Name That Engine Failure... Feel like I lost a child!
 

Well the most dreaded happened. Think it over boosted or afr off mid range with high boost. #6 skipping & leaking oil when running and after shut down. All head studs intact and just re-torqued to 24.3 ft/lbs. None budged.. Gonna continue checks and tests but would appreciate any and all ideas/thoughts/suggestions/wisdom!

Thank you,
Dante

Run Video Link ---> https://drive.google.com/file/d/1gLuRuw6cBoxZeVBd2TZEOArKTqhOOVm-/view?usp=sharing

#6 Plug
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Overboosted means what exactly? What boost are you running? Looks like that plug is running extremely lean. Video appears to show you have melted a head or cylinder top region where the mating surface is. Likely ring lands on that piston are damaged too. We've seen this many times sadly when folks turn the boost up, on pump gas , without adequate fueling mod's and ignition changes to suit, dyno testing etc, to go with the added boost on these aircooled engines.

Disconnect the coil wire and crank it and most likely you'll have very uneven cranking from a dead cylinder(no compression) . You'll need all the plugs back in. Also do a leakdown or compression check on that cylinder(and others -several may be wounded).

Sorry to share likely bad news.

Kevin
GAS Motorsport

That's what I was afraid of. Hoping for miracle its not that hurt.

Its my fault.

Been doing a bunch of different projects/things at once. Had forgotten that I adjusted boost controller map so to decrease spool up time. Didn't fully test it. Took car out to show a month after adjustment. Ran into fast company and then..... kaboom. Tell tale read 1.5 bar. Hoping it was chop throttle spike. Think it made a bunch of boost early and melted #6. Dang.... Thanks for the input.

I think you burned a hole through the cylinder, probably 1" or so down from the head surface. Piston will have melted through past the rings as well. With any luck there is no damage to crank, rods or bearings.

DSM 1.5 BAR is a whole bunch of boost and on pump gas especially. Stock or even modified CIS, still way too much.
Should you need any single stock 3.3 L pistons or cylinders, maybe a head or two , we likely have some once you get it all apart and assess the damage. Hopefully no crank damage is right...If you need one of those we also have Std std virgin 911/930 cranks on hand. DM me if desired.
Good luck.

Kevin
GAS Motorsport

Running EFI. Never was my intention to run 1.5 bar. Max target has always been 1 bar. I originally setup boost map for controller with 35 all over and 25 at limit(These numbers represent how much the wastegate is open). This yielded 1 bar max boost with great afr thru entire range. Data logged countless runs. Ran it for a few years this way with no issue. After watching this ( https://www.youtube.com/watch?v=qfvTr3TU0Hg ) I got the thought to adjust the map.

I rarely make this kind of error. Well now....guess I'm human after all. Now its time to pay the piper.

Still have the blue 930 running well so that will quench my thirst for air cooled fun!

Thanks for the part offers. After tear down I'll keep you in mined.

Good move on the EFI as even 1 BAR is pushing a well
Modified CIS system . You note boost controller , are you issuing an electronically controlled wastegate and can monitor actual valve position or are you using the common 3 port valve and wastegate control is pulse width modulated of a std external wastegate?
We’ve built many Turbo engines w EFI and I’m an authorized Mote dealer in North America.
Your system should have been set up with an over boost limit strategy to cut the engine ( fuel and or ignition but hard cut) should things get away from you. This would have saved you a bunch of dough. We only adjust those setting on the dyno where one can really watch the resulting boost level and lambdas on the laptop but I guess w these safety’s in place noted a guy could attempt to tune and set that on the road w a laptop( someone else driving).

Tec3r system. I used full table to run a mac valve. Do you know where the over boost limit strategy failsafe would be located in the tec3r software? I looked for it after all my bad luck but couldn't find. Ya wrong time to look. I got this complete engine over ten years ago from a guy that built it to run the Texas mile. Twin plug, GT35R, etc. Its pretty hot. Correction. Was pretty hot.... He gave up on it. Didn't want to deal with the tec3r so went LS swap.

GPO Table running mac valve
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Crossing fingers for a good outcome as you trouble shoot.

Looking forward to updates.

Hoping for minimal damage. Will be looking inside cylinder with borescope before tear down. Thanks for the input.

Ya me too. So depressed. Turn up the volume on video link. She was a runner.... ------> https://drive.google.com/file/d/1YTEx629fjkmgONxujIatQJKQW2mRAbUH/view?usp=sharing

Ya good luck I hope it's just a blown gasket or something...

