[Unknown User]

Akkkkk! Well my problem is this.. I have a 1978 Datsun 280Z, When I take my foot of the gas and the engine is a hi load/hi RPM, she blows white clouds of smoke.. Big ones.. Now a good example of when this happens is.. At about 110mph if I take my foot of the gas she Puffs continuously until I drop under 4k. Or if I am accelerate quickly and shift at about 6K I see small puffs. Now the obvious example is DON'T DRIVE SO FAST!! But **** those Hondas just piss me off... jj Now some things I know about the motor. I have 165?? on a compression meter on all cylinders. The plugs are old (I haven't looked at them for oil traces in a wile) and the PCV valve is old.. The head gasket is new, so it the timing chain and tensioner, as well as most of the gaskets.. I think this is the reason I blew my head about 3 weekz ago, Same situation, I was trashing a Honda, I know I know... And after the LONG run I slowed down to cruzing speed and made my exit, (about 2 miles) then I made a left under the overpass, I down shifted into 2nd, brought the tack up to 2.5k and pfft, lost all motor power.. Then she came right back up, slight loss in power and a pfft pfft pfft sound. I brought her home I lost all pressure on 3,4 and 6. But no Oil or water loss or mixture(kinda cool demonstration of Nissan Engineering). So I drove her to my buddies and he had know idea how that could be happening. So I brought it home, pulled the head and carbon traces between cylinder 3 and 4 and between 6 and the outside of the block. So i rebuilt it all. head up.. Don't worry I do good work.. In my mind at least.. so I scraped and polished all the gasket contacts replaced all the hoses, and it cranked over 1st try. But I still have this problem.. She breaths smoke... Sorry for the long post, I just need some advise and I think this is the best place to get it.

P.S. You can expect another one of these when I get my 280ZXT block.. ()

Anyway thanks for any advise you can give!!

 

[Ron]

> Akkkkk! Well my problem is this.. I have a
> 1978 Datsun 280Z, When I take my foot of the
> gas and the engine is a hi load/hi RPM, she
> blows white clouds of smoke.. Big ones.. Now
> a good example of when this happens is.. At
> about 110mph if I take my foot of the gas
> she Puffs continuously until I drop under
> 4k. Or if I am accelerate quickly and shift
> at about 6K I see small puffs. Now the
> obvious example is DON'T DRIVE SO FAST!! But
> **** those Hondas just piss me off... jj
> Now some things I know about the motor. I
> have 165?? on a compression meter on all
> cylinders. The plugs are old (I haven't
> looked at them for oil traces in a wile) and
> the PCV valve is old.. The head gasket is
> new, so it the timing chain and tensioner,
> as well as most of the gaskets.. I think
> this is the reason I blew my head about 3
> weekz ago, Same situation, I was trashing a
> Honda, I know I know... And after the LONG
> run I slowed down to cruzing speed and made
> my exit, (about 2 miles) then I made a left
> under the overpass, I down shifted into 2nd,
> brought the tack up to 2.5k and pfft, lost
> all motor power.. Then she came right back
> up, slight loss in power and a pfft pfft
> pfft sound. I brought her home I lost all
> pressure on 3,4 and 6. But no Oil or water
> loss or mixture(kinda cool demonstration of
> Nissan Engineering). So I drove her to my
> buddies and he had know idea how that could
> be happening. So I brought it home, pulled
> the head and carbon traces between cylinder
> 3 and 4 and between 6 and the outside of the
> block. So i rebuilt it all. head up.. Don't
> worry I do good work.. In my mind at least..
> so I scraped and polished all the gasket
> contacts replaced all the hoses, and it
> cranked over 1st try. But I still have this
> problem.. She breaths smoke... Sorry for the
> long post, I just need some advise and I
> think this is the best place to get it.

> P.S. You can expect another one of these
> when I get my 280ZXT block.. ()

> Anyway thanks for any advise you can give!!

Still sounds like a head gasket problem; that or a warped head. Did you check the surfaces of the head and engine block. If either of them was uneven you never fixed your problem. Also check the torque of ALL of the head bolts! make sure they are exactly the same.

You should also follow a break-in of no less than 500 miles after repair and re-torque the head bolts. I have (2) '77 280s and a 300ZXT that eat well but I babied them for awhile after they came out of surgery.

 

[Unknown User]

I checked the head and block. They are both flawless. That was the first thing I checked.. I torqed all the bolts in order as per Nissan. I double checked the bolts yesterday, same. I still have no oil in water or water in oil. The block is clean and shows no external oil leaks and the radiator is still full. So I don't think it is the block.. But I am going to recheck it again.. I do try and follow the break in rule.. And normaly i am a very saine individual.. I may have given you a unruly impression in my last post, and sometimes I am. But I take VERY good care of my baby.. I know that it only takes once to mess it up big, so I don't blame anyone for my misfortune I am thankfull for you advise thou, and I will continue be a Z guy forever!! Oh and I don't just Grudge on random Honda's just a few fellas I know who talk SMACK about Nissan. ;P

 

[Ron]

When I first bought my Z ,the previous owner took it to a insta-oil change
place. They put in fresh oil without draining the old. I checked the dipstick
which was way past the checkered marker. whoa.. same symptoms puff puff.
So I drained the oil and put in 4 qts as normal . viola. bye bye puff.
Is the smoke oil or antifreeze? , check fluid levels. also change pcv if needed.