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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Piston rings /cgi-bin/YaBB.pl?num=1252817801 Message started by BurnPgh on 09/12/09 at 21:56:41 |
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Title: Piston rings Post by BurnPgh on 09/12/09 at 21:56:41 Since I've got my top end and can't seem to locate a reason for my oil loss my one friend is pushing me to get an overbored piston and new rings. I don't need a new piston and my rings look dandy but he insists I should at least change the rings cause I "did all that work already" Is their a mechanical disadvantage to reusing piston rings that are in good condition? I figure they're already mated to the cylinder so I wouldnt have to concern myself with a new break in period. |
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Title: Re: Piston rings Post by justin_o_guy2 on 09/13/09 at 02:31:28 Its my understanding that if rings are moved( rotated) in the bore, then they are no longer seated.Theyll no longer be riding in the exact same place. If youve pulled the piston out, I think youll be reseating the rings. Not a big "Inside the engine" mechanic, tho, so youll need to wait on an answer from someone else, thats just my .02.. & I wouldnt be messing with the rings, even if I hadnt found the leak,not if it was running okay. |
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Title: Re: Piston rings Post by BurnPgh on 09/13/09 at 04:54:07 okay well...still...rings are in good condition. Worse case then is I have a break in period anyway and don't shell out another $40? Im hoping...maybe......say yes. |
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Title: Re: Piston rings Post by Routy on 09/13/09 at 06:18:29 In past years I have rebuilt many engines, small block chevs mosty, but several MC engines, along w/ Kohler mower engines too. And I have never known to reuse piston rings. But thats probably because the rings were most times the reason for the dismantle in the first place. But I know it is not commonly done, except maybe to save a buck. You say the rings were in good condition,.......so did you....or whoever, install a ring (off the piston) in the cylinder and check that the end gap was w/in tollerence ? All that a loose piston will do is cause noise, (slap) as all a piston does is move the rings up and down in the cylinder. A loose piston will not cause it to use oil. But rings w/ to much end gap will not only pass oil (oil ring) but will also pass compression. (comp ring) |
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Title: Re: Piston rings Post by BurnPgh on 09/13/09 at 11:18:11 same buddy pushing me for an overbore checked it. Now about whether or not I'll need to break it in again... |
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Title: Re: Piston rings Post by RidgeRunner13 on 09/13/09 at 11:53:44 Did your friend use a micrometer to measure the piston & compare to specs? Did he use a cylinder bore gauge to check cylinder wear, or an inside mic. to measure bore size to determine wear? Cylinders wear to a barrel shape so only by measuring this taper can you determine what needs to be done. Are you going to break the glaze on the cyl. walls (providing it doesn't need to be bored)? Just a few of the ? I have before deciding what to do. If you were using oil, I would replace the rings. While it's easy to check end gaps on compression rings to check for wear, I know of no good way to be sure oil control rings still have proper tension to maintain a good seal. If it was mine & didn't need boring I would still hone the cyl. & replace the rings. I would also do a search to see if anyone offers a 'gapless' ring set. Leakdown tests on engines I've built with them typically have 2-3% leakage compared to 6-7%+ with normal rings. After a full season of races they are still 2-3% & normal rings are as much as 12%. If you are already this far into it don't cheap out now, it will just bite you in the butt later. JMO And it might be worth it to take the piston & cylinder to a machine shop & pay them to check it for you. Hope this helps. :) BTW, I'm an ASE Certified Master auto tech. & I've built a few engines over the years. |
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Title: Re: Piston rings Post by Max_Morley on 09/13/09 at 17:59:41 Max an ex certified ASE master Tech and 29 year of teaching automotive technology says, "put in new rings after carefully measuring per the above post. |
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Title: Re: Piston rings Post by mikestrikes on 09/13/09 at 19:20:19 Rings rotate on the piston ! They dont stay clocked in the same place for very long. Valve stem seals are your best bet for oil probs... |
