vaccuum advance stock 240z distributor

[silverz]

Hi,

I have had some dramas tring to get the timing right on my 240z. In my efforts to sort it all out I found the vaccuum hose from the manifold to the distributor was blocked off with a ball bearing. I removed the ball bearing and set the timing etc. I then finally had it running well at medium to high revs but it was harder to start than before, had a huge flat spot when taking off from idle and when you let the revs drop to change gears etc. Cruising down the road, the car would jerk and surge and sounded like it was misfiring slightly. It ran great if you were accelerating however. I have blocked the vaccuum hose up again and now it starts easier, the flat spot is gone, pulls much better from low RPM and the surging and jerking is gone.

 

A friend has told me without the vaccuum advance working it will never run economically etc.

 

Has anyone else ever come across this issue? should I just leave the hose blocked up or do I need a new vaccuum advance unit to make it run at it's peak?

 

I am finally happy we have the carbies and the timing right. I just need to sort this last issue. When you set the timing you can see the mechanical advance is working as it advances under acceleration.

Any advice would be appreciated.

 

Thanks

Peter

 

[aegean]

Is your vacuum canister working ? That may be the reason why a ball bearing was put in there. Any auto electrician should be able to test the vacuum for you, and replacement should be relatively inexpensive - if available.

[Scoota G]

Yea the last thing you would want to tell an auszcar member is to suck on it......but that is the best way to test it ... the vacuum advance i meant.

[silverz]

Thanks for the advice. I tried sucking on it when I first pulled the ball bearing out. I could make the spring that moves the plate under the points contract,  but I couldn't suck hard enough to move the plate.

 

Regards

Peter

[Scoota G]

Hmmm that usually means it is gummed up really well but the diagphram is still in working order.

 

It's not difficult to pull apart but makin sure it goes back togeather the right way is important. I screwed mine up the first time i stripped it down and accidently set the rotor button position 180 degrees out.  If it helps with your problem is a mystery.

[silverz]

Finally sorted this issue out. When the Carbies were way too rich the car ran fine with the vacuum advance not working. However when we leaned it out, she ran fine while accelerating but took a prolonged time to warm up and run properly (even in Darwin's warm weather) and it would misfire and surge and generally run like crap when driving slowly with the throttle only slightly open.

 

This made it really difficult driving in the Army Barracks (40Kph limit) and even when cruising at anything up to 110Kph.

 

Turns out a clip was missing where the vacuum advance fits onto the post attached to the points backing plate, so it couldn't advance as the vacuum advance mechanism would come off the post.

 

I think there is supposed to be a very small circlip holding the vacuum advance mechanism on the points backing plate post - can any one confirm this?

 

Anyway for now I have secured it with a small speed nut.

 

The car now gets to a diveable state much quicker on initial start up and runs without missing, spluttering and surging at low throttle openings. When you put your foot down the response is sharper also.

 

Hopefully this info may help someone else with similar issues.

 

Regards

Peter