Merc 4.3 won't build RPM's after 2500

[drun_trucker]

Completed the rebuild. No I need to set timing or make sure it's correct but the old timing cover doesn't seem to be matching up the necessary location to correctly do so.

Lifter and pushrods are now set to spec (3/4 turn past zero lash). TDC has been confirmed and is correct.

3 things needed for a good running engine. Compression, Spark and Fuel. I have all the above.

Lets just say that the timing tab has broke off the timing cover....without it, how do set the timing or what is the best way to try? I have heard that the ignition timing will be at full advance around 2500 rpm. If I'm on the hose and I get 3/4 throttle and I move the distributor until I get max rpm would it be safe to say I have found the best timing...

Im lost and need some help. PLEASE

 

[bruceb58]

Don't set the timing unless you use a timing light. If your timing tab is gone, figure out where TDC is, mark it and use an advance timing light.

If you run it the way you set it, you may wipe out your engine.

What distributor?

 

[alldodge]

Pull the plugs, bring the harmonic balancer around to about where TDC would be. Doesn't matter if your at TDC on number 1 or 180 out. Put a stiff wire down number 1 on top the piston, rotate the crank by hand counter clockwise until the wire comes out the most. Mark the spot on the timing cover.

Now go past the spot enough until the piston starts going down, stop and rotate clockwise to find highest point, mark the spot. The difference in the two spots is TDC.

Now use an advance timing light as Bruce mentioned

 

[Scott Danforth]

if you still had the harmonic balancer off and the timing cover off, I would have said rotate motor until timing chain marks lined up, loosely install cover and balancer, mark where TDC is.

the other method similar to what AllDodge indicates is to use a stop-bolt and a degree wheel or like the video below.

https://www.youtube.com/watch?v=RENhHI9n65I

 

[Bondo]

if you still had the harmonic balancer off and the timing cover off, I would have said rotate motor until timing chain marks lined up, loosely install cover and balancer, mark where TDC is.

Ayuh,.... I'm pretty sure you'll find that Cam timin', 'n findin' Tdc for ignition timin' are Not the same,.....

Do the piston touch, 'n rock it back, 'n forth to positively mark Tdc,.... 20?, 30? to take up any slack in the system,...
Then worry 'bout findin' #1, Tdc, Compression stroke,.....

 

[bruceb58]

Doesn't matter if its on compression stroke if you want to mark TDC.