Quick SBC timing question

[dsommer]

Do you point the dist rotor to #1 or #5 (engine at TDC) when setting initial timing? My books are in storage and I can't remember right now.

 

Thanks,

 

David

[GabeRoc]

if cylinder #1 is at TDC, compression stroke, you point the rotor at #1 cylinder.

 

--gabe

[skipzoomie]

Be sure it's on the compression stroke or you'll be 180 out.

[dsommer]

Oh and make sure the oil pump shaft points to #1 too haha silly me had it pointing to #5 for the past 1/2 hour

 

d

 

Maybe I'll get the car started today...

[THUNDERZ]

Do you point the dist rotor to #1 or #5 (engine at TDC) when setting initial timing? My books are in storage and I can't remember right now.

 

Thanks,

 

David

 

So is the timing mark on the balancer supposed to be at 0 at TDC? What position are the rocker arms supposed to be in? I am just trying to straighten out the timing on my sbc...something isnt right with it.

[Teekass]

So is the timing mark on the balancer supposed to be at 0 at TDC? What position are the rocker arms supposed to be in? I am just trying to straighten out the timing on my sbc...something isnt right with it.

 

 

Yes, the timing mark on the balancer should be at 0 when the #1 piston is at TDC. As far as the rocker arm position, it depends on which TDC the engine is at. The rocker arms should be free (as in both valves closed) if the engine has just finished the compression stroke. If the engine has just finished the exhaust stroke, the exhaust valve should be almost closed, and the intake valve should be starting to open (this might not be exact though, because of your camshaft.....different lobe seperations, intake centerlines, etc. will cause the valves to be in slightly different postions at this TDC)

[grumpyvette]

 

 

how come its 180 degs out of phase?

I get this question all the time, well here’s something I see lots of guys don’t understand, ONCE YOUVE INSTALLED A CAM WITH THE TIMEING MARKS YOU MUST ROTATE THE CRANK 360 DEGRESS BEFORE DROPPING IN THE DISTRIBUTOR, while its true that if the, timing marks are positioned so the crank is at 12 o,clock and the cam gear is at 6 o,clock that the cam lobes will be in the position that fires #6 cylinder that HAS NO EFFECT AT ALL (on finding TDC,) for aligning the degree wheel with TDC,or THE timing tab pointer, for degreeing in the cam, the piston passes thru TDC TWICE in every firing cycle once on the firing/power stroke and once on the exhaust stroke, the cam rotates at exactly 1/2 the speed of the crank so to make it easy to line up the marks they install it with the marks at the closest point 6/12 for easy indexing, rotate the engine 360 degrees to the #1 TDC power stroke and the crank gear will still be at 12 oclock 12/12 but the cam will be at 12 o,clock also, rotate another 360 degrees and your back where you started. its simply easier to index the cam at the point where the index marks align closely. look at how the cam lobes themselves open the valves when the cam is just installed the #1 cylinder valves are slightly open and the #6 are closed per "Lunati" ‘’YES YOU ARE RIGHT - WHEN CRANK IS AT TWELVE AND CAM IS AT SIX THEN #6 CYL IS FIRING AFTER YOU LINE UP YOUR MARKS AND INSTALL GEAR THEN ROTATE YOUR CRANK ONE REVOLUTION AND THEN DROP THE DIST. IN - AT THAT POINT