Well for those following along on my Henry J build http://www.jalopyjournal.com/forum/showthread.php?t=517931 you knew about by my engine disaster on it's first time out. I took the engine to the builder today and tore it down, his answer to what happened was detonation. I guess I don't know enough about what a fresh engine looks like tore down to really understand how it happened. He said the pistons have burn marks on the intake side instead of the exhaust side, which I see, but don't understand how. Two pistons let go and punched a hole in the block, one piston only lost it's lower half from the wrist pin down. There's a couple bent push rods as well and the rest of the carnage that you see. Timing was set at 32 degrees at 3000 and I don't know how much advance was built into the distibutor, running a 93/100 octane mix on fuel. The engine had a miss around 5000 rpm but ran good up to that point. pan full notice the pistons wedged near the rods on the right side BIG HOLE in that cylinder
Ahh man the carnage..dam I hate to see that detonation is an ugly beast no doubt..kaboom with out having more information i would not hang my hat on this just yet Need to check and see what that full advance is at or if there is more after 3000..because if I were a betting man i think that is where your problem is, or was in this case, unless there was some other type of failure unknown to us, that started a chain reaction til distruction did the parting out
The number two piston on the right is the one missing it's lower half and here you can see the burn pattern on the intake side of them He said there was reversion due to the intake side of the head ports being black, why isn't it in all ports ? This is the stuff I don't understand. He said he can save the heads which took a beating too.
Better check that distributor timing. You could of had way too much total, like 50 or so if it came in after the 3000 rpm you checked it at.
Yes the distributor is going to get checked on a machine to see what it is, just so we know. It was a dual point with the rear set of points removed as per MSD's instructions to fire off of a 6AL box.
sure does suck I've spun a bearing before and had rod knock but never knocked the wall out of a cylinder before !
Oh Man, what a disaster... Sorry to hear this, and from following your thread, you did a lot of work getting this ready...sucks for sure... But, I am sure you will be back...(maybe even a little bigger next time ??) Good luck, Cheers.....
So how does "detonation" rip a piston in half through the pin boss ? It usually burns holes in the crown, or cracks something first. What brand pistons were they ? KB Hyper-eutectic ? How much time was on this grenade ? Judging from the underside of the dome, not much.
Can you post a close up picture of all the spark plugs? I see that one is still in the cylinder head, that one too please.
Yep, that sure does SUCK Phil! Sorry for see that especially on the first time out. Detonation is a KILLER man if that's the cause.. Had a friend rip up a newly built LS7 for the same thing, 'cept his loosened the mains and spun bearings...and i check my truck religiously for signs of it 'cause i'm still running 12:1 pistons.. Good luck man, hope your back together real soon!! Tony
yes on the pistons, engine wasn't going to see over 6300 rpm, I broke the engine in, set the timing and made 4 1/8 mile passes before it let go all I got right now
It's not uncommon for performance engines to be put together with no idea as to advance curve and total advance. Some get away with that, others don't. Not onl;y can performance be significantly effected performance, the engine can be damaged. It looks like you have an HEI distributor. If that distributor on your engine is stock you have a problem. Those distributors became available after engines had EGR. That means there is a 100% chance a stock HEI will have WAY too much total advance. Some will tell you they don't worry about it and have never had a problem. That doesn't mean it's ok. Some say they can tell by ear whether the advance is right. Long story short, don't believe that. Whether detonation actually was or was not the cause of the failure, you definitely need a distributor that's properly set up for the engine.
Does not look like detonation to me. Looks like a siezed wrist pin in the rod and / or piston...detonation will usually break the intake pocket on the piston and / or hurt the top ringland in that area. The black port or reversion, as he said probably came after the piston broke. Were the rods floated or pressed on? Looks like the pin tower broke to me...
See that picture ? NOT like that. Blows up after 3 runs, shifting at 5000 ? 99.9% sure it was assembled wrong.
I told him I wanted all the broken parts back, just for souviners I guess and I can use the block for a dummy. I have another 010 engine out there and he said he would work with me to save what we can and use in that block. He also said he would have no problem eating the cost of everything if it was something he did, but doesn't see it that way. I just don't get a 10.5 compression engine on say 96 octane could do this in such short fashion. I figure the amount of time at 5 grand had to be less than 6 seconds over the 4 1/8 mile runs, the car ran 8.24,7.75,8.03,7.60 then boom.
KB Hyper-eutetics need a LOT more end gap on the rings; because they hold a lot more heat. Some people ignore this, which KB explains very clearly. When the rings get hot, the end gap closes. Not enough gap, they will butt and stick the piston in the cylinder. Then you can rip a piston in half, or rip it into pieces. You did both.
Read this: http://www.kb-silvolite.com/kb_car/clearance_pop.php "Special Notice on Top Ring End Gap The Keith Black pistons unique thermal conductivity, ring location and varied end use requires special attention be paid to top ring end gap. KB pistons make more HP by reflecting heat energy back into the combustion process and, as a result, the top ring runs hotter and requires additional end clearance. Increasing ring end gap does not affect performance or oil control because normal end gaps are realized at operating temperatures. Failure to provide sufficient top ring end gap will cause a portion of the top ring land to break as the ring ends butt and lock tight in the cylinder. The broken piece may cause further piston or engine damage. Safe top ring end gaps can be found by multiplying the bore diameter by the appropriate ring end gap factor from the clearance chart below. Example: 4" bore "Street Normally Aspirated" = 4" bore x .0065 = .026 top ring end gap. NOTE: Second ring end gaps do not need extra clearance. Dyno and track testing has shown that 34 degrees or less total ignition timing makes the best HP and time. Excessive spark advance, lean fuel mixture or too much compression for the fuel and cam used will make heat sufficient to butt piston rings with as much as .060" ring end gap. The entire top land can expand enough to contact the cylinder walls, when close to melt down temperatures are reached" The same ring gaps and that work with regular forged pistons, will not work on Hyper-eutetics. They are a decent piston for the money, BUT you have to follow the instructions. According to the KB chart, you should have around .030" ring end gap on the remaining cylinders. If not, you know EXACTLY what happened.
In all fairness he built a duplicate engine of my friends which he has had together for two years running 6.90's in a 67 nova, my engine was a twin to that one. He does also use these type (Clamer) pistons in several street stock engines, I would think he would know about the clearence issues. A guy in my club says his year and a half old (street stock) motor from this guy ran quicker than a fresh engine from someone else. Like I said I don't know enough about what I was looking at other than the obvious. I wonder the if cam being to far degreed in advance would cause this ?
I say something let loose, I don't think detonation did that motor in. I've detonated motors before and looked like a blow tourch down the side of the piston but didn't scatter one like that. I vote for a wrist pin seized or rod broke, ouch, sorry for the mess!
Phil, just read through your build thread. Several items get my attention. The Mis-fire at 5000 RPM's, I could hear it on the 2nd round video. Only running 1/8 mile, approx. 8 secs a lap. And finally, the plugs- I dont see any real signs of detonation, none that would have caused that extreme damage. If they are KB Hyper pistons, yes they need that additional ring end gap as stated, its a must. That said, I have run these pistons up to 500 N/A H.P and much higher than 5000 RPM's. No issues what so ever. Many many things could have happened here, my advise is to try and work with your builder, as long as he is working with you, be grateful and respectful. Hopefully you can both move past this. It would be very good here to try and find out the problem WHAT happened and WHY. The thing to remember is the primary reason to find out WHAT happened, is NOT primarlily to point blame, but to NOT make the same mistake again. Build the engine again, this time better than before. Anyway I can help, please feel free to ask, TR
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