Finally cracked a piston at 179,000 miles

**boomtime** · 05-20-2024 08:37 PM

On my 3rd Audi now, 2.0T CPMB, had apr stage 1 for about 100k miles no issues, couple years back moved up to K04+e85. Had been running strong and pulling hard until one day after a hard hillclimb the EPC light started flashing. Popped a U-Turn and got back into boost, felt strong. Was still pulling hard but now had a persistent misfire code on cylinder #1 and rough idle.
Swapped plugs and coils no joy.
Later did compression test had 30 psi cold and dry on cylinder #1. Poured some clean oil in the bore, compression jumped up to 90psi, then dropped to 60psi, then back to 30psi. Pretty sure my problem was in the shortblock now.

So last wednesday I pulled the motor out, pulled the head, which looked ok, no valve witness marks but some scuffs on #1 bore. Pulled out the pistons 2,3,4 looked ok for the miles but #1 had a crack and ring lands missing on one side above wrist pin, snapped the second compression ring and both oil rings.

Guess its finally time to install forged pistons and rods!

**m95roadster** · 05-21-2024 04:50 PM

That sucks! Good luck with the build. What K04 and tune were you running? I plan to do mine soon.

**boomtime** · 05-22-2024 05:29 AM

Originally Posted by m95roadster

That sucks! Good luck with the build. What K04 and tune were you running? I plan to do mine soon.

Its a CTS K04-64 (TR1070) with an APR K04 93/e85 tune. Its been pulling hard even with the cracked piston, given the high mileage I really cant complain, I think the stock block held up real well for almost 150,000 tuned miles. That being said I knew it was just a matter of time before she blew. Had ordered IE forged pistons and rods back during the ECS black friday sale, along with new bearings and rings, so I had that stuff on the shelf. Thats why I just moved forward and pulled the engine with the rebuild plan.
Im trying to attach pics but AZ is not letting me for some reason.

**m95roadster** · 05-22-2024 08:47 AM

I'm currently on APR stage 1 and planning to go with the CTS K04 and APR K04 tune. Just wasn't sure how that combo would work. Were you running e85? I used to run nothing but e85, but used a quart of oil every 2200 miles. So far the oil level sensor only drops one notch per 1500 miles using 91 octane.

**boomtime** · 05-22-2024 09:07 AM

Originally Posted by m95roadster

I'm currently on APR stage 1 and planning to go with the CTS K04 and APR K04 tune. Just wasn't sure how that combo would work. Were you running e85? I used to run nothing but e85, but used a quart of oil every 2200 miles. So far the oil level sensor only drops one notch per 1500 miles using 91 octane.

Yes the CTS TR1070 K04 kit worked flawlessly for me with the APR K04-64 Tuning File.
Yes i usually prefer e85 since its cheaper and pulls harder. When i had it flashed from stg1 apr to stg3 k04 apr charged me $500-600 for the software because I didnt buy their kit for $3500, the CTS kit was $1300 back then so I still felt ok with the total upgrade cost being under $2000.

**m95roadster** · 05-22-2024 09:18 AM

Originally Posted by boomtime

Yes the CTS TR1070 K04 kit worked flawlessly for me with the APR K04-64 Tuning File.
Yes i usually prefer e85 since its cheaper and pulls harder. When i had it flashed from stg1 apr to stg3 k04 apr charged me $500-600 for the software because I didnt buy their kit for $3500, the CTS kit was $1300 back then so I still felt ok with the total upgrade cost being under $2000.

Awesome, I appreciate your response!

**boomtime** · 05-29-2024 02:54 PM

Originally Posted by m95roadster

Awesome, I appreciate your response!

Good news, got everything installed and back together. Started on first try.
Decided to replace most block seals, new updated elring rear main, new oil cooler, waterpump belt, waterpipe and orings for the rear heater core hoses and head outlet elbow. Also ordered and replaced head gasket, ARP head studs, assembly lube on everything, all upper gaskets including vacuum pump and HPFP, turbo oil feed line and oil pump chain. Timing chains done 2 years ago. Oil pump looked good inside, no witness marks and no wear visible on the scrolls. Upper oil pan screen looked totally clear. Lower oil pan pickup screen had the balance of the piston chunks, ring lands and a couple piston ring shards. Tagged and bagged everything, really helped me get it back together quickly. Just finished breakin 200 miles with Supertech 10w40, magnet looked clear, just some fine particles! Still cant upload pics from safari to audizine.

**audrobotic** · 05-31-2024 01:51 PM

Originally Posted by boomtime

Good news, got everything installed and back together. Started on first try.
Decided to replace most block seals, new updated elring rear main, new oil cooler, waterpump belt, waterpipe and orings for the rear heater core hoses and head outlet elbow. Also ordered and replaced head gasket, ARP head studs, assembly lube on everything, all upper gaskets including vacuum pump and HPFP, turbo oil feed line and oil pump chain. Timing chains done 2 years ago. Oil pump looked good inside, no witness marks and no wear visible on the scrolls. Upper oil pan screen looked totally clear. Lower oil pan pickup screen had the balance of the piston chunks, ring lands and a couple piston ring shards. Tagged and bagged everything, really helped me get it back together quickly. Just finished breakin 200 miles with Supertech 10w40, magnet looked clear, just some fine particles! Still cant upload pics from safari to audizine.

Nice! You found the failure limit of the pistons. I haven't had issues with uploading photos from Safari on a Mac, but it is very unintuitive.

**boomtime** · 06-01-2024 01:23 PM

Figured out to use Tapatalk to upload.
Heres the pictures! Pulled the engine May 15th, started her up on May 25th.

So far so good, boosting strong, no leaks, no smoke, no smell, oil level holding at full. Already put 1200 miles on it now, took my kid on a roadtrip to visit Grandma.

.