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New spark plugs...clouds of white smoke=failed tune-up misadventure!?!?!


CamoKing

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I thought I would be making some performance improvements to this '82, 720, Z22 acquired last June by changing plugs and checking timing. MISTAKE.

It was running OK; little noisy and complete with noticeable exhaust and fuel vapors.  So, I thought, let's get dirty.....tune-er-up....

Yes the old plugs looked a bit burned and oily.  One insulator was loose.  One had a significantly decreased gap.  

 

Pulled them; put new NGKs BPR 5es & 6es in then discover NO notch on the main crank pulley for timing purposes.  (I think this is NOT the original engine)  Proceeded to find TDC@compression via the dowel -in -#1 cylinder 'method' hand cranking with a socket on the crankshaft pulley bolt and watching the distributor rotor, too.  (Access very difficult, I might add) But, I was having a "Return to those Manly Younger Mechanic Days"

 

Long story - longer:   Timing was not really out.  It fired up and sounded better than before.  After a few minutes I see white smoke billowing out of the tailpipe.  WHAT?  Must be some oil leaked from the plug sockets or something.  I drove around the hood for about ten minutes, leaving a trail of white smoke in my wake.  Except for the smoke, performance seemed fine...This was last night.

 

This morning, I started it up from cold noticing it went into high idle quicker than before and as it warmed dropped rpms and started billowing white smoke again.

In the light of the morning, I could see that this was mostly water vapor and liquid drops, i.e., coolant.  NOT OVERHEATING, at least for the 20 minutes idling.  Shut down.  Later, colder, opened radiator cap to see horrors of horrors; verification of a coolant level drop though not much.

 

Why would changing out plugs result in an apparent head gasket failure? OR, an intake gasket failure?  OR BOTH! 

Would a compression test rule out/confirm a head gasket failure?  Any advice?  Thanks

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Easy test I found if your blowing coolant out the exhaust ... check the radiator if exhaust gas is getting mixed it would be blowing bubbles, as your up the throttle the radiator hoses would become rock hard with pressure...

And a compression test should tell you something. Or maybe a leak down test...

And it's probably been on the verge the whole time.... sometimes breathing new life into things exposes the next problem...

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One of the best methods is pressurizing the cooling system with a leak finder pump. Leave pressure on for 10 minutes or more if it will hold. Then remove spark plugs and crank engine. Do not stand by passenger fender! If gasket is leaking coolant into a cylinder, you will see it blow out the plug holes. If it does, pull head.

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Better identify what engine you have. Look between the two pair of exhaust manifolds below the #2 and #3 spark plugs, just below the head on the block there is a flat boss with the engine size stamped on it.

 

1985NissanPickup012.jpg

 

The Z24 is prone to blowing head gaskets every 100K. If the engine was swapped this is likely what you have.

 

 

Normally changing spark plugs will not cause water to steam out the back. The cylinder that had a loose porcelain insulator and also a reduced plug gap is indicative of damage or a foreign object getting in and bouncing around damaging the plugs.

 

I thought I would be making some performance improvements to this '82, 720, Z22 acquired last June by changing plugs and checking timing. MISTAKE.

It was running OK; little noisy and complete with noticeable exhaust and fuel vapors.  So, I thought, let's get dirty.....tune-er-up....

Yes the old plugs looked a bit burned and oily.  One insulator was loose.  One had a significantly decreased gap.  

 

Pulled them; put new NGKs BPR 5es & 6es in then discover NO notch on the main crank pulley for timing purposes.  (I think this is NOT the original engine)  Proceeded to find TDC@compression via the dowel -in -#1 cylinder 'method' hand cranking with a socket on the crankshaft pulley bolt and watching the distributor rotor, too.  (Access very difficult, I might add) But, I was having a "Return to those Manly Younger Mechanic Days"

 

 

 

 The engine was spewing 'noticeable exhaust and fuel vapors'. Putting in new plugs just pushed any damage or pre existing problem 'over the edge'.

 

When you pull the head take a good look at the piston tops. You may see marks from a foreign object or a piece missing.

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Thanks for the responses.  I have neither the facility nor experience to pull the head.  Can't afford to pay a pro for such a labor intensive job.  Looks like my relationship with this 720 has gone up in white smoke.  I will try to answer your questions......after a more thorough look at what has happened tomorrow....

Any opinions regarding those so called "Head Gasket Sealants" I've seen at the parts stores.

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Blew head gasket 2x and compression test verified since 2 cylinders nxt to each other had low compression.

What if the rings on two cylinders collapsed to give the same low readings?

What if two intake valves are burnt/leaking/bent?

Snapped cam?

 

Many things can lead to low compression. Head gasket being only one of them.

 

 

 

A compression test, again, will not verify a bad head gasket.

 

A compression test, dry then wet, should only be used to verify the next wave of diagnosis to perform.

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Any opinions regarding those so called "Head Gasket Sealants" I've seen at the parts stores.

 

Yes but I have maxed out my swear words quota for today. Only the truly desperate and the gullible buy that s_ _ _ . It gives the countermen something to laugh about after you leave.

