2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

how do you get to 0 degress TDC?

Thread Tools
 
Search this Thread
 
Old 05-16-12, 10:57 PM
  #1  
Retired Moderator, RIP

Thread Starter
iTrader: (142)
 
misterstyx69's Avatar
 
Join Date: Sep 2005
Location: Smiths Falls.(near Ottawa!.Mapquest IT!)
Posts: 25,581
Likes: 0
Received 131 Likes on 114 Posts
how do you get to 0 degress TDC?

A buddy is facing a dilemma and needs to find ZERO degrees TDC to set his PFC.
Can anyone shed light on this?
Thanks.STYX.
Old 05-16-12, 11:10 PM
  #2  
Unconventional
iTrader: (1)
 
Jet-Lee's Avatar
 
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes on 0 Posts
If the lead coil timing is 5 degrees ATDC when the notch and pin line up, advance your timing light 5 degrees and take note of the distance between the notch and the pin. After stopping the engine, set the notch to that point.

I'm no expert, but it's the only method that comes to my mind.
Old 05-17-12, 08:36 AM
  #3  
Senior Member

iTrader: (1)
 
Puck's Avatar
 
Join Date: Sep 2002
Location: Terrace Bay, Ontario
Posts: 357
Likes: 0
Received 0 Likes on 0 Posts
There is a write up around here somewhere. From what I recall, TDC occurred when an apex was halfway between the leading and trailing holes. Pull spark plugs, get a mirror (Canadian Tire has had those snake cameras on sale every once in a while, would work excellent for this). Apex is in trailing hole, mark pulley. Spin engine until apex is in leading hole, mark pulley. Back engine up, halfway between your marks. I believe that gets you very close.
Old 05-17-12, 11:16 AM
  #4  
Theoretical Tinkerer

iTrader: (41)
 
RXSpeed16's Avatar
 
Join Date: Oct 2003
Location: Norcal/Bay Area, CA
Posts: 1,589
Received 46 Likes on 32 Posts
Originally Posted by Puck
There is a write up around here somewhere. From what I recall, TDC occurred when an apex was halfway between the leading and trailing holes. Pull spark plugs, get a mirror (Canadian Tire has had those snake cameras on sale every once in a while, would work excellent for this). Apex is in trailing hole, mark pulley. Spin engine until apex is in leading hole, mark pulley. Back engine up, halfway between your marks. I believe that gets you very close.
I did this for a car using insulated wire and it worked pretty well. Using the rear rotor, gently pinch the wire between apex seal and edge of plug hole. That way it wasn't eyeballing. You will be surprised how far apart the two marks are on the pulley.

I'd suggest swapping the pulley for stock one or a more accurate racing beat one. Confirming timing and then transferring the timing marks to whatever pulley they are using. Is there any reason this wouldn't be an option?
Old 05-17-12, 02:17 PM
  #5  
My job is to blow **** up

iTrader: (8)
 
lastphaseofthis's Avatar
 
Join Date: Jan 2005
Location: palmyra Indiana
Posts: 2,900
Received 3 Likes on 3 Posts
Originally Posted by misterstyx69
A buddy is facing a dilemma and needs to find ZERO degrees TDC to set his PFC.
Can anyone shed light on this?
Thanks.STYX.
if you're doing it on the PFC, set the timing to the leading mark( as stated 5 degrees ATDC ) and set the pfc at 0. now turn the crank until the pfc reads -5, then reset to zero, done.

You could even rotate the engine a few times, and recheck it at the 5 and 20 mark.

Edit: now that i think about it, this may or may not work havent used PFC software, but some stock Crank sensors can read that precisely, but i dont think an FC will.
Old 05-17-12, 07:31 PM
  #6  
rotorhead

iTrader: (3)
 
arghx's Avatar
 
Join Date: Aug 2004
Location: cold
Posts: 16,185
Received 432 Likes on 265 Posts
If you trust your stock timing marks (the pulley and hub were never switched around between engines), use the stock -5 BTDC/+5 ATDC leading mark. This mark was created during the manufacturing process. It's better than anything you can do screwing around in your garage with a sharpie. The reason for this is because a bad timing mark would affect emissions.

There are a couple methods for setting this in the PFC. Here's one that can be done easily using just the Commander.

1) Install the crank angle sensor just like you would on the stock ECU. Follow the service manual procedure and search the gazillion threads about it. HAILERS has written extensively about installing it. If you got it on the correct tooth, the engine should at least start unless something else is wrong.

2) Go into your Commander's etc. --> Function select screen. Turn off "IDL IG Control" . If you have the old Gameboy-looking green Commander, there should be a funny Japanese character to indicate that it is OFF.

3) Start the Engine.

4) Go to the monitor screen--4 channel. Select RPM, IGL, IGT, and Water Temp.

5) When water temperature exceeds 60C, verify that your IGL = -5 and IGT = -20 . Turning off "Idle IG control" locks the timing at this setting as long as you don't have other loads coming on. You might be able to bring the Commander out into the engine bay to look at.

7.



I just check the leading side...

8. Put IDL IG control back on if you plan on using that feature.

9. Done
Attached Thumbnails how do you get to 0 degress TDC?-timinglight.jpg  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
stickmantijuana
Engine Management Forum
11
11-09-15 01:15 PM
GKW
1st Generation Specific (1979-1985)
5
09-28-15 04:34 PM
stickmantijuana
20B Forum
10
08-19-15 01:47 PM
fdracer
Rotary Car Performance
2
11-01-02 12:16 PM



Quick Reply: how do you get to 0 degress TDC?



All times are GMT -5. The time now is 12:23 PM.