DSM I haven't seen Electromotive's software in 5-7 years thankfully so cannot recall as my experiences w their systems was awful. There is a reason they are out of business in my mind.
I will send you a DM to help direct you though.
These don't run head gaskets, and even if someone did some additional strategy to say add Fire rings or something of that nature , those can still be melted under or blown out , as I've seen that too. You certainly have burned a hole through a head or cylinder and you'd be wise to inspect all the rod bearings and big end bores as those are the Achilles heals of these engines and will be pounded out w the detonation that caused the melted cylinder, head, maybe piston(or several) . Hopefully you didn't begin to spin a bearing, which is near worst case scenario.

Kevin
GAS Motorsport

I hit 2.0 bar twice when I forgot to hook up the wastegate signal and maybe only damaged the Nikasil on the cylinders.

Since rebuilt and corrected.

Didn't melt the pistons thankfully.

I was only on it for a split second to a second each time as it detonated so hard it lost power.

Were you in it for seconds?

Ya seems like lots of people do not like electromotive stuff. I didn't choose it. It came with the engine so I ran it. Got whole package dirt cheap. I do not have anything bad to say about the tec3r. It seems to work well. When I first got it running it was dynoed at Mustante. Did 430hp thru wheels @ .9 bar and ran great. As far as tuning on the road. I use the Auto VE. Turn it on after changes then run thru all gears and long pulls. The tec3r automatically adds/subtract fuel in VE table in realtime to keep AFR per desired set targets. No need for anyone else in car. All this is data logged so you can check everything after the run. Really works great but I just didn't do that after changing boost conrtoller map. Combination of doing to many other things and underestimating actual change made is my down fall I think. I added a knock sensor last year but haven't even used it yet. Hard lessons learned..

Thank you for your input.

Had to be in it at least a few seconds. Did a 2nd gear pull. Car usually beams out in front of anything just like Star Trek!

Just got a killer Borescope so should have some pics or videos to share soon.

Id say Kevin wins! Not a hole in cylinder. Even better. Massive crack.

Now to quote a part from one of my favorite movies to show how I'm feeling.

"Does anyone speak any English?" --- Hand Raised --- "SON OF BEECH SHEET"--- https://www.youtube.com/watch?v=M1UjlkQ8BN4

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Son of beech, that pretty much would not make my day. Sheet mahn, don't worry...be happy (uh-huh).
Just slap on a new cylinder and piston, call it good. I guess you'll find out soon enough if that's all the damage. Good luck and fingers crossed.

Dang that sux. Better than a head burned just slightly tho. Wow it's clean! How'd it get that clean?

Ugh. The worst feeling. Bummer - btdt. Cracked cylinder may just be best case scenario there tho - waaaay better than spun rods / mains (like mine ftmfl).

Best of luck with the fix from a fellow CT'er (I'm in Tolland)...

Couple videos for your enjoyment. Kevin right again. Didn't notice until watching videos. There are holes in both the piston and cylinder. Got awfully hot in there. My poor baby....

SON OF BEECH SHEET

View Thru Bottom Plug -----> https://drive.google.com/file/d/1mp0DlAEUaiLsD8G5zEiYZ43qzS1bmIHT/view?usp=drive_link

View Thru Top Plug -----> https://drive.google.com/file/d/1vVPy14E3Ut2zd-eScGDAc5pATROCFTV5/view?usp=drive_link

A little JB Weld and you'll be as good as new

Did you feel up a hot engine with your bare hands ?

Way to get close to your car !

Well it kind of appears you may have 98 MM 3.4 P/C combo as they may be 98s w that small dome(stock 97 mm do not have that nor a valve pocket) ? Did you get any other doc's when you bought the engine? I mention this as finding singles of those 98s , assuming only need 1 P/C pair may be harder to find...
Also, my experience w this situation is more akin to a cutting torch blowing a hole sideways through the cylinder , and it looks just like that, not a crack. Also often the ring lands of a piston or two will fall out in pieces when you pull the cylinder off....
The cylinder appeared to crack like a walnut. We lean more toward keeping the cylinders as strong as possible for a Tbo to improved power (leave 97mm, this is what we built last ) and stroke it for larger displacement 76.4 to maybe even 78.4 mm , or bore the case larger 2mm and make custom liners to 99 or 100 mm in stronger material pressed in ALum liners(on the drawing board) You can always increase the Boost 1 PSI to make up for the slightly smaller than 100 MM Bore size.

You'll have some deeper discovery to do ahead and not looking like a cutting torch hit it is good news !

Be well
Kevin
GAS Motorsport

Such a clean combustion chamber.

Yes, was sold to me as 3.4. Original owner stated slightly higher compression than stock 930 so to have a bit more more off boost.

That would be great!

Nice! Thanks

You still have work to do to find and fix the cause.

For future reference, your very first post showing the Spark plug told you you did not melt the Piston. The Spark plug looks clean.

