spark plug failure?

I've been waiting for this summer. finally decided to put in a newly rebuilt engine in my 85 Supra Sunsport. Father's Day was the first day I got out because I've been busy, and my boat lasted for about 5 minutes on the new engine. Not a good start. So I take it to my mechanic and he suspects timing. After making some adjustments and a lake test he realizes something is definitely not right. So he compression test and my new engine has 0 compression on cylinder 2. I called the engine mfg. and they suggest its a detinated piston. My mechanics pulls the heads and sure enough the piston is torched and he suspects it was due to spark plug failure (the spark plug is mangled too). So I just dropped 3k on a new engine to have it destroyed by a $4 spark plug? anyone ever have this happen? any advice as to what the hell I should do now? is there any recourse with the spark plug mfg? To answer any questions: I bought the engine from US Engine, with an 8 yr warranty, My brother-in-law installed it (he is a certified ASE and certified Ford Mechanic), my engine is a 351. So needless to say its almost August and I still have yet to get my first set in.....this sucks! any suggestions?

IMPO (ASE Master Tech, L1, IM240, and GM) Your ASE Cert bro-inlaw should be able to confirm this, but the sparkplug was not the cause unless he installed the wrong ones and the piston hit it. Pre-ignition damage takes many hours of operation to cause damage.

You state that you have an 8yr warranty, what more are you looking for.

Do you have pics, Id like to see this.

Spark plug failure will just drop the cylinder. It just becomes a "dead hole" and the engine will have a miss. Detonation usualy is caused by incorrect timing or firing order or a lean condition in that cylinder, but not spark plug failure.

The engine company won't cover warranty because the detination happened from a source not associated with the construction of the engine. Excuse me if I'm completely ignorant, I am admittedly clueless about engines. So I am just trying to relay info as it was presented to me. My brother in-law said the same about detination, it would take a long time of long hard running to detinate due to vacuum leak or other misc. My marine mechanic said he adjusted the timing a tad bit, but it wasn't that far off. But he did say he had to adjust the ignition quite a bit, but he still didn't think that would've been enough off to cause the detonation. He says it is a "textbook" detonation, the top of the cylinder is torched. I've haven't see it yet. Its still at shop. I'll stop by there to take some pics. The engine company sucks too because immediately they started the blame game. I went to them specifically for their 8 yr warranty. My first phone call with them, they said I probably bent a rod during install. They were great to deal with initially, but I can tell they are gonna suck to deal with. I'm not sure why my mechanic suspects sparkplug failure. Given your responses, it sounds like its not even possible. But this guy knows his stuff according to all my friends that have boats. I just noticed US Engine has link a the bottom of this page. Beware! I'm not sure where I'm gonna be with my engine, but I can tell from their accusatory attitude from my first phone call, they aren't very honorable. At the very least they could've at least entertained the idea that maybe their engine failed, but so far no sign they are going to try to help in the matter. There is less than an hour on my engine between install and diagnosing and my 5 minutes cruise time. any other feedback might be helpful. I'll try to get some pics to get some more info because I don't want to buy another engine..that's for sure.

couple of things pops bout to me from what you mentioned. 1. they accused you of bending a rod? is that push rod or actual piston rod? either way if you bought a complete long block from them (long block meaning entire motor assembled by them: crank, rods, pistons, heads, etc) fully assembled would mean to me all you have to do is bolt your accessories carb,intake,water pumps, dist., valve covers, etc on the motor and drop it in.
2. if you bought just the short block from them (block assembled crank, rods, pistons) then that leaves some chance for mistakes in the assembly by even the most professional of engine builders.
In the car world ill tell you first hand it only takes a 1/4 mile to completely melt the head off a piston with just a bad carb/timing adjustments. I could honestly see it taking a short time for a melt down. with that said I would take a hard look at your mechanic who was doing your timing adjustments. boats are constantly under load and that aids big in the detonation process it takes to melt a piston. you gotta have good ears to hear a motor "ping" to me it almost sounds like marbles being smashed or rattled together. good luck with your problem, let us know the outcome

You can tell by the rod bearing if you've had detonation. It seems to me almost inconceivable that a spark plug would cause the description you've given. (And I'm pretty good at blowing up engines)
My first guess would be a faulty piston, or the wrong piston, or a valve train problem on that cylinder.
IMPO any reasonable mechanic would have spotted a flaw on a plug big enough to cause detonation. Get the best advice from local mechanics that you can and stick with it.
I do have to say that wierd things do happen. It can be hard to find a single cause.

