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#1 Posted : Thursday, 9 August 2007 10:20:08 PM(UTC)
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Hi all I have problems with my 308 that has just been rebuilt. I had to take the heads off to replace with big valve jobbies, but I then found that one piston is almost perfectly clean with no carbon build up.The other remaining 7 have normal carbon build up across the top of the piston. The plug also looked like it was new. Now I do know that the engine was firing on all cylinders and ran sweet. ( engine has done less than 1000ks, no signs of water leakage into suspect cylinder I checked all plugs and leads, all firing, any idea
hz dude Offline
#2 Posted : Friday, 10 August 2007 5:44:29 AM(UTC)
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its a puzzle new rebuild only 1000k's old all
the pistons should look brand new no carbon at
all if it was an old engine might have something
to worry about. as long as the carbon build up isn't
to heavy or thick .never herd of this problem
dont quo
On The Other Hand There's Finger's
hz dude Offline
#3 Posted : Friday, 10 August 2007 5:44:29 AM(UTC)
hz dude

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its a puzzle new rebuild only 1000ks old all
the pistons should look brand new no carbon at
all if it was an old engine might have something
to worry about. as long as the carbon build up isnt
to heavy or thick .never herd of this problem
dont quote
On The Other Hand There's Finger's
Munromad2004 Offline
#4 Posted : Friday, 10 August 2007 5:59:25 AM(UTC)
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I think the issue is with the piston that doesn't have carbon on it. It's possibly a sign of water leaking in to the cylinder.
May be there is a small corrosion hole in the inlet manifold which is letting a small amount of water in to the cylinder.

Edited by user Friday, 10 August 2007 6:00:31 AM(UTC)  | Reason: Not specified

Munromad2004 Offline
#5 Posted : Friday, 10 August 2007 5:59:25 AM(UTC)
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I think the issue is with the piston that doesnt have carbon on it. Its possibly a sign of water leaking in to the cylinder.
May be there is a small corrosion hole in the inlet manifold which is letting a small amount of water in to the cylinder.

D

Edited by user Friday, 10 August 2007 6:00:31 AM(UTC)  | Reason: Not specified

Jim5.0 Offline
#6 Posted : Friday, 10 August 2007 7:19:12 AM(UTC)
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Carbon can also be washed off with oil but this would show up on the spark plug.

Start with a compression test. It could be that the rings have not fully bedded in yet.

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Guest
#7 Posted : Friday, 10 August 2007 7:48:16 AM(UTC)
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did you check your oil holes before but it back together again?. sometimes you may have slight dirt in side one of the holes.
Guest
#8 Posted : Tuesday, 14 August 2007 6:57:24 AM(UTC)
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rings were worn in one cylinder, tipped engine up side down and the piston almost just fell out by itself!
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