Hi there, Iv'e been trolling these boards for a couple of weeks now, but since my brother and I have gone out and purchased a 1975 260Z 2+2 (Sydney, Australia) I thought it was high time that I made a post here

When we went to pick up our 260Z I took it for a short drive around the block before we handed the cash over. It took off ok, but after about 2500rpm it had no power - felt to me like it needed a good tune & nothing more. So after having it for a week & ripping out the most crappiest headlight wiring that I have ever seen, my other brother and I thought we'd have a go at adjusting the timing.

Well to cut a long story short, we advanced the timing as far as the bolt would let us (which was very little as it was already fairly well advanced - the main mounting bolt was at full range & the adjustable one had only a couple of millimeters before it was at full range.) & it still ran like crap over 2500rpm's. We pulled apart the dizzy to check the movement of the weights - they where fine, so after putting it back together and onto the vehicle, we left the mounting bolt off so we could advance it past the bolt hole - started her up and advanced the dizzy about 5 - 10 degrees past the bolt hole - that's when the engine made more of a purring sound than a growl at idle speed .

So my question is, why the heck do we need to advance the timing just millimeters past the limits of the guide holes to get the engine running right? Maybe some previous owner took the gears out and when replacing them got it one notch out? It's got me baffled - I suppose I can always file the guide holes out a little, but still that won't give us much leeway for any future adjustments.

Any ideas?

Rob - it's almost certain that someone has put the timing gear back in a retarded position (this is actually easy to do). Don't file anything, what you need to do is drop the oil pump and re-position the gear - best get a w/shop manual which shows how to get the timing in the correct position. You will probably need to either jack up the motor or drop the front sway bar to drop the oil pump. It's not really a difficult job, but can be messy and best to replace the oil pump gasket at the same time.

Steve's suggestion is probably on the money but have you used a timing light to confirm how far out it is?

Make sure the centrifugal advance mechanism can move freely. I once had water get into a Z distributor and cause the ball bearings to rust over a period of a few weeks. This caused the advance mechanism to stick and the engine ran like an absolute pig.

Cheers,

_________________
Chris [;-{)>

Steve - I tend to lean strongly towards your opinion. I am picking up a Haynes manual in my lunchbreak today & that'll be the next thing I check out. Do you think this is a one man job, or is it the type of job that is made much easier with two?

Barry - When using the timing light I can't even see the notch (we even marked it with white chalk) so I am guessing that it is out of whack like Steve has suggested. When we manually turned the engine so that the dizzy contact was coming up to the contact for piston 1 the notch was still halfway round the pulley.

Chris - We fully dismantled the distributor & lightly greased the balls, they did sound a bit gritty like it had built up a little bit of rust, but not much. Anyway since we have done that the dizzy looks to be running nicely.

Thanks guys, I'll let you know how I go with the timing gear.

Sounds like the distributor drive is way out.
Easiest way to check is to set the crank with no.1 at TDC.
Remove the distributor. the tang (I think it is called) should be slightly clockwise of a line between the two bolts that hold the adapter to the timing cover.

To reset it is a one man job. As Steve said, remove the oil pump (I had to remove the sway bar (took off on one end and swung it out of the way),
line up a notch on the shaft with a hole on the oil pump body, then when inserting the pump allow for a slight bit of rotation as the drive gears engage. (it would be easiest if someone could observe the alignment as you push the pump in place).

I also operated from the top and dropped the pump down a bit then rotated the drive with point pliers to align it, pulled the pump back up and got a bolt in while holding it - bit fidley but found it the best way to get it aligned.

Finally, I found that if anything, the tang needs to be anti clockwise of the desired setting as the vacum advance mechanism on the dizzy fouled with the thermostat housing if too far to the right. The tang in line with the bolts worked ok for me.

Well last night I had some fun re-aligning the tang to it's correct position.
I developed a unique way to ensure that I had no.1 piston on a compression stroke: take the spark plug out of no.1, rip off about 10cm x 10cm of plastic shopping bag, double it over and place it over the plug hole, push some blue tac (about the size of a small marble) onto the plastic so as to seal the hole, then turn the crank by hand until the blue tac & plastic "pop" out of the hole voila, we are now on a compression stroke. An inspection of the positoin of the dizzy also confirmed this.

I then lined up the notch on the pulley, & removed the dizzy.... the tang was definantly not lined up with the bolt holes - it was close, but certainly not within 5 degrees.

Unbolted the engine mounts, jacked up the engine, unbolted the oil pump (it didn't come right out as the sway bar was in the way like you said) - it slid out enough to disengage the gear, I then had to have my wife watch from above to determine if I had the tang lined up -after a few goes we lined it up, bolted the pump back in & then had a look - much better, the alignment of the tang was now just like the workshop manual picture showed it should be

Put everything else back together, tried to start the engine and ...... flat battery - was too late in the evening to muck around trying to jumper it, so I'll do that this evening and see if it'll kick into life. *fingers crossed*