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Title: Re: Piston rings Post by BurnPgh on 09/13/09 at 22:00:30 He did all the measuring and assured me it was within specs in the Cylmers while silutaneously telling me I should get a overbore and weisco piston and maybe shave the head down for more compression. He's a huge gearhead and does all this kind of suping up on his quads and bikes. But yes, unless he's lying to me bold faced. He also recommended a similar break in procedure to that which was apparently used by stimpy except all of his references to duration was in hours of operation, not miles. When I asked if there was a mechanical disadvantage to using used but in spec rings he said he didn't really know. He'd always just replaced them. |
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Title: Re: Piston rings Post by verslagen1 on 09/13/09 at 22:35:59 I'm going in the way of the wiseco piston for the dr650. the stock size for a dr650 is a 1mm overbore for us. you can get them on fleabay search 4597M* and all the sizes will pop up. One guy has it for 126 and change. These are higher compression pistons with reliefs for the valves. That, a lancer cam and a super chain should do ya. I think it'll bring the compression up to 9 but not sure. and I'm getting the nikelsil. ;D |
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Title: Re: Piston rings Post by BurnPgh on 09/13/09 at 22:50:28 I dont really want an overbore and I apparently dont need one. Its just that since my friend always has used new rings he couldnt say whether or not it would be okay to use used, but in spec rings. The Clymers also does not specfically state that you must use new rings if they and the piston and cylinder are all okay. The basic consensus here seems to be that I ought to get new ones anyway as I'll have to break the old ones in all over again anyway. Am I correct in that? I COULD use old ones but I'd have to reseat the rings anyway so I might aswell get new ones? |
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Title: Re: Piston rings Post by mikestrikes on 09/14/09 at 07:22:00 5760677B45727D150 wrote:
NO you would NOT need to do a break in unless you used NEW rings and a fresh bore ! |
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Title: Re: Piston rings Post by Oldfeller on 09/14/09 at 08:16:14 Verslagen, We will await the post run in oil consumption report. Don't forget to the lap the valves in, check valve stems for rock and put in them new stem seals. Is there any PSI to compression ratio table out there that would allow you to easy calculate the compression ratio that you wind up with? I'd hate to have to go to premium gas, but the cost per two gallon fill up might be worth it ..... |
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Title: Re: Piston rings Post by verslagen1 on 09/14/09 at 09:00:38 If things go well, should start the rebuild this winter. 8-) As far as gas goes, I maybe siphoning by brothers race car when he ain't lookin'. ::) |
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Title: Re: Piston rings Post by BurnPgh on 09/14/09 at 12:11:39 alright...new rings it is. Might aswell I geuss. Thoughts on break in. Should I just ride easy and vary RPMs for 500 mi as per the owners manual or does anyone recommend the more agrressive break in method as used by stimpy? |
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Title: Re: Piston rings Post by Oldfeller on 09/14/09 at 12:28:50 Here is a meatball answer to my question on psi compression test vs compression ratio. This is an empirically derived range from car folks who do a lot of piston swapping. It assumes good ring seat and enough oil on the cylinder wall to create a good compression seal. 8:1 - > 102.9 psi 8.5:1 - 102.9 > 110.25 psi 9:1 - 110.25 > 117.6 psi 9.5:1 - 117.6 > 124.95 psi 10:1 - 124.95 > 132.3 psi 10.5:1 - 132.3 > 139.65 psi 11:1 - 139.65 > 147 psi 11.5:1 - 147 > 154.35 psi 12:1 - 154.35 > 161.7 p Do we know the expected PSI range on a stock Savage engine for a cold compression test (or a hot one for that matter)? What PSI range indicates shot rings, valve seat issues, etc for the Savage? Or, do we just keep running it until oil consumption gets bothersome or we have our piston skirt come a'knocking at us? |
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Title: Re: Piston rings Post by Stimpy on 09/14/09 at 13:00:13 Remember that new rings EXPAND. You may NOT need to go oversize in the first place. * LOOK at my new ring install here: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1246924611/0 http://img208.imageshack.us/img208/6326/10072009002.jpg OLD=on the left, NEW=on the right 1=top ring, 2= bottom ring ...look at the gap differences, good luck |