I'm gonna ask some basic, maybe dumb questons:

Was the sparkplug in that cylinder the exact same as all the others?

Do you have any pics?

What do you mean by the piston was torched and plug mangled? Piston looked burned? What color? Physical damage to the plug?

What do the bore and valves look like?

How did it run in the first 4 min? Normal, or rough the whole time? Did you notice if it overheated? Would it still crank after it died, and if so did it sound normal?

Most severe pre-ignition cases that i've seen/repaired, the piston(s) and head looked as if a handfull of BB's where dropped through the intake........you see all these little craters/pits.

Pre-ignition is caused by over-advanced timing (you would see evidence in all cylinders), high engine temps(coolant passage around this cylinder could be restricted causing poor heat transfer), extremely lean condition (could effect all, some, or only one cylinder depending on cause), or too low an octane fuel for compression level. A small nick/gouge in a piston top or combustion chamber will also be a source of pre-ignition as it will be hotter then the rest of the piston and ignite the fuel charge as it enters the cylinder

A melted piston certainly points to an overheated cylinder, I dont see a faulty plug as the cause.

Mike, to answer your question, I purchased a long block. Just had to drop in their engine

Art, when you say probably faulty piston, wrong piston, or valve train problem on that cylinder. Would there be a way to tell if either of those were the actual cause of the detonation? Because then I could hopefully get US Engine to honor the warranty instead of just being out an engine or having to buy a new one, or pay someone to rip out and replace the pistons.

Trace,
all the spark plugs were brand new and all the same. I'll get some pics. By torched and mangled, I'm just describing what my mechanic said to me. He said it looked like someone to an arc welder and torched the top the piston. He said the spark plug was "blown up" maybe. My mechanic told me the bores and everything else in the engine look new. He did say that the piston beside it had some damage as well. When I fired up at the dock the boat ran great, I immediately felt it dropping power within a min or two, but didn't hear anything unusual. shortly I after I started powering down and then engine started backfiring repeatedly then died. It didn't overheat and it would crank over like the battery was dead, but it wouldn't start.

I think we can all agree on one thing - "spark plug failure" is very unlikely to be the cause.

I would expect the bore to be trashed if it was a blocked coolant passage. I'd be looking at the head and valves very carefully.

The only other thing that makes sense to me is a lean condition in that area for some reason, but I just can't see something like that, or wrong octane, or advanced timing causing a total meltdown in 5 min, though.

This is what it looks like.

Where did you get that Sparky ?

I bought my first boat with a blown engine for cheap. The guy said it ran but had a miss. This is what I found when I tore it down but I knew the day I looked at the boat that it had a hole in the piston. The piston resides in my garage, among other mangled parts, on the wall of shame now. Ford 460 by the way.

I've never seen that happen from a spark plug. Ouch !

That's the result of detonation. Nothing to do with the spark plug.

I lost a piston on a Buick 430 to detonation but it was off to the side . It looked like someone had beat all the pistons with a hammer.

Good luck Jeremy !

here are some pics. the spark plug arm appeared to melt away. The weird thing about the detonation is that normally it looks like sparky jay's pic, but this one is torched on 2 of the edges. I don't know if you can see the top, but there is actually a chunk missing.

i'm afraid your marine mechanic may have adjusted the timing a tad bit too much. wonder if the distributor was put in off a tooth or two?? timing should be set to the manufs specs.

i had a mastercraft blow a hole in a piston at 200 hours many years ago...they said for some reason the engine leaned out.

Dont know if it's been asked yet, but what was the reason for replacing the engine in the first place?

What I see in those pics looks like the effects, but not the root cause.

i replaced the original because my first year as a boat owner I wasn't aware that I needed to winterize. cracked the block.

Being off a tooth or two shouldn't do that much damage to just one piston I don't think?

Im at Marine Mechanics institute right now and we are installing distributors and are adjusting timing. When installing the distributor the teeth can be of 1 or 2 as long as its compensated for when you set your base timing.

I have no idea what the cause of that kind of engine damage could be. Were the heads in good condition before being reinstalled on the motor? Im wondering if its related to your valves and timing being messed up by more than just one tooth. Good luck, hopefully everything will work out. Don't let thi give you a bad impression on what its like to own a boat :-) its usualy much better than your unfortunate situation

The more I look at this pic the more I lean towards a fractured piston during assembly.

