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Knackered piston

1.4K views 24 replies 16 participants last post by  STFUN  
#1 ·
Well guys, this is the result of a mild bout of detonation, a touch of dodgy fuel and a loose crank position sensor.
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Thankfully that was the only piston damaged, and the cylinder wall has suffered an 8thou deep hole. The cylinder head has some peppering on it, but that can be easily rectified.
 
#8 ·
paulhaskew said:
hmm... makes me want to get a J&S to be uber safe... any durkatec guys running them?
I dunno if any durkatec guys are using the J&S ;)

...but I think tymeks had one for a while. IIRC he sold it after only having it a few weeks or something. :dunno:

Not to pour salt in anybody's wounds, but the J&S Safeguard may be the best $592.75 I've ever spent. :thumbup:
 
#12 ·
Well I sold if for a couple of reasons. But After HOURS of trying to get it to work and a bunch of schemetics later. Me and John decided that the new Duratecs need the bosh knock sensor set on top of the factory knock sensor and then tied in that way.

So I sold it.

Don't get me wrong, I would definitly reccomend the J&S to ANYBODY and EVERYBODY. But IMHO with the technology that I have at my disposal, with all the datalogging and the UNBELIEVABLE support from Randy and the FEW conversations I've had with Randy about it. I decided to trade it off for a Quiafe Diff. :)

Don't get me wrong all that goes out the window with a tank of bad gas. But again. I've had the J&S on my last turboed Focus ( Casper Mobile ) and I know what it's capable and not capable of doing. So again I now have a SWEET Quaife sitting in the tranny. :)

Theres a couple of other reasons but I'll keep those to myself for now. :)
 
#17 ·
what a nightmare ian :(

that looks very pricey to put right. i bet your gutted having the car off the road.
 
#19 ·
Im right there, my motor is out and Im slowly ripping it apart. Today the head and pan came off. Head first, a peek down showed no ill signs. Then the pan. I saw bits that resembled ring landings.

So, the bad gas....what brand do you think It was? I know my demise was cheapo gas. I had like .2gal int he tank and pulled into wawa to add a few gallons to get me to work, then to BP for my normal tank. Lesson learned BP/Amaco or Exxon/Mobil only for me. BP preffered....
 
#20 ·
STFUN said:
Phil, block having to be bored, over-sized pistons (85.5mm), strengthened rods, Aquamist, oil cooler, uprated oil pump, and some other new goodies whilst the engine is off. Suspension is being done whilst I'm waiting for the engine to be re-built.

See! That's the spirit.

:thumbup:
 
#21 ·
Darth Focus To be honest I have a suspicion it was some BP Ultimate (97 RON) which I used on a long journey one weekend. Combined with a loose crank position sensor and high ACT's it probably started the initial detonation which has resulted in what you see above.

The car will be mapped on 97 RON fuel when it's re-built, but run on 99 RON (Shell V-power). A bottle of octane booster will be kept in the car for emergencies too.
 
#22 ·
your car doesnt seem to have lasted long since it had the SC fitted, how many miles you done on it?

i remember fastford mag done a test of fuels with a high boost cossy on a dyno and shell optimax won, with BP ultimate being about 10bhp behind it, then tesco's and all the dross much worse.

i'd be surprised if the BP caused that?

i thought the crank sensor had been fixed, have you got any comeback against P.E. if it was them who fixed it?

sounds like its gonna be even more awesome when its done i'm just disappointed it didnt last very long. i thought my SC was broke until recently but it turns out its just (another) worn idler pulley, phew!
 
#25 ·
First thoughts of a cracked piston ring land were when the car was idling a little lumpy, though there was no indication that things had gone very bad.
The car did get a little worse, but some days it was just fine and was like a rocket. I did think that maybe the lambda sensor had failed, so I replaced that and found the crank position sensor to be loose.

The day I was actually taking it to the shop where it was going to be worked on, it died big time. Lots of blue smoke out the rear end and vibrating heavily at lowish revs. Managed to nurse it to the workshop. To be honest I think I'm lucky that the overall damage wasn't greater.

Phil: The car has done over 18000 miles supercharged. The crank position sensor was replaced by the AA, but it seems that the recovery technician hadn't tightened it down enough, and it gradually worked loose. The car was mapped for Optimax, but I had to resort to using Ultimate one day, which combined with high ambient temperatures, and high ACT's in conjunction with the above, probably had a greater detrimental effect on the already weakened piston.

One of the exhaust valves has suffered a slight bend too.

When it's re-built and being re-mapped, we're going to do it on Ultimate(97), but I'll run it on Shell V-Power(99) as well as keeping a bottle of octane booster in the car.