Author Topic: CZ ignition timing  (Read 4889 times)

0 Members and 1 Guest are viewing this topic.

Offline Bamford#69

  • A-Grade
  • ****
  • Posts: 423
    • View Profile
CZ ignition timing
« on: November 10, 2014, 12:19:03 PM »
Hi, Does anyone know the CZ ignition timing in degrees,for 250, 400,
 I can only find mm BTDC
cheers

Offline yamaico

  • Legend
  • *****
  • Posts: 816
    • View Profile
Re: CZ ignition timing
« Reply #1 on: November 10, 2014, 02:32:04 PM »
If no one can help you and you know what the stroke and conrod lengths are you can calculate the ignition timing in mm BTDC by the following equation:
T=R+L x (1-cos a) - ?(L²-(R x sin a)²)
a = degrees before TDC
T = mm before TDC
R = engine stroke divided by 2 (mm)
L = conrod length (mm)

Offline Bamford#69

  • A-Grade
  • ****
  • Posts: 423
    • View Profile
Re: CZ ignition timing
« Reply #2 on: November 10, 2014, 06:36:54 PM »
Hi, that's what I was afraid of, but thanks
cheers

Offline Lozza

  • Legend
  • *****
  • Posts: 4206
    • View Profile
Re: CZ ignition timing
« Reply #3 on: November 10, 2014, 10:47:24 PM »
Jesus only loves two strokes

Offline Bamford#69

  • A-Grade
  • ****
  • Posts: 423
    • View Profile
Re: CZ ignition timing
« Reply #4 on: November 11, 2014, 08:42:04 AM »
Hi, thanks for that , I'll  have a crack at that.
cheers
ps,
 do you have the rear suspension travel calculator ?

Offline Bamford#69

  • A-Grade
  • ****
  • Posts: 423
    • View Profile
Re: CZ ignition timing
« Reply #5 on: November 26, 2014, 07:57:13 PM »
Hi, "did the sums" give or take a 'couple of seconds' it  works out both the 250 and 380 are
      22 degrees BTDC,       who'd a thunk
cheers

Offline jimg1au

  • Legend
  • *****
  • Posts: 3489
    • View Profile
Re: CZ ignition timing
« Reply #6 on: November 26, 2014, 09:30:09 PM »
please explain
if you know were tdc is why cant you use a micrometer.
as you said 22 deg from tdc so you must know were tdc is
jim

Offline Mick D

  • Legend
  • *****
  • Posts: 2915
    • View Profile
Re: CZ ignition timing
« Reply #7 on: November 26, 2014, 10:17:16 PM »
BAMFORD CLICK HERE  :D

That is a great link Lozza, kind of you to share it, thanks :)
"light weight, and it works great"  :)

Offline Lozza

  • Legend
  • *****
  • Posts: 4206
    • View Profile
Re: CZ ignition timing
« Reply #8 on: November 26, 2014, 11:06:25 PM »
I actually got it from here so I can't take any credit that goes to PCMAX

http://forum.ozvmx.com/index.php?topic=17431.msg230852#msg230852
Jesus only loves two strokes

Offline Mick D

  • Legend
  • *****
  • Posts: 2915
    • View Profile
Re: CZ ignition timing
« Reply #9 on: November 26, 2014, 11:13:41 PM »
Well then, instead you can take the credit for telling me to pour from an outlet point toward the bottom of the crucible(ladle) so I don't get the Dross in my casting  :)

Special secret cast filler rods for oxy welding fins back on.
So you cant see any difference in metal colour 8)
"light weight, and it works great"  :)

Offline Bamford#69

  • A-Grade
  • ****
  • Posts: 423
    • View Profile
Re: CZ ignition timing
« Reply #10 on: November 27, 2014, 11:04:39 AM »
 Hi, the reason you  use a degree wheel on the crankshaft to set the timing , and finding TDC is because , when the piston moves just 0.016mm at TDC the crankshaft rotates 4 degrees ! 
Setting TDC  using a "piston stop" and degree wheel method is an accurate way to be within  0.004mm ! I'll bet  you cant do that with a screw driver down the plug hole !
cheers

Offline jimg1au

  • Legend
  • *****
  • Posts: 3489
    • View Profile
Re: CZ ignition timing
« Reply #11 on: November 27, 2014, 05:03:16 PM »
when i had a yellow tanker cz380 it had points ignition made up for me by lee holth czguy.i used to get tdc on my micrometer and take it to the required mm and set.it started all the time with out any problems. even when running methenol.only problem i had is when it was wet and cold the methenol is hard to get going
just my experience with cz ignitions
i have a set of cz tools if anyone wants to buy them along with som parts ect
jim