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Discussion Starter · #1 ·
I'm stuck on a project that didn't go as planned, thanks to constraints placed upon me by an extended warranty. I have an '01 Concorde in the shop that smoked the #3 rod bearing. I was authorized to replace the crankshaft, main & rod bearings, #3 piston and rod. The cylinder heads were badly sludged, which is unfortunately very common, but I was only authorized to R&R one head. I cleaned everything as well as possible, put everything back together, etc. etc. I cranked the engine with no spark plugs to prime the oil pump, and started it up. The timing chains clattered like crazy, as did the lash adjusters, and did not quiet down after several minutes. I hooked up an oil pressure gauge and started it again. I had 25 psi at idle, going up as high as 75 psi at ~2500 rpm. I took the gauge off and attempted to start it again. The chain had obviously jumped, since the engine cranked fast as if there was no compression. I also heard knocking noises, which I assume is pistons hitting valves. AAARRRGGGHHH!!! :banghead: I don't know what the warranty people are going to authorize next, but obviously the heads have to come off, unless they give me another engine (I REALLY don't want to pull this one out AGAIN!) I'm quite sure remaining sludge in the oil passages came loose and blocked flow to the tensioner, preventing it from tightening up. If not, what did I miss? Does anyone know? :help: If I'm right (I REALLY hope I am!), then the quick, cheap, dirty repair authorized by the warranty co. bites them in the @$$ and they have to pay up. I don't want to consider the alternative, :nutkick: but If I missed an important step, I'd rather know now than later!:whackit:
 

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2.7 Trauma Surgeon
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That sucks man. I would speculate either a blocked oil gallery, improper pre-oil, (not long enough- took 4 minutes on my 3.2) or the incorrect pre-load on the tensioner. Your oil pressure seemed ok. I would say the first is most likely if the engine was sludged bad. I doubt your warranty company would authorize it, but you might want to look into a 3.2 or 3.5 engine conversion.
 

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Discussion Starter · #3 ·
I found the answer yesterday when I pulled the tensioner out. It has a 2-way ratcheting mechanism. After the plunger is fully extended, it ratchets in when you compress it. It's locked in retract mode and will not extend until it is fully compressed and the ratchet mechanism is reversed. It will then extend but not retract. Another lesson learned: DO NOT "hand tension" the chain if the tensioner has no oil in it! You can fully extend the plunger by doing this, causing the tensioner to go into retract mode. As soon as you crank the engine, the plunger will retract and stay retracted, allowing the chain to jump. Now, if everyone will excuse me, I have a pair of cylinder heads to remove and some bent valves to replace!:banghead:
 

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Discussion Starter · #5 ·
Well, the saga continues. I sent the heads out to the machine shop and had new intake valves installed. I put the heads back on, set up the chain, guides, and tensioner, and cranked the engine with the plugs out to prime the tensioner. The tensioner and chain were making clacking noises, but I figured that would go away once it was primed. Everything seemed fine until oil started spraying out of the pinholes in the core plugs. I stopped cranking and laid the valve covers on to avoid making a mess. I cranked it again and the chain jumped - 10 more bent valves! :banghead: Off come the heads and back to the machine shop they go! Today I got them back, put them on, and cranked the engine WITHOUT the cams in place, pumping oil all through both heads. I put a spacer behind the tensioner guide to prevent it from kicking back too far. After several minutes of cranking, the tensioner still hadn't tightened up. The plunger was also almost all the way out. I thought the chain might be stretched, so I replaced it. (Fully extending the tensioner by pushing out on the guide should have clued me in to this before!) What a difference! My spacer no longer fit behind the guide, so I squeezed in a socket instead. The tensioner tightened up a little and the socket fell out. But now, instead of slapping the guide back, the guide was moving smoothly back and forth. The tensioner still hadn't pumped up fully, but the starter was turning a bit slow. So I charged the battery and cranked it again. Bingo! It tightened right up. It was a tough lesson, but I learned it well: NEVER reuse the timing chain on a 2.7! Throw it away and get a new one!
 
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