Over tightening the caps wouldn't done that. You could tighten enough to either break or strip the bolt. There is not any pressure between the cam towers unless the engine builder started tighten the cam caps without aligning the dowels.
Im back w/ more bad news, broken MMR Motor
- Thread starter Hangman
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We will chime in one last time since our assembly has been questioned. The damage caused to the piston is from thermal (heat) expansion. The piston expanded beyond its piston to wall clearance due to excessive heat/overheating/detonation.
What was not mentioned is that the engine ran fine for 500-600 miles (as stated by the customer) , it broke after its 2nd pull on the dyno (similar to the customers last piston meltdown shown below) In this picture you will also see the same Marks on the skirt, these marks are a simple progression of the failure, had the engine run a moment longer at that condition a hole would have burned through it. The MMR coating is the only thing that saved the crown of the piston.
Picture from his first failure:
Picture from this failure:
As stated above, this piston was moments away from looking like the one above it.
Now lets look at Google pictures of pistons with signs of detonation:
Detonation pictures
Notice the similarity?
MMR accepts zero liability for this failure and no shop in their right mind would after seeing this customers history of engine failure, yet in the name of customer service we offered a full refund to him just days ago for the price of the original shortblock once the shortblock was returned to simply cut our losses and be done with this loosing battle.
MMR will not address this issue further, it is truly a dead horse. Based on the customers choice to continue the thread with pointing blame at MMR we will no longer offer any refund that was being offered as a courtesy. MMR as a courtesy will still accept the shortblock for warrranty consideration. Most likely this failure will fall under the "no question asked warranty" which means the customer will simply be responsible for the parts he damaged and MMR covers the labor as a courtesy.
Best of luck to all involved.
MMR Management
I would like to point out that the picture of the first piston that MMR is holding up as evidence of detonation is the same piston that was not replaced after the valve spring broke on the first motor, When the valve spring broke on the first motor it caused the valve to slam into the top of the piston. Go back and look at the OP's pictures and you will see that this piston is the same one with the valve mark on top that MMR ground down and put back in when they "fixed" the motor the first time.
I also followed the link that MMR put up regarding "Detonation pictures" and I did notice something.....all those pistons show damage to the tops of the pistons. Hmmm, not the case on the MMR pistons in the OP's motor.
sorry to see OP, its gotta be far beyond frustrating right now
mmrs rep continues to go further down the tubes
mmrs rep continues to go further down the tubes
Those spark plugs look FINE! Like I said detonation didn't occur on those dyno pulls, it's just a convenient excuse!!
What's your theory on what did cause them to split like that? torquing the bolt had zero to do with it?:shrug:
Damn, I'm sorry to hear all of this op. As someone pointed out its the same piston from the first motor blowing up. Coincidence? Hmmm
Detonation on the sides of the pistons and the tops are fine?? I'm a retard when it comes to motors but holy smokes even I know what detonation is and it definitely didn't cause these motor melt downs.
Now that these pics and observations and opinions are out, mmr is like a fat kid at a salad bar...no where to be seen!!
Sorry again op, I hope it all works out in the end and you can enjoy your car.
Detonation on the sides of the pistons and the tops are fine?? I'm a retard when it comes to motors but holy smokes even I know what detonation is and it definitely didn't cause these motor melt downs.
Now that these pics and observations and opinions are out, mmr is like a fat kid at a salad bar...no where to be seen!!
Sorry again op, I hope it all works out in the end and you can enjoy your car.
Wow... I take back what I said earlier about the tuner and tune. I'm back to thinking this is an assembly error.
Whats the piston to wall clearance? I'm guessing they blew that measurement.
This damage looks very similar to the sideskirt damage that happens to 03/04 cobras because of the tight PTW clearances.
Whats the piston to wall clearance? I'm guessing they blew that measurement.
This damage looks very similar to the sideskirt damage that happens to 03/04 cobras because of the tight PTW clearances.
I saw the first piston and thought "Well, no detonation, a little bit of piston skirt scuff." Then the second "Ok, that's a lot more scuff." By the third "DEAR GOD WHAT IS GOING ON?"
I agree. The heads and girdles/caps are fairly soft aluminum. Think about all the other holes you've probably stripped in one of these heads, like intake manifold bolts, exhaust manifold, etc...
Maybe if the base was a hardened steel and it had a substantial fastener you could break them like that, but I don't think that was the cause.
Not to mention you can feel the difference in over-tightening big time. When I was putting my cams in, they felt like they hardly wanted to spin. I was using a crappy torque wrench, so I borrowed a higher quality calibrated one. I re-torqued to spec and even though it was only off a few units, the difference was day and night. It went from being difficult to turn by hand to easily turning by hand.
As for what may have caused the cracks I don't think I can definitively say, so I'll hold my opinion.
I agree. The heads and girdles/caps are fairly soft aluminum. Think about all the other holes you've probably stripped in one of these heads, like intake manifold bolts, exhaust manifold, etc...
Maybe if the base was a hardened steel and it had a substantial fastener you could break them like that, but I don't think that was the cause.
