blue smoke on start up and deacceleration

[stvrn6]

My 80 series started puffing out blue smoke and it hasn't been to bad but yesterday it was blowing a lot but I figured it was because I was parked on an incline. But after seeing how much came out I decided to do a compression test. After reading a lot of older threads I've come to the hopefully conclusion that it is due to bad valve guides and not rings. Truck has been sitting for a very long time but I did a full tune up and maybe driven it like 30 miles since purchasing. Cat is not ready when I plug into the obd2 port. I would just like another opinion on this. They're is oil on most of the plugs beside maybe 1 or 2. I do have a full oem head gasket kit another member gave me but I want to avoid doing such a job (not going to lie scared of messing with timing and cams.) what about valve cover gasket ? I know it must get done eventually.
208k miles
OIL: Shell Rotella t6 15w-40
COMPRESSION
1. 175
2. 180
3. 180
4. 175
5. 170
6. 175

(sorry for the long video had my nephew helping me)

 

[TXMeatball]

Do a leakdown test to fully confirm it's not the rings. I'm like 90% sure mine is the valve stems too, but not nearly as bad as yours is currently. Not a job I'm rushing to do.
Can do the valve stems with the engine still in the truck. Valve cover/cams/buckets/etc need to be pulled. Need a larger air compressor (unsure of size to be honest) to pressurize the cylinder so the valves don't drop when you're swapping them out. And a brace on the crankshaft to prevent the engine from turning over. There's some good information hiding on the forum.
Stems are different for the intake/exhaust sides.12 of 90913-02096 and 12 90913-02105.

 

[mudgudgeon]

Plugs look OK, bit hard to see in your pic. But nothing I can see there that scares me.

A puff of smoke in start up is fairly normal with a 30 year old engine.
A lot of these trucks will burn some oil.

Compression numbers look decent, and consistent.
I wouldn't worry too much about a leak down test at this point.

Valve cover gasket is not going to lead to smoke from the tail pipe

If you've only driven it 30 miles, don't panic yet. Id suggest drive it some more. Get it good and hot.
Top off the oil carefully first so it sits right on the full mark when hot.
Keep an eye on the oil level to make sure it doesn't get too low, but don't top it up.
Wait and see his much oil it takes to top it back up to the mark after 1000 miles.

Degrease the engine so you can see if you have any significant leaks.

My truck is one that sat a lot for 12 years. The PO kept it at their holiday home and only used it to tow a small boat to the lake.
It had done about 125k miles when i got it
It was smoking a bit and using oil.
I changed valve stem seals along with head gasket. The smoke issue stopped with new valve seals.

Typical signs its valve seals:
It will give s blue puff when you pull away after sitting at traffic lights.
It will puff blue smoke when you get back on the gas after coasting down a longish hill.

Both these scenarios, the engine is puling a vacuum while the throttle is closed, and you have minimal combustion at idle.
Oil gets pulled past the inlet valve seals and accumulates. Once you get back on the gas, you'll see itga puff of smoke.

If that's the only time you see smoke, i wouldn't worry about it immediately. If oil consumption isn't obscene, you probably still have 10s of 1000s of miles up your sleeve before you need to fix it.

 

[VSTL]

When I first got my 93 FZJ80, if I let it idle from cold for 5-10 minutes, the first tap of the gas pedal would make a puff of blue smoke come out the tail pipe. 160K miles, okay maintenance history.

Previous owner always put in conventional 5W-30. I changed the oil to Shell Rotella T6 15W-40 about a year ago and I haven't seen it blow any smoke since. I also drive it every other day now. I only drove it on the weekends before I got it decently baselined.

That's my experience, yours may differ.

 

[mudgudgeon]

When I first got my 93 FZJ80, if I let it idle from cold for 5-10 minutes, the first tap of the gas pedal would make a puff of blue smoke come out the tail pipe. 160K miles, okay maintenance history.

Previous owner always put in conventional 5W-30. I changed the oil to Shell Rotella T6 15W-40 about a year ago and I haven't seen it blow any smoke since. I also drive it every other day now. I only drove it on the weekends before I got it decently baselined.

That's my experience, yours may differ.

I've recently been using Rotella T6 in my gas F150.
The 5.4 Triton V8 is notorious for valve train issues due to oil clogging up cam timing phasers.
I decided to run the T6 Rotella to try to clean out the internals because diesel oil have more detergents in it.
Mine was making some concerning noises.
In the past 2000 miles with T6, valve train noise has gotten noticeably quieter.
Not sure yet whether it's a placebo effect, but so far i think it's positive.
Gonna keep running it, and will probably run it in the 80 too when it's due for oil.

 

[bhsdriller]

I'd go with valve seals as well.

Mine does the same thing for probably 40k miles. Will do them if I ever need to do the head gasket for now just keep an eye on the oil level and add as needed

 

[stvrn6]

Plugs look OK, bit hard to see in your pic. But nothing I can see there that scares me.

A puff of smoke in start up is fairly normal with a 30 year old engine.
A lot of these trucks will burn some oil.

Compression numbers look decent, and consistent.
I wouldn't worry too much about a leak down test at this point.

Valve cover gasket is not going to lead to smoke from the tail pipe

If you've only driven it 30 miles, don't panic yet. Id suggest drive it some more. Get it good and hot.
Top off the oil carefully first so it sits right on the full mark when hot.
Keep an eye on the oil level to make sure it doesn't get too low, but don't top it up.
Wait and see his much oil it takes to top it back up to the mark after 1000 miles.

Degrease the engine so you can see if you have any significant leaks.

My truck is one that sat a lot for 12 years. The PO kept it at their holiday home and only used it to tow a small boat to the lake.
It had done about 125k miles when i got it
It was smoking a bit and using oil.
I changed valve stem seals along with head gasket. The smoke issue stopped with new valve seals.

Typical signs its valve seals:
It will give s blue puff when you pull away after sitting at traffic lights.
It will puff blue smoke when you get back on the gas after coasting down a longish hill.

Both these scenarios, the engine is puling a vacuum while the throttle is closed, and you have minimal combustion at idle.
Oil gets pulled past the inlet valve seals and accumulates. Once you get back on the gas, you'll see itga puff of smoke.

If that's the only time you see smoke, i wouldn't worry about it immediately. If oil consumption isn't obscene, you probably still have 10s of 1000s of miles up your sleeve before you need to fix it.

Thank you, I'm waiting to order some caster plates than it will become my daily, so I hope after 1k miles everything settles and hopefully the smoke doesn't get worse.

 

[RockJock82]

I would also check the pcv valve as in the past I had an issue with a failed valve sucking oil. Its cheap enough to replace.