so, i broke in the motor and it was running great then took it to get dyno tuned on last friday, it was running good till this saterday and then it blew up on the freeway took it home to find thishttp://s529.photobucket.com/al...ston/ piston melted and the two middle spark plugs are fried. the machine shop said the tuner either made it too lean or too much spark. The tuner says that the af was 13:1 and the spark was not that agressive and that i probably had a bad injector. what do you guys think i havent heard of many people melting a piston with simalar set ups.

97 civic coupe
b20 block and b16 head
84mm itr pistons
arp rod bolts and head studs
itr valve springs and ctr cams
skunk 2 pro manifold
4-1 header w/2.5" collector
endyn breather system
chipped p28 tuned on chrome pro

 

ouch!

has to be an afr issue.

send the injectors off and have them tested.
was the tuner a good one?
i cant see anything mechanical causing that sort of damage, what brand are the pistons by the way?

i have seen nippons do that on a built b16 over here, piston just melted and ruined the block, then again it was a bad choice of piston seeming as the guy was running it up into 9500rpm territory!

 

That screams bad injector to me >.< even if you were running a little lean It shouldn't have done that at that low a compression

 

I find it interesting that you didint notice the engine running strange and try to find the reason why, vs continuing to drive it till it broke. Must have sounded like a Suraru. what injectors are you running?

 

Sorry for your loss.

If fuel injector you have atleast 2 bad ones or the wiring is bad. Pretty improbable but still possible.

Take some close up macro shots of the plugs... if it's the tune we should possibly see some evidence of lean/knock on #1 and #4.

 

He was running obd2 prelude 290cc injectors.

 

there was nothing noticable until it blew it ran smooth until it detonated. i got the injectors from a 98 prelude with 60k miles the spark plugs 1 and 4 looked pretty normal and 2 and 3 were both pretty melted