North American Turbocoupe Organization



Engine rebuild
anasazi4st Offline
Senior Member
#1
I’ve just purchased a short block 2.3l 4 cylinder Turbo engine and cylinder head from my favorite salvage yard in Tucson. My TC just hit the 275K mileage mark and I think it might soon be time for a rebuilt engine. I’m blowing grey smoke and using oil; compression test is as follows: cylinder 1–150; 2–150; 3–135, retest also 135; 4–150. After adding about a tablespoon of oil to 3, new result is 160. Thinking it’s a valve or turbo issue, but no performance problems with that. In fact, car still runs great, but prone to clouds of smoke after deceleration, then some upon hitting the gas. Oil pressure lower than usual.

I’ve rebuilt engines before, but not this one, so I’m not a novice. I’ll need some parts—my plan is to take as little as possible from my existing motor, using mostly replacement items, to save on the down time. Suggestions for parts sources, both internal engine and TC-special parts, would be greatly appreciated.

While this is a functional task, it is also hobby related...I am looking forward to this rebuild.

I have also just joined the Facebook page of Turbo Fords. If you are also there, please feel free to send a message or friend request. Look for Forrest, that would be me.

Thanks in advance for any suggestions, advice, etc.

Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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Jeff K Offline
Administrator
#2
Smoke on decel is usually a sign of bad valve stem seals. Replacing them is a relatively straight forward repair.

Check out Stingers site for lots of rebuild parts.

When I bought my TC back in 2000, it smoked quite a bit and burned a quart of oil in 400 miles. Pulled it apart to find a cracked head and rock hard valve seals. Cylinders had almost zero ridge, and I could still see the hone crosshatch. Got hold of a reman head replaced the valve stem seals on the reman head with OEM Ford seals, and reassembled the engine. Now at almost 270K miles it doesnt smoke at all and burns a quart of oil every 2500 to 3000 miles.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Pete D Online
Administrator
#3
Compression readings that are lower and rise after adding oil to that cylinder(s) are usually a sign of a ring problem and/or cyl wear. Smoke on decel is oil pulled up past the rings due to vacuum (low pressure in combustion chamber from closed throttle. Decel smoke can also mean worn valve guides or bad valve seals as Jeff said.. No rise after adding oil usually means valve leak, head gasket leak/cracked head.
At 275K I would think seriously about a full rebuild if the smoke problem is found to be block related. Yes others have gone further but do you want to pull it apart twice?
Pete Dunham


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anasazi4st Offline
Senior Member
#4
Thanks, Jeff and Pete.

Yes, after some research I too think it’s the stem seals, especially since performance doesn’t appear to be that adversely affected.

I did fail to mention that I put the inspection camera in each cylinder as I was testing compression. While the plugs all were surprisingly cleaner than I expected, the tops of the pistons and cylinders all had signs of what looked like a small amount of burned oil; at least it looked black. Obviously due to the design I could not see much, only about half of the combustion chamber. But it wasn’t encouraging.

Pete, I agree that—at 275K—it’s a good time to consider a rebuild. That’s the plan with the second engine, which came from a TC with 130K miles. While I realize that a motor can be seriously damaged from poor care after only a few thousand miles—lower mileage isn’t always an indicator—from what I’ve seen so far it looks good. I’ll obviously know much more after I dig into it.

Jeff, I’ll pull the valve cover and take a look at the overall condition and the stem seals. And I do understand it’s not that that difficult of a job. Problem is that the wife’s PT Cruiser blew its timing belt around Thanksgiving and it is (ugh) an interference engine, I fear the worst. So trying to balance both right now.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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