It also is telling you your actual "in cylinder" Ignition lead.

Looks like there was some detenation on the intake side. It wasnt lean, but more than likely a little heavy on the timing at that boost setting. Detonation at high boost, will crack the cast cylinder. Not enough fuel will create heat and cause detonation, which would have torch a hole in the piston and crack or melt the cylinder too. Take the detonation and call it a win you really didnt want. Check the piston at it's ring lands for any signs of damage. I'm willing to bet there will be none. Find a replacement cylinder and put it back together. Set a overboost level and drive!

Okay have it torn down. Before removing cam gear I wanted to verify cam timing.

Set #1 TDC with Z1 located on case mark
#1 rocker is now loose and set to 0.004”
Rotate crank 1 revolution back to Z1
Dial indicator measuring 0.120” (3.048mm)
Now #4 rocker is loose and set to 0.004”
Move dial indicator to #4
Rotate crank 1 revolution to Z1 again.
Dial indicator measuring 0.119” (3.0226mm)
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Are these numbers right? Do they seem high?
Stock turbo is 0.7mm and I see people stating they set theirs with sc cams between 1.4 to 1.7?
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For reference, this is what I believe the engine build spec to be. This info was gathered from what I could actually see/verify and what was provided to me at time of purchase(Receipts/Documents provided by seller).

Case:
930/66
Cross drill @ #4 main journal, nitride and finish grind as necc.
Machine main webs: Boat Tail & increase oil passage dia. to #4.
Main Brg: Install 3mm piston squirters & shuffle pin case halves.
ARP Case studs, Nuts, & Washer Set

Crank: Factory 930 (Machined to GT-1 spec)

Cylinders: 98mm MAHLE Cylinders

Pistons: JE 98mm, 3.4L Turbo – Compression Ratio ?

Rods:
Pauter Machine
P/n: 964-230-580-1270F
Material: E4340 C’Molly Steel
Set ID#: J-1,30,32,62,85,106
Center to Center Length: 5.000
Overall weight: 596 grams

Camshaft:
Elgin 108 Lobe 296/276
Static Flow 10.8g/s @ 600KPa

Heads:
930 Twin Plug
Intake ports bored to 42mm
Port & polish intake and exhaust ports
Competition 3 angle valve job.

Valves:
Intake: ?
Exhaust: 930 105 419 50

Intake:
Factory Carrera 3.2

Intercooler:
Dp / Kremer

Engine Management:
Electromotive Tec3r (Upgraded Wintec 4)
Clewett Engineering Crank Pulley and Sensor
Clewett Engineering Scavenge Pump W/Cam Sync Sensor
Tps Sensor?
2 Bar GM Map Sensor
Bosch 2 Wire IAC
Mat Sensor?
CLT Sensor?

Injectors:
Siemens FI114961 63 lb/hr
Turn Off Time=.85ms @ 600KPa
Turn On Time=1.14ms @ 14VDc
Offset=.055ms
Gain=.110ms/mg
Impedance 12 Ohms (High)

Wideband: AEM FailSafe

Turbo Charger: Garrett GT35R, Dual Ball Bearings (Turbo Craft)

BOV: HKS Super Sequential (Part# 1421-SA001)

Fuel Pump: Bosch 044

Dyno Sheet (.9 Bar Boost)
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Crack runs entire length of cylinder right along head stud. The two pics are at slightly different angles of #6 to show entire crack.
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Great advice and that's my plan.

What are you running for a knock sensor?

Thank you!

Agreed, way better scenario than dealing with rotating assembly.

Thanks!

Re: the cam, it looks like longer duration and has a narrower lobe center, so almost 3 mm of lift at overlap is believable.

That engine deserves a set of Nickies.

sc cams 1.8mm. that's what mine are set to anyway

J&S Electronics SafeGuard Indivdual Cylinder Knock Control

Standalone knock system. These are the guys who practically invented it. Lots of variations but these guys are always there when you need them for any customer support. It is good extra insurance.

Those don't look like 98mm cylinders.. they should be full fin unless the stock ones were bored and plated.

+1
Those are standard 1978-89 97mm "bald" cylinders i.e. no fins across the tops of the cylinders.

We've seen them fail this same way, along the clearance groove for the head stud, the thinnest point of the cylinder.

If they've been bored and re-plated, that's not good. It's taking an already weak design and making it weaker.

GJF
This is my knock sensor. Where is yours located? Just curious. I’ve seen a few different setup. Installed this one because at the time engine was in car. This was the easiest to install. Again, I would use a custom table to run/tune it. Didn’t get that far but that was the plan.

Others
I know others have this setup. What are your experiences with how well it works or doesn’t.

Thanks!

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