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C2H5OH
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11,867 Posts
Discussion Starter #1
205, 210, 205, 180

Put the leakdown on #4 and I can feel what I'd consider too much air coming out the PCV/VC breather port. At least more that I can feel from 1-3.

So my assumption is that I cracked a ring.
Anyone agree?

Car misfires badly at part throttle, but WOT it runs great. Tried adjusting the tune and it's the same on a new tune as it is on a known good tune. So it's not the tune IMO.
It feels like a massive misfire and low compression would certainly cause that, even though it's only a 13% loss ... you can probably double that loss at actual compression. It's a 13% loss @ 100psi.
Last time I checked I was between 3-5% @ 100psi.

So, teardown is in the very near future I guess. Replace with good JY shortblock and hopefully be back running in under a week.
 

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401 Posts
Try squirting some oil in #4 and see if the compression goes up, if it does it's the rings if not it could be blown head gasket or valve issues. Either way you are right I guess a teardown is in your future. Great time for a real engine build.
 

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GT40 all the things!
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9,482 Posts
Well what are your plans since your have to tear into her anyway? I'm sure you could find some SVT internals pretty cheap. You going to take more off the head while its off?

I ended up taking 0.090" off the ZX2 head [shhh]
 

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1,486 Posts
Put 1oz of ATF in #4.

Hand crank the engine 2 revolutions.

Let sit over night.

Run engine till warm and then test again.

ATF has alot of cleaners in it, so if the rings are just slightly gunked up, it might fix it.
 

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I need BOOOOST!!!!!!
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6,125 Posts
Add blinker fluid and it will be fine [hihi]

It sounds like a cracked ring to me too. You going with a different piston or just replacing rings?
 

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I agree with adding some oil to the cylinder to see if it improves things or not before teardown. Either way the engine has to come apart but id be nice to know you were going for a bad ring or a burnt valve first i'd think.

Have you verified there are no obvious ignition or fuel issues first?
 

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C2H5OH
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11,867 Posts
Discussion Starter #7
^ No I haven't. I didn't have much time this week and a half hour before work today was all I've been able to do mechanically. I have today off so I'll dig in a bit deeper and more thorough testing.

But excessive air out the PCV won't be a valve or HG issue, FYI. That is strictly a ring issue.


Far as rebuild,
On the cheap. Stock parts but fully balanced for the new FW ... being I'm pushing the RPM limit I need to get that done so I don't shatter the CFM oil pump gear, and it should quiet down the activity of my KS.
Stock zetec rods/pistons with new rings and ARP rods and mains, which I'll have to clearance for. Along with a JY lower mileage rotating assy.
I think if I can find a 95' Contour engine I'll use those rods/pistons with my crank and block ... seem to recall that being able to make kinda a stroker. But I'll have to find out for sure. maybe it's the other way round, 95 Contour crank and Focus rods/pistons.
 

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I need BOOOOST!!!!!!
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6,125 Posts
That stroker deal is news to me. Let me know what you find out about making that stroker and if it works out I will probably try it myself.
 

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C2H5OH
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Discussion Starter #9
As if I needed more proof my car is weird.

Adjusted cam timing just a smidge, cars back to normal. No part throttle misfires.
WTF?

I had it retarded from where I am right now 2-3*, if that. Makes no sense to me at all.
I haven't rechecked compression/leakdown and don't plan on doing so. Don't see the need.

But I did almost finish my CAI, put new plugs in and gaped them a bit smaller (0.045" vs 0.055"), put a new fuel filter in and cleaned my grounds.
I have 4 brand new coils and a new sock filter to do yet.

BTW, the new CAI (which I made) is awesome. Before my IAT's averaged around 105*F driving. Now they are damn near ambient temps ... and makes the clutch slip even more, LOL. Good sign I'm making more power than I really should, but I'll have to put a stronger clutch in to actually use it. Guess stock wasn't the brightest idea, oh well.
 

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FF's Night Security
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28,766 Posts
^^Nice. Also cam timing can make a huge difference. I don't know why people so easily dis miss it due to what some others have said. That and being that all the zetec's are up in age and will need there t-belt changed which in turn it will be different due to the belt change. Though cam timing should effect compression on all cyl. I'm sure your first diagnostics was right. Funny how one thing can lead to another causing you to find another problem you weren't even looking for lol.
 
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