical explanation of Cylinder honing any why it is needed and carried out can be found at the link below... why don't you try arguing your point with people like Galloway Engines or ANY performance engine builder... http://www.gallowayengines.com.au/cylinder-honing I will leave this all alone now, good luck with your re-build.
Honing is necessary after a re-bore. Still don't think it's necessary when changing rings provided (1) your bore is round (2) it is within specification and (3) it is in good condition. I sorta get what Murdo was saying about roughening up the bore surface a bit, as it would expedite the wear-in period on the rings - so I'm gonna go with that. So to be very clear - I'm not saying honing isn't important. I'm saying it is important under certain circumstances. If you watch the video he explains the difference between honing and what he calls "deglazing". The confusing part on all this to me is that "glazing" was an old term attached to diesel engines that left a physical deposit on the bore. The bores in my head do not have that problem so they are not "glazed". They are just a finely polished surface like they would be in a lubricated moving part after they have been worn in with the rings. So for me, I get the roughness bit when changing rings but i wouldn't call it de glazing and I don't think you need to hone. Make sense?
In the end it's up to you, i have seen plenty of smoky engine's that were re ringed and the bore's were just cleaned up with some 320/400 w&d paper. Guess it's not that hard or expensive to pull an engine out or apart and do it all again later (replace ring's and gasket's and this time hone) if it does use oil/blow smoke. Maybe honing is just a way that mechanic's can make extra money off us without us questioning it. My machinist recommend's it so i'm happy to trust his knowledge.
It's funny because I have a good friend who is a very old school and experienced machinist and he totally agrees with me... This is the battle, so many opinions... little evidence. But it seems digging for evidence just ends up annoying people as it's way easier to accept what people tell you and just run with it. Let's see what happens though, I'm prepared to walk the talk and see what happens.
Sanded back the base gasket which I will coat with copper gasket cement and re-use. I thought about using gasket paper but decided against it while I had one of these I could use. All the rings are on... need to wash the rest of the engine in a bit of diesel before reassembly but getting there...
Ok, for those who have been annoyed and/or entertained by my various rants on honing: please see summary here. http://www.2fiftycc.com/index.php?threads/bore-glazing-honing.3720/
Just a quick Q, I've emptied 3 cans of degreaser through the bottom end trying to flush out all the dust/grains of sand etc that have accumulated when this was rolling around a shed somewhere but I'm not satisfied I'm getting it all. Don't have an air compressor... so any other ideas what might work? I am tempted to hit the thing with a pressure washer but I can see why that could be a relatively bad idea...
Could you not bring it to a local fuel station and blow it out with the airlines they have for inflating tyres?? compressed air makes life very easy!!