View Full Version : Blown Motor - Split Piston Pictures Added
ProjectCougar
03-10-2003, 09:00 PM
Well I had to make a new one since my other one got hijacked....Typical eh?
Well I should have Photos of the motor internals later today. Talked to my new engine builder and he said Cylinder 2 Piston was "Split" Definite Detonation Issue wouldn't you think?
Thanks
naynay
03-10-2003, 11:06 PM
Same topic as the other one....or am i missing something!:confused:
What kind of chip and or ignition do you have??
ProjectCougar
03-11-2003, 09:27 AM
Well here are the Photos... Under EngineBlock01... Can you tell which cylinder had detonation? hehehe
Those pistons do not look blued/overheated to me, though I'm not there looking at them. They look oil fouled, and since oil burns hotter than gas, it may have caused a temperature-related failure of the crown. That white spot between the cracks in the piston shows a hotspot, but caused by what I'm not sure.
Normally when I've seen failed engines like this there's a blue tint to either the piston top (but otherwise clean) or a blueing of the cylinder walls.
Looks like there were several things going into this cylinder that weren't supposed to be there, either way. Did you not say something about puddled oil in the turbo housing?
Also- In the #1 pic, there's a gouge in the piston top- Looks like the pieces were flying around in there pretty good- I'd figure the head looks about the same as my 3L head did...
Anyone else with possible causes?
FastCougar
03-11-2003, 11:44 AM
If the piston where blue, you would have to scrape away all the oil fouling to see it ;)
Not knowing the specifics of the incident or seeing pictures of the turbo's puddling/draining of oil, I will take a stab in the dark here. Detonation induced by whatever <insert cause here> damaged both the piston and rings. This damage was sever enough to produce fragments large enough to damage the turbo's turbine. This would cause an unbalanced shaft and the turbo's internals would then "wobble", thus causing bearings to fail inside the turbo. That could account for the turbo leaking oil.
The pictures do not however lead to any conclusions as to the cause of the detonation. I will file this in the NECO files until Fox and Scully get a change to look into it. Some field investigation by my two best officers is in order :biggrin:
PuckPuck
03-11-2003, 01:12 PM
James how do the valves look?
bnoon
03-11-2003, 02:17 PM
Originally posted by: PuckPuck
James how do the valves look?
Minimum work on any type of failure like this would be a valve seat resurfacing and a valve lap job. Might just want to spend the extra dough and get new valves though since they could also be bent slightly.
Pistons normally don't have time to blue when detonation kills them. It's just a wham, bam, thank you maam failure. Blue-ing usually results from lack of lubrication or lack of proper cooling.
The cylinder walls have time, though- Any time the metal is discolored, it's from an extreme temperature. Plenty of which to kill the piston. The oil fouling is pretty obvious. Oh well.
PuckPuck
03-11-2003, 03:59 PM
me thinks the oil fouling came after the detonation and piston break... as soon as that piston broke, the top ring became useless and well from that point forward i'm sure a good amount of oil started to find it's way into the combustion chamber....
i would also go with trevor's theory that some piston parts went through the turbo causing the oil leak with the turbo....
and cause of detonation could either be low octane or even possibly a failed fuel pump....
http://www.fastcougar.com/forums/attachments/SplitPiston02.JPG.jpg
FastCougar
03-11-2003, 07:15 PM
After looking at the pictures for a few minutes, it all started to fall into place. Hear me out:
Piston rings "float" in grooves cut into the head of the piston, thus creating 4 strata (layers).
Strata 1: Top of the piston, inside the combustion chamber.
Strata 2: Between the first compression ring and the second.
Strata 3: Between the second compression ring and the oil control ring.
Strata 4: bottom of the piston, everything below the oil control ring.
Notice how in my first marked up image the breaks occur on the apex of the leading edge of the valve reliefs? This is the thinnest part of the piston because the relief shortens the distance between the strata. Also, notice the discoloration. I am not sure if this is a visual effect from the oiling or of the JPEG image process or from detonation. Best way to find out is to remove as much of the oil varnish and see. Also notice that the piston is completely undamaged except for the strata breaks ... definite signs of detonation OR valve floating! Think about it, a valve floats, or sticks open and guess where the piston will break ... right at the valve reliefs!
The second picture points out small stress cracks ... I now suspect valve interference as a possible cause, but the heads need to be analyzed to assess this. GET PICTURES OF THE HEADS! A stuck/bent valve would also explain how these chunks of piston got out of the engine without damaging the piston crown.
http://www.fastcougar.com/forums/attachments/SplitPistonDiagnosis1.jpg
http://www.fastcougar.com/forums/attachments/SplitPistonDiagnosis2.jpg
PuckPuck
03-11-2003, 07:37 PM
i broke 10 of 12 valves on my head.... the pistons at most had a small scratch on them... some of the valves were very badly bent.... unless the heads are completely destroyed (from the valves becoming implanted sideways in them) i doubt valve/piston contact was the cause....
