The #8, and why it failed. An inside look.
4/24/14, 06:36 AM
#41
Mach 1 Member
You're right I have no idea why. :-) I just assume that anytime there is a design change it is part of the continuous improvement process. That said if that is correct then there was something Ford felt needed improvement within the piston design and it very well could have been to help them survive bouts of mis-detnation.
I believe they also changed the timing chain tensioners too. There was room for improvement there too I assume.
I have heavily been into supercoupes all my life and modded a number of them. A couple of them were 12 second cars pushing low 300 HP to the wheel. At any rate, over the 7 year production run of the SC Ford changed numerous internal engine parts. For example in 94 they switched over to a full floating wrist pin. Now no one in the club was having issues with the older pressed in style but we assumed ford wanted to improve the design. Additionally ford changed to a larger oil pump in 94. Again no one was having oil pump failure or low oil pressure, again Ford was making improvements. Thy cylinder heads also went through a revision in 93. although we all speculate this was done to help eliminate the head gasket issues these cars were known to have. The updated head was made from a harder casting but it didn't help solve the head gasket failure issue. In fact the folks with the newer heads typically find they crack over time as they are too hard There were numerous other internal engine changes. I know you get the point. There are always updates taking place on engines during production runs and to be honest I have no idea why any take place LOL All manufacturers do it and they do not make us aware. The obvious answer regarding the change in the piston in 13 was the removal of the oil squirters. That said Ford had to revise the oiling mechanism for the piston . The piston needs oiling somehow due to this change. This is a great discussion and one we could discuss for hours and maybe not get any closer to determining the reason for the change.
4/24/14, 01:50 PM
#42
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Thanks for the great info Matt.
<QUOTE=fdjizm>
https://themustangsource.com/f800/tu...4/#post6067451
It was also mentioned that the hood vents were added to the 13 forward at the same time:
<Overboost: Something else interesting, the 2013 GT and Boss have vents on their hood...coincidental? I think not. >
Both of which lead me to believe there were more issues than just the tune. Any info on the reasons for the piston re-design?
Thanx!
<Pics posted by MARZ>
https://themustangsource.com/f800/co...4/#post6280407
<QUOTE=fdjizm>
https://themustangsource.com/f800/tu...4/#post6067451
It was also mentioned that the hood vents were added to the 13 forward at the same time:
<Overboost: Something else interesting, the 2013 GT and Boss have vents on their hood...coincidental? I think not. >
Both of which lead me to believe there were more issues than just the tune. Any info on the reasons for the piston re-design?
Thanx!
<Pics posted by MARZ>
https://themustangsource.com/f800/co...4/#post6280407
Is the 13/14 the one on the left? AKA the one which isn't broken up? Or another way. In the picture where they are side by side, is it the one with a solid mid section, or the one with the split mid section?
Last edited by 5.M0NSTER; 4/24/14 at 02:05 PM.
4/24/14, 02:58 PM
#43
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To me it just seems that removing the squirters was such an about face to how they touted them initially when rolling out the 5.0. All the mag rags had write ups about it. It was pretty innovative for a street car. Ford has always been good at getting power out of smaller displacement engines and this seemed a sound method for allowing higher compression in the 5.0, adding to higher HP.
The removal for 13 forward was much too coincidental with the #8 failures the 11/12's had, to be just an improvement vs solving a very real failure rate. The combination of squirter deletion, revised oil rings, piston coatings, hood vents - all at the same time - points to a (heat related/upper cylinder oiling) engineering change to resolve the piston failures that were triggered by unsafe tune parameters.
Also, if the failure was only related to the tune allowing knock/detonation to stress pistons beyond their capability, why only #8 failures? (I think I only read of one #4). Why weren't other pistons failing? Detonation does not happen only in #8 cylinder and not others.
But I am just observing with some old school common sense and reasonable mechanical aptitude point of view. I don't have the technical/engineering expertise some of you have. So I am hoping for something concrete to resolve my restless mind.
Granted Ford has been very tight lipped for obvious reasons, and what info we have collected has only come by tidbits here and there by some that either work at Ford or have technical involvement with Ford products.
