died on the dyno. your veiws please

[nando]

i got this from someone....
it sounds to me like your tuner could have advanced your timing forwards in an effort to find MBT (mean best torque). Problem is, being a high CR (even 10:1 is high CR by modern unleaded standards) your engine probably started to detonate long before MBT, resulting in extremely high peak combustion temperatures and pressures, to the point where you quite possibly now have a broken ring and/or ring-land on one or more of your pistons. He may have even thought it was safe to advance the timing because he saw the power falling, but in reality it was dropping because he was pushing your timing into dangerous territory, not because he was still well in advance of MBT. Usually if you hear full blow detonation its too late. Detonation starts long before we can actually hear it,

they are wrong. 10:1 is basically a standard these days - my M20 reached MBT with 10:1 CR on pump gas *long* before the detonation threshold.

and unless your engine is turbo, a bit of detonation isn't going to kill it that fast.

[z31maniac]

they are wrong. 10:1 is basically a standard these days - my M20 reached MBT with 10:1 CR on pump gas *long* before the detonation threshold.

and unless your engine is turbo, a bit of detonation isn't going to kill it that fast.

This.

Hell the turbo engine in my Speed 3 was 9.5:1.

[LJ851]

All of this is speculation. You need to inspect the engine damage, and if you don't know exactly what to look at or for ,find or hire someone who does. If the engine was detonating enough to cause engine failure it will leave it's mark on the head and pistons. Are you running a forged crank? A lot of diagnosis can be done with the engine still assembled. Get out to garage, man!

[Brandon12V]

Agreed, look for the basics first. specks in the oil and remove that valve cover to check the rockers. a leak down test would be a good way to narrow it from rings or a valve. where is your timing right now? specs on the short block? what cam? remove the head and inspect the valves. Still nothing? remove the oil pan and crank. check the bearings. if none of this helps, you could have torqued your crankshaft out of timing, but I highly doubt it. I've seen this happen, but I don't think i've ever heard a case on the m20 NA.

Edit: it would normally take alot of transverse load for this to happen, even on a 2.5 crankshaft.

[Kershaw]

10:1 is pretty much standard compression these days...

my rx8 is 10:1. a 2012 honda civic si is 11:1...

[329jay]

ill take it apart saturday and hopefully get some nice pics for y'all

[LJ851]

Pics of carnage?

[329jay]

i only just started taking some bits off yesterday. engine isnt even out yet. i lost interest in it.

[!kid]

You obviously haven't been around too many engines. Rod bearings fail, pistons start stroking 1 or 2 mm more than normal, piston hits head, compresses ring land, and massive blowby/leakdown occurs.

I think you may be over exaggerating just a little. If this dudes little m20 Is causing a bearing to fail at 2000+/- miles he's got other problems. And 1-2mm? That's about .080 thou. I don't think there would be much of the bearings left after,or much oil pressure left. haha and again he would need to have major issues to be eating away that much bearing in such a short time.

[Good & Tight]

Sounds like there was something wrong with the engine before tuning it. Who rebuilt the engine?

[ROLLingKING]

you got this bruh..pull that motor apart and play doctor!

bring it to life again!

[329jay]

the pics arnt great i know but look at the way the shell has been rolled thin and pushed up the sides of the rod. the piston has touched the head obviously because the bearing is so thin. i have spoke to some one about the shell and have an idea what caused it. im sure you will have an opinion on it.

[nando]

you spun a bearing, severely.

[kingston]

Holy SH*T!!

[Massimo]

That sux dude. I will be interested to know the cause of the problem.