Author Topic: Tdc after the trigger settings  (Read 7400 times)

Offline Duveit

  • Jr. Member
  • **
  • Posts: 8
  • BHP: 0
Tdc after the trigger settings
« on: September 19, 2015, 02:58:43 am »
Im having problem understanding the "tdc the after trigger" setting.

Ive got my first trigger tooth on 3 and im wondering what the "tdc after the trigger" setting is suppose to be?
ive made a picture to show where the trigger is placed, this is where the trigger will be when the engine is in tdc on cylinder nr 1

Offline gunni

  • Hero Member
  • *****
  • Posts: 1492
  • BHP: 37
Re: Tdc after the trigger settings
« Reply #1 on: September 19, 2015, 09:14:00 am »
If you look in the visual trigger setup you can see a trigger wheel like yours.
From the picture you have shown you are going to be too far away from the tdc mark to be able to use cyl1 as your first cylinder firing after your trigger tooth

What engine is this?

If we say that the TDC mark is 100degrees from your missing tooth then you need to tell VEMS this, if each tooth represents 6 degrees and you have selected 3 (18° total) then the remainder is 82° , that would be your tdc after trigger.

If you said 4 teeth, then you would deduct 6 degrees and have 76°


Offline Duveit

  • Jr. Member
  • **
  • Posts: 8
  • BHP: 0
Re: Tdc after the trigger settings
« Reply #2 on: September 19, 2015, 10:28:59 am »
Its a mercedes m103 3 liter 12v, The triggerwheel is custom since the engine has ke-jetronic originaly and didnt have a triggerwheel that i could use.

And yeah ofc i mean 4th after the missing tooth, wrote this at 4am here in norway^^

Just ignore the "Tdc, cylinder 1-6 on top" mark i made in the picture.
When the engine is in OT on cylinder 1 the trigger is pointing on the tooth that i illustrated on the picture, the 4th.

Offline Duveit

  • Jr. Member
  • **
  • Posts: 8
  • BHP: 0
Re: Tdc after the trigger settings
« Reply #3 on: September 19, 2015, 06:49:48 pm »
Here is a picture how it looks when first cylinder is on top.

Offline gunni

  • Hero Member
  • *****
  • Posts: 1492
  • BHP: 37
Re: Tdc after the trigger settings
« Reply #4 on: September 20, 2015, 01:17:58 pm »
Can you adjust the fitment?

It looks like the TDC mark is after the missing tooth which isn´t helpful.

Ideally the missing tooth is about 80-120deg before the OT mark

Offline Duveit

  • Jr. Member
  • **
  • Posts: 8
  • BHP: 0
Re: Tdc after the trigger settings
« Reply #5 on: September 21, 2015, 10:17:51 pm »
Yeah, i can adjust the wheel so the missing tooth is there.
But how do i set it up in the config?

This shit is realy getting me lost.

Offline gunni

  • Hero Member
  • *****
  • Posts: 1492
  • BHP: 37
Re: Tdc after the trigger settings
« Reply #6 on: September 21, 2015, 10:41:50 pm »
Try pressing F1 in the menu, it will give you some hints.

However if you can adjust the missing tooth to about 90deg, then put in 3 teeth and 72deg if you have 6° per teeth (60 total teeth)

Then adjust the 72 value using a timing light.

Offline Duveit

  • Jr. Member
  • **
  • Posts: 8
  • BHP: 0
Re: Tdc after the trigger settings
« Reply #7 on: September 21, 2015, 11:36:47 pm »
So

put the engine in tdc, loosen the wheel and place the missing tooth about 90deg before the trigger?

Im running a 36-1 wheel so its 10deg per tooth
« Last Edit: September 21, 2015, 11:40:59 pm by Duveit »

Offline gunni

  • Hero Member
  • *****
  • Posts: 1492
  • BHP: 37
Re: Tdc after the trigger settings
« Reply #8 on: September 22, 2015, 07:34:10 am »
Yes