crushed spark plug

[sacrileger]

just bought a donor 94 eagle talon w/ 7-bolt 4g63 nt. the motor would start w/o hesitation but it would run extremely rough. it wouldnt idle. it would stall. the motor misfired badly. i had to keep the rpm above 1500 to keep it going. i took it for a short test drive, about 1 mile. even w/ a motor that sounded like it ran on 2-3 cylinders w/ extreme knock, i was able to get around in it. i was 99.99% certain the head gasket was blown. it wasnt.

i checked the compression (dry) and it read 185,175,175,175 (throttle closed). all spark plugs had heavy, black and wet deposits on them. it didnt appear to be oil and there were no signs that the motor burned oil. however, droplets of water were spitting out of the tail pipe.

i checked the coolant. it was clear. i checked oil. no coolant in oil; or under the valve cover. the only way i say that coolant would get into the motor and interfere w/ the fuel mixture, and caused it to misfire, was via intake manifold, i.e. hair line fracture in the intake coolant passages, or broken seal, and the vacuum would be sucking in coolant along w/ air/fuel mix. it had to be tiny since the engine would start and run; even though it misfired badly.

before i get to the punch line, i want you to keep this in mind: before i bought the car, i drove it. i revved the motor to at least 5-6000 rpm. while i had the car in garage and was diagnosing the problem, i started the motor countless times, i idled it, i revved it, sometimes as high as 6000 rpm. and no doubt the previous owner did the same - before and after the leak developed.

in any case, to solve this, or at least temporarily and partially, and at bare minimum to see if i am on the right track, i bought rislone liquid copper intake and radiator "stop leak". i poured about 200g directly into the cooling system.
i start the motor and idle it at about 1500rpm, while listening for any changes. after about 10 minutes, the temp rose to about 60-70c. then i hear this thump. and the motor stopped. i turned the motor w/ starter and heard more thumps. and then the motor seized up and wouldnt turn over.

i started taking the spark plugs out. i get to #2 and cant even turn the spark plug loose. with some force, i start taking it out feeling like i am stripping the thread. i take it out and it's smashed. below are some images.

it is clear that as much as i dont want to, i have to take the cyl head off to survey the damage, but before i do, i am asking you for feedback as to what happened before i destroy the evidence that would point to the cause of this. what is it that smashed the spark plug and why after the engine was run for that long? why after the rislone solution? or was that coincidental and it would've happened anyway. any ideas what to look for so this doesnt happen again?

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[pauleyman]

You have severely jumped timing. you can see it just by looking at the cam sprockets. it was a coincidence. car was probably already mistimed and hence why it ran poorly. probably was mistensioned too which is why it jumped. cylinder head will have to come off. bent valves at a minimum. It probably wasn't leaking. water is a by product and will condense when the car is cold.

 

[sacrileger]

You have severely jumped timing. you can see it just by looking at the cam sprockets. it was a coincidence <snip>. .....

thanks for the reply. that was my theory as well. i didnt mentioned it because it was just my speculation - as unlikely as i thought it was.
now i am going to go and kick myself. many times. and hard.

after i checked the compression, i thought i should check the timing. but didnt because i couldnt keep it at idle w/o stalling. plus, since the plugs were wet and excessive amount of water was spraying from the tailpipe (it's about 27c here - too hot for condensation) i focused on the "leak".

the misaligned cam sprocket, specifically where i have the white line, happened after i tried to turn the motor. the belt jumped; and then i thought the tension had to be insufficient.
however, what was the tell for you to pin it on timing just by looking at the cam sprocket? i sort of ruled out timing and valve positioning since i got good compression. too good in fact; maybe that should have been the warning sign?

 

[pauleyman]

both cam sprockets should be in relatively the same position. that is clearly not the case here.

 

[sacrileger]

both cam sprockets should be in relatively the same position. that is clearly not the case here.

ok. the exhaust cam positioning mark jumped on me by one notch when i tried to rotate the motor manually - which goes w/ your diagnosis that the timing belt was not sufficiently tensioned. i can see how the timing belt could jump by a little bit and kiss the valves but i cannot get my head around the fact that the spark plug got crushed like that. frankly, i am afraid to take the cyl head off to find out what it looks like inside.
you're not thinking i am going to find broken valves that got banged against the spark plug as well as crushed piston/s and ruined cyl head? and all that at idle speed?
from your experience, can you prepare me for what i am going to find inside and the potential extent of the damage?

