took motor apart...look what i found..pics

[Craving4Boost]

remember i pulled my motor after messing something up. I wanted to find out really badly what happened. I thought it was ring lands but it ended up being the rods because the ringlands were fine.



guess which one is bad...il give u a hint...my compression test was 150 150 100 130



if you guys see on the 3rd piston...theres scratch marks on it...i had ticking sounds a lot when the motor was still in and i think with the bent rod it kept hitting the cyl. walls...is this possible?? sometimes it would not revv at all also..

[Craving4Boost]

[Craving4Boost]

this was with 20psi...(boost spike)

[sunnys14]

wow... stock rods are powerful!

[Craving4Boost]

lol...apprently not for 20psi (right fiznat? haha jk)

im suprised my ringlands are fine though

[sunnys14]

o well, lets drop the new motor in!

[frsh13]

dam***** that rod is bent

[eddiec]

makes a nice paperweight.

or maybe some ricer would give you some cash and turn it into a rear view mirror ornament.

[duncan351]

What RPMs did you rev at? Did you over rev any?

[driftin2trance]

makes a nice paperweight.

or maybe some ricer would give you some cash and turn it into a rear view mirror ornament.

i made a dog out of my buddies rods and crankshaft. its pretty sweet.

[4felix20]

DAM! that #3 cylinder sure is a ***** to everybody...

[virus77]

welcome to the club buddy

[fiznat]

lol...apprently not for 20psi (right fiznat? haha jk)

LOL yup! Damn, its a good thing you took those out when you did. I'm sure it only would have taken a few more runs of boosting before that rod let go and wrecked your entire motor. ...And yet the ringlands are perfectly fine! Odd huh, It was always the assumption that the ringlands would go, then the rods-- but here we are again with the rods proving to be the weaker part. Interesting. I wonder if down the road we're going to start seeing pauter rods/stock piston combos haha

[nismofly]

thats a lot worse than Ivan's

like everyone said, youre very lucky to still have an engine

[1WheelWonder]

Damn, that sucks.

[Florida240sx]

Turn it into your your gear shifter

[nissanfanatic]

I think it was a lubrication problem and/or excessive clearances that lead to the piston wedging inside the bore and bending the rod. Cylinder pressures alone could NOT have done that...

Just look at the direction by which it bent. That is mechanically wrong for the rod to fail in that manner. It had no other choice. Cylinder pressures would have made it bend in a perpendicular manner, AKA it would have bent the way it looks easiest to bend.

[pancho y onions]

HOLY CRAP that looks like a rubber pencil

[Craving4Boost]

I think it was a lubrication problem and/or excessive clearances that lead to the piston wedging inside the bore and bending the rod. Cylinder pressures alone could NOT have done that...

Just look at the direction by which it bent. That is mechanically wrong for the rod to fail in that manner. It had no other choice. Cylinder pressures would have made it bend in a perpendicular manner, AKA it would have bent the way it looks easiest to bend.

so you think i didnt have enough oil or something? what do you mean by excessive clearences? trying to make sure i dont make the same mistake..

btw...it was a lot of fun taking that motor apart...i wish one day maybe in the long road i can rebuild myself

[sunnys14]

i dont get how your compression was 150 across except for #3. maybe your rings WERE going out.

[naed240sx]

Lol maybe everybody should just buy one rod, and use it for #3.

[nismofly]

are those lined up in order? if so is it just me or does your #4 have a very slight bend to it as well?

[Craving4Boost]

are those lined up in order? if so is it just me or does your #4 have a very slight bend to it as well?

yes they are in order...and yes #4 is slightly bent

compression test - 150 150 100 130

you can see why the compression is the way it is

[WDRacing]

Somthing doesn't jive with the Number 3..measure the bore for us. It has got to be somthing no one is seeing. I aint buying fatigue as a reason...why always number three??

[hek1620]

i read somewhere that the reason everyone blows #3 is because of a design f up. some how at high revs sufficient oil pressure doesn't get to #3's bearing that joins the rod to the crank. sorry i forget names. so when this one kinda dryes out(at high revs) it causes the rod to take all the force. again i only read this, i don't know if it's true. but i'm going ahead and putting in an L28 oil pump before i go turbo just in case. its only 75 bux. just my $0.02.

[nissanfanatic]

Excessive clearances from piston to wall. It woudl give the piston enough room to "Clock" itself in a manner that wouldn't allow it to travel up the bore. Hence, it woudl lodge itself in there and I doubt the entire rotating assembly is going to stop on a dime at WOT or even under very light load. The law of inertia says no no...

[UK-SRi]

Or the head could have lifted, then before it closed some water gets in and you hydrolock, that bends rods.

Once bent it will have excessive volume at TDC so the compression will be low.

Mike

[WDRacing]

Not enough boost to lift the head...well I seriously doubt it anyway. Unless you have bolt failure.

[UK-SRi]

If its a boost spike how certain are nay of us of the peak pressure??

Mike

[180sx]

20 psi on what turbo size? and is it e or de

HMM WELL KA FIRES 1342 so looks like it was boost spike/detonation related 1 was on exhaust stroke , 3 was on compression stroke ...was.... and 4 was on intake...explains why # 3 rod looks like that ... what u controll timing with? it was quiet aggresive at the time of the spike ....

i think if it was over rev piston would be hanging on the side of the block

craving 4 boost how do bearing look like ?

ka rods are long and skinny so they don't like detonation much nor do factory pistons with those skiny ringlands.

stock de can handle up to 400whp if fine tuned properly and about 200 whp without tuning or with ur crappy safc etc