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JEDGE1.8T Feb 28, 2012 04:18 AM

Damage of time belt jump
 
long long story, but after my dad dropped a bit in my time belt cover, and unaware of this and started my engine, i jumped my time belt to the 7 oclock when should be at 12 oclock via crank shaft pulley. pulled the head off and heres the damage:

http://i42.tinypic.com/293hwew.jpg
http://i44.tinypic.com/kaobdk.jpg
middle intakes are bent and permantly open, the rest seems okay but im no mechanic.

plan to replace head with another amu head for $300 unless you have one cheaper.

pistons:
http://i40.tinypic.com/345gef5.jpg
they have an ugly ping in the center however they also looked to collided at the edge, its minor and the cylinder walls seem okay.

plan to sand the pistons and hone the walls just a tad.

does it look like i need new pistons??? any advice???

M5S5 Feb 28, 2012 08:45 AM

Might want to remove the pistons & check ring land for cracks. It looks like that outer edge took a pretty hard hit.
Once the pistons are removed , make sure the piston ring has enough clearance to move in the land freely. There is a spec for it , will look up later when i am less lazy. (hung over from trying to watch the whole race & drinking):(
Personaly i would not bother with cylinder honing. If there was no compression issues previously i would let well enough alone.

Also check the cylinder wall for any signs of scoring where the piston contact took place.

cincyTT Feb 28, 2012 10:17 AM

Plenty of people have jumped teeth or broke belts and only thing needed on the block is to sand any sharp edges from the dent on the pistons. Throw a good head on and go.

M5S5 Feb 28, 2012 10:24 AM


Originally Posted by cincyTT (Post 1368049)
Plenty of people have jumped teeth or broke belts and only thing needed on the block is to sand any sharp edges from the dent on the pistons. Throw a good head on and go.

Cincy , i agree but it does look like the outer edge of the piston took a hard hit by looking in the photo.

cincyTT Feb 28, 2012 10:31 AM

That's the relief cut in the piston.

M5S5 Feb 28, 2012 10:38 AM


Originally Posted by cincyTT (Post 1368054)
That's the relief cut in the piston.

O , Ok. It looked like a squished mark on the piston.

On that note , leave the pistons alone , just put a head on it.

JEDGE1.8T Feb 28, 2012 01:16 PM

your both right, they did collide with the edge, but only in the two inside corners where the edge shallows, the walls look fine.

should i sand the top of the piston down still or just leave it?

I want to hone it just a smudge to make the walls smoother since the block does have 106k or is this not a good idea?

guy raised his head up to 350, what an @$$

M5S5 Feb 28, 2012 01:39 PM


Originally Posted by JEDGE1.8T (Post 1368099)
your both right, they did collide with the edge, but only in the two inside corners where the edge shallows, the walls look fine.

should i sand the top of the piston down still or just leave it?

I want to hone it just a smudge to make the walls smoother since the block does have 106k or is this not a good idea?

guy raised his head up to 350, what an @$$

Please keep the sand out of your engine! Just clean with rags & gum cutter. If there is a bit of left over carbon so be it. It will not harm anything.
Use scotch pads to remove debris from deck surface unless you have a compressor & a whiz wheel.

NO Sandpaper!!!!!!!!

JEDGE1.8T Feb 28, 2012 07:34 PM

well i was planning on having a vacumn steady next to the cylinder when its at TDC while sanding them down, and im going to use a abrasive pad to, dont think sand paper would make it alot worse. i wanna make this nice in shiny so if i ever sell the car ill have a picture of the nice reconditioning.

as for my old head, i was planning on porting out the intake and making the valv openings a millimeter bigger at the machine shop at my school. get it ready for BT build so i can sell it for more or upgrade mine.

cincyTT Feb 28, 2012 08:04 PM

You don't want to sand the pistons, just smooth out and sharp edges on the marks because these will cause hot spits and can cause predetenation. Pistons don't stay pretty for long unless you use water meth injection


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