omega0684
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| posted on 19/9/09 at 06:05 PM |
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honing
can someone explain the steps to deglazing/ honing a cylinder bore please.
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Ben_Copeland
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| posted on 19/9/09 at 06:10 PM |
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OOooo was wondering this myself.
Remembers to check Receive Email Notifiations....
Ben
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Z20LET Astra Turbo, into a Haynes
Roadster
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http://www.facebook.com/EquinoxProducts for all your bodywork needs!
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flak monkey
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| posted on 19/9/09 at 06:14 PM |
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Step 1 - Buy honing tool
Step 2 - Set tool for bore size if required
Step 3 - Select suitable drill and set speed nice and slow, mount honing tool
Step 4 - Slide tool into cylinder bore and start the drill, nice and slow. Work the tool up and down the bore fairly quickly without twisting it.
Your aim is to get an even, matt, cross hatched type appearance over the whole length of the cylinder walls.
Engine needs to be totally stripped before you start as well. Otherwise you will end up with bits of metal and grit everywhere.
There are several types of honing tool available, from ones with 3 stones on legs, to ones which look like flap wheels. All will work.
Sera
http://www.motosera.com
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omega0684
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| posted on 19/9/09 at 06:19 PM |
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cheers dave, legend as usual!
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britishtrident
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| posted on 19/9/09 at 06:24 PM |
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A brand new piston ring will only actually touch the bore in 3 or 4 places around its circumfrence.
The piston rings need a slightly rough surface so they wear (bed) in to exactly fit the curvature of the bore.
The rough surface texture also allows the cylinder wall to retain an oil film which is vital to prevent hot spots forming on the piston rings during
running in.
If the piston ring locally over heats it looses its spring tension and won't be held against the bore to form the initial seal.
Although gas pressure behind and on top of the ring is what actually push the ring out to form the seal, it is vital there is enough spring tension in
the ring to allow the pressure to build.
With a worn bore thre is the added problem of the top piston ring hitting the wear ridge made by the old ring at the top of the bore, so the wear
ridge should be honed smooth before fitting new rings.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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philw
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| posted on 19/9/09 at 06:26 PM |
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You're looking for between 30 and 45 deg angle on the honing marks
Must try harder
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Ben_Copeland
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| posted on 19/9/09 at 06:31 PM |
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That cant be easy to master !!!
Ben
Locost Map on Google Maps
Z20LET Astra Turbo, into a Haynes
Roadster
Enter Your Details Here
http://www.facebook.com/EquinoxProducts for all your bodywork needs!
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thunderace
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| posted on 19/9/09 at 06:43 PM |
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http://www.youtube.com/watch?v=82OMO1ArSkk&NR=1
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MakeEverything
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| posted on 20/9/09 at 10:42 AM |
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quote:
Originally posted by britishtrident
A brand new piston ring will only actually touch the bore in 3 or 4 places around its circumfrence.
The piston rings need a slightly rough surface so they wear (bed) in to exactly fit the curvature of the bore.
The rough surface texture also allows the cylinder wall to retain an oil film which is vital to prevent hot spots forming on the piston rings during
running in.
If the piston ring locally over heats it looses its spring tension and won't be held against the bore to form the initial seal.
Although gas pressure behind and on top of the ring is what actually push the ring out to form the seal, it is vital there is enough spring tension in
the ring to allow the pressure to build.
With a worn bore thre is the added problem of the top piston ring hitting the wear ridge made by the old ring at the top of the bore, so the wear
ridge should be honed smooth before fitting new rings.
Did i read somewhere that with new rings, because of the cross-hatches on a new bore the harder the engine revs the better for the first few miles?
This is so that the cross hatching and rings press hard against eachother (or the rings against the hatching), matching them before the bore becomes
smooth again?
Makes sense to me, but i know that manufacturers insist on a running in period (or used to).
This will open up a nice debate, but logic does suggest that if an engine is run in hard, it seals better in its bores?
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MakeEverything
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| posted on 20/9/09 at 10:46 AM |
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http://www.youtube.com/watch?v=ZOAdIQsWoPM&NR=1&feature=fvwp
Rebuild a zetec in one minute!
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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rusty nuts
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| posted on 20/9/09 at 11:38 AM |
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As an apprentice I was taught to oil pistons, rings etc on assembly but it seems that may have been the wrong approach? I remember reading, possibly
in the old CCC magazine assembly just using WD40 on the pistons allows to rings to bed in better. When I rebuilt the engine in my car I did try this
method and can say I'm pleased with the engine BUT if you try this don't blame me. Also seem to remember race gearboxes being run in
filled with Brasso to bed in the gears before final rebuild?
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britishtrident
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| posted on 20/9/09 at 12:15 PM |
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When I was a marine apprentice with BP I worked for a few months in the long gone Isle of Grain oil refinery. After overhauling big gas compressors
they added a self destroying bedding in compound to the oil, the idea was the bedding in compound disappeared to nothing after a few hours running
and you didn't even have to change the oil . Although it looked like sulpher powder and looked like Brasso when you mixed with oil to add to
the sump it was very special stuff and imported specially from the USA.
The Brasso in the rear axle trick was an old Colin Chapman dodge learned from his secondhand car dealing days, it fixes final drive noise due gear
problems but ruins the bearings.
[Edited on 20/9/09 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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| posted on 20/9/09 at 12:19 PM |
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Found this
http://www.bunkering.co.kr/bp/products/H15_BP_RUNNING_IN_COMPOUND.htm
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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02GF74
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| posted on 20/9/09 at 12:45 PM |
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^^^ wot the monkey said.
you are aiming to cross hatch the bore, around 45 degrees or a bit less ot the horizontal.
old skool honing is done by hand using 600 wet'n'dry and will work just as well s the cheap DIY honing tools.
and that is fine on loose tolerance engine, oi.e. old ones such as pinto, crossflow .
modern engines are built to much tighter tolerances e.g zetec and the honing is to two stage process - the second one smoots of the bumps left by the
coarser first stage and is probably harder to replicate at hone. (<--- geddit?).
googl will provide you with more info. as well as any correctrions to the above.
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rusty nuts
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| posted on 20/9/09 at 12:55 PM |
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quote:
Originally posted by britishtrident
The Brasso in the rear axle trick was an old Colin Chapman dodge learned from his secondhand car dealing days, it fixes final drive noise due gear
problems but ruins the bearings.
[Edited on 20/9/09 by britishtrident]
Heard about the strips of heavy duty plastic bags in the diff to sort out noise
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britishtrident
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| posted on 20/9/09 at 01:08 PM |
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600 grade is much too fine it will polish the bore --- to get the rings to bed in the bore has to be surprisingly rough 120 grade Emmery is nearer
the mark.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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