Just additional information on 85 Nissan 300ZX. The belt is breaking almost as soon as it is installed..

If the timing belt is immediately slipping off when you attempt to start the vehicle, that means that there is a camshaft problem, most likely the shaft bearings or clogged oil channels. If the belt stays on for a time then slips off, that means that the belt may be distorted, deformed, or otherwise defective.

Hi Lori,love 300zx's,got a 85 Nissan 720 4x4,Here's a link to the stoplight switch,directs current to the brake lights,could be bad.It is connected to the brake pedal,get a flashlight and a adjustable wrench and remove nut and electrical connector,when installing,make sure it is adjusted correctly.

Hi, you have to start by setting the timing belt, then align white lines on timing belt with matching mark on camshaft sprocket and crankshaft sprocket. Point arrow on timing belt towards the front.

if it is the top belt it is ac . you can take it off .you will not have ac . the bottom belt is power steering and altenator , you be walking soon after it breaks.

Here's some very good information on that subject:

http://www.costhelper.com/cost/cars/timing-belt.html

if you are running an amp, you need a much thicker positive wire coming directly from the battery, i pushed through the clutch linkage grommet on my 85 300zx

Dear jmjkruger, Fri 2-19-2009 4:22am EST (USA)

RE: Online Auto Parts Stores 1985 Nissan 300ZX 3.0L VG30T

My first choice is @ http://www.autopartswarehouse.com/search/parts.php?N=11374+1684+4294965564&ddKeyword=rotors

They have 9,803 items for your 1985 Nissan 300ZX!

If they won't ship to you try one of the Online Auto Parts Stores listed on Google Search @
http://www.google.com/search?q=auto+parts+online+1985+Nissan+300ZX+3.0L+VG30T&rls=com.microsoft:en-us:IE-Address&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA_en

This should FixYa!
jack
Please Let Me Know How You Make Out or If I Can Help In Any Other Way!

well if you have a Ka you should know it has three belts. Alternator belt closest to the engine, then power steering/ ac belt second and finally you have you clutch fan belt

the timing belt should be changed every 60,000 miles.
your engine is an interference engine, which means if the timing belt breaks or skips, the valves will hit the pistons.
if your belt broke you will have bent valves. so the heads will need to come off and bent valves replaced.

hows the engine mounts? did anything happen leading up to this problem?