 rebuild again, does Nikasil go bad? |
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| worn |
 Dec 27 2015, 07:03 PM
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#1
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can't remember  Group: Members Posts: 3,164 Joined: 3-June 11 From: Madison, WI Member No.: 13,152 Region Association: Upper MidWest 
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Saw a thread on the Pelican site showing a set of delaminated Nikasil cylinders. After cleaning up mine I see a few pinpricks. Cylinder 5 is by far the worst offender with what looks not so good to me. Would value response from those who know. I recognize that no 914 came equipped with them.
Longer view  Closer up  Would you be worried? Reusable? Thanks!! |
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Replies(1 - 8)
| mb911 |
Dec 27 2015, 08:47 PM
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#2
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914 Guru Group: Members Posts: 6,883 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest
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I would use or send to us chrome in fondulac and have them redo them..
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| Jake Raby |
Dec 27 2015, 09:43 PM
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#3
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Ring tensions were ran too high for Nikisil in these pics. 8-11# is perfect for Nikiail, but you'll usually need to fish scale them to get them there, or work on the oil ring expanders to drop them.
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| Mark Henry |
Dec 28 2015, 08:39 AM
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#4
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Simple test feel the top ring ridge, if you feel a rolling ridge (opposed to a used steel cylinder's harder, sharper ring ridge) then you should have it replated. If unsure you should have it checked with a bore gauge.
Very high milage cylinders will begin to fishmouth, meaning the top of the bore will be bigger than the bottom. A few small pits in nikasil is normal and OK. Delamination looks sort of like chrome has flaked off a bumper and needs replating. |
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| worn |
Dec 28 2015, 10:12 AM
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#5
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can't remember Group: Members Posts: 3,164 Joined: 3-June 11 From: Madison, WI Member No.: 13,152 Region Association: Upper MidWest
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QUOTE(Mark Henry @ Dec 28 2015, 06:39 AM)  Simple test feel the top ring ridge, if you feel a rolling ridge (opposed to a used steel cylinder's harder, sharper ring ridge) then you should have it replated. If unsure you should have it checked with a bore gauge. Very high milage cylinders will begin to fishmouth, meaning the top of the bore will be bigger than the bottom. A few small pits in nikasil is normal and OK. Delamination looks sort of like chrome has flaked off a bumper and needs replating. Thanks Mark. Initial measurements were very encouraging but I haven't run the mic that way. When I washed them there was no perceptible ridge. |
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| worn |
Dec 28 2015, 10:13 AM
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#6
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can't remember Group: Members Posts: 3,164 Joined: 3-June 11 From: Madison, WI Member No.: 13,152 Region Association: Upper MidWest
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QUOTE(Jake Raby @ Dec 27 2015, 07:43 PM) Ring tensions were ran too high for Nikisil in these pics. 8-11# is perfect for Nikiail, but you'll usually need to fish scale them to get them there, or work on the oil ring expanders to drop them. As in 8 to 11 pounds of tension needed to...pull the piston up or down with rings installed? Thanks Jake. Learning slowly but steadily. |
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| Luke M |
Dec 28 2015, 10:20 AM
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#7
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Senior Member Group: Members Posts: 1,377 Joined: 8-February 05 From: WNY Member No.: 3,574 Region Association: North East States
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I just had my brothers 3.0 cylinders redone in Nikasil. Waited 5 weeks for them to come back to only find one cylinder had a deep pit in it. I'm still waiting for a call back but I know with the Holidays most places shut down until the new year.
If you do send them out take good pics of the cylinders and note any issues on them. The cylinders where real smooth when I sent them in so my issue is with the process/final inspection at the shops end. I got the same cylinders back that I sent in but some places do a swap for your cores. |
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| Mueller |
Dec 28 2015, 10:25 AM
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#8
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None
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QUOTE(worn @ Dec 28 2015, 08:13 AM) QUOTE(Jake Raby @ Dec 27 2015, 07:43 PM) Ring tensions were ran too high for Nikisil in these pics. 8-11# is perfect for Nikiail, but you'll usually need to fish scale them to get them there, or work on the oil ring expanders to drop them. As in 8 to 11 pounds of tension needed to...pull the piston up or down with rings installed? Thanks Jake. Learning slowly but steadily. I'm guessing lubed with oil as well? |
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| sixnotfour |
Dec 28 2015, 10:46 AM
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#9
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914 Wizard Group: Members Posts: 10,436 Joined: 12-September 04 From: Life Elevated..planet UT. Member No.: 2,744 Region Association: Rocky Mountains 
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Use Goetze piston rings ,you will have no problems....
when you took off the old rings was the oil ring one piece or 3 piece ?? if one piece those are just well used , no ring problem... |
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