unleaded gas?

[inlawZ]

i've been having some white smoke coming from the exhaust while driving (more comes while excelerating) and ive had my su's tuned to be running lean. now im wondering after doing some research, what gas should i be using? i only have headers on the stock l24, ive been told a few things, here's what might be the cause:

1- valve seats are worn down

2- compressions off

3- coolant or oil is burning

 

now im not a mechanic, but ive been learning alot with this 71 240z (my first z) and i want this car to be a daily driver, i drove it daily for a few weeks and it seems really reliable, but the smoke has not gone away at all. i hate that everytime im at a stop light im smoking up the person behind me, cops arent to fond of "racer looking cars" in san diego and im not trying to get cop attention, so i would really like to minimize the amount of smoke coming from the car. please any suggestions would help and if someone is in san diego i have no problem letting you check it out.

 

 

also, im not sure which gas i should be running on an l24, should i use 91? thats what ive been using, but a friend of mine that is into older domestic cars told me just use 87 because it didnt matter

thanks

[Thumper]

White smoke is usually burning coolant. Check your head gasket. Check oil if milky etc...

[inlawZ]

so checked under the oil cap, not milky at all just looks like regular oil

 

any other things i should check?

[Mr.INSANE]

Drain the oil out completely, My Old Chevy Truck has worn valve seals but the white smoke only happens during startup.

[Pop N Wood]

The owner's manual for the early Z's say they need 95 octane gas. Common in the 70's, non existant now. When I first got my 70 240 it would ping if I used anything less than premium (93 octane?) and octane booster. When I replace the worn out carbs with ones that didn't leak air through the throttle shafts, I could run regular without pinging/detonation.

 

Do a compression and leak down test on your car. Do a search to see how to do that and how to interpret the results.

 

Also does your car use coolant or oil? How often do you have to add either?

 

Old Z's are notorious for having weepy head gaskets. But there is also a chance your car is just tired and needs a rebuild.

[inlawZ]

im guessing that i might need a rebuild, it doesnt use up the coolant or oil, im going to do the compression test soon here. i might just throw in the spare motor i have, it was rebuilt in the 90's so should be at least better than the original one i have now

[justinr54321]

I had this problem too when I first got my Z. The valve clearances weren't set right, and there was some rockers off their knockers, so to speak. (In other words, the rocker arms were off the valves, not engaging the intake and exhaust valves. They can come off when the valve clearances are not set right). But I'd look under your valve cover first and make sure of this before doing a rebuild or engine swap.

 

Justin