Smoke when cold, oil consumption?

[4000 Pounds of Iron]

OK, I drive a 1991 Crown Vic with the drivetrain from a 1988 Mustang, including the HO 5.0, and I'm having a little oil consumption problem with the mileage-unknown motor I'm using.

It's been this way since I got it, I just want to know if it's normal for an old HO to blow a little dark-colored smoke when it's revved before it's warm. I understand the 85-92 HOs have forged pistons, does that mean they expand more than castings and will allow some blow-by until the engine warms up? I have no knocking, and strong oil pressure, I just don't know if I'm due for a rebuild or should just ignore it. My pipes are a little sooty too, but the only engine code I have is 67 (my car was looking for a neutral safety switch, which I don't have)

4k#Fe

 

[Michael Yount]

What's a little oil consumption mean? You say dark smoke - black smoke means it's too rich. Blue smoke is oil consumption.

If it's not making unusual noises, and it's running ok (drivability, fuel mileage hasn't drastically changed, etc.) and people aren't trying to hire you to lay down a mosquito-killing layer of smoke in their neighborhood each summer -- then I wouldn't worry too much about it. Just drive and enjoy the car.

 

[4000 Pounds of Iron]

I'm a little colorblind, so I can't really tell what color it is. It smells like gas AND oil, which is a little disturbing. I have a crackle from the pipes when it's cold, but my 1995 GT did that as well, so I dunno really. I have an idle surge problem, but all else is pretty much well except for some electrical gremlins.

I also have a very slow coolant loss, but I think my EGR spacer is leaking into the intake.

4k#Fe

 

[Michael Yount]

Perhaps you can get a buddy who's not colorblind to help you with that. You never answered the question - how much oil is it burning? miles/quart

 

[4000 Pounds of Iron]

Roughly a quart every 500 miles or so. How blue should it be? If we're talking azure sky blue, definitely not.

4k#Fe

 

[Michael Yount]

500 miles a quart? Yup - you're either burning or leaking a good bit of it. Sounds like the motor is indeed 'tired'. You could run cranking compression and leak down tests - perhaps tell you if it's just a few cylinders, or if everything is equally weary. But it sounds like it might be time to freshen things up. How many miles on the motor?

 

[4000 Pounds of Iron]

Mileage unknown. I bought it out of a guy's shed where it had been sitting for a couple years, good news is that I got the motor, EEC, two MAFs, the harness, intake, TB, injectors, everything including headers, a T5, flywheel, bellhousing, and 5-speed pedal assembly for $500.

So I can't complain much. He said the wreck it came from was south of 100K, but God only knows what it really was and what damage was done from it sitting for so long unprepared.

Bad side was that I had to replace an injector, the EEC, and the T5 turned out to be a 4cyl. I was able to score a decent T5 for another $100 so I think I'm still in the black. What really sucks is that I just spent eight months in the garage engineering the 5-speed swap into my Crown Vic and now it seems the motor is going to have to come out again. I may elect to rebuild the CV's original 5.0 with some E7 heads instead, but it knocked a little when it was cold.

Crap.

4k#Fe

 

[Michael Yount]

More diagnostics will help you decide - cranking compression numbers will probably tell you what you need to know; a leak down test will help you figure out if it's getting past the rings, valve to seat seal, or guides/seals. However, given the history of the motor - I'd say you've gotten your money's worth. Time to spring for a rebuild I'd say.