I had a someone inspect my car the other day and he informed me that my vacuum advance was shot. Can anyone tell me what this is, if it can be repaired or if my whole distributor needs to be replaced? The car seems to run fine as it is.
Hi Adam---------------The vacuum advance is the round "canister" that is attached to the side of the distributor. It should have a small diameter hose connecting it to the intake manifold.The vacuum advance is important when under partial throttle, after the first stages of acceleration the counter weights on the bottom of the distributor shaft take over and advance the timing the rest of the way. It's primarily for better performance and fuel mileage at lower engine revs. If your car is running well now, don't worry about it. There are many cars with triple carb setups that don't use the vacuum advance at all. FWIW
Beside the actual advance, (40-50 bucks for nissan unit) there seems to be an inherent problem with the piviot assembly within the distributor getting gummed up with age. Even if your advance is working proper it may not be able to pull the pivot if its froze up, this can be cleaned up and lubed. As I remember it should open at about 7 psi of vac. The 280s of my vintage had a cutout switch which only allowed the advance to operate in high gear for emission reasons. So with that in place you wouldn't appreciate much function of the advance anyhow. It all depends on how much you like to tinker...
My 2 cents — you need to take the distributor apart to get at the 'bearing' inside. That's not something everyone is comfortable doing. However, the V.A. makes a big difference in the way the car runs. You'll be amazed. It's worth getting a new one IMHO. You'll get better mileage, too. Or you could comb the junkyards until you find a good one.
Well mate considering I live in Australia and drive a 79 280ZX I may be able to help you. Our friends in the US have the advantage of buying parts from various sources at cheaper prices but here is Australia things are a little different and with the current exchange rate the thought of importing parts isn't a great one. I just installed my new vacuum advance unit and I ordered through Nissan Australia (Rockdale NSW dealership Ph. 02 95971155) Part No 22301N4700 It cost me $101.95 AUST (INC GST)
They ordered it from Japan it took only 1 week to arrive. Now I checked with Z-Spares in Victoria and the price I was quoted and paid was correct. Now remember thats about $50 US So if you decided to order one from the US it will probably cost you around $40 US plus international postage and 2 weeks delivery time. (in other words more than what I paid!)
Being an older car the part did help but you know how things happen. You fix one problem and another one develops.
I live in Sydney and its taken me a few months but I'm slowly finding some good "Z" contacts in the arsehole capital of Australia.
(ex- Tasmania and proud of it)