Out of curiousity i decided to check my timing recently. I noticed the timing marks were quite shaky when checking with a timing light. I consulted an ex nissan tech i'm friends with and he was saying that the crankshaft position sensor may be wearing out. Is this common on the VE? I had never heard about it before.

Well I'm pis$ed! I rebuilt the vtcs about 20k ago and the bastards are clacking again. When I tore apart my ve last summer i rebuilt them and replaced a smashed piston and two busted valves. Replaced the knock sensor and sub harness plus the timing chain tensioners and a few other odds and ends. Everything was perfect except i forgot to leave the valve lash adjusters soaking in oil when the heads were apart. At first I assumed something was wrong with one or two of the adjusters. Maybe air inside them? But surely it would've escaped by now...
Anyways, is it common for the vtcs to crap out so soon after rebuilding? I know they were rebuilt correctly.
Any other ideas why they could be clacking?
I change my oil at least every 2k and use the toyota filter. Even with such short intervals my oil is really black.
Should i give synthetic a try?

 

did you flush the engine when you rebuilt them?

 

I think a few OG guys that remember reading about rebuilt VTCs and they crapped out again.

I got a JDM engine that was clean as a whistle and my VTCs are clacking.

Those things really p!ss me off.

 

oh yeah.
i stripped it down to just the block and cleaned it well. the vtcs had blown up (literally) before i bought the car.

 

funny enough a friend of mine rebuilt his at the same time as me. i showed him how to do as well... yet his never clacked at all.... arrrghhhh

 

any more input on this?

 

yeah -- VTCs are like playing poker -- sometimes you win, sometimes you lose.

You can take precautions, but that doesn't mean you will win.

 

Not really sure how the CAS would reall "wear out". As the reader doesn't touch what it's sensing. You could take the cap off to inspect maybe.

I would think maybe the timing chain might be stretched or a tensioner might be worn out.

Black oil within 2000 miles. That seems REALLY odd. I would guess is valve guide seals are all worn out or maybe the rings are bad

 

Before you checked the timing, did you put it in 'base timing mode' following the FSM procedures??

If you don't do that, the ECU will adjust the timing constantly, giving you the jumpy timing problem you're seeing. put it in base timing mode and set the idle properly and the timing will sit rock steady for you to adjust. then you plug all the sensors back in and you're good to go.

 

Yup, what Matt said.

And the CAS doesn't 'wear out' its just an led and sensor, so it will simply fail completely, not paritally.

 

actually, the CAS on both VE and vG can have intermittent problems before completely failing. the bearings can eventually go bad in them, causing vibrations, which cause the signal plate to vibrate and give erroneous readings.

 

thanks for the input.

jeff,
all three tensioners were replaced when i rebuilt the vtcs and tore down the engine. is it common for the chains to stretch? do they stretch equally or usually just one of them? as for your theory on why my oil is so black, it seems possible but the engine has under 200,000kms on it which really isn't that much mileage.

matt,
no actually i didn't use the fsm procedure for checking timing... didn't even know of it.
when you say vibrations from an intermittent cas problem, do you mean just when checking timing or actual vibrations from the engine?

 

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