Honing and new rings

[The Calibrator]

Found this wtite up which explains things pretty well. MAy bebefit the DIY guys.

Tips -

glue/gaffer tape an old head gasket down to avoid scratching up the block deck as it goes in and out.

If you are only going to re-ring it you _can_ leave the crank in there. Wrap the rod journals _tight_ with electrical tape, and lots of overlap. after honing all cyls, spray the bejesus out of it with high pressure kero, then thinners, esp around the crank, THEN go high pressure hot water and a stiff nylon brush all over the bores. metal debris will stick in there and no hydrocarbon solvent will get it all off the bore walls. If you don't do this, you'll cut ring life in half or worse - seriously.

Get some clean white lint free cloths. After drying it, run them through the bore with a firm pressure out on the bore wall. If they come out anything but 100% clean - any staining at all, and you'll have to repeat the cleaning process. no bullshit.

If you aren't willing to do those cleaning steps for whatever reason - seriously don't hone it. Just use plain rings, which are the softest, not moly or anything, and fit them as is. They'll still bed in somewhat, and it's better than not cleaning it like above imho.

As to the honing process - use a lubricant - 50% kero and 50% elcheapo oil works reasonably. put some in a big cup or jug and then brush it all over the bore, as if rust coating it. and hit it with the hone. Move it in and out of the bore as quick as you possibly can in approximately 3inch travel in each direction, up to around 5 inch. More than that and it'll likely bottom out on the crank, or pop up and out (esp if you use the 3 stone flat hones)

You aren't trying to rip it a new one, just quickly 'dress' the bores - rough them up to allow good ring bed in, and no more. Any more than that will increase the bore size (and every tenth of a thou counts) and lead to it being more likely to burn oil. Just a quick touch up - say 20 seconds per bore, 30 tops, and you're done.

If there's a big ridge at the top of the bore, don't use a ridge remover. That will sound wrong, but here's the reason. The ridge remover is actually to take off the lip so you can get the pistons out without breaking them. Realistically if they are that large of a ridge, it needs to go to the next oversize. Since the ridge won't be perfectly circular, it'll never all be taken by the remover, meaning if it was going to break the new rings, it would anyway, ridge remover or not. The new rings won't hit the ridge. The other thing is if you take out the ridge, it means the top ring is _far_ more exposed to the burning charge than before, and it'll cost ring life _big time_. At absolute most, don't touch the ridge with a ridge remover, but slowly with a _very_ sharp scraper (use an old band saw blade to make one as it'll flex but also be sharp enough to manage cast iron easily) cut the bottom 1-2mm of it and taper it down to the work bore. If that doesn't make sense, I'll do a picture in mspaint.

move the drill in and out as quick as you can. due to most hand drills rotational speed, you'll want to look like a rabbit on ice having a root to get the cross hatch pattern right. You do have to thrust it in line with the bore. This might well mean that you have to turn the engine stand to a 45 degreee angle to reach it, or stand apon the fenders if it's still in the car.

On oversize rings - rings are sized _to_ the pistons. You don't run oversize rings with std pistons. They'll never conform properly to the bore. If the ring gap is way to large - like double the factory tolerance, just go with it, the difference in leakdown will be fuck all over a smaller gap, but oversize rings won't seal well at all. clean the top of the pistons, there's likely a part # or the abbreviation std or '0.020' and so forth to indicate std bore or oversize - get the rings to match that or if in doubt, measure the pistons to find out.

Also - with a new ring in the piston, check the clearance between the ring and top and bottom ring lands. Than can get excessive. If it does, forget using the pistons as is. Once apon a time you could get custom made rings that were 'taller' or thicker to suit, good luck these days. If it's to that stage, go to the next bore size. retain the old rings, and snap in half (if they aren't broken already) then with a file and a sharpening stone, round off the edges, then use that to scrap out the ring grooves in the piston to clean them.

Once you've cleaned the block (sand the deck lightly with emery paper on a wooden block, don't go beserk, but go for clean rather than 100% even (you won't take that much with emery, so it'll only look uneven usually) wash it down again, and then a final wipe on the decks with acetone to clean before the head gasket goes on (clean rags, and then let it air dry)

And


REPCO ENGINE SERVICE MANUAL 1972 (re printed '73-1980)
ISBN 0 909638 00 4

pg.30
"Crosshatch angle too low

This is one of the most common honing faults. The low shearing angle can cause higher impact loadings on the rings, leading to scuffing problems and premature ring wear. In addition the finish is apt to be burnished and some of the grooves can have folded and torn material on their edges, which being easily removed by the rings, and being large in size compared with the oil film thickness, cause scuffing and/or high initial wear. ...."

pg.32
"When to hone worn cylinders
Essentially the optimum bore finish described is centered around newly bored cylinders and the case of re-ringing engines which have been in service can most times be regarded as an exception in considering the need for a honed surface. So long as the cylinders are not scored, wavy, scuffed or distorted it is generally best practice not to hone or de-glaze. Modern ring sets when subjected to the reccomended running in procedure, can satisfactorily bed in to the worn glazed cylinders. During previous service the cylinders develop smooth work hardened surfaces which present an ideal scuff resistant bore to the new rings and bed-in can be achieved in these cases by an accelerated running in procedure. Furthermore where deglazing is practiced there is often a danger from inadequate cleaning of the bores, which will speall disaster to the life of the rings.

If it is necessary to degalze by honing when re-ringing, the importance of thorough bore cleaning cannot be over-emphasized."


pg.33
"Cleaning cylinder walls after honing

To remove the grit the use of a detergent such as hot soapy water highly reccomended. The best alternative is to swab with a light oil and wipe carefully with a clean lint free cloth. This should be repeated several times until a clean cloth remains absolutely unsoiled after wiping over the cylinder walls.

Do not use petrol or kerosene to clean cylinders after honing, as solvents of this nature will not remove the grit from the walls."
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[Toby]

Thanks, that's a cool article! I'm moving to the articles section.