FastCougar
03-11-2003, 07:52 PM
I was thinking that it wouldn't be enough to crack off part of the piston. My main reason towards bringing this up is the break point ... the leading edge of the valve reliefs. However, since this is the "weakest" part of the piston, it only makes sense that detonation would cause it to break there as well. If you look at my discoloration points, that to speaks of detonation. Subsequent oil fouling has obviously covered up any "blueing" marks.
Aries
03-12-2003, 02:58 AM
wow.. CSI Neco... I wish I had half the knowledge of engines that you people did.
MercMobile
03-12-2003, 09:52 AM
Originally posted by: FastCougar
Subsequent oil fouling has obviously covered up any "blueing" marks.I wouldn't say.... ANY... ;)
While most of the piston has a strong yellow tone coloring (oil, burnt or not is comprised of yellow color chart minerals).. the strongly noticeable marks on the piston have a lot of blue colors.. in fact.. the darker more noticeable portions are the ONLY ones I could find blue on the top of the piston. I figured that would be the case before I even did any color charts.. it obviously marred the piston enough in those dark areas that it showed up through the oil.
http://www.fastcougar.com/forums/attachments/piston-bluechart1.jpg
http://www.fastcougar.com/forums/attachments/piston-bluechart2.jpg
I am vindicated!
:banana:
Sorry, that's it- Nothing else to add. Good job Trevor- I like the analysis.
FastCougar
03-12-2003, 11:23 AM
Yes and No ... this could very well be a byproduct of the Camera's CCD or of the JPEG process. The real evidence is the "clear" spot between the valve reliefs ... purple and blue tones there. Much like the rainbow effect you get when you anneal metal ... evidence of "super heating". I just would have figured that fragments of that size on the piston would scare the surface more. I guess the fragments acted like ping-pong balls in the combustion chamber, bouncing off the chamber roof and piston crown. Had there been larger fragments, they very well could have "wedged" themselves between the piston crown and the cylinder roof. Had that happened, most definitely there would be scaring/holes. Needless to say, I think we can put this one to rest:
Catastrophic Detonation > Fragments exit the cylinder > Fragments enter the turbo > Turbo goes south due to damage to the turbine
James ... Have them get some pictures of the turbo's turbine ;)
MercMobile
03-12-2003, 11:33 AM
Originally posted by: FastCougar
Yes and No ... this could very well be a byproduct of the Camera's CCD or of the JPEG process.*sigh* ;)
You can also check where he lost the two chunks of his piston.. since there is less oil there, those are also primarily blue colors.. while the surrounding is all yellow/brown.
Also, in the stress cracks there is an abundance of purple/blue
While I believe trevor's explanation to be probably dead on, and while I agree the best and only way to truthly know is to remove the oil, I have to say the blue is not from the JPEG Process, but yet enough coloration on the piston to show up through certains spots..
FastCougar
03-12-2003, 11:37 AM
Originally posted by: MercMobile
Originally posted by: FastCougar
Yes and No ... this could very well be a byproduct of the Camera's CCD or of the JPEG process.*sigh* ;)
You can also check where he lost the two chunks of his piston.. since there is less oil there, those are also primarily blue colors.. while the surrounding is all yellow/brown.
Also, in the stress cracks there is an abundance of purple/blue
While I believe trevor's explanation to be probably dead on, and while I agree the best and only way to truthly know is to remove the oil, I have to say the blue is not from the JPEG Process, but yet enough coloration on the piston to show up through certains spots..I completely agree ... just trying not to base my entire diagnosis from a JPEG ... I would need to see it in person, or like I have stated, clean the piston up.
ProjectCougar
03-12-2003, 11:42 AM
Turbo is fine at this time.... we had it tested already. More testing is still going on with the motor at this time
PuckPuck
03-12-2003, 02:44 PM
Originally posted by: ProjectCougar
Turbo is fine at this time.... we had it tested already. More testing is still going on with the motor at this time
have you found the source of the oil leak in the turbo?
Furious1
03-13-2003, 05:12 AM
A few q's:
1) Dont mean to bring up an old debate from James' first thread on this, but James, that little video clip of you doing a burnout on the parking lot, did you have the Turbo then? Not sure if it was the recording, but it sure sounded like you hit the rev limiter a few times.
2) This was also brought up in the first thread. The SVT supercharged Stang. You know someone has had to at least hit the rev limiter in that thing at least once, especially after a good night out drinking. How is that car not detonating? It does have a rev limiter, no? What about the Lightnings?
3) StreetConcepts, Atomic, and anyone else charged, have you guys ever hit the rev limiter?
ProjectCougar
03-13-2003, 09:22 AM
My Burnout was in September at Nopi Nationals for a photo shoot with Opgezet Magazine
My Turbo Install was a month later right before SEMA.
So No the burnout was not with the turbo.
Originally posted by: Furious1
A few q's:
2) This was also brought up in the first thread. The SVT supercharged Stang. You know someone has had to at least hit the rev limiter in that thing at least once, especially after a good night out drinking. How is that car not detonating? It does have a rev limiter, no? What about the Lightnings?
