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- 03.5 YLW MSP
damn that looks like fun
MP5 Quiz time: Blown rings.. Head gasket, both.... Valve guides, bent valve?
- Thread starter dany10boy
- Start date
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
The low compression cylinder indicates there are ring sealing probs. A head-gasket doesnt acct for the loss of pressure that cylinder,...if it did, there would be massive loss of compression between the head and block,..that cylinder. But by far the most indicative sign is oil over the intake filter which you have already identified as blow-by. This is directly related to that low cylinder.
A rering may get you past the post
or, if you want to do a longer lasting job, either get a 2nd-hand engine or pull the engine down, mic the bores for wear, if within tolerance a rering, if not a rebore. This last one should include a check on bigend journal wear, if out of tolerance,. grind 10 thou under and replace bearings that are 010" undersize. The head itself should be crack tested, gound if out of tol flatness-wise. The rule of thumb for head warp is 1 thou" per inch of head length can be tolerated.
JJ
A rering may get you past the post
or, if you want to do a longer lasting job, either get a 2nd-hand engine or pull the engine down, mic the bores for wear, if within tolerance a rering, if not a rebore. This last one should include a check on bigend journal wear, if out of tolerance,. grind 10 thou under and replace bearings that are 010" undersize. The head itself should be crack tested, gound if out of tol flatness-wise. The rule of thumb for head warp is 1 thou" per inch of head length can be tolerated.JJ
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
The pictures of broken ring-lands on pistons looks more about how much lip the bore had when you removed the pistons. If the bore-lip is pronounced, you'll break the rings and even the ring-land [that's the piece of ally between the top and bottom compression-ring] as they are shocked out of their bores.
Apart from that, the pistons are showing some carbonation due blow-by, so they are a write off. For the sake of record, a new piston in a new bore, runs around 0.7 thou to less than 2 thou clearance..
JJ
Apart from that, the pistons are showing some carbonation due blow-by, so they are a write off
. For the sake of record, a new piston in a new bore, runs around 0.7 thou to less than 2 thou clearance..JJ
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- Banned For Being A Troll
You should not reuse any of that motor
The block will be out more than 0.40 thou
and
The head had likely seen severe trauma
The block will be out more than 0.40 thou
and
The head had likely seen severe trauma
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
Yeah,..I think the OP has done us a service uploading the photos. If as I suspect the bores are heavily worn [going by the lip]then it must have done many miles or a medium amt turboed . Compression rings work by exerting radial force on the bore wall. Apart from the normal tension in each ring, the rings are forced against the cyl-wall by the expansion of burning fuel-air. This gas gets in behind the ring forcing it out. In a turbo, this force is much greater and hence-forth accelerates bore wear,..still I wouldn't mind a turbo .
The 2002 P5 I bought 2nd-hand sounded good in the motor until winter set in. During sub zero mornings, I can hear one piston slapping for a couple of minutes. Hmm... :-( It had 140,000 ks on it.
JJ
. Compression rings work by exerting radial force on the bore wall. Apart from the normal tension in each ring, the rings are forced against the cyl-wall by the expansion of burning fuel-air. This gas gets in behind the ring forcing it out. In a turbo, this force is much greater and hence-forth accelerates bore wear,..still I wouldn't mind a turbo .The 2002 P5 I bought 2nd-hand sounded good in the motor until winter set in. During sub zero mornings, I can hear one piston slapping for a couple of minutes. Hmm... :-( It had 140,000 ks on it.
JJ