One big chunk of piston top broken off down to the ring grooves. Then you have a few gouges and then a bunch of dimples where that chunk was smashed up and either exited the exhaust or melted.

If this was timing related, it would be seen, to some degree, on more then one cylinder. If it was pre-ignition, it would not have happened in the first few minutes of operation. This was not caused by the plug, the damage we see on it, is from being struck by the broken piston parts.

IMPO, this is a warrantable failure.

You are correct tige mike.If the timing was out far enough to kill a engine in five minutes it would run like crap and burn the entire motor but I don't think you could even do that shy of a full race engine.There was something else at play here on just this one piston.

It's not detonation it's a water leak. Water leaks cause the piston to get hot and swell which is the opposite of what you might think. If you look at the head and the deck pics you'll see the water leak. It's at the 8:00 position on the deck pic, about one red square above and to the left of the red square. It's at the 4:00 position on the head pic. That is a warranty issue and not a timing issue. All the oil is there after the fact when the piston broke and you lost oil control. The builder should send you a new long block and enough money to R&R the engine again.

"He says it is a "textbook" detonation". Who's "he", your mechanic or the engine builder? The engine builder would have no way to psychically see what happened and if it was your mechanic I would find a new one. Show those pictures to the engine builder and have your "mechanic" tell them he found a water leak which caused the failure. Hopefully you didn't already tell the engine builder that you thought it was detonation or a failed plug. Next time don 't say anything until you know what the real cause is.

we didn't mention the spark plug. And the engine company says it has to be detonation, therefore not their fault. any lawyers on this board?

Jeremy,its a small block motor and not a real big deal.Fighting with the manufacture can ware you down and prolong your downtime.If it was me I would replace the piston resurface the heads and put the motor back in as fast as you can.That way you can enjoy the rest of your season and still have a new motor.Sometimes cutting your loss is the easiest most painless route.I see no damage to any other part of the motor and the parts to fix will bring you back to new status.
Piston-$45
Gaskets-$50
Boarding next week-pricless

ryan, very true....except I don't know how to do the work myself. so I have to enlist the help of my brother-in-law is great, but also has time commitments. But that looks like that will be my only option to get running. anybody else in Seattle area who is really skilled at doing this type of work wanna lend a hand? I'd love to be ridin' like yesterday...

John,

You mentioned you think its a water leak? how can you tell? and do you think that is a result of the piston or will I have the same problem with new pistons?

Thanks for the responses. I appreciate all the help.

Jeremy, Look at your own pictures. You can see a small crack in the head gasket at the 8:00 position and the marks the water left as it got past the compression ring. The white spots are water residue. The piston failed AFTER it got stuck in the bore. The engine builder has no way to determine the cause of failure without seeing the damage so if they keep wanting to say "detonation" until their face turns blue it doesn't really matter. Go take your pictures to any local engine building shop and they'll tell you the same thing. Is it too late to file a claim with your credit card company?

You don't have detonation on one cylinder alone. Not a timing issue. Not a lean issue. Its a bad piston issue.

I also noticed the crack on the piston. Could be from heat, could be a bad piston. Either way, its a warranty issue. The head/valves/piston is bad causing the failure. or causing the detonation and heat which lead to the failure.

It will seem a daunting project, but its really not that bad to tear into.

My marine mechanic said he adjusted the timing a tad bit, but it wasn't that far off. But he did say he had to adjust the ignition quite a bit, but he still didn't think that would've been enough off to cause the detonation.

"But he did say he had to adjust the ignition quite a bit"


what is he talking about? adjusting the ignition?

I'm with TigeMike, looks like a broken piston from the assembly process. The white spots on the valves are aluminum residue, the spark plug was broken by the flange of the piston hitting it. If the engine builder has any credibility they will repair the engine for you. If not you may have to go more drastic measures to recover your money. That was not a timing or fuel problem.

just thought I'd pass along the latest from the engine mfg. I sent the pictures and descriptions from this website and this is their response:

"Whom ever you are showing this to is not skilled. The piston is melted. How else can you melt a piston, head and detination. There is no warranty for this error its yours not ours. Sorry for your problems but you cant blame us."

Be very aware of US Engine. They're good for nothing!

I'd file a claim against my credit card if it's not too late. There is no evidence of any 'melting' in those pics.

Andy, "adjusting the ignition" not sure what that meant either, unless it's an old points system that needed some maintenance.

