I'm stumped on mechanical LNF issue. Suggestions before teardown.

[codename Bil Doe]

Here's the scenario - Have the racecar out at Buttonwillow, putting around 6/10th's because of brake and camber issues, get T-boned by car in another class when he lost control. Dent to driver door, but no major issues. Here's where the problem comes in.

Two laps later, I think I heard a loud whistling (had earplugs in this race), car drops to 3500rpm and holds. Coasts to a stop and shuts off. No pop, no bang, no blown motor parts, ZERO OIL BURN OUT EXHAUST. It was the smoothest "failure" I've ever felt in an engine. Just felt like I ran out of gas (no, it's not out of gas). Won't start, when it does it runs like it has zero compression and there's a giant hole in the block. Get it home, not sure if the tensioner failed, but intake and exhaust cams are off 3 teeth.

Known facts:

-Engine, if I get it to start, won't idle, spins up like it has zero compression
-Intake & exhaust cams were both off 3 teeth
-Full timing set ordered and done: new crank gear, int & exh timing gears, chain, bolts, tensioners, etc.
-Also did balance shaft/water pump chain and tensioner
-Crankcase is getting pressurized, blowing oil out pcv
-OIL LEVEL FULL
-WATER LEVEL FULL
-Engine only burns oil from pcv
-Turbo spins freely
-Plugs show no oil
-No broken valve springs
-No broken rockers

Rings? Sure, even though it burns zero oil. Bent valves? Understandable. Compression check done 3 times. Last compression check was today at lunch. 190psi all 4 cylinders.

So, what causes the engine to run like it has zero compression, not even want to idle before shutting off, not throw any codes, only burn oil through pcv and crankcase being pressurized (vapors out oil cap).

Last check will be high pump fuel pressure (tank pressure 60psi) before I guess pull the head. I don't like doing that without any indication of what's going on. Leakdown showed no issues. Friend's dad came over today (Ford mechanic for 20yr) and was stumped. I was hoping he would say "It's right here, stupid. You have a broken booziewhatsit." Could it be something as simple as blown valve stem seals? Visual inspection showed nothing obvious.

edit: I have looked up several videos of cam and crank sensor failures. The engines still idle normally. They throw codes and rev up all funky, so that has been ruled out. The engine will rev up 'normally' (real quiet like it's zero compression) when you get it above idle.

More info - the engine is of unknown origin. I have no idea what was done to it or how it was driven. Went through 99% of the racecar, but that obviously isn't 100%. The engine has never felt as powerful as my other. So, this issue may have been around since I got it.

Coolant temp was 212° when the incident occurred. Runs like I left the spark plugs out. Real quiet and more like a giant air line than compression occuring.

[T-Man]

Best of luck CNB! Let us know how it turns out.

Edit - I wonder if you might have cracked your intercooler?

[codename Bil Doe]

Aftermarket intercooler and radiator. Wouldn't be an issue at idle. Searched for over a week and a half online, checked everything I could on the top end. The ONLY suggestion I found anywhere near what I experienced (actually pretty close) was right here:

http://www.hptuners.com/forum/showth...LNF-wont-start

Verified last night that the exhaust reluctor wheel did not spin and lines up properly with the deck when #4 valves are fully opened. Viewed from front of block. Note how the reluctor is parallel with the cam cover gasket surface and the little tab is sticking up matching the pic below.

IMAG2344.jpg

edit: here's example of how the exhaust cam should be positioned with the #4 valves wide open. Viewed from BACK of the block. Note little tab on reluctor wheel is pointed up while the edge of the big tab is parallel to the cam cover gasket surface.

techlink exhaust reluctor example.jpg

So, it's down to checking the intake reluctor with #1 valves open before pulling the head. Very weird because it affected power on all four cylinders.

[codename Bil Doe]

I MIGHT have found the problem. First, the TSB I found on the cam reluctor position problems.


