So here's the beginning of a case history posted for general information. I had read of one similar situation where an '04 4.2 engine had broken a primary chain after the camshaft siezed at the front journal: no follow-up was presented to identify the specific cause, so I was left to assume this was a case of the oil gallery to the camshaft journal being blocked.

My case is a 1999 VDP, 85,900 miles, only a sketchy Carfax service history and a lube sticker that shows the car was 2,000 miles past the last recommended oil change. I bought this car as-is, never having seen it before: I could get the engine to start and run, although very poorly, but enough to get it onto the trailer and into my shop. Wicked missfires, no discernable mechanical noises in the short time I was peddling it around.

WDS to scan and determine which bank has the problem, so I know which cam cover to pull first. Code for CVVT solenoid #2 failure, so I pull the left cam cover expecting to see a secondary tensioner failure.

The engine is a 6 out of 10 on the sludge scale, there's a fair amount built up and no obvious signs to this point that anyone's been inside before. Second generation secondary tensioner (spring-loaded type) in perfect condition. Left bank intake and exhaust camshaft index flats are approximately 180 degrees opposite. Nothing evident with primary or secondary chains or hardware. Huh?

So I hook up a remote starter button and watch everything spin when I crank the engine...no broken camshafts, no loose CVVT or exhaust sprocket retaining bolts 'cause everything is rotating.

I plug in the flywheel index tool and have a look to see which camshaft has gotten so terribly confused. The exhaust cam looks very close to spot on, the intake cam is upside down. Huh?

Through the sludge, the front intake cam journal looks a little funny on the edges. Off comes the front bearing cap, it's melted and there is aluminum slag picked up on the cam journal. I dig a few more pieces of slag from the oil return pocket in the head. The head does not look happy, alot of the slag is from the saddle for the front camshaft journal.

So at this point I am assuming that the oil passage to the cam journal was blocked, the intake cam started to sieze, and the primary chain kept driving the CVVT until it slipped on the camshaft. Maybe when it's torn down I'll find that the CVVT retaining bolt is twisted, they went to hollow ones on the AJ27 engine.

I didn't bother to check for bent valves, and suspect there are at least two pairs. It's a moot point now, as the head has to come off for welding/ re-machining of the front intake cam saddle...or for the scrap pile. Hopefully the piston crowns are not badly damaged and I can at least save the engine. Two other AJ27's I have in pieces were desroyed that way because of secondary tensioner failure: as luck would have it, both of those resulted in ruined Left cylinder heads. Anybody need a Right head?

I'll follow this up with a post once I pull everything apart, but for right now I am assuming that this all was the result of neglected oil changes. This case also speaks to the issue of cam sensor/ (C)V V T solenoid fault codes, 'cause I have read many posts by people who developed problems after they were mucking about with their chains. Trouble codes are only telling you that the electronic functions are confused, thy're not telling you that you messed up your cam timing.

 

I have one ancillary thing to add to this...

Apparently, the VVT does not like the "engine restore" oil additive. I have a worn nikasil engine that engine restore makes a big difference in compression but trips VVT fault codes. I presume the additive does something to prevent the VVT actuator from working properly.

I have tried it a couple of times with different oil viscosities and it would always trip the code until I stopped adding it.

Just thought I would put this out there for anyone who may experience this problem...

 

Thanks Ron, very helpful tip. I haven't tried the engine restore on a Nikasil engine yet. They're still out there, I had one come in for the first time last week at 106K.

 

I have a Nikasil engine at 123,xxx on the clock and runs like a champ Doesn't burn a drop of oil either...

 

Mine doesn't burn oil either, runs pretty good.

Unfortunately it doesn't burn rubber anymore :-) ....