Never a dull moment... (or a good, exciting one.)

Was driving at a leisurely pace yesterday to get the low-load (-14 to 0 psi range) tuned on the AEM in my car. Everything was going well and starting to smooth out nicely, and I was decelerating using the engine down a hill when suddenly there was a disgusting sound from the engine bay. The car stalled. The sound didn't last very long, so I wasn't too sure of what had happened. I attempted to start the car again, only to hear the starter grind against the flywheel. I then tried pop starting it, because maybe the starter had locked up; same sound.

Pulled the starter today... a couple of teeth on the starter are chipped, but it operates properly. No damage on the flywheel. I then rotated the crank assembly by hand with a breaker bar at the crank pulley - the crankshaft rotates, but the cams don't, and you can feel it skipping the teeth on the belt. Place your bets on what's fucked.

Obviously the cams were spinning properly before, so that has to leave out the cam caps bieng the right ones and being in proper location.

Removed lower intake plenum; intake valves aren't bent. I suppose the next step would be to remove the timing belt, place the crankshaft at TDC, and attempt to move all of the camshafts by hand. Or perhaps remove the valve covers to see if perhaps a rocker fell off and jammed one?

You can't tell if the valves are bent just by looking at the back of them... You need to do a leakdown test. Looking at the back of them will only tell you if they are REALLY bent...

Put the crank 4 teeth back from TDC to turn the cams. That puts all pistons as far from the valves as they're going to get. If you turn the cams at TDC you'll hit #1 and #4.

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Originally Posted by RealMcCoy

Put the crank 4 teeth back from TDC to turn the cams. That puts all pistons as far from the valves as they're going to get. If you turn the cams at TDC you'll hit #1 and #4.

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I don't mean to go off topic, but that's very helpful info. I was wondering where the safest place to leave the crank would be when I replaced my lifters, I ended up just leaving it at TDC and tried to be as careful as possible when I reinstalled the cams. Thanks though, I'm going to keep that in mind for next time.

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Originally Posted by JGreenwood238

I don't mean to go off topic, but that's very helpful info. I was wondering where the safest place to leave the crank would be when I replaced my lifters, I ended up just leaving it at TDC and tried to be as careful as possible when I reinstalled the cams. Thanks though, I'm going to keep that in mind for next time.

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It's just math... :D There's 24 teeth on the crank gear, so each tooth is 15 crankshaft degrees. There are two pistons at TDC every 120 degrees. If you turn the crank 60 degrees, you'll have all the pistons as far from TDC as they're going to get.

Even if they were bent, it wouldn't PREVENT the cams from turning.... that's the weird part...

But if they bent and threw rockers...

Froze water pump, or pulley. Is exactly what mine did at 50 mph. Thought I f-d all the valves, but the crank spun in the belt. Only slightly bent 2 valves, not enough to prevent a seal. Bearing from pulleys everywhere as when one froze the rest were nuked. the belt welded to the water pump, and prevented the cams from turning.

I would just proceede to check out why the belt spit... Just because the cams aren't turning doesn't mean there's anything wrong up top. If the belt has a bunch of teeth torn off around the crank gear, or if the belt tension is gone, it's not going to turn the cams...

It's extremely rare to spit a belt on one of these cars and NOT bend valves... If you did, my advice is buy a lottery ticket.

I should buy a few as I have spit two. One on a 92 auto at a stop light, and my 94. Neither did damage enough to warrant head rebuilds. Lucky, yes.

hope it's not as bad as i fear.

Belt is still properly tensioned, actually. It just doesn't take much to defeat the hydraulic tensioner when you're using a 2 foot breaker bar :-P

However, I believe I have the diagnosis....

I pulled the rear valve cover and could immediately smell burnt rubber. I noticed the rubber on the valve cover seal was charred where it goes over top of the caps near the cam gears, so I checked the camshaft caps. They were very difficult to remove, and when I did remove them, I saw this:

https://www.dropbox.com/s/q385coeprdcgps3/IMAG0050.jpg
https://www.dropbox.com/s/uteloxazbuprudy/IMAG0049.jpg
https://www.dropbox.com/s/659nmgoiurxkd7s/IMAG0051.jpg

As you can tell, the first one is clearly smashed. The second appears to have gotten hot enough to go molten - which likely caused the camshaft to weld itself to it. I noticed that the cam caps are *not* numbered right. I suppose I should have checked this prior to installing the caps instead of just trusting that the right ones were put on there. I did notice that they were marginally difficult to turn on the stand when torqued, but didn't think much of it. So, the head must come off, as I'm SURE that the journals are trashed. Just wonder how big of a pain in the ass it's gonna be to get that damn thing off with that turbo on there......

