Straight 8 help.......

HELLO ALL,

I have a 1950 pontiac with the straight 8 in it. The question i have is when i bought the car they guy i bought it from said that the engine has been "rebuilt" not that long ago.(story we have all heard before). But anyway i get the car home after some small tinkering around i get the engine to start it accually started right up plugs looked good the oil was new but as i let it sit and run it smokes really bad. So my questiion is other than the obivious thinking that the rings are bad or were not gap properly i wanted to know what else could cause this before i rip the engine apart to replace the rings ? Any info on this would be helpful. Thanks again.

 

How long did it run for?

 

Drive it for awhile and see if it clears up. You might wand to dose it with some MMoil-thru the carb (or SEAFOAM) in case the rings are stuck.

 

White smoke, blue smoke, black smoke???

Jon.

 

I bought a nova about 30 years ago that was rebuilt smoked like hell the ring were not set right the oil ring were put in wrong my dad took it down and rotated the the ring 120 degrees apart we honed it and put it back together and I drove the wheels of of it . if you go in it check the ring gaps and positions on the piston rings maybe a head and pan gasket !!

 

it ran for about 15 mins

 

also it was white smoke .

 

White smoke is usually coolant. Pontiac 8's are notorious for cracked blocks from exhaust valve seats into cyl. walls, but you may have a blown head gasket as well. Have you looked at the oil after running it? If it's not milky, just fire it up and run it for a while, but white smoke is usually very much bad.

 

I it only ran for 15 minutes, are you sure it wasn't just condensation in the exhaust from sitting for a good long while?

Shawn

 

I have ran it for a total of an Hour now i put some seafoam into the fuel and oil it help a little but once it heats up to operating temp when you rev it up it still smoke real bad . i didnt rebuild this motor someone else did so i was told when i bought it so im just trying to limit it down to one or two things so i can try to fix it. But oil is not milky so the head gasket is good i dont see that any coolant is getting into the oil .

 

Could be stuck rings from sitting.

Don't just put seafoam in the oil and fuel. Rev the motor by hand to about 1500 - 2000rpm and pour the stuff down the carb throat slowly, while keeping the motor running until you have about half a can left, then dump the last bit in until you stall out the motor.

Leave it sit for a few hours, even overnight. Now start the car.

It will look like you're fogging for mosquitos for a while but will clear out after a few minutes. If this doens't fix the problem, you might need to open the motor.

Shawn

 

ok i will try that . Will it matter that i already put half a can in the fuel and the other half in the oil ?

 

Should be fine.

 

do those things have valve seals? I know ohv engines can do that.. intake seals harden and engine vacuum ****s in oil.. smokes like a *******. but I know nothing about flatties. if its not using coolant its proboally just oil.. for starters change the oil... oil does break down with age...

 

just because the oil is not milky doesn't rule out the headgasket as the problem coolant could be leaking into the combustion chamber. you should really try to have it professionally diagnoised before you jump in and start tearing parts off. have seen lots of people jump in only to find no cause to the problem because they went right by it looking for something else.
Good luck