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What if the rings on two cylinders collapsed to give the same low readings?

What if two intake valves are burnt/leaking/bent?

Snapped cam?

Many things can lead to low compression. Head gasket being only one of them.

A compression test, again, will not verify a bad head gasket.

A compression test, dry then wet, should only be used to verify the next wave of diagnosis to perform.

In the OP's situation though...

 

It more than likely is a bad head gasket/combustion leak of some sort.

 

Hell, you could have a crack in the head or the intake manifold gasket is leaking coolant in to the intake. Rare circumstance, but you could have a cracked water jacket in the block.

 

I just wanted to dispel that a compression test alone is not trustworthy enough to verify anything short of bad/collapsed piston rings.

 

If I sell a customer on performing a compression test to verify a concern- I better be selling them more diagnosis afterwards or reringing their engine. That's it.

 

 

GL. Report back with what you find.

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What if the rings on two cylinders collapsed to give the same low readings?

What if two intake valves are burnt/leaking/bent?

Snapped cam?

 

Many things can lead to low compression. Head gasket being only one of them.

 

 

 

A compression test, again, will not verify a bad head gasket.

 

A compression test, dry then wet, should only be used to verify the next wave of diagnosis to perform.

if you read what I wrote, compression test is not the only test to determine his head gasket is a gonner, u can also see mixture of oil and water on the dipstick, valve cover cap.
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if you read what I wrote, compression test is not the only test to determine his head gasket is a gonner, u can also see mixture of oil and water on the dipstick, valve cover cap.

 

 

Yes, a compression test will tell you if head gasket blew, specially if 2 cylinders next to each other are low. Did you check your dipstick, oil and water mix looks like chocolate malt.

 

 

 

Maybe you should reread it yourself. 

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Better identify what engine you have. Look between the two pair of exhaust manifolds below the #2 and #3 spark plugs, just below the head on the block there is a flat boss with the engine size stamped on it.

 

1985NissanPickup012.jpg

 

The Z24 is prone to blowing head gaskets every 100K. If the engine was swapped this is likely what you have.

 

 

Normally changing spark plugs will not cause water to steam out the back. The cylinder that had a loose porcelain insulator and also a reduced plug gap is indicative of damage or a foreign object getting in and bouncing around damaging the plugs.

 

 

 The engine was spewing 'noticeable exhaust and fuel vapors'. Putting in new plugs just pushed any damage or pre existing problem 'over the edge'.

 

When you pull the head take a good look at the piston tops. You may see marks from a foreign object or a piece missing.

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This 720 King has a Z22 177664 engine (It does not have a roof!).  Odometer @ 88,883.  I started it up on 3rd try.  Ran it to normal op-temp in idle for about 15 minutes with the radiator cap off to see if there were bubbles or anything.  I couldn't even tell if/when the thermostat opened.  I could see the coolant get hot and vaporize a bit, but no flow, no bubbles?  Yet, tailpipe was putting out white smoke (image).   Is the thermostat stuck?  Upper hose is warm....Seems like the temp gauge would be rising rapidly if the thermostat was not opening??... Still not certain about what is causing the white smoke.   Has to be coolant leak, right?  Maybe I'm witnessing the 'beginnings' of a total gasket failure.  I do not think I should take this vehicle  fishing..

2nd question:  If I do a basic compression check, I assume I put the gauge on the Intake Spark holes?

 

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I only asked about the ID because you said it may have been swapped.

 

If head gasket leak it could push out steam yet run at normal temperature. For a while at least. When the coolant gets low the temp will go up.

 

If an extreme amount of steam, and driven long enough, some will get pushed past the rings and condense in the oil. It will turn to 'chocolate milk'

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Some images of what

 

This 720 King has a Z22 177664 engine (It does not have a roof!).  Odometer @ 88,883.  I started it up on 3rd try.  Ran it to normal op-temp in idle for about 15 minutes with the radiator cap off to see if there were bubbles or anything.  I couldn't even tell if/when the thermostat opened.  I could see the coolant get hot and vaporize a bit, but no flow, no bubbles?  Yet, tailpipe was putting out white smoke (image).   Is the thermostat stuck?  Upper hose is warm....Seems like the temp gauge would be rising rapidly if the thermostat was not opening??... Still not certain about what is causing the white smoke.   Has to be coolant leak, right?  Maybe I'm witnessing the 'beginnings' of a total gasket failure.  I do not think I should take this vehicle  fishing..

2nd question:  If I do a basic compression check, I assume I put the gauge on the Intake Spark holes?

 

 

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To do compression check take all spark plugs off. Better to use screw in type, open throttle all the way. Disconnect coil. Write down compression for each cylinder. Check your spark plugs, do they look super clean? Have you checked ur oil dipstick? If so, how does the color look like, if like chocolate malt, then strong case for head gasket failure.

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I can't post images.  Tell me what I'm not doing.

 

Go to..  https://imgur.com/   .. sign up, it's free and they will host your selected pictures. When you want to post a picture here go to imgur, select and copy the picture, come back to Ratsun, click on the tiny green square within a square border just below the happy face emoticon. Follow the directions and post.

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