How do you know when to rebuild the engine in a car? Right now, I have 140,000 miles on my car, and tonight, I thought I saw smoke when I started it up. I'm not sure though. If I did, I hope it's only upon startup, and not while I'm driveing. I just want to know what the general signs of a rebuild are. And also how much I can expect to spend for one. I could do 50% or more of the work myself. Thanks for any help you can give.

 

When it smokes all the time or won't run.

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1989 Pontiac Firebird Formula LO3 Auto
-180 degree stat
-Hooker Cat-Back
-velcro t-top bag
-Wonder Bar from my IROC
-IAT MOD, 3.3ohm resistor
-Open element 14x3

*****Possible future mods*****
4th gen seats, fiberglass spoiler, rear disc, 3.42, torsen(posi)

1985 IROC-Z, TPI Auto
-Accel Super Coil
engine and tranny overhauls coming this summer


http://www.geocities.com/krt80/

 

The smoke on startup is most likely your valve guides. After a while they wear out and start to leak. As long as it's not a 5 minute long smoke-screen, I wouldn't worry about them. GM engines are known for them going bad rather quickly, even faster if then engine sits alot.

As for knowing when to rebuild an engine? When it can no longer spin the tires Seriously though, when you start to notice a decrease in performance thats not major tune-up related, when you start getting alotta rod knock/valve tap or even any other good excuse.

At 140K (roughly the same as mine... 143,740) you've still got a lotta life left, although it does depend on how well it's been cared for, and somewhat to the luck-of-the-draw. As a general rule though, these engines can go 200K and beyond as long as their not totally bashed to hell.

And who knows, if you've got a 'sweet' car and the paint is good (and kept well waxed of course), you may even outrun the cops.

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1985 Camaro SC - 2.8L, auto.

http://www.xenodrgn.f2s.com/Frontright.jpg

 

Do a compression test and a leakdown test. Maybe the rings are in great shape but you need a valvejob. Run a compression test and log all your psi readings. If they are all within 10% or so it should be healthy. If one is low, shoot some oil in the plug hole and retest it. If it came up, the rings are wore out. If it's the same, the valves might be to blame. The leakdown test will further verify it's condition. High milage with good maintanence on a 'street warrior' taking an occasional wringing out is better than a low milage motor that grandma drove to the store and never changed the oil.