Metal Guru

To make matters worse, you had a chunk of ring and/or piston bouncing around the chamber and being repeatedly crushed in the quench areas.

Basal Skull

I've recently learned that cylinder 1 is prone to detonation for some reason in flat 6's.
Didn't think it would happen to a stock motor using reasonable gas. The motronic is supposed to protect the motor. So what gas and what ecu were you running?

msw

looks (to my amateur eye) almost like chunk of cylinder wall destroyed...if you're gonna do it...let's do it right i guess

always premium

stock turbo s ecu...vin verified when engine bought.

read somewhere if oil getting in (?wondering prior smoking on startup issue)...can lower octane and raise detonation chances

would be nice before i stick another $35K+ into the rebuild knowing wtf can do to prevent this from happening again...

all this is eating into my profit when i sell the car in 20 years after it's a true collectible classic

Kevin

The quick answer is.. Your fuel octane did not support the timing and boost to ensure ECU knock retard. The ECU will and can pull timing and boost. But the retard is limited to 12 degrees. On pump 91 you can be hitting 6 to 8 degrees on a stock ECU. When you introduce oil into the combustion chamber you are lowering the octane rating. The ECU will max out the timing retard limit and detonation is 100%. The engine will shutter and you should hear the noise. Pressing the throttle and powering thru this event can produce this engine failure> broken rings and ring lands. Rod bearing damage will also occur from the hammering effect.

Poor fuel quality, cheaper brands, mistaken fuel tanker fills, and oil in the intake system from a overfill or failing oil filter can produce this failure. If you seen the engine smoking prior to the fluttering CEL event, that might have been the tell tail sign of a overfill or failing oil filter or turbochargers.

Basal Skull

Did the turbo s come with a slightly more aggressive ecu? Even if it is the correct ecu that came with the car, is there the possibility that it could have been flashed? Would have thought this type of thing would be quite unusual with stock mapping ?

Kevin

This engine has gone 76K miles without issue. The broken ring land/ring is from detonation. Poor fuel octane, lack of fuel pressure, high boost pressures, failed knock sensor or oil in the intake system is the root of this failure.

msw

Thx Kevin.

So in a nutshell...what is your algorithm for going forward from here to prevent recurrence once rebuilt....ie

? Dont drive at all if smoke on start up til checked out

? Dont use same gas stations

?pray to a different god

Hope u r well...

Tia

Kevin

Mike, I am sure that you heard detonation.. I'm sure that you felt the engine shutter or stumble. What did you do when you heard it..

The only reason why you have oil on startup, the cats are burning the oil AFTER start up. You don't have a trace of smoke when the cats are hot and working.

Buy better fuel.. And when you see the flashing CEL, most likely from ignition events and hear the audible engine noise and shudder>>change your driving habit, less throttle (NO BOOST) and get the car checked out.

For those that are interested.. Mike your cats from your previous engine, were 99% plugged. I have never seen anything near that level. You have the record!

msw

Kevin. Thank you.

The car made a ?flutter noise a couple blocks from home...cel had already been on and had appt to drop to rmg. Street driving in sf... dont think it was on boost. This is after already having it into rmg a couple months earlier for the smoke on start up issue in which mothing was found/done.

Few days later is next time driving... Ironically into rmg to check out. Thats when cel flashed...lost power...did not hear any noises then but contemplated pulling over but watched temp gauge and stopped flashing after a minute or two... So kept going to drop at rmg.

So i guess it was the prior drive when heard what sounded like card against a bike spoke...but that went away and was not there when driving into rmg days later.

As for the cc record... Not sure its a record i want...:-)

Not sure can get any better gas in sf than premium 91...at least on a regular basis.

Best.

Kevin

Yes, I would re-examine the events prior to hearing the noise... 91 octane fuel is available at Costco> however, I wouldn't recommend it. Top tier service stations with high volume traffic.

Do you still have the rebuilt/spare turbochargers? You will need them on this build. The damage and metal that you seen from cyl 1 has gone thru the drivers side turbocharger..

msw

No...again ironically...sold the turbochargers to a rennlister. Was getting nervous about them just sitting there after three years that by the time i would need them...they would need to be rebuilt just from laying around.

Figure if these need rebuilding...rmg will b sending to you...👍

DM993tt

pfffft - that's nothing!!!

msw

ok dave...you win...:-)

did you mount that piston on the wall as a trophy?

PiB993

FWIW I often drive down to Woodside CA and get Sunoco 100 octane at the Kings 76 station beween 101 and 280 on Hwy 84. They are open late and have free coffee! That's the best around here I think. East bay has a high octane gas station too but I forget where.

KM

In east bay, Richardson's Automotive, a small independant gas station in downtown San Leandro. Located on Hayes St, one block south of Davis St. 100 octane at the pump.