 

[pauleyman]

expect the worst. hope for the best. broken valves. yes given what we see that's possible

 

[TheFlashDSM]

its not timing the piston will never hit the spark plug and the valves wont either hahahahah... the plug would be flat. that looks like pre detonation... basically the plug melted... or the plug broke inside and got bounced around and chewed its self up. put a new plug and try again i bet thats what it is happened to me befor on my quad!

 

[sacrileger]

well, broken valves. not only possible. it is now certain. i looked inside the spark plug hole w/ a flashlight and poked around w/ a piece of wire. what i thought was the top of the cylinder were, in fact, pieces of crushed and broken metal.
i know it's a judgment call, i've been working on these cars for ages, but never had anything like this happen before, so i wonder, should i just not waste time w/ this, cut the engine out and put in my spare 6-bolt and be done w/ it? am i looking at a comple write off?

 

[bryzenga]

its not timing the piston will never hit the spark plug and the valves wont either hahahahah... the plug would be flat. that looks like pre detonation... basically the plug melted... or the plug broke inside and got bounced around and chewed its self up. put a new plug and try again i bet thats what it is happened to me befor on my quad!

The valves in the head can be bent over far enough to hit the spark plug. Especially if one of them broke off and fell into the cylinder. Can gaurentee that it is timing.
* Edit
Now that he confirmed it...
If you are lucky enough to not have caused severe damage to the pistons/walls of the cylinder, you may be able to get away with a swapping a different head on and making sure your timing components are good. You wont know until you pop the head off. Spare engine would be the way to go in my opinion.

 

[sacrileger]

its not timing the piston will never hit the spark plug and the valves wont either hahahahah... the plug would be flat. that looks like pre detonation......!

you know, that was one of my theories as well. a severe knock that blew a hole thru the piston. but now i can see crushed metal through the hole and can move it around. so i dont know....

...
Now that he confirmed it...

i cannot turn the engine anymore as the crushed valves push against the head;
nevertheless, can you estimate by how much was the timing off to end-up in such disaster? especially after the motor was thru all that i described at the top? frankly, the timing belt is not that lose and as you can see it's solid. any way to find out, measure, how much the belt jumped and got the timing off?

 

[bryzenga]

Don't quote me on it, but I think if the crank jumps 2, you can get away with a timing job. Anymore, and there is going to be damage. I have not had one jump on me, so I can't speak from experience. I'd start by pulling the timing cover and see where the crank timing mark is in relation to the cam gears' marks. Either way, that head has to come off.
The timing tensioner can be a bit finicky. I've had one fail that still needed a bench vise to push the rod back in. Luckily, I caught it before it decided to let the timing jump. The oil from the inside of the tensioner had been spitting out of the seal on the top.
Another thought is of the balance shaft belt... If that breaks and gets caught up in the timing belt, that will most deffinately be a timing death sentence.

 

[sacrileger]

...
Another thought is of the balance shaft belt... If that breaks and gets caught up in the timing belt, that will most deffinately be a timing death sentence.

i dont want waste everybody's time here if i am beating a dead horse, meaning, what just happened is a pretty regular occurrence that everybody here saw many times over;
needless to say, i am mortified that something like this can happen at idle speed (1500 rpm), with the belt on (and not being too loose).
moreover, when i got such good compression (185,175,175,175) - initially.
furthermore, how much off must the timing be to crush valves and spark plugs like that??? after 280000km, were the valves so brittle that they just broke off? let's say if the coolant was getting in, did that have any role in that? was it the pre-ignition/knock/detonation?

however, if it's going to be of any interest here, perhaps even educational, i can take the time to take the head off and post some pics of progress for you guys to comment on. but i can say this right now, i am at the point to say f*** it and call the scrap yard guy to take it ! i dont have that much money in it to care. it's just hobby. these cars served me well over the years but this is nonsense if these motors are this delicate. i've lost faith after this...

 

[pauleyman]

its not timing the piston will never hit the spark plug and the valves wont either hahahahah... the plug would be flat. that looks like pre detonation... basically the plug melted... or the plug broke inside and got bounced around and chewed its self up. put a new plug and try again i bet thats what it is happened to me befor on my quad!

