jamie_v1

Hi guys i am looking for some suggestions on what would cause wrist pin clips to come out of the pistons allowing the pin to move in the piston,

The car is a evo 6 that has had the standard pistons machined to accept floating pins to allow the fitment of forged rods the affected cylinders are numbers 2 & 3

The clips have come out of the same side on both pistons

The clips were found in the sump when it was removed any comments would be very helpful

jamie_v1

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EVO8_PR

iTrader: (5)

The grooves were not machined properly

cfdfireman1

iTrader: (11)

or the clips were not installed properly.

jamie_v1

Thanks for the replies more suggestions welcome

SeanC

iTrader: (7)

Did the piston use 2 locks per side or only one? I can see you installed aftermarket rods. Many pistons use 2 spiro locks per side, but some people only install one. Big mistake! The pin will eventually push the lock out.

If not, you may want to check the end float when the wrist pin is installed. In others words, how much can the wrist pin slide back and forth in the pin bore before hitting the lock?

jamie_v1

There was only one clip installed on each side of the pin,

It has been suggested to me that ignition det has shocked the clips and pins out

Does anyone think this would be possible or has anyone heard of det causing wrist pin clips and pins to come out ?

SeanC

iTrader: (7)

No, detonation did not "shock" the clips out.

Measure the thickness of the lock (not diameter) and compare that to the width of the lock groove in the piston. If there is too much room for the lock to move back and forth with the pin, it will eventually get pushed out. The lock must be supported in the groove.

If this isn't the case, it was mostly likely installed incorrectly or didn't have enough clearance from the end of the pins. The edge of your wrist pins is straight, right? If there is a taper on the end, that will also push the lock out.

jamie_v1

Yes the wrist pins do have a straight edge they are worn away because they have been wearing on the cylinder walls

sabastian458

iTrader: (25)

Why did you stick with the stock pistons? Just curious.

I dont think you will get any other possiblities. The ones that are already listed are more than likely the reason.

jamie_v1

Its a quite popular mod that a couple of tuners do in the u.k but looking back i wish i had fitted forged pistons


Thanks for the relplies they are very helpful