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Old 07-22-2019, 03:11 PM   #1
GalaxyWide
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Default 04 FXT low compression cyls 1 & 3, options/opinions

I finally took the first steps towards the basic build that I've been planning for way, way too long, starting with a compression test. Unfortunately, the results were less confidence inspiring than I'd hoped...

CYL 2: 130 PSI CYL 1: 100 PSI

CYL 4: 125 PSI CYL 3: 101 PSI

This is with a cold engine, I took too long getting the plugs, etc out for it to be warm. From the research I've done, it seems likely that I have a failing head gasket on the left side, which probably won't play nice with the new turbo and higher boost that I was planning. I know the numbers are low overall, but this motor has over 190k miles on it, so I think 130 cold is fair.

I tried putting some oil in cyls 1 & 3, that got me about 110 PSI on both. So while the rings are worn, they don't seem to be the issue. I'll also be doing a leakdown test tonight to gather more data.

My dilemma is what to do next. Should I:

A. Leave it all alone and hopefully it won't get worse.
B. Replace just the head gaskets, leaving the motor in and not milling the heads.
C. Pull the engine out, replace the worn rings, hone the bores and reassemble with new gaskets.
D. The above with the addition of oversize forged pistons and bore & hone to match.

I'd really like to minimize the extra time and expense on this project, I wasn't planning on major engine surgery! At the same time, dumping money and effort into upgrading and tuning what amounts to a time bomb seems a little silly. My power goals and build are modest, just a VF48, exhaust, STI TMIC and possibly EL headers. 300 hp was a goal, but I'll take whatever is nearest to that as still safe/reliable.

Hopefully this is the right forum section, I was between here and 2.5 turbo powertrain.
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Old 07-22-2019, 03:22 PM   #2
Waddlz
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if this were me

I'd buy a new OEM EJ257 shortblock, R&R heads, gasket kit. Done

However, with 190k miles I'd be selling it for what I could(unless you have sentimental value, which I understand)
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Old 07-22-2019, 03:41 PM   #3
GalaxyWide
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That is a valid approach, I just can't really swing 2200 on a new oem short block at the moment. It took long enough to acquire the parts I've got as it is. Thanks for the reply though!

I get where you're coming from with selling it, but I don't think I'll ever sell this one...there's nothing like it for sale new, and I love it far too much. Something about the lack of modern electronic nanny gadgets and AWD turbo lifted wagon is just irreplaceable to me.
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Old 07-22-2019, 04:17 PM   #4
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that makes sense then.

if thats the case, and you have the time. you could pull the engine apart, get it honed/decked etc. Thats what I would do given your choices

Assuming its just worn rings, which it looks like, you could get some new pistons rings, bearings, and gasket kit and get it all assembled. the machine shop I use charges 256.00 for 4 cylinder assembly. but I'd call some machine shops around you and get charges.

Forged pistons would be nice, but over-kill for your goals. I know people have a hatred for the stock EJ255/57 pistons but they are fine for those goals.
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Old 07-22-2019, 04:32 PM   #5
bdubblu
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+1 on the above. If you have the time to pull it and do most of the work yourself, why not do ALL of the gaskets and new rings? Refreshing that motor before your upgrades is the ONLY thing that makes any sense. Anything short of that would be foolish.
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Old 07-22-2019, 06:43 PM   #6
theotherguy
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If it were me, I'd also buy a factory shortblock and move on but I'm old and have money to burn. I'd pull the motor, remove both heads and check them for flatness, if they're good have them surfaced, cleaned and tested, get new head gaskets and bolt the heads back on and do another compression test. A spare trans and some lumber will let you build a test stand or drop it back into the car. If it hasn't improved, you really haven't lost anything. If it has gone back up and it's the head gaskets like you thought, run it until you have the money for a full rebuild or new shortblock.
I'm a big FXT fan of that generation too, I know how you feel.
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Old 07-22-2019, 07:28 PM   #7
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Quote:
Originally Posted by theotherguy View Post
If it were me, I'd also buy a factory shortblock and move on but I'm old and have money to burn. I'd pull the motor, remove both heads and check them for flatness, if they're good have them surfaced, cleaned and tested, get new head gaskets and bolt the heads back on and do another compression test. A spare trans and some lumber will let you build a test stand or drop it back into the car. If it hasn't improved, you really haven't lost anything. If it has gone back up and it's the head gaskets like you thought, run it until you have the money for a full rebuild or new shortblock.
I'm a big FXT fan of that generation too, I know how you feel.
+1
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Old 07-22-2019, 09:45 PM   #8
GalaxyWide
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The more I think about it, the more getting an OEM short block makes the most sense, and is probably the cheapest in the long run. Unfortunately, it's not in the cards financially at the moment...I know, I know, always budget for the unexpected, but this is a rather large unexpected.

