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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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Join Date: Dec 2001
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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
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Upland, CA |
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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. |
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Join Date: Oct 2002
Location: Phoenix, AZ
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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.
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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
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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. |
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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).
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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.
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Ole Skool - wouldn't have it any other way |
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Hoping for minimal damage. Will be looking inside cylinder with borescope before tear down. Thanks for the input.
Last edited by DSM; 07-01-2024 at 05:05 AM.. |
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Brando
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Ya good luck I hope it's just a blown gasket or something...
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Turbo powa! 1977 911s. it's cool |
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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
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Chain fence eating turbo
Join Date: Dec 2008
Location: Austin, TX
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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?
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Cory - turbo'd '87 C3.2 Guards/Blk, 3.4, 7.5:1 CR P & C's, 993SS cams, Borg-Warner S366 turbo @ 1.2-1.5 bar, depending on mood ![]() |
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Thank you for your input. Last edited by DSM; 07-02-2024 at 04:43 AM.. |
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Just got a killer Borescope so should have some pics or videos to share soon. |
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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 ![]() ![]() Last edited by DSM; 07-02-2024 at 06:43 AM.. |
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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.
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Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, B&B intercooler, stock 3LDZ. |
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Brando
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Dang that sux. Better than a head burned just slightly tho. Wow it's clean! How'd it get that clean?
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Turbo powa! 1977 911s. it's cool |
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Join Date: Nov 2001
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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)... |
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