Fireindc's attempt to build a decent miata. (the search for more torque).
12-21-2013, 01:04 AM
#503
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It was, at least judging from the accessories. It had a drive by wire throttle body and a much beefier intake manifold on it, but i swapped everything over to what came on the foz. (some sensors, crank gear with different triggers, and the dr. side cam gear because it was different.).
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12-21-2013, 11:47 AM
#504
Most people do leakdown testing at TDC. This assumes that cylinder condition on the entire stroke is the same as cylinder condition at TDC -- which is often an incorrect assumption.
Best to do both leakdown and compression testing. During a compression test, you monitor the pressure built by traversing the entire stroke.
$$0.02.
Best to do both leakdown and compression testing. During a compression test, you monitor the pressure built by traversing the entire stroke.
$$0.02.
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12-21-2013, 11:58 AM
#505
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Most people do leakdown testing at TDC. This assumes that cylinder condition on the entire stroke is the same as cylinder condition at TDC -- which is often an incorrect assumption.
Best to do both leakdown and compression testing. During a compression test, you monitor the pressure built by traversing the entire stroke.
$$0.02.
Best to do both leakdown and compression testing. During a compression test, you monitor the pressure built by traversing the entire stroke.
$$0.02.
Leakdown resulted in good even readings, less than 15% across the board.
Compression test resulted in:
drivers side bank = 130psi (both within 5 psi of each other.
pass side bank = 160psi (both within 5 psi of each other)
This is part of why i suspected a HG initially, because the drop in PSI on the entire bank made me suspicious. Not so sure anymore! We shall see, off to go snowboard for now though.
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12-21-2013, 02:12 PM
#506
Leakdown resulted in good even readings, less than 15% across the board.
Compression test resulted in:
drivers side bank = 130psi (both within 5 psi of each other.
pass side bank = 160psi (both within 5 psi of each other)
This is part of why i suspected a HG initially, because the drop in PSI on the entire bank made me suspicious. Not so sure anymore!
Compression test resulted in:
drivers side bank = 130psi (both within 5 psi of each other.
pass side bank = 160psi (both within 5 psi of each other)
This is part of why i suspected a HG initially, because the drop in PSI on the entire bank made me suspicious. Not so sure anymore!
Damn you and your snow and your mountains. Jealous.
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12-26-2013, 07:34 PM
#507
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Okay guys, sorry.. no pictures. But bear with me here, this is the synopsis.
So far, even just pulling the valve covers this is internally the cleanest motor I've ever disassembled. I got the heads off and they are in great condition, pistons look good from the top with minimal carbon, cylinders don't have a scratch on any of them and the hone looks brand new.
Also, the head-gaskets are fine. This is all good news, but it leaves me wondering WTF the problem is. I guess the next step is going to be to pull the pistons (which you have to do before splitting the cases anyways) and look further. I know the motor sat, so maybe I'm dealing with a stuck oil control ring.
I'm thinking about re-ringing it and leaving the bottom end. This motor clearly is around the 60k claimed miles, and I'd really like to slap it back together and run it seeing how nice it is internally. I'll get pictures tomorrow!
So far, even just pulling the valve covers this is internally the cleanest motor I've ever disassembled. I got the heads off and they are in great condition, pistons look good from the top with minimal carbon, cylinders don't have a scratch on any of them and the hone looks brand new.
Also, the head-gaskets are fine. This is all good news, but it leaves me wondering WTF the problem is. I guess the next step is going to be to pull the pistons (which you have to do before splitting the cases anyways) and look further. I know the motor sat, so maybe I'm dealing with a stuck oil control ring.
I'm thinking about re-ringing it and leaving the bottom end. This motor clearly is around the 60k claimed miles, and I'd really like to slap it back together and run it seeing how nice it is internally. I'll get pictures tomorrow!
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12-26-2013, 08:42 PM
#512
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Plus i'd like to get this thing up and running asap so I can focus on the BP.
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12-27-2013, 04:42 PM
#513
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True no point spending more money on it then you have to. Once you find the issue slap it back together and get that waste gate on your Miata so I can see what my car will be doing in a few months!
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12-27-2013, 05:09 PM
#515
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LOL, yeah man. I'm completely ashamed but I'll own up to it. I'm a n00baru.
So, I basically hooked up the subaru PCV system backwards. I hooked up the valve cover breather directly to the intake manifold. SO i believe it was acting like a straw, sucking tons of oil from the valve covers and dumping it in the intake.
This explains why the airbox itself was clean, yet there was oil literally pooling on the intake valves.
Apparently this isn't a miata. Sideways valve covers, wtf?!
So, I basically hooked up the subaru PCV system backwards. I hooked up the valve cover breather directly to the intake manifold. SO i believe it was acting like a straw, sucking tons of oil from the valve covers and dumping it in the intake.
This explains why the airbox itself was clean, yet there was oil literally pooling on the intake valves.
Apparently this isn't a miata. Sideways valve covers, wtf?!
Last edited by Fireindc; 12-27-2013 at 05:23 PM.
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12-27-2013, 05:19 PM
#516
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Please notice the "fail" behind the coilpack there running to the pas side head.
Did not figure this out until i pulled the motor apart to find pristine internals, THEN of course i second guess my pcv routing.
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