Jeremy, there's more to the story. At this point its easy for them to say "not our problem". Someone else looked at and tuned the engine after it left their location. If it were mine, I'd tear into it. The cylinder wasn't getting the same air/fuel mixture as the others. Too little fuel and it started popping. I'll go out on a limb on a couple options: some obstruction in the intake. Or a lifter/pushrod/rocker/valve problem that made the intake valve not open all the way. You got less fuel than you needed and it started to pop. Could be a collapsed lifter, more likely in the first 5 minutes.

So, ya gotta decide how you're going to go about this. I would assume you've used up most your BIL's free time, but maybe he could look over your shoulder for a few minutes at a time while you got it back together. Chances are you'll find the problem as you teardown. Whether or not US Engine cares at that point is anybody's guess.

I would tear into it yourself. You clearly have the support of everyone on this site and I am sure you could find someone on here in your area that is mechanically savey and for a little beer they would come by and tear into it (fly me to WA and I will help you for a weekend. Have that bad boy torn apart and fixed in a weekend.)

From what I can see in the picture its just the piston that needs replacement, and the head needs to be taken to a machine shop. I have not read the whole forum. Is their any damage to the cylinder wall?

Jeremy, I think you need to get the paid opinion of a real live certified mechanic if you want to go after US Engine/warranty, Melted? they were looking at the piston someone else posted with the hole burned in it!)your piston does not show melting, they do not sound at all helpful though but I do not blame them because you need a professional opinion to fight them as to warranty (opinions on a forum don't mean diddley squat) I am sorry for you to be in this position...the best route may be to just tackle the problem and get it repaired, it could take more energy and frustration to fight them than to just fix it. you have to decide which way to go. It's a tough situation.

I have to ask too...you said it lasted only about 5 minutes...during this time did it ping or knock? what did it sound like, because you would hear detonation occurring. pinging.

I'm a lawyer, and I know something about automotive mechanics. Here are a couple of thoughts:

1. IMHO, the damage is not the result of detonation. It looks like defective parts and/or machining in the build process.

2. The attitude of US Engine (USE) definitely is a major problem, making their so-called "8 year warranty" worthless.

3. Using a lawyer to try to resolve this will cost more than repairing the damage -- a lot more. USE is not going to fold just because they get a letter from someone with "JD" after their name.

4. Contact the Better Business Bureau or state consumer protection agency where USE is located and see if they can offer assistance (mediation, etc.). The problem is that even if you do have an avenue of recourse through the BBB or the state, it will take time.

5. Or, replace the piston and rings, have the con rod checked, check the cylinder wall, get the head cleaned up, get a new plug, assemble, and then get out on the water.

6. In the meantime, check out "Find a Third/Be a Third" here on WW.

"You don't have detonation on one cylinder alone." Nacho, not true. The pic above of my piston was the only one out of eight that looked like that. It can definetly be cylinder specific. And Andy, you won't always be able to hear detonation especialy in these boats with very minimal muffler systems, and tucked away in an insulated engine compartment. It usualy occurs when the engine is in the higher RPM range and under load. Mine was in a flat bottom boat with open headers and you would not here the detonation occuring in that boat at all.

we blew a hole in only one too it looked like yours sparky about a .25 cent hole in the center on a 454.

Yep. It's actualy pretty common in boats cuz it's just not as easy to know when it's happening with the added noise levels verses a car where it's easy to detect/hear.

I could see a single piston doing that on a big block drag boat but a low compression small block would require major ignition problems to the point of the boat hardly being operational.I would think to have that kind of damage from detonation you would be forcing the boat with full knowledge of there being something wrong.
Just not possible to do that kind of damage to a stock low compression motor in five minutes on one cylinder without any prior warning.

Nope Ryan, my flatbottom was a stock 9:1 compression 460 Ford engine. It ran fine until it dropped the cylinder and developed the miss. You couldn't hear it detonating while driving the boat. I do agree that five minutes seems short but his piston doesen't have a hole in it either. Detonation usualy hammers the center of the piston but the damage on OP's is to the side, and that could happen relatively quick...

