I have had a couple of threads about an intermittent clack/knock that started one day at the end of June '09 in my 426. The 426 was installed May '08 at The Modular Depot (DCX Depot) which WAS Power Ported Performance's install shop at the time. Here is a brief history of my car and the path to my 426 short block sitting at a machine shop after 7000 miles and 14 months later. March '08: I worked with Jeremy and Andy of PPP about a 426 build, etc. My car arrives via semi transport to the install shop near Cincinatti, OH. May '08: I fly to Cincinatti and Tim Combs picks me up at the airport so I can drive my car home. I get to watch the initial tune on the dyno there: I hit a deer on the way home near Peoria, IL at midnight doing this: I finally end up with this and drive it for around a year: May '09 I drive to SVS in Sacramento and have a Mondello ported intake manifold installed and my car tuned by Bob Crespo. I meet sgtstanko there. I also find out some interesting things about my initial tune. June '09: I get a disturbing oil sample report back from Blackstone saying something appears to be abrading my bearings, as in "other metals in my oil": June '09: I start my car up one morning and hear the clack/knock. I drive it no further and begin troubleshooting the noise. I pull off the valve covers and rocker shafts and look for a broken valve spring or rocker arm or whatever: I find nothing and the sound is still there when I fire the car back up again (I replaced the exhaust pushrods with slightly longer pushrods to account for my cam grind). I take the car to the dealership where they have an awesome SRT Tech and he takes the front of the motor off and inspects the timing gear set. I find that the original installer improperly ground (chamfered) my crank gear to accomodate my K-1 crank which put my timing chain and oil pump in a bind. This made a metal factory out of my oil pump gears and case: We install a new timing set and oil pump and reassemble hoping the chain was popping somehow in the case and fire it up. Same noise. August '09: We pull the motor and inspect the short block. Piston #1 has a broken ring land, the piece of which made it to cyl #8 and made it presence known on the head. There is severe scuffing on the cylinder walls, especially on the bottom half of the cylinder walls: My short block is being disassembled at a local machine shop so that everything from ring end gaps to piston skirt clearances to bearing clearances can be measured. It will be rebuilt and reinstalled in my car. There are a few things still up in the air but I have had a few PMs asking about where my motor issue was at. This is it
Jesus Jon, that really sucks... Sorry you are having to endure such issues. Hope the beast is back on the road soon.
So it looks like the cause was the tune. The question I have is (since it looks like it's going to be a couple of years before Cam has time to lead that thread on EGTs): Do you think an EGT gauge would/could have given you warning before any damage or at least serious damage? I wonder what the margin is on EGTs? How much room is there between where a tuned engine would be running and the critical temp.
That's funny you post this question. IMHO I think it would have given me an indication something was different. My knock sensors were turned off below 212 degrees in the initial tune, so I would have had to use something like EGT's to notice something diffferent (compared to my stock motor) to see a problem. It also appears that I have scuffing in 4 corners of my cylinder walls, although we haven't pulled the pistons out yet. The extra metal in my oil from my oil pump gears and case didn't help matters but it sure didn't break off my ring land. Disassembly will truly shine the full light.
That's what I'd like to understand. I think it's a pretty sure thing that heat causes the ring land failures. I think it's a sort of sure thing that heat causes the ring gaps to close and then the rings either bind against the cylinder wall and pop the ring land or the ends of the ring climb over and under each other and pop the ring land (I'm guessing the former or maybe a combination). Let's use some bogus numbers. Let's say a tuned high hp engine in some configuration is expected to run up to 1350 chamber temps. Let's say that ring land failure occurs at 1450. If you had a gauge with a high warning set at 1350 and you were headed for failure (due to tune or whatever). Is it generally going to be the case that you might be able to see a warning for 10 seconds or so? Is it less critical than that? more critical? For example if you're running WAY lean on afr and go WOT you can fail in a second or less right? Is it something like that? or are you liable to to have a good chance at saving it if you're paying attention. In any event, I would expect it to be useful for initial tuning/checking where you could sort of progressively load it more and more and sort of creep up on full out WOT runs. Any thoughts?
Quick, I totally agree. Based on my experience with EGTs on Caterpillar engines it takes a matter of seconds before temperatures can destroy parts of an engine...as in, there is nothing you can do at full throttle once you see what is happening...something is already hot and going to fail. Man, it happens sooo fast. Although I am working with methane-burning monster engines the principles are the same. I don't know when my ring land broke, nor why. But a N/A forged Arrington engine should have been pretty resistant to, ummm, failing.
Well... you said the tune was the root cause? and I was assuming that resulted in chamber temps too high that led to the ring land part of the failure. I agree that if something goes south under full load to cause a spike in temps you're probably not going to have a chance at prevention. But if you were easing into things during test'n'tune it probably could. In your case you were running it pretty easy for a while right? I think friggin Cam took on all that work just so he wouldn't have to do that thread...
What a mess Jon. It's impossible to trouble shoot that much damage from 2K miles, but I highly doubt it was any one thing. I would be interested in knowing what your engine guy finds after all the clearances are checked.
At this point I don't know what caused the failure. I am laying the facts out there that I know so far, that may have played a part. 7000k miles is a little small on a purposed built, N/A forged 426.
He looked at the block after peeling the wrap away and made a few comments. Until he measures things it's all a guess, as you well know Cam. Needless to say, I'll grab my wifes checkbook in the meantime This one's gonna cost a bundle.
I have had many good conversations with Eric Hruza since my 90 mm TB #3 and block purchase. After a brief conversation about what I was seeing with my short block a week ago, he said he would warranty my short block. I asked for an email confirmation or phone message and haven't heard anything back. This was/is kind of important as I don't have infinite money. The last thing my wife and I can afford is my short block in VA with an offer to rebuild my motor at my expense. Any indication one way or the other would have been good. I continue to pay $768/mo for my Charger.
Depends who builds it I have seen much less unfortunately! On a serious note, hope you get it figured out and on the road soon!
Jon You called me but didnt leave me your #. Send it to me. On a lighter note....when in Sacramento, your engine was making more noises than mine but similar. Remember the next morning you fired it up and i wanted to listen to it? The problem was the crank gear as I posted months ago. More and more of these are going to be popping up. This is NOT Arrington's issue since it appears the PPP authorized shop DID NOT properly chamfer the gear. Obviously they were aware of the K1 crank snout issue, otherwise why make a half assed attempt to get the gear to fit over the radious. Arrington puts a notice out with each short block. Arrington doesnt make the K1 crank, they buy it and then machine the journals to their specs like other engine builders who use the K1 parts. Your engine damage looks IDENTICAL to what mine did after pulling it out of my Jeep. PM me your #! Steve .
PM sent BTW Steve, I was too hung over to hear much except that my car was running We had a good time.
