Setting ignition timing Spit Mk3

[SpitfireGeorge]

Hi Guys,

I want to check the static timing of my Newman camshaft. The engine runs well when warm but has a slight backfire through the carbs when starting from cold. Is there a write up on doing this as my 2 Haynes WM are different. One says use No4 cylinder valves set at 40 thou the other says No1 cylinder at 40 thou. 

What I can make out is set 1 or 4 to 40 thou, align timing mark on crank pulley, check the valve clearance on 1 or 4 to see if they are equal. If not rotate crank until they are to get idea of how much they are out. Is that it?

Cheers Brett

 

 

[JohnD]

Unless your new camshaft is asymmetrical, which I doubt, then another way to check is by the method, "Equal Lift on Ovetlap" (ELoO).   

I've described this in detail over on Sideways:  https://sideways-technologies.co.uk/forums/index.php?/topic/9639-a-new-method-of-cam-timing/#comment-134275

John

Edited June 11 by JohnD

[SpitfireGeorge]

Hi JohnD,

Very extensive description of how to do it. I will give it a good read and see if I have the necessary tools to do it.

Cheets Brett

[SpitfireGeorge]

Hi Guys, The equal lift on overlap is a great method when setting up from scratch but I just really want to check if it is about right now.

Should I use number 1 cylinder or number 4 cylinder on the rock when the crank is at tdc? If I use the wrong one then it could be 180 deg out.

Cheers Brett

[DanMi]

it really doesn't matter whether you use 1 or 4 to check the camshaft timing they are the same, the only thing that it does matter for is setting up the distributer

[SpitfireGeorge]

Thanks DanMi that clears it up. Cheers.