How hard where you pushing that big block when it blew?Supra with a 13/13 prop would be hard pressed to pull 4300 rpm's.Im not saying it can't be done just that somethings not adding up.In reality it could have been a cracked piston,something dropped in the intake or pretty much a number of things but five minutes on a new motor with no symptoms?Not likely

Like I said before you can fight with the builder till your face turns blue but the sooner you take my advice and fix it yourself the sooner you will be on the water.

well, I've been battling what to do. From what I've read here and from showing the pics to a local machine shop, it appears that US Engine builds a crap engine. Or at least had one faulty part, that caused a faulty engine, and an 8 year warranty that is good for nothing. I feel confident that it is their fault and should be warrantied, but if I wait for them to do anything or try to stick'em in court...I won't be riding on my boat this summer. I twisted my brohter-in-laws arm to help with another install so we're scheduled to do it Tuesday/Wednesday this coming week. Hopefully be riding by next weekend.

Hey Jeff,
Can I get them to pay for install costs (by mechanic) after the fact?

I'll keep y'all posted. Thanks for your help. I really appreciate your opinions and feedback.

Jeremy,No matter what you do us engines will never pay for anything short of you spending ten times as much on a lawyer.Its one of those deals where the builder has a infinite list of excuses and theres nothing you can do.I consider a purchase like yours to come with certain risks,engine faliure being one.
Sucks but could allways be worse

No mechanical knowledge here. Make sure you know who you are talking to at USE. The tone of the reply sounded like a service agent. Ask politely to speak to a supervisor and do not take no for an answer. You need to get to someone with real authority who can hopefully help you.

I feel very bad for you bud. I am on season one in an 87 SunSport. When things go wrong it really is a punch in the gut. Best of luck.

Jeremy try to get documentation from a real mechanic, even if its opinion, in writing, keep all of your receipts, then sue in small claims-no lawyers, 35 bucks or so to do it, a judge is more likely to give you the benefit of the doubt than he is to US Engine. Obviously your piston is not melted. Thank goodness you have warned us all about US Engine not backing up their product. an 8 yr warranty that covers nothing.

I've been looking for a stroker motor and they have a pretty good price on it, but I would never buy it from them now.

(Message edited by bftskir on August 11, 2008)

wakemikey...I like the service agent. The guy at the counter, answering calls is super nice and helpful. He even told me to bring the engine down and he'd restore the pistons to help me out. I still have the labor of removing the whole engine and replacing the whole engine which, if I had to pay a mechanic, is $2000. So it doesn't save me much, but its a nice gesture from what he may be able to do for me. Its when I talk to "the man" (Mike C.) I don't know if he's the owner or been there the longest or who he is, but if there is a warranty question you have to talk to Mike and he's the one who jumps straight to the "its your fault" comments. So, mechanically, the buck stops with Mike C. and he's not budgin'. I've even showed the pics to a local machine shop and they think it should be warranty also. But, like its been stated, if I try to wait for USE to do anything, I won't be riding this summer...whats left of it.

Andy, good call..I would definitely choose another option. I've heard some good things about Rapido Marine engines if you want to check them out...I was debating between USE and RM when I purchased.

Ask the cool guy if they have ever paid out a warranty claim.

What did the lifters look like?

Well, things went from bad to worse. I figured I'd at least take USE up on their offer to replace the pistons. Again, not saving much since the $$ is in the labor, but better than nothing. They'd told me on the phone if I bring the engine down, they'd replace the bad piston free of charge. They said it should take half hour maybe. me and my BIL remove the engine, I drive 2 and half hours to their shop. I hang around the area for a good portion of the day. Finally 4 hours later, I call them and ask about my engine...they tell me it's gonna take longer than they thought and oh by the way it's gonna cost you $600. Wow! I explained that the whole distance thing, I only brought it back to them because they were supposed to replace them for free and they explain that it's more than they anticipated. They proceed to accuse me of dropping something in the intake, so its not warranty.

Arguing with these types of people is like arguing with umps and refs. it doesn't change the outcome. so....I'm back to square 1. I wasn't about the pay them another dime, so I took my engine and left, still not fixed.

So, I know I am just one small voice if this huge forum, but for what its worth, I don't think ww should allow US Engine to advertise on this site. I guess its a money thing so maybe that's not an option, but that advertisement link got me where I am today.

Well, doesn't mean much now, but it looks like they agree with us that this was not pre-ignition. Now they just need to concede to the fact that they built a bad engine.

did this something end up in the cylinder?? if so, its lawyer time.

How can the cylinder bore still be good if it was running for 5 minutes with something that was dropped in the intake? Not likely to happen from what I understand about foreign objects being inside engines when they're running.

definately not buying from them.....

I will pass the word on to everyone I know as well.