I am looking to buy a 240sx Conv from a family member. The car has about 120k miles on it. It has new paint and a new convertible top. The only issue is the engine smokes real bad on start up and at idle. Its blue smoke, not white. I drove behind the car and about 1/4 mile down the road the smoking stops.

I looked over the motor and I think it can be 3 things.
1-Head gasket allowing oil into combustion chamber
2-Valve stem seals are shot
3-Blown piston rings (I hope this isnt the problem)

I have a spare KA head that I am going to get some work done on.
Is there anything else that can cause a motor to smoke like that?? And how much do you think I should offer??

11/11/2005 10:35:43 AM

Valve stem seals/worn valve guides.

But you won't really know until you do a compression test.

[Edited on November 11, 2005 at 10:37 AM. Reason : more info...]

11/11/2005 10:36:56 AM

more than likely valve stem seals and guides.

11/11/2005 3:59:28 PM

Quote :

"1-Head gasket allowing oil into combustion chamber"

highly unlikey you'd get this condition without some other sort of issue (burning coolant, mixing coolant/oil, etc.)

Quote :

"2-Valve stem seals are shot"

sounds like a classic case

Quote :

"3-Blown piston rings (I hope this isnt the problem)"

generally blow by is an rpm/load related problem.

Quote :

"Is there anything else that can cause a motor to smoke like that??"

could possible be the pcv system or valve, but i doubt it. my money is on the seals/guides.

11/11/2005 4:13:46 PM

I've got a Ford truck with a 390 that had the same problem. A set of valve seals took care of it. If you get a fitting with the same threads as a spark plug, you can use an air hose to hold the valve up and won't have to pull the head off.

11/11/2005 6:16:47 PM

I have the fitting.

Wesley...the 240 is on hold right now.

11/11/2005 9:42:14 PM

that's cool- I'll go turn it over in the next few days. I doubt it's going anywhere

11/11/2005 9:56:43 PM