Last edited by cdynaco; 4/24/14 at 03:21 PM.
4/24/14, 03:07 PM
#44
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This thread has been fantastic and packed with great info. And I'm sorry but I have a dumb question...So which of these is the 11/12 and which is the 13/14?
Is the 13/14 the one on the left? AKA the one which isn't broken up? Or another way. In the picture where they are side by side, is it the one with a solid mid section, or the one with the split mid section?
Is the 13/14 the one on the left? AKA the one which isn't broken up? Or another way. In the picture where they are side by side, is it the one with a solid mid section, or the one with the split mid section?
If you look closely at the new 11/12 piston on the left, the oil control and compression ring lands match the failed piston in the first pic.
I'm also curious as to the added groove (not a ring land) between compression rings. Would love an explanation for that. Does this allow a bit of oil to remain captured and provide extra upper cylinder lubrication? Or does this capture a bit of blow by gases that somehow stabilize the piston to avoid cylinder wall scuffing, skirt damage, and/or piston rattle?
As Robert pointed out, the failed piston does have scuffing.
Last edited by cdynaco; 4/24/14 at 03:17 PM.
4/24/14, 03:20 PM
#45
Legacy TMS Member
To me it just seems that removing the squirters was such an about face to how they touted them initially when rolling out the 5.0. All the mag rags had write ups about it. It was pretty innovative for a street car. Ford has always been good at getting power out of smaller displacement engines and this seemed a sound method for allowing higher compression in the 5.0, adding to higher HP. The removal for 13 forward was much too coincidental with the #8 failures the 11/12's had, to be just an improvement vs solving a very real failure rate. The combination of squirter deletion, revised oil rings, piston coatings, hood vents - all at the same time - points to a (heat related/upper cylinder oiling) engineering change to resolve the piston failures that were triggered by unsafe tune parameters. Also, if the failure was only related to the tune allowing knock/detonation to stress pistons beyond their capability, why only #8 failures? (I think I only read of one #4). Why weren't other pistons failing? Detonation does not happen just in one cylinder and not others. But I am just observing with some old school common sense and reasonable mechanical aptitude point of view. I don't have the technical/engineering expertise some of you have. So I am hoping for something concrete to resolve my restless mind. Granted Ford has been very tight lipped for obvious reasons, and what info we have collected has only come by tidbits here and there by some that either work at Ford or have technical involvement with Ford products.
4/24/14, 04:16 PM
#46
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Inside, the new engine uses piston-cooling oil jets mounted in the die-cast
aluminum block that allows a higher compression ratio and a greater amount of spark advance for power production. With check valves in place, the cooling jets work only when the engine is hot and highly stressed.
http://v6mustangperformance.com/news...ine-explained/
aluminum block that allows a higher compression ratio and a greater amount of spark advance for power production. With check valves in place, the cooling jets work only when the engine is hot and highly stressed.
http://v6mustangperformance.com/news...ine-explained/
I wonder if the 2012-14 V6s have them too...
4/24/14, 04:55 PM
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lol - that's what I wondered too... but everything I searched about the deletion takes me to a 5.0 discussion or article.
I also think its odd that some say the increase from 412 to 420HP was due to deletion of the squirters since they added to 'windage'. Huh?
The squirters were mounted to the block.
http://www.mustangandfords.com/parts...to-gallery/#19
You may also think "weak" when viewing the Coyote's racy-looking but hypereutectic pistons. But there's a twist: oil-cooling jets. A fine mist of oil is squirted continuously from jets in the block's main webs. This oil sprays directly on the underside of the piston, at the vulnerable piston boss and bottom of the crown. The engineers sold the expense of oil jets to management by
telling them it speeds engine warm-up (which is true), but the real reason was for piston cooling, hence longevity. This means the lighter, quieter, tighter-fitting, less-expensive hypereutectic piston can be run in this demanding high-rpm, high-load application.
Benefits of the squirters are extensive. Testing shows the crankshaft runs 25 degrees cooler with them, and they help with octane sensitivity. Combined with the heads superior water-jacketing they are one reason the high-compression Coyote can feed on 87-octane gasoline.
http://www.mustangandfords.com/parts...e/viewall.html
telling them it speeds engine warm-up (which is true), but the real reason was for piston cooling, hence longevity. This means the lighter, quieter, tighter-fitting, less-expensive hypereutectic piston can be run in this demanding high-rpm, high-load application.