Not to mention you can feel the difference in over-tightening big time. When I was putting my cams in, they felt like they hardly wanted to spin. I was using a crappy torque wrench, so I borrowed a higher quality calibrated one. I re-torqued to spec and even though it was only off a few units, the difference was day and night. It went from being difficult to turn by hand to easily turning by hand.
As for what may have caused the cracks I don't think I can definitively say, so I'll hold my opinion.
yeah you can feel the difference when you over tighten them, with your fingers, but not a air tool.
Since MMR is longer willing to work with me because I didn't remove this thread, I have been looking into legal action, I have an appointment with an attorney so I can see what options I have. If anybody knows about the legal processes of this please PM me.
I feel this thread should stay up so people can see from their own point of view what they think, what happened and how it is resolved. I will also post this thread on many other forums that I am apart of so I can see if there is other help to be found, also so more people can see all of this stuff. I mean 2 years of STILL ongoing frustration and wasted money and multiple engine failures, everything is documented, all receipts, and I have written statements from a reputable tuner and an engine builder of what happened. Ill see what happens, at this point I have nothing but time.
I will continue to update this thread when things come up.
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it was not a full refund, it was a refund for the shortblock, if you were out thousands of dollars in labor costs after multiple failures plus additional parts you paid for, and it appears there is more money going to be spent in the heads after the damage to the tower caps. $4000 does not cut it. The word "FULL" should not be used lightly.
If they offered a complete and utter refund for everything I paid for and I send them back all their parts, that would be acceptable. That would be the short end for me also but I would most likely take that offer, I'm out tons of money on labor for the shop having to take the motor out multiple times, hence why I am going to talk to an attorney. This just sucks, but one thing I wont do is let this situation go.
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the cam caps are clearanced to clear the lobes for the larger cams, the cracked cam cap is most likely due to installation, but hard to say...my guess, installation of the cam caps with the cam followers loaded the cam cap and cracked it, caps are specific to each cylinder head unless align honed after replacement, had my machinist do this...we always install cams check clearances (many) and then once everything is good install the followers. for shits and giggles, was this a standard bore block?
Hangman
I feel real bad about what you have been going thru. As we all know engine building is a risky business especially when you add a blower to the mix.
This is not a tuning issue! Judging by the massive skirts damage in the photos this looks to be clearance and dynamics related and nothing else. The fact this occurred "across the board" to every slug means its likely this engine was doomed from the start :nonono:
The PWC may have been too tight causing the skirt to expand and gall or it was too loose allowing the piston to rock excessively in the bore at BDC. You're stroked motor pulls almost all of the skirt out of the cylinder at BDC plus the stroke aggravates side loading on the piston. When the piston transition from down to up it will rotate on the wrist pin and if the piston is not registered in the bore the leading edge of the cylinder wall scrape the skirt as the piston try’s to straighten itself. This can happen regardless of the PWC. There are a lot of stroked engines running around with no problems but they do run a higher risk of failure for the reasons mentioned above. The dyno is what usually pushes an engine over the edge which is apparently what happened here. I am very distrustful of a brand new engines and a dyno is not a place I would be in a hurry to get to until I am confident the engine is well broken-in and sound. Those piston look like they just came out of the box sans the side scoring.
A brand new engine with a long arm crank and improper clearance screaming at 6000 rpm on a dyno under boost is a roll-of-the-dice affair where you cross your fingers hoping nothing goes wrong and in your case it did. Very seldom do you see engines with lots of miles on them fail........... IT's THE NEW ONES YOU NEED TO WORRY ABOUT! :uh oh:
I can only imagine your level of frustration :cuss: and you have been very mature through this whole ordeal. Reading your post you certainly seem to know what you’re doing and capable of building your own engine. As bad as this looks chances are you can get this cleaned up with no too much trouble. If I were in your shoes I would take the block to a local reputable machine shop and get them to clean up the bores then sell or swap the crank you have for a stock stroke unit which will do a better job of keeping the pistons running true in the cylinders. Look carefully at the oil pump to make sure it did not ingest any shavings off the skirt. Break it "in" in gently running low boost and a "seat of the pants" tune and not measuring max power by strapping it down on a torcher chamber table. After the engine has a few thousand miles and I'm more confident its sound I would be more inclined to get more aggressive with the tune.
You can probably salvage the cam basket by getting it heli-arched.
Keep us posted on your progress.
I feel real bad about what you have been going thru. As we all know engine building is a risky business especially when you add a blower to the mix.
This is not a tuning issue! Judging by the massive skirts damage in the photos this looks to be clearance and dynamics related and nothing else. The fact this occurred "across the board" to every slug means its likely this engine was doomed from the start :nonono:
The PWC may have been too tight causing the skirt to expand and gall or it was too loose allowing the piston to rock excessively in the bore at BDC. You're stroked motor pulls almost all of the skirt out of the cylinder at BDC plus the stroke aggravates side loading on the piston. When the piston transition from down to up it will rotate on the wrist pin and if the piston is not registered in the bore the leading edge of the cylinder wall scrape the skirt as the piston try’s to straighten itself. This can happen regardless of the PWC. There are a lot of stroked engines running around with no problems but they do run a higher risk of failure for the reasons mentioned above. The dyno is what usually pushes an engine over the edge which is apparently what happened here. I am very distrustful of a brand new engines and a dyno is not a place I would be in a hurry to get to until I am confident the engine is well broken-in and sound. Those piston look like they just came out of the box sans the side scoring.
