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Melted spark plugs


pwrcat4000

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Well F*ck,

Dove the truck out of town yesterday kept it around 60 mph started running a little hot just slightly over the mark on the gauge with my history of burning down my 1600. It was idling fine running fine but I did not want to trash another motor. I pulled over let it cool down and checked the coolant level it was maybe a pint low added a pint of 50/50 and restarted the motor of course the #3 rocker came off again so pulled over in the shade to put it back on got it all back together and it would not start acted like no spark so I test lighted from the coil to the distributor (a common occurrence my truck) had power up to the dizzy tried again cranked still no fire then huge backfire out the exhaust. Pulled the #4 plug the gap was smashed closed pulled #3 the electrode was smashed and missing the electrode #2 Electrode intact but obviously damaged #1 looked great. What the Hell could have happened? Trust me it was not running it hard and it was not very hot for a 104F day. 60 miles from home as a last ditch effort I replaced all the plugs with new NKG's still wouldn't start but by now the battery was really low. I called my sister and we loaded it up the truck in the car trailer and drug it home. For the life of me I cannot understand what could have caused this it was running fine just a little hot barely over the black line on the gauge.
too lean, bad gas,

I know I will have to pull the head and look for the spark plug parts before I can even attempt to start it again probably looking at a total rebuild to use the L20B, or I am going to swap in my 3.8 GM v6 from a S-10 I have laying in the boneyard, or just stop being a ratsun guy and buy a newer small truck. I love working on this truck it it like therapy in a way making something like this run and usable, on no budget, but I am war weary with it right now.

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Well, that's a horrible story to hear when I'm minutes away from going on a 200 mile trip.

 

 

So, something smashed the plugs.

What's up with your rocker falling off?

 

Bad valve? Bad spring/retainer?

 

Valve was far enough down that it collided with piston, which made every other piston react as well.

 

Check your chain timing. How many teeth is it off.

 

 

 

Time to stuff that L20B in there. And don't skimp on head work.

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Just to clarify it is the L20b not the stock 1600 I did the swap last year and it is a great improvement I must say. thanks to this list it was fairly painless.

 

#3 rocker the board consensus is that it is the valve guide.  I need to rebuild the head but I have been trying to make it work the tappet comes out infrequently and it is not hard to pull the valve cover and put it back in.
banzai510

I will recheck the timing but I cant understand how it runs great then not at all,  When I had the head off last winter (to repair the bent valve on #3) the timing chain was in good shape plus I have heard that it is hard to jump a tooth on a double roller chain.

 

As for the v6 swap I am way more familiar with those motors and would also gain a 5 speed trans would have to do some rerouting of stuff don't know if its too big for the tunnel and I have not measured but would assume I will need to mod the yoke and shorten or lengthen the drive shaft. maybe easer to put the 521 body on the s10 LOL

 

After winning i win the loto. Though it would be amazing to drop in new 2.0-liter turbocharged I4 275 hp and 295 lb-ft of torque from the 2016 Camaro

but as they say plans without fiance are fantasies LOL
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so you have another head? cheap and ezest way to get by on this.  I done this in 2.5 hours. as the l16 is the basic emissions. waiting for a head in the mail is still faster than a V6 swap.

 

no they don't jump timming chaines unless the tensioner is most likely gone

 

don't do the V6 ,the torsion bars will be in way exhaust need to be routed and that will cost you.

 

PS if you when the lotto just buy one done.  But really just for buy a African Landcruiser!!!!!!

 

 

as far as the lash pan falling out. Have a photo? of the rocker on the lash pad? 

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Although a V6 is nice in the dream stage, it's a whole other nightmare making it a reality. With the money and time you'd be putting into that engine swap, you could build one hell of a mean L20. I totally agree with Flatcat19 on the "don't skimp on the head work." That's the key to getting serious power out of an L  Bigger valves, porting, and a meaty cam to get it breathing right and you won't miss those other two cylinders. 

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Are you going to pull the head and show us?

 

 

If it detonated bad enough to kill the plugs, then there will be no ring lands left. Or maybe the ring lands killed the spark plugs...

Death of internal components has probibly happened though.

 

Stock for stock i wouldnt gm v6 anything. 2.8/3.1/3.4's have shitty intake gaskets and crack heads like crazy, 3.8's are best left in turbo buicks and need rod bolts before they explode... Nice head and block castings though. 4.3's vibrate.

 

Not saying a datto motor doesnt vibrate but im not a fan.

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  • 3 weeks later...

GODDAMIT!

SUWeVKn.jpgHEAD

pvLkfau.jpg

 

JLo1GzI.jpgBlock

80iUTgM.jpg

 

 

So it appears to me that the valve seats fractured and went in to the combustion chamber I need a minimum of a new head (probably a new motor or rebuild this one)
(Since I already did the L20B swap)  What  are my engine choices at the salvage yard I want to stay with a carburetor for simplicity and it needs to fit in the truck and bolt to my 4 speed
Cost is a bigger factor than time But i don't want to cut the truck all up for fitment

 

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I had a valve guide fracture, and start going through the cylinders on an L16 once.

But as soon as I heard it, I pushed in the clutch, and killed the engine.