Valve can break off and destroy a plug which apparently has happened. The cam sprockets show it was clearly timing.

i dont want waste everybody's time here if i am beating a dead horse, meaning, what just happened is a pretty regular occurrence that everybody here saw many times over;
needless to say, i am mortified that something like this can happen at idle speed (1500 rpm), with the belt on (and not being too loose).
moreover, when i got such good compression (185,175,175,175) - initially.
furthermore, how much off must the timing be to crush valves and spark plugs like that??? after 280000km, were the valves so brittle that they just broke off? let's say if the coolant was getting in, did that have any role in that? was it the pre-ignition/knock/detonation?

however, if it's going to be of any interest here, perhaps even educational, i can take the time to take the head off and post some pics of progress for you guys to comment on. but i can say this right now, i am at the point to say f*** it and call the scrap yard guy to take it ! i dont have that much money in it to care. it's just hobby. these cars served me well over the years but this is nonsense if these motors are this delicate. i've lost faith after this...

It was either loose ( doesn't matter how it looks you have to check) or something foreign got in the way. Valves dont get brittle and break. There's no need to further analyze what happened you already know what happened. It was a mechical failre. Take it apart to assess damage

 

[TheFlashDSM]

The valves in the head can be bent over far enough to hit the spark plug. Especially if one of them broke off and fell into the cylinder. Can gaurentee that it is timing.
* Edit
Now that he confirmed it...
If you are lucky enough to not have caused severe damage to the pistons/walls of the cylinder, you may be able to get away with a swapping a different head on and making sure your timing components are good. You wont know until you pop the head off. Spare engine would be the way to go in my opinion.

yes i agree if you broke is metal bouncing around i must of read something wrong, i though u ment the piston hitting it or the valves because it was out of timing

 

[waterlance]

It's really up to you what you want to do. Ironically I'm in an extremely similar situation. I jumped timing out of nowhere and the side of my belt (facing the head) got shredded, and now I don't know what to do. For sure take it off to assess the damage, but if you have a backup 6 bolt, that seems like a good answer. I wouldn't even try to spend a bunch of money if you have a 6 bolt spare and don't care about the original 7 bolt all that much.

 

[silverex]

i dont want waste everybody's time here if i am beating a dead horse, meaning, what just happened is a pretty regular occurrence that everybody here saw many times over;
needless to say, i am mortified that something like this can happen at idle speed (1500 rpm), with the belt on (and not being too loose).
moreover, when i got such good compression (185,175,175,175) - initially.
furthermore, how much off must the timing be to crush valves and spark plugs like that??? after 280000km, were the valves so brittle that they just broke off? let's say if the coolant was getting in, did that have any role in that? was it the pre-ignition/knock/detonation?

RPM doesn't really matter if the timing is far off....its going bend valves no way around that. Since the valves broke you have a slim chance of only needing a head. Usually when that happens it takes out the pistons and bearings also. Like another member mentioned not much else to do then pull the head and hope for the best. If its bad get another longblock or junk the car...FYI scrap by me is way down I know of people getting under 100$ for a car.

 

[sacrileger]

.....Since the valves broke you have a slim chance of only needing a head..

so i looks like i am dealing w/ the worse case scenario. the head is done and so is the piston. probably bearings as well. i uploaded some pics to look at. pretty horrific.
1st pic shows broken rocker arms roller bearing

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2. here's broken intake valve, hole in the cylinder and various metal fragments from the spark plug and broken exhaust valve.

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3, here's a pic of damaged head gasket and the top of cylinder wall

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4, here's another shot of the damaged cylinder as well as aluminum particles that got washed out of the head by the coolant and caught between the head and block

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5th pic shows empty intake valve seat (the valve itself is sitting on top of the cylinder and the valve stem most likely went through the piston and is now sitting in the oil pan) and fragmented exhaust valve. also, extensive damage to the head can be observed as well.

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6, pic show damage to the valve seat

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7, pic shows actual shavings left behind by the milling machine

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8, pic shows where some part of the broken valve wanted to bust out of the cylinder by breaking through the side of the cylinder

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9, pic shows another close up of the same above

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10, pic shows a better view of cnc milling machine shavings and chips left behind in the cavities of the head. the black blobs are aluminum particles caught in the coolant passages.

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11, pic is another shot of the crap left behind by the factory. this head obviously must have passed qa somehow....

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12 pic is another shot of all the aluminum particles forming a metallic sludge.

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so, any comments? good thing i have a 6bolt on stand-by...

 

[silverex]

Those shaving arnt from Mitsu factory.

