timing belt change - factory timing is 15deg off??
 

Hi, Im new here, and Im not a mechanical guru, so please bear with me.

I've got an old '98 tacoma v6 w/ 126k miles that Im about to attempt a timing belt change on. Now that Ive gotten the timing covers off, Im seeing that cam marks are off by a bit, and only line up with the backplate marks when the crank pulley is set to '15 degrees btdc?' on the timing indicator. The FSM says that the timing should be set based on the marks/indicators on the engine, and from what I understand, timing belts dont stretch, so there's no way my timing could have slowly changed over time, right? it either had to have come that way from the factory, or have been altered by the stealership at some point, correct? (the truck was never serviced by anyone other than toyota)

background: I bought the truck new (in southern california) & had the 1st gen TRD supercharger installed by the stealership soon after (I did this to maintain the 60k warranty at the time, since the truck was new...now I wish I would have just installed it myself). Pretty soon after that, I was forced to move & get another car, and so the truck ended up being handed off to a younger (female) relative for a few years (who, btw, did a horrible job of caring for & maintaining it), before it ended up being parked/"pno'd" for another few years. Now, 10+ years later, the truck is back in my possession, so my goal is to fix it up. The first step has been to remove the TRD SC & do the timing belt change in one shot, which is what Im in the process of doing...

So now my big question/concern is: why is the timing 15deg off & what should I do about it? was this something done from the factory (for CA smog/emissions?), or, could it possibly be something that the stealership did when they installed the TRD SC (which doesnt sound right, cuz its not in the SC install manual)? And, now, when I install the new timing belt, should I leave the timing 'as is', or remove the 15deg timing offset & move the cam pulleys back so that they line up with the backplate marks???

I can provide pictures if needed...
any help would be greatly appreciated

Pics of both cams and the crank would be good. There are Cali guys on here that may chime in on the supercharger and it's impact. I dunno, I don't have one.

here are the pics
crank
http://www.changosurf.com/dump/crank.jpeg

left cam
http://www.changosurf.com/dump/lcam.jpeg

right cam
http://www.changosurf.com/dump/rcam.jpeg

note:
the last time I hand-cranked, I over-shot lining up the cam marks by like a couple of millimeters, so you can see that the marks are off by a tiny bit, so the crank pullley timing is probably a little over 15 degrees...

Im wondering if the truck was serviced at a smog place at some point (I dont recall ever hearing about the truck failing smog or having work done due to a smog failure, but who knows...), and, if so, if adjusting the timing would be something that a smog place would have done (as far as I know, the truck always passed smog, even with the SC installed).

spin it once or twice more. I think those marks line up more then just once.

Since you pulled the TRD SC, I'd set it back up per the FSM (Factory Service Manual) paying particular attention to pages EM-19 and 20:

http://www.ncttora.com/fsm/2000/Repa...nical/inst.pdf

http://www.ncttora.com/fsm/index.html

if your rotating it the wrong way you will be 15 degree's off. you have to rotate it with the crank bolt (don't laugh, I've seen this problem) and turn it so the belt is tight on the non tentioner side. the tentioner side of the belt should have all the slack.

There would be no benifit to have both cams off but I would not take it apart until you figure it out. unless you want to do it again. I don't think the smog check police made Toyota change the cam timing for a supercharger. I could see backing the distibutor off a few degree's to not burn a hole in a piston but not cam timing. I'm not saying this is the case but it doesn't sound logical. I've never seen it on any other supercharger instal weather it be for california Smog Check or not.

I was rotating clockwise, triple-checked it, and it was definitely 15 btdc;
Im convinced stealership did this at some point, either when the sc was installed or at some point after.
Now that I realize it, the timing covers were all sealed with grey RTV instead of having the oem adhesive 'foam weatherstrip' gaskets, so someone's definitely been in there before. I vaguely remember hearing about the truck being taken into the shop years ago due to the infamous 'pinging problems' caused by the SC; I dont remember hearing about them having done something about it, but now Im figuring that they must have changed the timing as a way to try to fix the pinging.

anyway, Im going to go ahead and set it back to 0degrees.
thanks for the help.

Please update this thread when you do.

the dealer installed a bigger supercharger pulley to combat the "ping" It just looks like a faulty t-belt install. No where in my trd sc install manual does it say to change timing. Timing can jump if the belt is worn.