NB8B timming belt change...

StanTheMan · Postby **StanTheMan** » Fri Oct 16, 2009 11:22 am

I should have marked the VVT cam, but the number of teeth on the belt between the two cams are right. Im not sure if ha I have to move it up or down one gear but will find out when I have time...

how are you able to tell?
there is no vertical marker on the intake camgear. Or at least its not visible as far as i can tell.
However the marker you do have, does not line up with the backing plate behind the camgears at about 4 O'clock it appears 1 tooth too far up where you have it secured with all the tools in the pic above.
again I've never put together the timing on a mx5 with VVT so I'm not certain.
:mrgreen:

meanmx · Postby **meanmx** » Fri Oct 16, 2009 12:10 pm

Good spotting STM. Looking at that pic the timing is definately out of whack. You should have let me and Mick help you. Admitedly if I didn't do timing belts at work everyday I probably would have screwed it up as well. Fortunately it has become like an instinct now and I was able to do mine without clamping anything in place. Kudos to you for giving it a go though. At least you leap in and give it a go even if you are dodgy as all hell.

Ben

wun911 · Postby **wun911** » Sat Oct 17, 2009 8:23 pm

I took it apart today, I think I'm one tooth out but I will post up some pics later.

I think the car ran with one tooth out because it was on the intake cam and that has vvt attached to it...

[img=http://img203.imageshack.us/img203/2048/dscf1441.th.jpg]

wun911 · Postby **wun911** » Sun Oct 18, 2009 12:58 am

Im out by one on the timming belt install on the intake cam..

StanTheMan · Postby **StanTheMan** » Sun Oct 18, 2009 2:20 am

did you get it sorted ? :mrgreen:

indeed the intake is 1 tooth out

wun911 · Postby **wun911** » Thu Oct 22, 2009 10:13 am

Hi

Im wondering if the marks on the cam gear is suposed to line up with the letters I and E on the back plate OR are they suposed to line up with the lines just under the I and E on the back plate...

This is where Im at at the moment...

Also I got the crank lined up perfectly as seen in the pic below

However when I put the lower cam belt cover on and the crank pully on it looks like im 10 degrees off time 0 :?:

StanTheMan · Postby **StanTheMan** » Thu Oct 22, 2009 10:46 am

intake is still one too far up.

i'll draw something up

wun911 · Postby **wun911** » Thu Oct 22, 2009 10:52 am

with regards to the crank and the pully and cover not linning up is that simply due to me bolting and un bolting the main crank bolt (120 pounds) and the movement is due to some drive train flex...

also in regards to the exhaust cam gear... I think the vertical 12 o clock mark would be more vertical if i dropped one tooth down, there is also a dot on this cam gear gear the letter z what is this for? (a smilar dot appears on the VVT cam does anyone know what they are for??)

StanTheMan · Postby **StanTheMan** » Thu Oct 22, 2009 10:55 am

you have 6 points of reference

1) point 4 should line up with point 5
2) point 3 should line up with point 6
3)point 1 should be 16 teeth away from point 4 same on the other side. Mark that point.
4) point 1 & 2 should be very close to vertical
5)you should have 19 teeth between point 1 & 2 currently you have 21
6) you should have TDC on No 1 cyl. check it with a screwdriver.
7) crank mark is spot on

timing mark is a little off it should be on TDC but thats because the timing is out currently.

Pretty sure im rioght with these steps.
but please can someone also check on me.

wun911 · Postby **wun911** » Thu Oct 22, 2009 10:58 am

Thanks for the help stan

so marks 4 and 5 to line up and 3 and 6 to line up...

StanTheMan · Postby **StanTheMan** » Thu Oct 22, 2009 11:02 am

sorry I've been editing.

wun911 · Postby **wun911** » Thu Oct 22, 2009 11:15 am

Im taking the belt off now...

with the bottom crank pully and cover what should line up with what when its all done???

StanTheMan · Postby **StanTheMan** » Thu Oct 22, 2009 11:32 am

on this one I'm guessing. NA6's only have 1 notch.
however you can gently insert a screwdiver into No1 cylinder through the spark plug hole. make sure its long enough & its resting on top of the cylinder. Move the crank back half a turn. then turn it the correct direction. when the screwdriver stop moving upwards. You've hit TDC. Then you can also check the mark. one of them will be on TDC

Thats the way I 'd do it.

wun911 · Postby **wun911** » Thu Oct 22, 2009 12:22 pm

I have 5+4 and 3+6 linned up along with the crank bolt on the bottom lined up as per usual...

I turned the crank clock wise twice and its still all linned up perfect

Turned it 1 5/6 turns tightend the tensioner pully to 38 pounds

turned it 1/6 turns to tdc and its still all linned up

I thin Im home free!