A brand new engine with a long arm crank and improper clearance screaming at 6000 rpm on a dyno under boost is a roll-of-the-dice affair where you cross your fingers hoping nothing goes wrong and in your case it did. Very seldom do you see engines with lots of miles on them fail........... IT's THE NEW ONES YOU NEED TO WORRY ABOUT! :uh oh:
I can only imagine your level of frustration :cuss: and you have been very mature through this whole ordeal. Reading your post you certainly seem to know what you’re doing and capable of building your own engine. As bad as this looks chances are you can get this cleaned up with no too much trouble. If I were in your shoes I would take the block to a local reputable machine shop and get them to clean up the bores then sell or swap the crank you have for a stock stroke unit which will do a better job of keeping the pistons running true in the cylinders. Look carefully at the oil pump to make sure it did not ingest any shavings off the skirt. Break it "in" in gently running low boost and a "seat of the pants" tune and not measuring max power by strapping it down on a torcher chamber table. After the engine has a few thousand miles and I'm more confident its sound I would be more inclined to get more aggressive with the tune.
You can probably salvage the cam basket by getting it heli-arched.
Keep us posted on your progress.
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MMR offered $4000.00 and they wanted the shortblock back. Seems like a goood deal for MMR and really bad deal for the OP. He's already paid for 2 boss blocks and the crank and rods seem to still be ok. My guess is MMR would have machined the block, reused the crank and rods and sold it to someone else. At least OP has a block he can use(maybe) and a crank and rods. He would have to spend about $4k just to get back to where he was. That's not to mention the time, frustration and thousands of dollars he's out. And I happen to know that is now over $20,000.
Hangman
I feel real bad about what you have been going thru. As we all know engine building is a risky business especially when you add a blower to the mix.
This is not a tuning issue! Judging by the massive skirts damage in the photos this looks to be clearance and dynamics related and nothing else. The fact this occurred "across the board" to every slug means its likely this engine was doomed from the start :nonono:
The PWC may have been too tight causing the skirt to expand and gall or it was too loose allowing the piston to rock excessively in the bore at BDC. You're stroked motor pulls almost all of the skirt out of the cylinder at BDC plus the stroke aggravates side loading on the piston. When the piston transition from down to up it will rotate on the wrist pin and if the piston is not registered in the bore the leading edge of the cylinder wall scrape the skirt as the piston try’s to straighten itself. This can happen regardless of the PWC. There are a lot of stroked engines running around with no problems but they do run a higher risk of failure for the reasons mentioned above. The dyno is what usually pushes an engine over the edge which is apparently what happened here. I am very distrustful of a brand new engines and a dyno is not a place I would be in a hurry to get to until I am confident the engine is well broken-in and sound. Those piston look like they just came out of the box sans the side scoring.
A brand new engine with a long arm crank and improper clearance screaming at 6000 rpm on a dyno under boost is a roll-of-the-dice affair where you cross your fingers hoping nothing goes wrong and in your case it did. Very seldom do you see engines with lots of miles on them fail........... IT's THE NEW ONES YOU NEED TO WORRY ABOUT! :uh oh:
I can only imagine your level of frustration :cuss: and you have been very mature through this whole ordeal. Reading your post you certainly seem to know what you’re doing and capable of building your own engine. As bad as this looks chances are you can get this cleaned up with no too much trouble. If I were in your shoes I would take the block to a local reputable machine shop and get them to clean up the bores then sell or swap the crank you have for a stock stroke unit which will do a better job of keeping the pistons running true in the cylinders. Look carefully at the oil pump to make sure it did not ingest any shavings off the skirt. Break it "in" in gently running low boost and a "seat of the pants" tune and not measuring max power by strapping it down on a torcher chamber table. After the engine has a few thousand miles and I'm more confident its sound I would be more inclined to get more aggressive with the tune.
You can probably salvage the cam basket by getting it heli-arched.
Keep us posted on your progress.
^this...my other question was maybe the block was brandnew standard bore block, and the pistons maybe coated after intial sizing is done in manufacturing, hence adding the coating would have reduced the piston to wall clearance, im sure MMR can clarify that.
Have you engine diagnostic technician measure the one good piston and mic the od and id of each bore 180 degrees from wearing (good part of the bore) and determine the ptw clearance.
Here is the photo of the piston that WASN'T replaced when MMR "fixed" the motor after the valve spring broke. As I said in my previous post, it's the one they are showing to point out it was detonation that ruined the SECOND motor.
You can clearly see where the valve struck the piston. It appears they actually ground down the area that the valve damaged when it hit the piston. And coincedently that is where the failure occured on the motor they "fixed".
You can clearly see where the valve struck the piston. It appears they actually ground down the area that the valve damaged when it hit the piston. And coincedently that is where the failure occured on the motor they "fixed".
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That first piston probably created a hot spot on the top part therefore more prone to detonation/melting which happened when they turned the boost up..
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