'97 Taurus GL Wagon, 3.0L, 226k: Compression Test Results, Perspective, and Opinions

Maintenance/Repairs
21

New rings require a hone on the cylinders to seat properly. SO…if you’re gonna ring it, you need to hone it.

In addition to that, you may (almost certainly will) have to remove the ridges to even get the piston out. Once that’s out, you’re still dealing with main and top end bearings (both ends of the con-rod). Do you stop there? Heck, it took a hone and ridge clean just to get it out. Did I get the little metal bits out? Crap. Might as well pull the crank and make sure it’s clean, otherwise those bits will kill it and waste my time. Well, crap the whole engine’s out now. Might as well go through it…

It’s a never ending quest for the perfect repair. BTDT. Don’t. Just swap the gaskets, and roll on.

22

OK, I’m back! Lots of rain on successive weekends and just not a lot of time and/or energy after work during the week. But finally got those heads off. Turned out head gasket was leaking around cylinder #1 (which was expected) as the #1 piston head was noticeably “cleaner” than the other five, more blackened heads.

Got a few questions for you guys:

1.) Are these two heads identical and interchangeable? I initially had the short exhaust manifold pipes still attached which made it obvious, but then I forgot to mark them before removing the pipes. IIRC, I think there was an extra bolt hole on the driver’s side of the firewall side head under the throttle body that held a bracket for something. I know I made note of it. I’ll have to check for that. Maybe this is the only difference between the two heads?

2.) I haven’t wiped out the cylinders yet, but I did notice the cross-hatching pattern on at least two of the cylinders. My concern is with cylinder #1, which had the coolant leak. The very outer rim/ridge of the piston face appears to have trace/tiny specks of rust visible. Is this something I need to address?

3.) I kept all the pushrods and rockers straight as they came out. Everything looked good and straight. However, does the rectangular piece that has the bolt going through it, that sits in the rocker “valley” have a particular orientation? I’m not sure if I spun one of those as I was wiping off the rockers as they came out. The piece looks symmetrical to me.

4.) Does the coolant leak in cylinder #1 mean those lifters (or even all lifters) should be replaced? I replaced all the lifters on my 2002 Impala when I did the Intake Gaskets on that one because I was starting to get a tinge of mettalic ticking. I think I heard some of that with this Taurus, too, just before starting this project.

5.) Should I rotate the engine by hand to get each piston to its lowest point so that each cylinder wall can be cleaned as good as possible? And should the piston faces be cleaned, too?

6.) What if it turns out that after cleaning, one or more cylinders does not show the cross-hatching pattern on the cylinder wall? Would honing be the only solution at that point?

7.) As a first step, I thought I’d take the heads to be pressure tested. That’s not something I could do myself, right?

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  1. If you want to know if the heads are identical go to AutoZone website and check the part numbers for reman heads. If the part no. varies from L to R you know there’s a difference and which may or may not be able to be worked around.

  2. I wouldn’t worry too much about those “rust specks” on the piston.

  3. I believe that part is symmetrical.

  4. The first thing to check on the lifters is the face; the part that rubs against the cam lobe.
    Use a magnifying glass and check for pitting and flaking. Also lay the edge of a single edge razor blade over the face each lifter. The razor blade should rock a little if the face is good as the center of the lifter face should be taller than the edges. If you see daylight under the middle of the blade the lifter is no good.

  5. I don’t know what you’re getting at here unless you’re planning to hone the cylinders as best as possible to deglaze them without replacing piston rings. That can possibly work. Do not bottom the hone on the piston top as you may likely break the stones.

  6. See No. 5. Cylinders can have a cross-hatch and still be glazed. If the pistons are remaining in place I’d leave them be as far as cleaning them. Once running you can dribble some water into the intake manifold (slowly) and the water should clean them up.

  7. The heads can be sonic checked for cracks at the auto machine shop. If you get in to sonic checking, surfacing the heads, valve job, or whatever that can get a bit pricy.
    If you’re just trying to cobble this a bit on the cheap I’d probably skip the sonic check.
    Turn the heads up with the spark plugs installed and fill the combustion chambers with gasoline, kerosone, mineral spirits, etc and allow them to sit for 10 minutes. Then check to see if the valves are leaking fluid down through the ports.
    If there is no noticeable leakage then just clean them up and stick them back on the engine if you’re going the cobble route. Hope that helps.

25

It seems that if it is a DOHC { dual over head cam } the heads are different but if it’s a SOHC { single over head cam } the heads are the same . From what I found the 3.0 comes both ways .