I can almost guarantee the cause is from the previous owner getting the head decked and no one cleaned out that passages. IMO that motor is trashed. Junking it and starting over on a new longblock would be the way to go.

 

[sacrileger]

Those shaving arnt from Mitsu factory.

I can almost guarantee the cause is from the previous owner getting the head decked and no one cleaned out that passages. IMO that motor is trashed. Junking it and starting over on a new longblock would be the way to go.

i've already started working on the 6bolt i had for parts - that's the motor in the first post first pic beside the car.
if the head was decked, as you suggested, it was not done recently; but if that's the case, i wonder if too much was taken off (even by the size of the shavings) and there was pretty much no margin for error re timing. it still bugs me what went wrong - i checked the timing belt tension and it was w/i spec. there was no reason for it to skip.

 

[IMPERIALISTICAL]

engine is no good. Get new blocks and Rebuild. Request Timing Accumlation to Precision Spec. Turbine the Cold Air Intake. Cold//Water Inject the Turbo Exhaust.Spark for the Best/.

 

[Murdertalon]

The 4g63 is an interference engine, so like every interference engine it will do this if timing goes. The belt has specific tension you must set and special tools to do it correctly. This can happen from a snapped timing belt too. Sorry for your engine loss man. These cars can be a black hole for money.

 

[ChessmoDSM]

Hey guys, appreciate you both responding but the OP was from 2 yrs ago.

 

[sacrileger]

engine is no good. Get new blocks and Rebuild. Request Timing Accumlation to Precision Spec. Turbine the Cold Air Intake. Cold//Water Inject the Turbo Exhaust.Spark for the Best/.

the engine is actually quite good - I replace the piston head, put new rings all around and then put a 2g head on the same block. I have already put another 15K on it since then...

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The 4g63 is an interference engine, so like every interference engine it will do this if timing goes. The belt has specific tension you must set and special tools to do it correctly. This can happen from a snapped timing belt too. Sorry for your engine loss man. These cars can be a black hole for money.

Exactly right. The belt jumped a few teeth. But the engine is not a write off...see above... the motor runs fine. Fixed.
crushed spark plug

 

[Murdertalon]

Glad to hear that! Also somewhat surprised nothing was too out of spec from that happening. Sounds like you must have pulled everything apart and cleaned it, did you end up replacing bearings or did the bottom end look fairly good still?

 

[sacrileger]

Glad to hear that! Also somewhat surprised nothing was too out of spec from that happening. Sounds like you must have pulled everything apart and cleaned it, did you end up replacing bearings or did the bottom end look fairly good still?

Frankly, what I had done would be considered sacrilege here and that's the reason I dont have a DSM profile. I examined all I could on the bottom end. The rod bearings looked fine so I did not replace them. I did not look at the main/thrust bearings. I just made sure there were no metal pieces from the piston head and valves and shavings or debris left after honing cylinders to prep them for rings. I even left most of the ridge at the top of the cylinder.
cylinder ridge - photo

Also, I replaced the damaged piston head with a 2G turbo piston head mounted on the original 1G rod. Obviously there was a weight difference - the turbo piston head was heavier so I rebalanced all pistons within 1 gram. I have a lower compression in the turbo cylinder but they are all, surprisingly, within 7% of each other (lowest to high).
pistons - photo
( yes, your eyes are not fooling you - I put washers, nuts and bolts right into the wrist pins to balance it all w/i 1gram ) The last pic is the 63DTEV installed.
The leak down test is on average 90% (10% loss).

So I put the bottom end all together after that. And then I put a 2G head and the 7bolt 1G block:
2g head on 1g 7bolt block

The 2G head came from this motor:
2G turbo motor

and so did the 2G turbo piston head - only one did not have broken ring lands like these three:
Turbo piston head - broken ring lands - pics

Then I put new water pump, belt and timing gears on but I did not really replace all seals and items I should have (i.e. oil pump, etc.) because I fully expected that the car will not run after such a tear down and I will have to take it apart again to find out what I missed and then do it. Well, as it happens in cases such as this, I kid you not, I did not even have to crank the car - it just started as if nothing was ever touched and has been running since w/o giving up on me even once. It does not leak any oil, coolant, or liquids.

I find the 4g63 very forgiving if it is not abused. Please keep in mind that I dont race this car, I dont have a turbo on it and seldom do I take it to the red line. It's turning out to be a very reliable daily driver.

And that's pretty much my DSM profile for this car.