Cost me $60 (15 years ago) to have it towed home, but saved me hundreds in engine parts,

and just took a day to repair.

 

Looks like you didn't recognize the sound of trouble.

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The only thing that will bolt right in is another L series, or an LZ series custom built engine. Everything else will require other changes.

 

Both Z and KA tilt the other direction from the L, so you would need a bell housing from one of them on your transmission.

 

And both of those would require modified motor mounts and likely some other work, like perhaps a flipped center link or something, but I'm not sure.

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I am thinking either you are hearing impaired or your truck is very noisy that you could not hear it coming apart, that should have sounded terrible when you shut it down that last time.

Do you still have the 1600cc engine, or did that melt down also, I know it's a step backwards, but it's better than nothing, what casting is the 1600 head?

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I am thinking either you are hearing impaired or your truck is very noisy that you could not hear it coming apart, that should have sounded terrible when you shut it down that last time.

Do you still have the 1600cc engine, or did that melt down also, I know it's a step backwards, but it's better than nothing, what casting is the 1600 head?

No I shut it off when it was running just over the center on the gauge with my history of getting my L16 too hot I stopped and I checked the fluid it was about a pint low added it  restarted and the #3 rocker came off shut it off to put the rocker back on after that it would not start I am guessing when I turned it off it super heated the head and the seats came out and started getting destroyed when I tried to restart it other than the noise form the lifter it never made any noise

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Number 3 cylinder didn't get beat to hell like that from being turned over, that engine looks like it was running.

The engine would have been blowing out all the water if it had over heated, you could not have taken the radiator cap off to check the level unless you had let it sit long enough for it to cool down(30 minutes), and it would still have been making these popping noises(water boiling) if over heated but not blowing the water out.

My engine goes over the half way mark all the time if going up an extended hill where I start putting my foot into the pedal, and if it is hot out it don't cool down right away, I have had the temp needle go over 3/4s of the way up without issues, just the other day I noticed that my water level was so low that there was no water covering the fins in the top of the radiator and it still didn't over heat, and it's been hot out till recently.

Do you know what detonation(pinging/knocking) sounds like?

Detonation could do this without over heating the coolant, if one keeps driving/running the engine while detonating badly, it can come apart.

The thing is that the seat bouncing around in a cylinder could sound like detonation itself.

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yup valve seat went bad or bad install.

 

L16 18 20. Pretty much a 4/5 hr install if you have everything

 

L16/18 use a 5 bolt flywheel. 

so dont mix up the T/O bearing collar stuff.   But We dont know what flywheel you have as soem are 200mm form the cars and 225mm from the trucks!!!!!!!!!!!!!

The current motor is a 225mm L20B from a 1979 620 that was a rollover (parts truck) I still have my L16 that i am thinking just cavitated (I read one of your old posts after i did the swap to the L20B)

 

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Number 3 cylinder didn't get beat to hell like that from being turned over, that engine looks like it was running.

The engine would have been blowing out all the water if it had over heated, you could not have taken the radiator cap off to check the level unless you had let it sit long enough for it to cool down(30 minutes), and it would still have been making these popping noises(water boiling) if over heated but not blowing the water out.

My engine goes over the half way mark all the time if going up an extended hill where I start putting my foot into the pedal, and if it is hot out it don't cool down right away, I have had the temp needle go over 3/4s of the way up without issues, just the other day I noticed that my water level was so low that there was no water covering the fins in the top of the radiator and it still didn't over heat, and it's been hot out till recently.

Do you know what detonation(pinging/knocking) sounds like?

Detonation could do this without over heating the coolant, if one keeps driving/running the engine while detonating badly, it can come apart.

The thing is that the seat bouncing around in a cylinder could sound like detonation itself.

Yes Your assessment of what happened is correct Wayno I f*cked it up bigtime!

After I added the coolant it made it about 2 blocks I though it was just the lifter again then it completely stopped running. Thought I might have got lucky and had got away with it (I did not)

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So i posted this now
http://community.ratsun.net/classifieds/item/7705-wtb-l20b-long-block-near-kansas/

I really like this truck the attension that it gets.  When people are amazed that something that looks so tattered and crappy runs and drives
Also I enjoy the awesome people on this board. I want to remain a datsun owner, even though I am RIGHTFULLY getting my asshole ripped apart right now for being a moron.

 

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I smoked a Chevy 235 straight 6 a long time ago, it started leaking oil, i was unaware till it started making noise, so I stopped at the auto parts store and bought oil, put it in and drove home, it didn't sound to bad, but the oil didn't quiet it, the next day I went out and started it when it was cold, it sounded like the rod was ready to fly out of it the knock was so loud, I put a Chevy 350 in it over the next few months, it was a great truck after that.

 

The reason the rocker arm likely came off was because the seat got caught in the valve and held the valve open a little when it came out of its seat, that allowd the rocker arm to get so loose that it came out of the lash pad and moved to the side.

Then you put it back on and the seat popped out into the cylinder when the valve opened and started destroying everything including the seat itself.

I would guess that the rocker arm went back into position very easy and seemed very loose, or it was very hard to get back on and had no valve clearance and needed adjustment because it was so tight meaning the valve seat was already in the cylinder.

You know the seat could of just fell out on you, and all this was just bad luck.

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