cygnusx1 Posted April 8, 2011 Share Posted April 8, 2011 The NYZCC went out to run with the Porsche Club at Lime Rock Park today. I was pushing 18psi and running a tune that was somewhat un-tested over 6000rpms. Well, playing with the P cars, I had to reach into the 6k's a few times and eventually she popped. Flooded a cylinder or two with coolant. I got right off the track and rolled it to the paddock. Trailered it home. Time for a fixer upper. It was running so fast, handling great, all it needed was a fast driver....and a proper dyno tune. Ah well, what do you expect from a 160k+ mile junkyard motor running 18psi with a shady tune at the top. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted April 8, 2011 Share Posted April 8, 2011 Now we expect more of you than this Mr. jk. Sorry man, I have used your tunes and settings since I installed megasquirt 3-4 years ago. So this weekend comes the new headgasket right?. ) Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 8, 2011 Author Share Posted April 8, 2011 (edited) Are you running 18psi? It could have been sloshing fuel that caused a lean out, who knows. Edited April 8, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
jt1 Posted April 8, 2011 Share Posted April 8, 2011 Sorry you blew it up, Dave. Tracking a car is a boatload of fun, but it will find the weak links right quick. I hope it's an easy fix. Nice vid. LRP looks like a fun track. Lots of guardrail though! jt Quote Link to comment Share on other sites More sharing options...
EvilC Posted April 8, 2011 Share Posted April 8, 2011 JT - you are correct! I tracked Joe's (RAGS) yellow turbo car and it taught me a few things for the day. Turbo cars are much harder to drive and 30-40 min sessions expose ever weak point in a cars build. It was still a fun day and glad the group of guys really enjoyed themselves. Dave - are we talking full rebuild here? The car did look like it was running great for the day cause I couldn't find you all day! The July event will be fun! Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 8, 2011 Author Share Posted April 8, 2011 (edited) Yeah it was fun, one of the Porsche guys asked about the car because it was outrunning him on the straight. I waved most of them by because it was my first time in the solo run group and I didn't want to get in the way. I figures I could try to catch them or at least keep them in sight to learn their lines. Yeah Joe caught me with the LS1 Z, but he didn't pass me, so we could let some Porsches by. Then the motor popped and he went by me as I pulled over for pit lane. Clive, I didn't see you all day! On a 1.5 mile track we must have been equally slow! Motor is coming out and full rebuild will occur. Nothing fancy, just a clean stock rebuild, maybe a hotter turbo cam or a 280Z cam, turn the boost back to 16psi, and FINALLY get a real dyno tune. I should also say that if you are using my tune, rest assured that it has survived and evolved fairly heavy street use for about 3 years. 30 minute track sessions do not compare to street use. The engine is used in a MUCH different way. Edited April 8, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 12, 2011 Author Share Posted April 12, 2011 So I pulled off the top half of the motor today. #4 and #5 had some fire ring push out, and #4 had a shatter in the fire ring that exposed the nearby coolant passage. The head, block, and pistons look great so far. Tomorrow I'll pull out the lower end and take a closer look. I still can see crosshatch on all the cylinder walls. With a caliper I measure 3.387 +/-0.003 but I am getting a bore gauge tomorrow to check them all the way around. What I found amazing was that the exhaust side of the turbo had about 3/8" radial play in it! The turbo was spooling fine and making its setpoint of 18psi with no strange sounds. So far the turbo looks fine and I already have a rebuild kit for it on the bench. Plan: -"A" N/A E31 Cam conversion, externally oiled -Full bottom end rebuild with new OEM turbo pistons -Rebuild turbo -Dyno tune -Maybe replace the 15 year old radiator, pro actively. Quote Link to comment Share on other sites More sharing options...
cockerstar Posted April 12, 2011 Share Posted April 12, 2011 (edited) I was always under the impression that breaking stock things gave an excuse to put in some wild performance replacements No aftermarket cam? The day looks/sounds like you had a blast! Edited April 12, 2011 by cockerstar Quote Link to comment Share on other sites More sharing options...
1 tuff z Posted April 13, 2011 Share Posted April 13, 2011 i found the problem- it's the flannel shirt! Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 13, 2011 Author Share Posted April 13, 2011 My tux rental deal fell through David. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 13, 2011 Author Share Posted April 13, 2011 (edited) Ryan, I was over budget thousands of dollars ago. Edited April 13, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted April 13, 2011 Share Posted April 13, 2011 Sorry to hear about that Dave..It sure brings back memories of my brand new engine going boom due to lack of oil pan baffles. Who woulda thunk an extra 12" of rear track would allow for higher G turns?!! I hope you get it sorted. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 13, 2011 Author Share Posted April 13, 2011 Haha, yeah this makes you appreciate what those 24 hour race cars need to deal with. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 13, 2011 Author Share Posted April 13, 2011 Some photos as I work... Look at that crosshatch! Could that be original at 160k miles? The bores are not over bored at all. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted April 14, 2011 Share Posted April 14, 2011 Dave, if you haven't already thought about it, you might consider adding a knock sensor. I used the factory turbo sensor with this: KnockSense It comes with a red LED that lights when it detects knock. It also has an output for the ECU. I had initially tuned without the sensor listening for knock with my ears and taking a few more degrees out for safety. After adding the knocksense I found that there was still occasional detonation, especially in the 5k rpm range. If you use MS2/extra, there is an option to retard spark when knock is detected and then return it when it stops. I figured it was cheap insurance, as well as another cool feature The knock retard can also be seen in the MLV logs so you can see exactly at what rpm, advance, and AFR the detonation occurs. It takes some more of the guessing out of tuning. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 14, 2011 Author Share Posted April 14, 2011 I will definitely look into that. This is an opportunity to upgrade the MSII firmware as well. Thanks. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 19, 2011 Author Share Posted April 19, 2011 (edited) Little by little I make headway. I finally got the motor on a stand and pulled the oil pan to the sound of clank, clink. Yep, #4 and #5 pistons decided to cross dress, so they removed their skirts. I suppose JB Weld is not the right solution here, so I guess I'm definitely buying pistons too. Edited April 19, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
EvilC Posted April 20, 2011 Share Posted April 20, 2011 Sounds like piston upgrade time......yum fresh built l28et! Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 20, 2011 Author Share Posted April 20, 2011 (edited) ..and piston # 6,5,4 #4 fire ring...note the flame path into the cooling jacket, lower right. However...look at the bores. Edited April 20, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 21, 2011 Share Posted April 21, 2011 I've only been inside a few engines. But that doesn't look like factory honing crosshatch, does it? It looks more like someone honed a worn engine with one of those ball honers. Just wondering. I thought that detonation led to broken ring lands and that broken skirts was more a fatigue/high rpm problem. Maybe your oval bores led to the piston skirt breakage. Thanks for the pictures. Quote Link to comment Share on other sites More sharing options...
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