Gtr Ignition Timing?

[gillies2001]

I have just changed the cam belt and bearings on my R32 GTR . Cam sprockets, crank sprocket, harmonic balancer all line up with the correct marks. But when i checked the ignition timing it was showing 35 BTDC at idle. I had to adjust the crankangle sensor fully to the right to get 20 BTDC (prior to changing the belt the crankangle sensor locking bolts were always around the centre of the slot) So any idears why the ignition timing could change 15 degrees after changing the cam belt "Please"

[BHDave]

Sounds like you have inadvertantly advanced the exhaust cam, or your cas has a broken locating pin which has allowed you to install it out one tooth

[gillies2001]

Thanks for the reply, I tried a spare cas. (locating pins are all good) same result ! The cam timing is spot on, cam belt marks, sprocket marks, and front cover marks all line up ????

[Craved]

which line on the HB are you using?

[gillies2001]

NO1 cylinder primary line (loopped)

[StockyMcStock]

if the car is cold your timing will be way advanced, this is normal ignition correction at idle for cold conditions. make sure it's warmed up.

if you're doing it when the car is at full operating temp and still getting 35 degrees, then you're right on, it is probably something else.

[gillies2001]

Yes the engine was all warmed up, about half an hour. Thanks

[32R]

Could possibly be a spun balancer,pop a screwdriver in No 1 and check if it lines up..

[gillies2001]

Good thought, Balancer is perfect, I took it off and also checked the dot on the bottom belt sprocket which lined up, (all marks line up including balancer TDC mark ?????

[blind_elk]

Some timing lights seem to double the reading by firing the strobe too early. Have no idea why or how it could happen.

If this is the case, the car should feel a bit sluggish because of the late timing you have set (you effectively have timing at 10 rather than 15).

As a check, insert a spark lead between #1 coilpack and #1 spark plug and check the timing the "old-fashioned" way.

[gillies2001]

Good one !! That sounds very possible, as the timing light is new and i am using it for the first time. I will check with the old t/light when i refit all the bits. It has to be something like that as everything else checks out

[T04GTR]

swap the direction on the pick-up on the light.

you havent some how managed to mix up the lower cover with the mark on it?

if all you did was a cambelt. the cas will "sit" nicly in one spot. just leave it there.

worst case you will need to find tru tdc.

[9krpm]

As a check, insert a spark lead between #1 coilpack and #1 spark plug and check the timing the "old-fashioned" way.

This is the best and most reliable way of doing it. There are too many variation with the other techniques.

[gillies2001]

Yes it was the new timing light. Thanks BLIND-ELK 10 points to you. Also thanks to all the others that replied. Regards, Clive