#PIP4548C: Repeat DTC P0016 And P0017 - keywords cam camshaft correlation crankshaft CKP CMP code exhaust intake L61 LAP LAT LE5 LE8 MIL position SES solenoid timing unwanted - (June 3, 2009)


Subject: Repeat DTC P0016 and P0017


Models: 2008-2009 Chevrolet Cobalt SS

2006-2009 Chevrolet Cobalt

2006-2009 Chevrolet HHR

2008-2009 Chevrolet HHR SS

2008-2009 Chevrolet Malibu

2007-2009 Pontiac G5

2008-2009 Pontiac G6

2006-2009 Pontiac Pursuit (Canada Only)

2007-2009 Saturn Aura

2006-2007 Saturn Ion

2006-2009 Saturn Vue

OR

Equipped with the following engines

2007-2010 2.0L (RPO LNF)

2007-2011 2.2L (RPO L61/LAP/LE8)

2006-2011 2.4L (RPO LE5/LE9/LAT/LAF)
--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
These DTCs may be caused by a camshaft reluctor that has moved on the cam.

Recommendation/Instructions:
This condition is more prevalent if the engine has been overheated. The camshaft reluctor may have moved on the cam causing this DTC. The CMP phaser and or the actuator solenoid may have been replaced with no change after following SI diagnostic for this code. Additionally the tech may state that the engine is timed correctly and all timing indicators line up correctly.

Note: Each of the procedures below may not detect a small movement in the reluctor, it may be necessary to compare to another like vehicle. Also note that the rocker cover gasket surface does not line up with the same face or slot on the intake and exhaust reluctor.

To check the Exhaust Cam reluctor position:
With the exhaust camshaft positioned so that the valves for #4 cylinder are at maximum lift (fully opened valves), the reluctor should be flush/parallel to the rocker cover gasket surface as shown in the attached pictures. After comparing the camshaft reluctor position to the illustration and the reluctor does not line up correctly the camshaft must be replaced. The reluctor is press fit and is not indexed/keyed to the camshaft, it is an interference type fit. An overheat condition may contribute to the concern, causing the reluctor to spin on the camshaft when hot.

techlink exhaust reluctor example.jpg

To check the Intake Cam reluctor position:
With the Intake camshaft positioned so that the valves for #1 cylinder are at maximum lift (fully opened valves), the reluctor should be flush/parallel to the rocker cover gasket surface as shown in the attached pictures. After comparing the camshaft reluctor position to the illustration and the reluctor does not line up correctly the camshaft must be replaced. The reluctor is press fit and is not indexed/keyed to the camshaft, it is an interference type fit. An overheat condition may contribute to the concern, causing the reluctor to spin on the camshaft when hot.

techlink intake reluctor example.jpg

[codename Bil Doe]

First, set intake cam valves to max lift on cylinder #1:

intake max lift cyl 1.jpg

Check position of the intake reluctor wheel relative to the cam cover gasket surface. Viewed from the front of the block:

intake reluctor misaligned.jpg

From the TSB, here is the example of the intake reluctor position aligning with the cam cover gasket surface when viewed from the back:

techlink intake reluctor example.jpg

Seems clear that even rocking the cam some that it's nowhere near aligned.

[extremevx]

Yes...sounds like a reluctor wheel on a cam. I had this problem. I re clocked the reluctor wheel on my intake cam using green loctite. All was good after that..look at my previous posts with pics.

[cobaltssoverbooster]

I check the metal types then tig weld them into place. The ones that don't match get replaced with a similar replacement cut on the lathe and mill.

I have a factory set of cams with aftermarket reluctor tig welded and a set of billet cams with a billet reluctor tig welded as well.

[codename Bil Doe]

extremevx - after weeks of searching for ANY engine with this problem, I finally found your thread and linked to it above. Being a TSB, I'm surprised there aren't any other threads on it anywhere.

[cobaltssoverbooster]

most of the reluctor issues are from long auto x tracks and circuit racing...check those forums for the reluctor issues bill

[codename Bil Doe]

Interesting. Even searching a bunch of different terms for a week nothing came up. If it wasn't for extremevx's thread I would have been pulling the head.

Now I know, too. And, knowing is half the battle. GI Joe! Anybody else with this issue can know, too. That's worth at least 4/5ths of the battle.

[gone_in_10_sec]

it maybe a silly question = did you check your cam sensor? I had a very similar issue with a customers Cobalt.. "checked everything", even swapped out both cams, still the same problem - until I swapped in a new cam sensor.. worth a shot.

