Damaged pistons from OE spec 1585 - detonation ?

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Piotrek125p
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Location: Lodz,Poland
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Damaged pistons from OE spec 1585 - detonation ?

Post by Piotrek125p » Sat May 20, 2017 3:27 pm

Hi GC.

Last days I stripped one of my 1585 Fiat TC engine from 131.

I bought it last year on a scrapyard so I wasn't dissapointed about his condition.

Two of four pistons from this engine were badly damaged. First of them had a broken rings, a second had a broken land between top and second ring.
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GC, could you tell me a reason why this piston could had a broken land ? I think it was detonation.

An engine was fully stock from passenger car.

Sincerely.

Piotrek.
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Guy Croft
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Re: Damaged pistons from OE spec 1585 - detonation ?

Post by Guy Croft » Sat May 20, 2017 7:45 pm

Detonation, yes.


1. Overheating intake air
2. Over-advanced ignition
3. Low octane gasoline


etc etc

fractured ring lands on cast OEM type pistons is CLASSIC DETONATION.

Detonation firing pressures can be 20 times the normal pressure which means 20 x 1200 psi those pressures will EASILY fracture rings and ring lands on OEM type pistons.

With cast pistons like this the ring lands break easily. With stronger forged pistons the pressure normally breaks through the head gasket.

From my professional perspective, detonation "per-se" is less of a problem than the fools of the world who never listen to what I say far less read all the things I have written on the subject.

GC
Guy Croft, owner

Piotrek125p
Posts: 209
Joined: Sun Dec 02, 2012 3:45 pm
Location: Lodz,Poland
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Re: Damaged pistons from OE spec 1585 - detonation ?

Post by Piotrek125p » Sat May 20, 2017 8:41 pm

Many thanks for your reply dear Guy, this is what I am looking for.

I am happy that my suggestion are simillar with your professional experience.
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