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Lets figure out what happened to my motor
Hey ladies, hope everyone is doing well. So yesterday I was doing an HPDE and NCCAR. My problems began on my second session. Mid way through I started blowing oil from under the hood up to the windshield. I initially thought it was the oil line but then soon realized my dip-stick was popped out. To avoid it popping out again I zip-tied it down. Ran my 3rd and 4th session with no problems. Mid way through my 5th session after going down the straight hitting approx. 125 mph I hit the brakes slow down to 50 ish mph, drop the gear to 2nd and soon as I let off the clutch there was a pop followed my smoke. When I got back on the gas there was clearly a problem. I could tell that I was down a cylinder and the car now sounds like a Subaru. I limp the car back to the paddock and pop the hood, everything looks good, no leaks. There was however blue smoke from exhaust, my VTA catch can is breathing heavily and I also noticed smoke coming from behind the timing cover whenever Id rev the motor. The motor is fully built, Supertech pistons, manley rods, cometic HG, supertech valve springs, billet oil pump, ATI damper. The motor has about 700 miles on it, most miles coming from 2 HPDE's and 3 autocrosses. I'm running a brain built ms3, flowforce injectors, mkturbo manifold/DP with a 2860 strapped to it. I was only running it at 14 ish psi and the car was dyno tuned by a very reputable tuner here in VA bch. So far I've only done a compression test. Test was done at operating temperature.
Cylinder 1 2 3 4 Initial 0 90 90 90 Peak 0 103 105 105 WET IN 0 120 100 100 WET Peak 0 145 130 120 When you crank the motor with it all together you can clearly hear the lack of compression before the motor starts. So, there's all the information I have so far any input is helpful. I am going to do a leak down test today. Later ladies. |
Lots of possibilities; possible holed piston in #1. Have you verified that the timing belt has not slipped? Normally, if you develop a head gasket leak, it will be one low cylinder, or more often a pair next to each other, but all your 2-4 look way low, which makes me wonder if timing is now off. Can you see anything looking down #1? What do plugs look like? Wet, oily, or flattened ends?
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Wait.... dipstick popped out, zip tied it down, then ran with no problems ....
As an engineer this kind of stuff just blows my mind. |
Originally Posted by tomrev
(Post 1528975)
Lots of possibilities; possible holed piston in #1. Have you verified that the timing belt has not slipped? Normally, if you develop a head gasket leak, it will be one low cylinder, or more often a pair next to each other, but all your 2-4 look way low, which makes me wonder if timing is now off. Can you see anything looking down #1? What do plugs look like? Wet, oily, or flattened ends?
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As you noted, pretty wet. Hard to do now, but the best look at them is to be at full throttle, warm engine, then clutch in, and shut off engine. If it sits at idle, even a healthy engine will often soot up the plugs, and make it hard to see anything. I know that's kind of late advice... All the #'s are way down, and #1 either has holed piston, broken ring lands, or a burnt valve, or head gasket shit out on one end. Almost always my H.G. failures come in pairs, with the thin sealing area between two cyl's being breached, but the fact that all your #'s are down seems to point to something else, especially with so fresh an engine, which is why I wondered about cam timing. Do you have the tools to do a leak down? That should show a more likely culprit.
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Your compression numbers are way low for stock head/cams. My 8 year old 8.6:1 JE piston engine has 150 dry compression across all cylinders.
Clearly #1 has damage on it, but either your compression tester is leaking somewhere or your other cylinders are going out as well. |
Originally Posted by tomrev
(Post 1528987)
As you noted, pretty wet. Hard to do now, but the best look at them is to be at full throttle, warm engine, then clutch in, and shut off engine. If it sits at idle, even a healthy engine will often soot up the plugs, and make it hard to see anything. I know that's kind of late advice... All the #'s are way down, and #1 either has holed piston, broken ring lands, or a burnt valve, or head gasket shit out on one end. Almost always my H.G. failures come in pairs, with the thin sealing area between two cyl's being breached, but the fact that all your #'s are down seems to point to something else, especially with so fresh an engine, which is why I wondered about cam timing. Do you have the tools to do a leak down? That should show a more likely culprit.
I did leak down test. I can hear air on all 4 cylinders from every where but most air is definitely coming from crankcase. |
This stinks for everyone involved.
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Time to pull the head if you can't get the bore scope to work.
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Pulled the head and it's bad.
https://cimg1.ibsrv.net/gimg/www.mia...736a5e5e4a.jpg https://cimg4.ibsrv.net/gimg/www.mia...19df36b2d2.jpg https://cimg6.ibsrv.net/gimg/www.mia...aaf0acbf5f.jpg https://cimg0.ibsrv.net/gimg/www.mia...a84f91b93d.jpg Clearly there was detonation on #1. AFRS were always good, never heard pinging. I'm wondering if an injector died. Now for the million dollar question. Replace the 1 piston and all 4 piston rings, replace all 4 pistons and rings, or full bottom end rebuild? FYI, the head looks good, no damage on any of the valves. |
No damage? Where did that piece go? It had to of went through the exhaust valve if it wasn't sitting in the cylinder. Then through your turbo. I guess it could have turned to dust.
Who did your engine build, what were the rings gaped at? If one was bad, they all were bad. Don't do just one. The discolor of the pistons is odd to me too. No two seem to be alike with 1 being very bad. One dead injector you would have noticed, it would run like trash. |
Remove all four pistons before making any decisions.
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No evidence of pieces going through the head or turbo. I can only assume it went down. My block is trashed.
https://cimg6.ibsrv.net/gimg/www.mia...4e7724925f.jpg https://cimg8.ibsrv.net/gimg/www.mia...dd3394bdc9.jpg |
The #4 intake side shows slight detonation as well. Looks like it was either slightly lean or maybe the timing was too aggressive and cylinder temps got really high. What's your timing map look like?
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That sucks.
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^^I should hope it's E85.
How much offset is in the timing table? You're not actually idling at 23 degrees are you? Even if it's actually 10 degrees retarded from that table it's still pretty aggro for pump gas. |
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