How does this keep happening

[GreenS550]

Check out my experience with Livernois Motorsports. I had the IDENTICAL problem after a Magnuson supercharger. Car ran too lean. After they replaced the short block, I paid very close attention. Took it to another reputable shop that tuned it and the owner immediately said "it's running way too lean". Then I showed him the piston which looked identical to yours and he said. "yes, detonation". I asked if the tune would have caused it and he said "yes, if it was tuned the same way". Photos of the pistons look exactly like yours. They tried to blame it on the factory ring land thickness.
https://www.mustang6g.com/forums/threads/livernois-motorsports-675-package-engine-damaged.105940/

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[WhippledS550]

x100!

busted ring lands are usually from ring gaps set too tight. Loosen them up while the motor is apart.

Also buy some ARP head studs.

Truthfully, I'd also slam a set of forged pistons on the stock rods and go after it.

Wouldn’t putting pistons on top of stock rods be a waste ? As in the rods are also a weak link ?

 

[gimmie11s]

Wouldn’t putting pistons on top of stock rods be a waste ? As in the rods are also a weak link ?

While you’re in there, yeah definitely.

If on a budget, rods would be last on my list. They are very strong.

 

[GreenS550]

BTW, sorry for the issues. I know what a hassle that is. Did your tuner datalog the tune after you installed it? Also, the pistons are not forged while the rods are therefore put forged pistons in. They can take tune issues and abuse better than the hypereutectic stock pistons.

 

[robmustang201528]

Check out my experience with Livernois Motorsports. I had the IDENTICAL problem after a Magnuson supercharger. Car ran too lean. After they replaced the short block, I paid very close attention. Took it to another reputable shop that tuned it and the owner immediately said "it's running way too lean". Then I showed him the piston which looked identical to yours and he said. "yes, detonation". I asked if the tune would have caused it and he said "yes, if it was tuned the same way". Photos of the pistons look exactly like yours. They tried to blame it on the factory ring land thickness.
https://www.mustang6g.com/forums/threads/livernois-motorsports-675-package-engine-damaged.105940/

That's exactly what the shop said. "Factory issue". It's just hard for me to belive that the same issue happened twice. Granted the first time it happened I had the cats on but i only had the car for maybe a little over a week. The second time new short block, took the cats off and I have the same damn issue .What caused the cat to fail that fast?? I have American racing headers and I had American racing high flow cats. Lund says it over boosted but I've never seen more then 10.5lbs. Let me make sure I understand what over boosting means.... if it's set for 10lbs and it goes over 10lbs that means it over boosted correct? Also I found out that the tune was never finished but they said the tune is safe. Said it's a base tune. Also timing on the base tune was super low as they we're not finished.

 

[GreenS550]

Another comment. When LMS put in the engine they rebuilt and I had the same tune/drivability issues, the backup camera and cruise control were not working correctly. This, along with the terrible tune convinced me that LMS had issues greater than just tuning. I think their software was corrupted. When I took the car to another shop, he had Ford re-flash the CPU to stock and built the tune from there. Backup camera, cruise and car ran correctly. Lund should get back with you on the tune and have it datalogged several times.
I went to PBD at the recommendation of a member here and they required me to datalog the car several times.

 

[Crackerjack17]

Thought I'd add this to the thread... I pulled the rings off piston #8 tonight and pushed them into the cyl. (This is from my failed short block, which broke the ring lands on cyl 7 & 8)

top ring = 0.011 (factory specs .015-.025)
2nd ring = 0.031 (factory specs .030-.055)

 

[engineermike]

Crackerjack, thanks for checking and posting that. I’m confused about the spec though.

https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-6007-A50SC.pdf

This shows the top ring gap spec to be .15-.25 mm which is .006-.010. This seem erroneously small. I would expect more like your numbers. Where did you get your spec from?

 

[GreenS550]

The last engine I built was 36 years ago. I hand filed the ring gaps. I clearly remember having fairly visible ring gaps when the pistons were installed. I cannot imagine any ring gaps that tight. Maybe this is an issue from the factory?
Here is a great article explaining the engine failure from improper ring gap:
http://blog.wiseco.com/everything-you-need-to-know-about-ring-gap

 

[Crackerjack17]

Crackerjack, thanks for checking and posting that. I’m confused about the spec though.

https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-6007-A50SC.pdf

This shows the top ring gap spec to be .15-.25 mm which is .006-.010. This seem erroneously small. I would expect more like your numbers. Where did you get your spec from?

Hmmm. Same sheet as you. When I get home, I'll measure the feeler gauge with my micrometer. But that feeler gauge is the one that fits perfect in the top ring gap. I'll check cyl 7 too.

 

[engineermike]

Can you check all of them?

 

[ahl395]

That's exactly what the shop said. "Factory issue". It's just hard for me to belive that the same issue happened twice. Granted the first time it happened I had the cats on but i only had the car for maybe a little over a week. The second time new short block, took the cats off and I have the same damn issue .What caused the cat to fail that fast?? I have American racing headers and I had American racing high flow cats. Lund says it over boosted but I've never seen more then 10.5lbs. Let me make sure I understand what over boosting means.... if it's set for 10lbs and it goes over 10lbs that means it over boosted correct? Also I found out that the tune was never finished but they said the tune is safe. Said it's a base tune. Also timing on the base tune was super low as they we're not finished.

"Overboosting" would be more than 10psi yes, since that's what your set for. However one or two psi wouldnt cause motor failure it would have to be more than that. I've "overboosted" to 19psi more than once on my stock motor without issue lol. Driving regularly and going into boost on the base tune is a bad idea and I wouldn't be surprised if thats part of your problem. It may have timing low but the fueling and everything else is not fine tuned yet. if you did go lean that could be why.

 

[Crackerjack17]

Can you check all of them?

I could but, maybe over the weekend. I only have cylinder 7&8 out. the shortblock is sitting on a moving dolly on the floor. I never removed the other pistons because when I compression checked them they were ok.

 

[robmustang201528]

Thinking about getting rid of the tq booster and boost controller. Stick a 12lb pully on there and call it a day. What do you guys think? Lund swears by the tune, TQ booster make more heat. Maybe that's why It keeps fucking up the rings in cylinder 8?

 

[ahl395]

Thinking about getting rid of the tq booster and boost controller. Stick a 12lb pully on there and call it a day. What do you guys think? Lund swears by the tune, TQ booster make more heat. Maybe that's why It keeps fucking up the rings in cylinder 8?

"tq booster" or wastegate even on the most extreme pulley adds 20 degrees to IAT at WOT. That's not going to fuck up the rings and your tune will pull timing to keep the motor safe if IAT gets too high anyway. But if you want to try it, it may work ok for you since you had issues setting up the boost controller anyway, so it will make things simpler.

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