When replacing distributor, do you need TDC or just rotor position?
(2011-02-17 15:21:17) 1. Says: Well i am looking to change my distributor in my 1993 gmc sierra that has a chevy 350 engine. I am going to do it myself and would like some tips that will help. I have been watching some videos to help me visualize what needs to be done.One main question i have is that when putting the new distributor in, do i need to have the number 1 cylinder at top dead center, or could i just put the new distributor in as long as the cap and rotor are in the same position?2. Says: Both will work . BUT I suggest that you remove the cap and line up # 1 with the cap and tdc on the balancer./ That way , if you take a break and have a few to many suds you still know it was set up to # 1. Btw, the rotor will point to # 1 cylinder if it is at TDC on # 1 , If it backfires , you are off 180 on the rotor. If you need to " bump" the motor to line up the dist. Do it by hand from underneath from the crank. You can jump a tooth so easy. Don`t forget to set the timing slightly behind what it should be at first, I think it is 0 degrees , with the jumper off set your timing as per the sticker on the rad or under the hood. Fun job to get to wasn`t it? Just a dumb question, but as the actual dist does rarely wear out , what are you replacing and why? The module can be done without removal , the pickup is a different story.Are you sure you need to pull the dist ? Just asking.3. Says: TDC is best and what's really best is to remove the old distributor at TDC. Before lifting it out make a reference mark where the distributor vacuum advance is pointing and where the rotor is pointing. mark again where the rotor is pointing when the distributor comes up and the rotor stops turning. Set the rotor on the new distributor to the same position and point the vacuum advance the same way when you drop the new one in. When it's all the way down check to see that it lines up the same as the old one.4. Says: It doesn't have to be at TDC. Just make sure to mark the position of the rotor when you pull the distributor. It may be possible to get it off by one or two teeth. If that happens, just lift the distributor and adjust the position of the rotor. Oh, and when you put the new distributor in, make sure to bump the starter a few times to make sure the distributor lines up with the oil pump drive shaft before you start it. Otherwise you could damage the shaft or even the engine (no oil flow).5. Says: getting your #1 at TDC is not that difficult to do put a ratchet on your crank and get your timing marks lined up.
It will give you a better starting place but you could probably slip the distributor in as long as it lines up it will be close enough to set the timing by twisting the distributor.
make sure your timing marks on your crank are clean and you know where they are and which one means what.
Also make sure you get the right timing position how many degrees out you need to be.
A dwell indicator is also good along with a good timing light.
hmmm what else...
oh yea go overboard and mark each wire and each place on your cap with tape and numbers ... black sharpy is good. it only takes a couple minutes.
make sure your oring is on good and the distributor is lubed
and say a little prayer heh6. Says: top dead center is the most reliable way to insure accuracy. I've tried what your talking about It just didn't work for me.7. Says: Follow the installation instructions of the other poster, BUT you must also do this- On this engine and control system you install the distributor straight up, Index the crank pulley at top dead center and check distributor, the rotor should be pointed at number one and the reluctor wheel teeth on (distributor pick-up coil) should be tip to tip (within a sixteenth of an inch) once you have the distributor @ 0 degrees (there is NO timing specification for this engine) now it is time to set the CAM RETARD OFFSET! First thing to do is disconnect the ESC (electronic spark control) bypass connector this is a single wire connector located on the firewall at the main harness that runs at the top (the wire color is tan with a black tracer. This procedure is best done with a compatible scan tool by Checking the timing with a timing light and retard the distributor when says knock yes. to be perfect! But you can do it if you have a good ear, With the engine running at operating temperature snap the throttle frequently while advancing the timing (turn the dist.counter clockwise) Listen for the knock (pinging) as soon as this is heard, Retard the timing (turn dist. clockwise)1/16 of an inch, turn off the engine and lock the distributor down, re enable the ESC by reconnecting the connector and start the engine! ADDED: There is NO vacuum advance on this Dist! Tag: When replacing distributor, do you need TDC or just rotor position?