If the SVT cobra hits the rev limiter, it stops producing boost for like 10 seconds or something... There is some valve on the back of the SC that routes the boost away from the engine... Dont know if it goes out to the atmosphere or exhaust or what... The Lightning has the same feature... Or so I've read on stangnet and svtperformance.com... They can buy kits that block the valve so itll keep making boost when they hit the limiter
bnoon
03-13-2003, 01:30 PM
Originally posted by: FastCougar
http://www.fastcougar.com/forums/attachments/SplitPistonDiagnosis1.jpg
http://www.fastcougar.com/forums/attachments/SplitPistonDiagnosis2.jpg
The problem with these images is that I see NOTHING discolored about those pistons at all. They seem to actually have very little carbon build up on them. Most Duratecs I've taken apart are dirtoer than those are, aside from the piston skirts being blackened because of the failed rings that is. Aside from the detonation damage, that piston is totally running fine fuel/oil wise and there appears to be no fouling issues what so ever from looking at the piston itself.
Furious1
03-13-2003, 06:06 PM
Originally posted by: ov3n
... They can buy kits that block the valve so itll keep making boost when they hit the limiter
But if this is what detonated James' car, wouldnt the same happen with any SVT Stang/Lightning with such a kit? And if this was the cause, could Street Flight look at such a boost release valve for the rev limiter?
Originally posted by: Furious1
Originally posted by: ov3n
... They can buy kits that block the valve so itll keep making boost when they hit the limiter
But if this is what detonated James' car, wouldnt the same happen with any SVT Stang/Lightning with such a kit? And if this was the cause, could Street Flight look at such a boost release valve for the rev limiter?
Not particularly.... the SVT Cobra and Lightning were designed to have a SC from the factory, so aside from that thing, the engines themselves were designed to run reliably with one.... the cougar was not.
DemonSVT
03-17-2003, 04:29 AM
Originally posted by: ov3n
Not particularly.... the SVT Cobra and Lightning were designed to have a SC from the factory, so aside from that thing, the engines themselves were designed to run reliably with one.... the cougar was not.
One can just bring up the argument about all the S/C Duratecs with tons of hard miles on them. Chris has close to 1000 dyno runs last time I checked plus several thousand hard miles on his setup. (those harsh dyno runs equal untold thousands of miles)
The only thing that may hold water in this argument is that the stock engine may just use much weaker pistons and it's known they use lower grade rings.
So maybe the statement applies that "a stock Duratec engine should never be forced induced but SVT engines can all they want." Back to a "blanket" statement based on conjecture.
Either way it's NOT the tuning (my original sticking point) & we really don't know nor never will what other outside/self induced factors/changes may have taken place as well.
exigent
03-17-2003, 08:16 PM
Hrm.. im not going to start another holy war but couldnt someone PLEASE put the issue to rest by telling me for certain that the tunning done to the SF car included seting the ignition rev limiter to a low enough point to stop detonation before hitting a fuel rev limiter?
As far as the Vortech cars? They all had thier eec's sent out for reprgraming.... what vortech does to them while they have them.. im not going to venture a guess but im going to say they move the fuel cut up high and leave the ignition cut low....
James.... please... Unless you are bound by SF to not discuss please just let us know whether or not somthing was done to protect against rev limter induced detonation.
Also, I still think you guys are wrong about the "weak" ford rings... rings have a HUGE effect on polution and econ... you KNOW ford doesnt skimp when it comes to that...
Dont forget guys... those pistons are a diffrent material then the pistons you may be accustomed to seeing... if im not mistaken they have high quantities of silca in them... they are also "sinter forged" like the rods arnt they? Perhaps the lack of discoloration is a symtom of this diffrent material. If detonation didnt happen then what did? The piston wouldnt do that just because of a oil problem...
Again.... I just want to know for sure that SF thought about the rev limter in all this.
:) Thanks for letting me know about the by-pass on the stock ford S/C... I was not aware of this :) Remember that the S/c's boost is in direct relation to the rpm.... a turbos boost is not. It still makes boost after the throttle closes hence the BOV. Following that... the amount of boost entering the clylinder on a rev limited combustion cycle would be even greater then that of a S/C in theory. James says he thinks its detonation... assuming that then we have to think WHY was thier detonation...
I actually would tend to agree with hangtime too.... if it wasnt the rev limiter then id say its definatly a delivery issue. I already have plans of going to a (reliable) return fuel system for my 3.0 twin turbo motor. At least that way I KNOW im getting correct fuel pressure...
Kaiser
03-17-2003, 10:33 PM
The program for James car was written by the man with no name. He is the same guy tuning Kinger's car in Michigan. He knows what he is doing. It wasn't the tuning. If anything I would say those valve marks in the pistons could indicate a shift to 2nd instead of 4th. Also look at the way the rings are positioned. That piston had a direct blow to the top so the rings probably are stuck in place. They are almost lined up. If that was the way they came out of the block then no, they don't suck they were just lined up wrong and that's why he had a blow by oil problem.