[codename Bil Doe]

IF the problem still existed I would check sensors. No codes were ever thrown, though. If you check post #5 I think I found the issue with the intake reluctor.

[extremevx]

My car was off so bad it wouldnt even start. Mine would throw CEL P0336. I replaced CKP sensor and even made a tool to measure the airgap between the sensor and the crankshaft reluctor wheel. I even checked to make sure the crankshaft reluctor wasnt bent. All good..It should have threw the CEL P0345 code for CKP/CMP corellation . But it never did. I wasnt until I came upon a GM Service Letter that talked about the possibility if the camshaft reluctor spinning on the cam if the engine got too hot..But my problem started after startup in the morning and pulling out of the driveway...My cam was a ZZP stage one cam with lobe. Of course these blanks come from GM before Comp cams grinds them. Luckily mine had witness marks on the reluctor and cam from when GM pressed it on..I removed it and reclocked mine using high strenght retaining compound and I havnt had any problems since. If I am not mistaken, I believe you have to crank the engine long enough for the ECM to try and synch the correlation..After it trys some 200 times to synch up is when I believe it throws a code...But if your is atleast running, then I dont know what it will show. In mine I was able to rule out cam pos. sensors early because my father has a 2.4 in his solstice. Same cam sensors in his and it ran fine. I swapped his for mine and his car ran fine. Of course if you read my thread, link in post #5, you will see the headache I had and all the money I spent trying to find this problem...Hopefully now, no one will have to spend the money like I did. This info is here.

[codename Bil Doe]

I read your thread in its entirety twice. That's how I found mine just before I pulled the head. Hadn't found it mentioned or discussed anywhere else. Only the tsb on an HHR SS forum.

Tough to say on mine because of the combination of the intake reluctor shifting AND someone who previously clocked the intake and exhaust cams 3 teeth advanced. PO prob had some old school engine guy or backyard mechanic who thought he knew a secret to making more power outside the rules. Gotta love surprises from PO's. smh

[cobaltssoverbooster]

last time i saw an lnf 3 teeth off it was getting bent valves removed lol

[extremevx]

I agree, if you have stock pistons and especially the stock valves. I would say they are bent. But how do you know you were three teeth off? Your colored links wont be lined up on your cams even if you have the one on the crank lined up. As soon as you take out your tensioner, they are gonna jump because of valve spring pressure. If Im not mistaken, just one tooth off and stock valves can be bent.

[codename Bil Doe]

The cams have been raced this way before I ever received it and several events by me. Cams were positioned 3 teeth advanced. The chain did not jump. The timing teeth were checked before removing the tensioner as were compression and leakdown tests. Pretty simple to test everything with the cam cover off before pulling or removing anything. Luck running it this way is an understatement.

[codename Bil Doe]

Thought I'd throw up an update. Everything checked out great with no results still. So, I'm in the process of pulling the head. First thing I checked on the car was the intake impeller. It spun freely with zero slop. Well...

I just got the turbo off this morning so I could pull the head later today. As I pulled it, my finger hit the exhaust impeller:

IMAG2506.jpg

Houston, we finally have a problem. The exhaust impeller is completely broken off of the shaft and just sitting inside the housing. I guess because of the bearing construction and how it broke off the shaft this did not affect the intake impeller side. This is also why it didn't throw any codes and died so gracefully without a sound.

Fortunately, this failure forced me to start tearing the motor apart, and I found the spun reluctor wheel and timing chain issue by coincidence. The reluctor wheel being off 10-15° was not enough to throw a code, just affect my cam timing. Because of my cam tables being so modified, I got lucky that I didn't bash a valve. I think it would have been really bad if I ever ran the stock cam tables.

Now to find a turbo. Anyone have a ko4 from a GXP lying around?

[cobaltssoverbooster]

that sucks man...just sold my last factory turbo last month. since you auto x the best turbo for that is a gt28 size if you wish to upgrade. beastly flat trq curves from that turbocharger.

[codename Bil Doe]

Thanks, but I road race. The class I'm in requires showroom stock condition unless specifically allowed in the rulebook. Has to be exactly how it drove off the dealer lot.

MikeM may be able to help me out, tho.