Realistically, I think I will try to find someone to surface the heads, hone the bores and then put in new rings at least (are new pistons a requirement?).

Just did a leakdown test, again with the engine cold. Also note that cylinders 1 & 3 still have oil in them from the compression test, cylinders 2 & 4 are dry.

CYL #2 0.5% CYL #1 7.0%

CYL #4 4.0% CYL #3 9.0%

No, 0.5% is not a typo...it was actually closer to 0! All cylinders blowby seems to come from the engine oil fill, and on cylinder #3 I noticed air coming out of cylinder #1, basically confirming a head gasket issue.

Thanks everyone for the advice and input, I really appreciate it! This is my first venture into actual engine interior work, so I'm sorta in uncharted waters here.
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Old 07-23-2019, 08:50 PM   #9
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New pistons aren't a requirement, measure them per the FSM and go from there. I've flex honed cylinders before without splitting the block, honing the cylinders upside down on a stand, sealed it off using a random rubber pipe plug that fit in snugly, then washed it all down. Probably would have been less effort to split the block in the end and take it to a machine shop.
I'd check the avcs gear on that side for ****s and giggles while its apart.
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Old 07-24-2019, 12:12 AM   #10
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After giving it more thought and considering the options, I think I'm leaning towards just picking up a new OEM EJ257 short block and dropping that in. Given that I plan to keep the car for a long time yet, and that I'm adding mods, it's really the only thing that seems to make sense. Rebuilding my used block won't save me much money, and I've only got about 2 months before I have a long trip planned that I was really hoping to use the car for. The piece of mind of a new block is extremely tempting, especially with how uncertain a rebuild could be. The money will just have to scrape itself together somehow...

It's either that, or simply do nothing but head gaskets and hope for the best. Which i'm really not too keen on, since I really don't think I want to attempt HGs in the car and that's a lot of effort for not a lot of gain.

My next question is heads...what should I be looking to do to them? I would LOVE to avoid taking them to a shop, and it seems like they should still be plenty flat (no overheating or any other issues at all). Should I just do valve seals? Springs and valves? What about guides? I guess I'm just not really sure what exactly a typical "head refresh" consists of. Again, I'm new to engine internal work, just want to make sure I don't miss anything while I've got the chance.

And of course I'll get to do timing belt, etc service while it's out, and get the bay cleaned up some. With a new short block, should I replace the oil pump, pickup and/or pan? I've seen some people putting in STI oil pumps and aftermarket pickups, but my stock oil pump seems to put out plenty of volume (80+ psi anywhere above ~2000 rpm). The closest to tracking the car I plan to get is maybe some ice racing.

Quote:
New pistons aren't a requirement, measure them per the FSM and go from there. I've flex honed cylinders before without splitting the block, honing the cylinders upside down on a stand, sealed it off using a random rubber pipe plug that fit in snugly, then washed it all down. Probably would have been less effort to split the block in the end and take it to a machine shop.
I'd check the avcs gear on that side for ****s and giggles while its apart.
Good idea on the AVCS gears, I'll make sure to check them! And thanks for the advice, though I've heard enough horror stories about flex/ball hones to make me more than a little wary of them.
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Old 07-29-2019, 01:08 PM   #11
Waddlz
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I'm having SOHC Forester heads rebuilt/cleaned/decked etc for $400 for both.

How many miles are on your heads? at minimum you should get them decked so they are flat. but ideally you should get a full rebuild
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Old 07-29-2019, 04:54 PM   #12
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I'd just check them for warpage with a straight edge and feeler gauges. If warped then they need to go to a shop, if good then proceed...

The full gasket set has head gaskets and valve seals.

You'll definitely want to check valve clearances and get them within spec, as often the clearances get too tight.
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