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Title: Re: Piston rings Post by verslagen1 on 09/14/09 at 13:04:28 From the "I hear you knockin' "thread... 4B584F4E515C5A58530C3D0 wrote:
105 dry / 110 with a squirt of oil. [/quote] So I don't think those numbers are right for us. |
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Title: Re: Piston rings Post by BurnPgh on 09/14/09 at 13:15:49 that post has been handy stimpy. The link you had to the VW break in was pretty good although considering it is for a VW im curious what exactly you did for your break in. The big part of the link that confused me was the part about removing the oil filter while cranking to prime the oil pump or something of that nature. Im really hoping that isnt needed on the savage. |
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Title: Re: Piston rings Post by Stimpy on 09/14/09 at 14:37:04 yup, that VW engine rebuild page is great! *what I think they mean with that "prime the oil pump" thing is trying to get all that "contaminated" oil out of there as much as possible before pouring fresh oil in, not sure, gotta re-read. || STIMPY'S NEW RINGS BREAK-IN METHOD || 1st OF ALL: it worked! over 2k miles w/new rings and not a drop of oil on the floor, not a drop of oil missing IN the bike and not a black puff of smoke to speak of and all that torque is still there, yay! anyway ...after putting the bike back together in the garage where I kinda work (I'm their webmaster, page designer, PR guy, etc so they lent me the space & tools to work there) I) ... basically (after warming it) I ran home like a bat out of hell trying to rev the engine/gears/speed up & down as much as possible, specially down shifting a lot, I immediately drained that nasty jet black, scorched, boiling hot oil outta there, this run was about 6 city + 4 highway miles, engine ran fine but it got hot, REALLY hot cause of all that friction! II) then filled it with 2qt of good fresh semi-synth oil and took a short roadtrip on the weekend w/friends (70mi total w/3hr pause in middle), did the reving/gear thing again and did not go over 65mph, then drained the oil again; oil was in bad shape but not as bad as the previous run, this time I changed oil filter too; there were a lot fewer metal shavings this time but bike did get really hot that day as well (think friction, but this is a GOOD thing). III) Then rid the bike normally (85+mph at times) for about 300mi and then dropped the oil again; this "4th oil " was in there for over 1k miles before I dropped it with no problems at all and lasted a good deal of time nice and brown and eventually got black after about 500mi. After all this it's back to normal w/regular oil changes twice a year, 5w40 for winter and 10w50 for summer So that's the story, hope it helps ;) |
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Title: Re: Piston rings Post by boofer on 09/14/09 at 14:51:26 BurnPgh, I agree with Stimpy. Because of mettalurgy these days, break in time is reduced quite a bit. I have not heard anyone recommend honing a crosshatch pattern in the cylinder walls unless that is what they mean by "lapping". Plus any rebuild I did on cars used Siloo tub grease. I took some on my finger and rubbed all bearing surfaces as I put them back. My proof is running up and down the road in a Chevy PU. I bored a 350 .030 over, turned crank .010-.010., put it together and let it sit for 12 years. Friend bought it. I told him tear it down to check it. He didn't need to. Bumped piston with hammer handle and it turned freely. Put some grease on that cam and other surfaces before you put it back. The grease is about the consistency of Goop or Go Jo, Not thick. For cars there is also a break in procedure for cams. Boofer |
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Title: Re: Piston rings Post by mikestrikes on 09/14/09 at 17:52:27 Let it fully warm up, ride slow for about 5 miles then in 3rd gear nail it then let up hard until you get slow again, then nail it hard. Do this for about 5 min and go home and change the oil. You have now seated the rings ! But you cant just put in new rings, you need to resurface the bore. And to the prime the oil pump..... thats to get oil all in the motor before it first fire up after a rebuild... or total oil drain. |
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Title: Re: Piston rings Post by justin_o_guy2 on 09/14/09 at 19:13:09 The idea behind letting off the throttle hard & using the engine for braking is to allow the suction in the combustion chamber to "suck" the rings out hard against the cylinder wall. |