26

AFAIK . . . this is a Vulcan engine

3.0 OHV V6

27

@db4690
You are correct about one being a pushrod engine which I mistakenly called a SOHC & they also list a DOHC 3.0 for a 97 Taurus .
I reread the original post & this is clearly the pushrod engine .

28

Gosh, I don’t think I’d worry about any of that. The engine ran smooth and quiet before, with no lifter noise or excessive oil consumption, right? It never really overheated, did it?

Those heads are cast iron and robust, not really prone to cracking. I would clean the heads, put on my reading glasses and take a good look and reuse them as is. If you have the tools I might install the new valve seals that come with the head gasket set.

Coolant in the cylinder has nothing to do with the lifters. If they were quiet before and aren’t obviously worn just leave them alone, don’t mix up their position.

I would clean the cylinders out with some brake cleaner and rags and call it good.

29

keith:

Hey - that looks like a pretty good find, but I’m just going to sit tight and live or die with what I have. Probably keep the cost under $200.

ok4450:

Well, AutoZone is saying the two heads are interchangeable. Could’ve sworn there was that extra bracket bolt hole in the firewall-side head. Need to check those notes I took to prove them wrong. Also - realized later that I never took the spark plugs out of either head, and I had Sharpie’d numbers on each plug, so I should be able to put them back in their original places.

I’ll probably go ahead and check the lifter faces. All that’s in the way is just a flimsy sheet-metal retaining bracket over the tops of them. I know they need to go back in their original locations, but is the orientation critical, too, or will they only drop in one way?

Regarding the honing - still not sure if I’ll do it. Part of me says, “Go ahead … no guts, no glory … you’ve got everything apart right now … this isn’t your primary vehicle … the extra parts aren’t going to cost much … and this is as much about the experience as anything”. The other part of me says, "who’s kidding who? … you’ve barely had enough time and energy to get as far as you have to this point … and you want to EXTEND this project??? Just get those new gaskets and seals installed, throw in the new T-Stat, and “drive on”! Can’t decide …

As for the heads, I DID clean them up and the only thing I noticed was a pinhole in one of the freeze plugs (even though they all LOOK clean, shiny, and new). So probably need to replace all four plugs, right?

sloepoke, db4690: It’s the Vulcan. Sorry, but I thought all 3.0L’s were Vulcans, no?

asemaster:

Funny you mention these cast iron heads are “robust” and “not prone to cracking”. That’s what I thought, but I called two machine shops and they BOTH said the same thing: “believe me, they’re cracked … they all crack … blah, blah, blah”. Made we wonder about the veracity of these places.

I have to admit, your advice makes the most sense to me: just throw it back together and “drive on”. Even so, I’ll need to at least get those valve seals, and now new freeze plugs, installed. Never done either of those before. Another project within a project. That’s the problem with me: everything is always the first time, so it takes me forever …

30

Pretty much all heads are cast identical. They may do some final machining, i.e. bracket mounting holes etc. to make the sides different, but they started out the same. That includes the DOHC engine which came in the SVO model. The rest got the Vulcan.

31

Absolutely don’t try to hone without removing the pistons.
You’ll never get all the abrasive grit and metal particles out of the gap between the piston and cylinder.

32

keith:

But assuming they pass the straight edge test, I’d probably still want to put the heads back where they came from … I would think … or would it be a good idea to swap them?

circuitsmith:

Yeah, honing with the pistons in place doesn’t seem like a good idea to me. What would be the point there anyway … just to re-seat the existing rings??

I guess the big question with doing the honing (with the pistons removed) is … is it possible to cover the crank journal below to keep debris from falling in there? I mean - can you thread a tarp through there, or is that not possible? And if not, then is there a way to “power wash” the crank afterwards with a compressor and a tank of kerosene or some other cleaning agent?

33

I checked a couple parts places & they list the same head for both sides of that engine .

34

I wouldn’t swap sides, even if they are identical. The pistons are identical but you wouldn’t swap them around would you.

Not sure why you want to hone the cylinders unless you are replacing the rings. If you just want to break the glaze to help the existing rings reseat, you could hand wipe the cylinder walls with red (or green) scotchbright soaked in light oil, kerosene or ATF and follow with an old t-shirt soaked in oil.

35

My experience honing cylinders (assisting an experienced mechanic):
After honing (pistons removed) the cylinders and crank were washed down thoroughly with rags dipped in hot soapy water.
Then wiped dry and sprayed with wd-40 before rust could start to form, later wiped down with 20w-50 oil.
Main bearings un-capped, inspected, cleaned and liberally oiled.
That was a part of a mild rebuild with some high performance parts that lasted 100k miles, until the car was wrecked.