Would these heads be salvageable or are journals impossible to fix? Luckily, I have a couple more heads laying around here.

So I guess my diagnosis was actually right? Sucks man. :(

Anything aluminium "can" be fixed... As damaged as those are, the chances of it being econimically feasable are slim. I'd plan on changing the head.

Any idea what caused it yet? Did it have an oiling problem?

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Originally Posted by RealMcCoy

Anything aluminium "can" be fixed... As damaged as those are, the chances of it being econimically feasable are slim. I'd plan on changing the head.

Any idea what caused it yet? Did it have an oiling problem?

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They weren't the right bearing caps. They must have been from another head. Good thing no one bought the ones I just had for sale not to long ago.

SURPRISINGLY GOOD NEWS!!!!!

I removed the rear head today and none of the valves were bent! I SOMEHOW got lucky enough that the camshafts seized in a closed position... what the hell are the odds? The heads and camshafts are definitely toast though. I think the heads could probably be salvaged if the (misplaced) caps were put back on and the heads were line bored again, but I'm not sure whether I want to go through the hassle... Lucky for me, I have four TT heads sitting in my garage, so I'll be taking another one to the machine shop to be checked and decked tomorrow.

Seeeeee, no damage ^_^
http://dl.dropbox.com/u/16844509/IMAG0053.jpg

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Originally Posted by Memphetic

SURPRISINGLY GOOD NEWS!!!!!

I removed the rear head today and none of the valves were bent! I SOMEHOW got lucky enough that the camshafts seized in a closed position... what the hell are the odds? The heads and camshafts are definitely toast though. I think the heads could probably be salvaged if the (misplaced) caps were put back on and the heads were line bored again, but I'm not sure whether I want to go through the hassle... Lucky for me, I have four TT heads sitting in my garage, so I'll be taking another one to the machine shop to be checked and decked tomorrow.

Seeeeee, no damage ^_^
http://dl.dropbox.com/u/16844509/IMAG0053.jpg

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is that rtv?!

You are going to have to tear down, and clean the entire engine, including the turbos, to get the aluminum out of everything.

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Originally Posted by futurevr4man

is that rtv?!

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Looks like copper spray.

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Originally Posted by futurevr4man

is that rtv?!

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Copper gasket spray ;) You coat both sides of the MLS gaskets with it to get a better seal.

oh ok, i was about to say....

So I spent the better part of the weekend putting the car back together with a head I had in the garage. After buttoning it allllll back up and getting it to the point where I had nothing left but the alternator, P/S, upper intake, etc., I hooked up the compression tester and tested the cylinders. ~150 PSI across the board - not too shabby for a completely cold engine :-P

At this point, I continued on and got everything put back together. When I went to start the car, it took seemingly forever to start - then jumped to idle of ~1000rpm for a short moment - then died. Tried it again... same results. So I got out of the car and had a friend crank the engine while I watched.

I noticed smoke coming out of the throttle body, seemingly consistent with the exhaust stroke. So.. at this point.. either I have bent intake valves on the front head, the rear cams were mismatched, or something else (??). I await the leakdown tester's arrival......

swapped exhaust, and intake cams?

D on the intake cam, V on exhaust.... they're fackin swapped. I'm the dumbest smart guy you'll ever meet, I swear...

I even marked them when I pulled the head apart to convert it to a rear head/clean it/etc. - but I suppose that wouldn't account for the fact that if they were in the wrong position in the FIRST PLACE on the head that it wouldn't matter :-P

you just can't catch a break, lol

Does that mean bent valves also?

Sent from my GT-I9300 using Tapatalk 2

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Originally Posted by GTOJOE

Does that mean bent valves also?

Sent from my GT-I9300 using Tapatalk 2

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No, the same thing happened to me in '04... Machine shop installed my cams. I didn't realize WTF was going on until a fireball came out the throttle body, LOL. Swapped the cams and I haven't taken the heads off since.

When it rains, it pours eh?

Glad you didn't have more damage!

Nah, it just means the valves are phased 90* off of what they should be. They still open during a stroke - just during the wrong stroke :-P It switches it from intake -> compression -> power -> exhaust to like... compression -> exhaust -> intake -> power. :-P