Benefits of the squirters are extensive. Testing shows the crankshaft runs 25 degrees cooler with them, and they help with octane sensitivity. Combined with the heads superior water-jacketing they are one reason the high-compression Coyote can feed on 87-octane gasoline.
http://www.mustangandfords.com/parts...e/viewall.html
Last edited by cdynaco; 4/24/14 at 05:16 PM.
4/24/14, 05:15 PM
#49
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Hmmm... maybe another clue...
The thought just hit me that since the squirters are mounted to the block, did this mean oil only hit the underside of the piston on the downstroke and not at TDC?
That could mean there's a very strong probability that this DID contribute to an upper cylinder lubrication issue, adding to the factors leading to #8 piston failure.
Since the oil rings/drain holes had to be adjusted to avoid too much oil consumption with the squirters (as has been suggested in other threads), that could have led to not enough upper cylinder oil. Squirting the pistons at BDC is not as important as upper cylinder lubrication IMO.
Deleting the squirters and going back to 'old fashioned' oil control rings/drain holes allowed proven lubrication of the cylinder wall throughout the piston stroke.
The thought just hit me that since the squirters are mounted to the block, did this mean oil only hit the underside of the piston on the downstroke and not at TDC?
That could mean there's a very strong probability that this DID contribute to an upper cylinder lubrication issue, adding to the factors leading to #8 piston failure.
Since the oil rings/drain holes had to be adjusted to avoid too much oil consumption with the squirters (as has been suggested in other threads), that could have led to not enough upper cylinder oil. Squirting the pistons at BDC is not as important as upper cylinder lubrication IMO.
Deleting the squirters and going back to 'old fashioned' oil control rings/drain holes allowed proven lubrication of the cylinder wall throughout the piston stroke.
Last edited by cdynaco; 4/24/14 at 05:18 PM.
4/25/14, 12:12 PM
#50
Mach 1 Member
All engines have some type of oil squirter. Engines of old would squirt oil up and out of the connecting rod. Of course these were not designed to cool the piston but to merely lubricate the cylinder.
4/25/14, 12:42 PM
#51
Mach 1 Member
Perhaps some of you are overthinking this. It's similar to the corvette forums about the z06 heads/valve train issues,...threads full of people over analyzing and repeating each other's perspectives. I say the #8 failures are obamas fault,...the end.
Last edited by Thamac15; 4/25/14 at 12:43 PM.
4/25/14, 12:45 PM
#52
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I agree everyone is probably over thinking ... Ford reduced complexity of the engine. Less parts that can go wrong. Less parts on the assembly line and less parts to purchase. I bet Ford saved a few dollars per engine total buy not using them.
Does anyone know if the F150 also used OIL SQUIRTERS and now no longer does?
Does anyone know if the F150 also used OIL SQUIRTERS and now no longer does?
4/25/14, 05:40 PM
#54
Legacy TMS Member
Charlie I think you're not far from reality with your train of thought. Especially being as there have been 8 failures on stock (untuned) cars. Sure not as many as tuned cars but still there was an underlying problem and some if the early tuners only exploited the problem and subsequently took the majority of the blame.
4/26/14, 05:53 AM
#58
Mach 1 Member
Thread Starter
Funny thing is... You actually may be right.
You should share!
Same here.. Computer Engineer.... KU!
Same here.. Computer Engineer.... KU!
4/26/14, 09:00 AM
#59
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I dunno about sharing. I'm certainly no great writer...as I learned when my girlfriend (English teacher) ripped my paper apart when I asked her to proof read it. Lol.
4/26/14, 04:36 PM
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The reason for the #8 failure on stock cars was due to a weird problem in the stock tune. In certain cases, the tune will command an afr of 13.5-14.7 during WOT. Sean from AED has documented the issue and has seem it numerous time on cars running the stock tune. The problem only occurs on MT cars. For whatever reason, the failures don't seem to be as frequent with the newer cars.