scooby seb

iTrader: (1)

hi all,just changed the cam belt,idlers and tensioner (1 bolt type) on my 96 classic sti

timed engine up before i stripped it and found the n/s bank to be 1 tooth out on the marks,(car pulled fine before i took it off the road) did'nt think to much of it as i thought i'd just reset it when i timed it on fitting the new belt.

fitted the new idlers and tensioners and belt and timed it up,double checked triple checked and quadrupple checked the the timing and all marks were spot on, turned engine over 2 revolutions and rechecked and found the n/s bank to be one tooth out again the o/s bank marks were all spot on as was the crank timing mark.

the belt is not an oe part but is gates so not of poor quality

just wondered if anyone has had this before??

cheers scott

Slowboy Racing

If the lines on the gates belt matched the correct marks on the cam pulleys exact, then it will be fine. It can somtimes appear to be a half a tooth to a tooth out of line.

Hobstar82

If you turn it another 2 revs does it make it 2 teeth out or still one? Genrally the n/s cams are the ones that spin when you take the original belt off! Did this happen? Also did the new belt have the guide lines on?

scooby seb

iTrader: (1)

yeah the lines on the belt matched the timing marks spot on, it's just the pulley marks on the n/s don't line up with each other or the marks on the caseing??? but the pulleys seem to be in the same place before i stripped it which looked a tooth out???

scooby seb

iTrader: (1)

yeah i tured it about four more revs to see and the were still in the same place? yeah i could turn the o/s bank by hand and the n/s was under tension, yeah the new belt had the guide lines on and lined up fine

Hobstar82

What I meant was the n/s spin back (or right bank as you look at engine) off the cam lobe by themselves if you give it a gental nudge or catch it as you take the belt off as, like you said, its under tension from the valve spring. So you'd have to of spun it back round to get it back on its timing mark.

When you put it all back together you need to make sure that when you turn it over you turn it slowley, clockwise and you dont allow engine to rotate bac as you approach the crank mark to ensure what slack (even after releasing tensioner) is in the belt is taken up by auto tensioner rather than the slack being by the n/s cams making them roll off the lobe (this is called back lash in the trade) and making them appear as tho they aren't lined up.

Failing that you got the timing out in the first place. But like you said you checked n checked and as long as the lines on belt lined up with the marks on gears you should be ok. Hopefully your just doubting yourself cus if its wrong you'll kill it.

Plus the other side of it is if you can turn it over by hand and your not hitting the valves, it'll either fire up and run fine or it'll be a pig to start or be hesatent cus the timing is a tooth out but you aint gonna damage it! Its when its 2 or 3 teeth out you gotta worry!

Sorry bout essay n hope you get what i'm dribbling on about