Interesting mod motor spark plug failure

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So I blew out another spark plug, but it didnt fully eject. The combustion pressure blew through the threads on a small section then proceeded to Oxy-gasoline torch the spark plug and cylinder head.




Its cut the head so bad it might actually be non-repairable. I dont know how long it was leaking for since I had my radio cranked. Finally I went WOT around a truck and o boy was it loud.
Im glad I already got the ball rolling on getting another engine in it rather than do the timing chains on this engine, since it might need a cylinder head now.
 
I'm surprised the compression gases - even blowing the spark up would be hot enough to melt the plug.
 
This is abnormal, I suspect a combination of not torquing them enough then cleaning your engine perpetually with water and letting the threads rust out.
 
Combustion gases not hot enough to do that damage ?

I don't fully understand the mechanism at work but it's more erosion than melting. if you have a gasket failure on a steam pipe and leave it to leak long enough without repair it will cut a groove in a sold steel pipe flange that looks a lot like that spark plug damage.
 
That's impressive if anything. Do you have a borescope to take a peek at the underside? I agree with you that it may be "unrepairable" as in the head would need to be removed and welded, then worked, then an insert put in.
 
That is a deep reach plug. How does it "blow out" ? There is nearly an inch of thread on the plug. Could somebody s'plain the mode of failure to me? Once again FOMOCO metallurgy fails to impress. Colt45ws isn't at fault here. TIA
 
I'd bet it was giving indications of a problem for quite awhile, but like you said, if your stereo was cranked, I guess you didn't hear it.
Which cylinder was this one? Like you probably guess, I bet this one will require a new cylinder head.
 
Is this the generation of 2V's that only had something crazy like 4 threads?

I know in later years they added more threads to prevent this from happening.

Fordtechmakuloco advocates overtorquing the plugs to about 20 ft. lbs, instead of the called for 10ish ft lbs. I did that on my Town Car 6 months ago and no issues.

Did you use a torque wrench on the last plug change?
 
Al heads, peanut plugs with no gasket. Nice design.

I do like this engine though for many REAL advancements in mfg that would make Grumpy ole Henry happy.

I Specifically find the assembled camshaft(s) with sintered lobes to be real out of box thinking.
 
You plan to replace the entire engine , not just the head ? What , salvage yard engine ?

Best luck to you , :)
 
Originally Posted By: WyrTwister
You plan to replace the entire engine , not just the head ? What , salvage yard engine ?

Best luck to you , :)


Swap in a 5.4 2V from a truck or van and if funds allow, throw on some trick flow heads, port the exhaust manifolds and make some real power!
 
Originally Posted By: OVERKILL
That's impressive if anything.


I have never seen anything like this in my life.

I mean, I have seen spark plug failures (center blows out of steel shell) and spark plug holes fail in numerous ways, but this is COMPLETELY new.

Yes, time for that engine swap we were talking about!
 
What cubic inch and miles is your existing engine ? If it is in good shape , you could throw on some trick flow heads, port the exhaust manifolds and make some real power! On the existing engine .

But , hey , it is your money . Have fun !

Best wishes , :)
 
Originally Posted By: ARCOgraphite

I do like this engine though for many REAL advancements in mfg that would make Grumpy ole Henry happy.


For the millions and millions and millions of these engines on the road with WELL over 100,000 miles (many over 200,000 and 300,000 - and counting), It can unequivocally be called a "successful design".
 
Originally Posted By: WyrTwister
What cubic inch and miles is your existing engine ? If it is in good shape , you could throw on some trick flow heads,


He has another good 4.6 with fewer miles he's going to swap in.

Does trick flow even make 4.6 heads ?!? (I really don't keep track anymore)
 
No clue either , I have not owned a ford in quite a few years .

I was quoting his wording .

No doubt some aftermarket vendor does . As some one said , there are millions of Ford engines out there .

Best wishes , :)
 
Originally Posted By: Dave9
This is abnormal, I suspect a combination of not torquing them enough then cleaning your engine perpetually with water and letting the threads rust out.

Lol! I never clean engines because it causes too many problems. Ive posted my engines on here before and people have insisted I need to wash it. Nope, not gonna happen.

Originally Posted By: OVERKILL
That's impressive if anything. Do you have a borescope to take a peek at the underside? I agree with you that it may be "unrepairable" as in the head would need to be removed and welded, then worked, then an insert put in.

I do have one of those $20 usb ones from Amazon. I have to get a USB-C adapter cause I upgraded my phone a few months ago and obsoleted all my adapters and charging cables.

Originally Posted By: andyd
That is a deep reach plug. How does it "blow out" ? There is nearly an inch of thread on the plug. Could somebody s'plain the mode of failure to me? Once again FOMOCO metallurgy fails to impress. Colt45ws isn't at fault here. TIA

While the plug has an inch of thread, in reality only half of that is threaded in the head itself. People call these the 4 thread heads because you can count only 4 threads holding the plugs in.
Originally Posted By: Kruse
I'd bet it was giving indications of a problem for quite awhile, but like you said, if your stereo was cranked, I guess you didn't hear it.
Which cylinder was this one? Like you probably guess, I bet this one will require a new cylinder head.

#3. Second from the back on the passenger side.
Originally Posted By: Canadastang
Is this the generation of 2V's that only had something crazy like 4 threads?

I know in later years they added more threads to prevent this from happening.

Fordtechmakuloco advocates overtorquing the plugs to about 20 ft. lbs, instead of the called for 10ish ft lbs. I did that on my Town Car 6 months ago and no issues.

Did you use a torque wrench on the last plug change?

Im not convinced 20ftlbs is safe on the 4 thread heads. The later heads, yes and I have taken a torque wrench to my other engine with 8 threads and torqued them to 20ftlbs.
 
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