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Title: Re: Piston rings Post by Oldnewguy on 09/15/09 at 09:46:11 The question about whether to replace the rings or not comes down to one question. How much is your time worth to you? If you have to replace them later and spend 6 hours doing it for a $40 savings now, your time is worth $6.66 per hour!! :o |
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Title: Re: Piston rings Post by justin_o_guy2 on 09/15/09 at 10:24:03 Gotta add in another head gasket & the gasket sealer for the head cover. Id drop the pennies now & not be worried about it. |
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Title: Re: Piston rings Post by Oldnewguy on 09/15/09 at 11:20:24 Pennies seems to be the key word. |
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Title: Re: Piston rings Post by BurnPgh on 09/15/09 at 11:54:35 yea...it is pennies which is why im going ahead and changing them out. Im just that kind of like that with everything though. My pizza trays are from my parents and have to be 20 years old. They rust so i scrape the rust off before popping a pizza in the oven BUT they still hold the pizza so im not getting new ones. |
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Title: Re: Piston rings Post by justin_o_guy2 on 09/15/09 at 12:07:12 Wipe your cast iron & pizza pans with a light coat of olive oil. Theyll stop rusting. My cast iron never sees any dish soap. I get it hot, if its nasty, & hit it with water & wipe it out. Soap screws it up. |
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Title: Re: Piston rings Post by BurnPgh on 09/16/09 at 06:02:43 7450525C4A6D4B50525C4A390 wrote:
Not to be rude at all but are you implying that rapid accel/engine decel for a mere 5 minutes will seat the new rings just fine? If it isnt obvious already im fairly ignorant with engine work in general and I've never had a new vehicle so I've never had to do any break ins but 5 minutes of whipping it up and down doesnt seem sufficient. Add to that, that Stimpy just did all this to his bike fairly recently and reported significant amounts of metal filings in the oil filter after just 70 miles of moderate riding on fresh oil (see above). He also did not have his cylinder honed. |
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Title: Re: Piston rings Post by verslagen1 on 09/16/09 at 07:18:05 Hey burn, the method has been posted on the site a couple of times by a few people. And it recounted many times on the web. What mike said maybe abit abreviated but esentially correct. search for mick's ninja post for the full procedure or search the internet. the truth is out there. |
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Title: Re: Piston rings Post by mikestrikes on 09/16/09 at 08:38:53 What I am say'n is if you take it out and do a dealer type break in it will take a lot longer and never really be done right. But if you get it up to temp, and set out not to move the piston up and down, but in a short time force the rings against the walls by going full throttle in 3rd gear from a low rpm, over and over it wont take very long at all. NO.... it wont all happen in 5 min.... but the most important of it will be done. The first few miles is so very important, believe me or not ? |
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Title: Re: Piston rings Post by BurnPgh on 09/16/09 at 09:59:31 Sorry. I really wasnt trying to be rude I just couldnt word it in any way that didn't sound rude. Im just sketchy since I've never had to do it before and dont want to screw up. I have a knack for doing that. Im assuming it doesn't necessarily have to be done in 3rd? It sounds like my neighborhood would really be the only place I could do that without falling into general traffic, which i wouldnt want to do while trying this, and/or attracting the attention of authorities. Unfortunatly, by the time I get to 3rd i wouldnt have time to WOT it before the stop signs. |
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Title: Re: Piston rings Post by mikestrikes on 09/16/09 at 10:25:34 Quote:
You dont need to get going fast, just 1st 2nd then 3rd all in a short time and then nail it.... this can be done in a big parking lot even... And its ok to tell me I'm crazy, most of the time I am, and not many people believe me when I say things like this as its just not what they have been taught.. plus what do I know... my whole motor is in a cat litter tub fully apart... :P Just what ever you do change the oil and change it again until it comes out clean. |
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