OMC COBRA 3.0 timing marks

[VMAX]

Hi, I have a 1986 3.0 Cobra, and I was attempting to check the timing yesterday, when I found that the numbers on the timing tab were unreadable due to rust. I tried to scrape the rust off, but it was too deep, and there is no sign of a number anywhere.The tab has 4 or 5 "points" on it, each one representing 4 degrees, but it lacks the pronounced valley (indicating TDC) which GM used on thier car engines. I don't know if this is a common problem, but any help would be appreciated <br />Thanks, John

 

[VMAX]

Re: OMC COBRA 3.0 timing marks

Can anybody help with this? If anyone has a 3.0 OMC with readable timing marks, just let me know which point lines up with 0 degrees (TDC)and I can figur out the rest. <br />Thanks, <br />John

 

[Boatist]

Re: OMC COBRA 3.0 timing marks

VMAX<br />If the zero mark is wider you can do it the old way and set motor to TDC and mark it your self. I would suggest getting a service manual, well worth the money.<br />One way I find top dead center is to take an old spark plug and break the center out. Put a balloon on it with a rubber band to clamp it down. Install it in # 1, put a wrench on motor and turn it till you find the top. Mark it and you are all set. Turn the engine in the correct direction if you do back it up to find TDC make sure you turn it in the correct direction before you start it. On my motor each peak is 2 degrees and each valley is two degrees.

 

[Turge]

Re: OMC COBRA 3.0 timing marks

Hey VMAX,<br /><br />Hope this helps: Click Here

 

[VMAX]

Re: OMC COBRA 3.0 timing marks

Hi Turge,<br />My engine timing mark is pictured in the link --<br />Picture #5. The problem is that the numbers are not readable due to rust, and 0 degrees is not identified by a different notch, like it is on the other engines, as pictured in photo #6. If anyone knows which numbers correspond with the "bumps" in picture #5, please reply.<br />Thanks, John

 

[adrew]

Re: OMC COBRA 3.0 timing marks

I have 3.0l, 1985. It is the same as pic #5. Top dead center is the point the 3rd from the right, and/or the 4th from the left. Each point is, as you say, 4 degrees. there are 6 points on the plate. Hope this helps, adrew.

 

[VMAX]

Re: OMC COBRA 3.0 timing marks

Yes,Adrew, your post is exactly what I needed. As I have suspected, my timing is over-advanced, and may have something to do with my engine noise,(pinging). Thanks to all who have taken the time to help!<br />John