Question (for you experts) about ignition timing...

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There is 10-12 degrees where the piston doesnt move. You are trying to find the exact center of this movement. Which will be true top dead center. If your tune really doesnt matter that would be sufficent!

 

Valve timing and ignition timing are kinda two separate issues.

You can't ballpark TDC if you are questioning a 4 degree difference in ignition timing. I would do it over from scratch getting true TDC.

 

'Sounds like that's what I need to do...

 

The way I found TDC on my was shadetree style, before I put the pan back on, I turned the crank, making sure both #1 valves were closed. Timing marks on cam and crank were in perfect alignment. Then, I turned the crank backwards untill the valve just started to move, and marked the balancer. Then I turned the crank forward untill the valve just started to move on the other side of TDC on the balancer, marking this position. Then I moved the crank backward to the center of these two marks, which in turn turned out to be the factory TDC or 0 Degree mark on the balancer. Mine was dead on the factory marks, but I didn't change balancers, just timing chain and gears when I put in the new cam. It's possible your replacement balancer is mismarked or marked for a different pointer on the timing cover...

 

I know you did what you thought was rite, But this is no way to find true TDC. Not only are you dealing with cam chain slack, there will be lifter slack not to mention the ramps on the cam being differnt on the opening and closing side. It always does not have to be the balancer, it can be the key way in the crank, it can even be the key itself, It does not take much to make 4 degrees. I have what i would consider top of the line crank and balancer,( no names named) and its off 2 degrees. You can even take a wrench and bump the pointer and make it off 2 degrees. There is NO SUBISTUTE FOR KNOWING TRUE TDC. and no reason for not being able to find true tdc. its a simple process that does not cost anything. Use a old spark plug and make a piston stop, just find true tdc, dont guess know for sure.

 

Intresting thread...not trying to hyjack but what's with the old spark plug? can you give details?...

 

Its just a way to keep from buying a piston stop, most store bought stops are not long enough for a FORD with stock heads. Tear or bust out the center(the part that goes to the inside of the cylinder) You can then either tap or solder a short bolt or pin in place. Just be sure its stable and wont give any what so ever. Remove Battery cable, remove all spark plugs, Lower # 1 piston down into the cylinder, Screw piston stop in # 1 hole BY HAND ONLY. Take a 15/16 socket and ratchet or pull handle. Gently turn motor in whichever direction you want (this is the reason for removing all plugs) When piston contacts stop mark balancer at timing pointer. Turn engine oppsite direction till piston contacts stop, Mark balancer at timing pointer again. Exactly half way between these two marks is TRUE TDC. I hope this will help .

 

This is some homemade piston stops, the left one is the one i use the most.

 

So you stop the piston? I thought the idea was to know where it stops... By stoping it, what happens if it still goes up a couple of thousands when you remove the stoper?

 

You cant stop the piston at true TDC, because there is dwell time the piston comes to a complete stop, and the crank is still moving. Therefore you have to stop the piston Before and After TDC to find true TDC.

 

Just to add to this Blown 5.0l is on the money. For any street motor I built I could care less. On the 2.3l turbo with 28lbs of boost in a turbo coupe I did it exactly the same way. I learned the same trick except we did it with a dial indicator when the motor was built. Thanks and RIP Red Davis for all the knowledge you shared.

 

You stop the piston in one direction and make a mark on the balancer, then you rotate the engine the other direction and stop it the other way, making another mark on the balancer. TDC would be dead center of your two marks.

 

TL, if you don't want to make your own, you can just Google "piston stop" and a number of vendors sell them.