Inliners International Forums General Discussion Engines 250 Timing issue

Hi guys, I have a timing issue with my freshly overhauled 250. Info-- .030 over, 268 comp cam, clifford intake and exhaust, HEI, 390cfm Holley. The stock timing is advertised at 6-8 deg BTDC. To get it to run I estimate it closer 16 -18 deg BTDC, it is not even close to the timing tabs or the timing cover. It seems to run O.K. with an expected slight lope. I have the vac. to the distrutor off. I am 99.99% sure the timing marks were aligned on the timing gears. When adjusting the valve I went 1 complete turn past zero lash. I buddy of mine said that was to much only needed 1/4 to 1/2 a turn. I just went by the book. I just thought you guy might have some ideas before I take the oil pan an timing cover off to double chech the timing marks.

is it a new balancer?

Different year damper for the timing cover?
Damper slipped?

MBHD

New dampener from NAPA ordered for 67' 250 foriegn made. The machine shop that did the rest of the engine work ordered it.

I would use a positive piston stop & make sure of your TDC on the damper.

MBHD

Being it is running good I would add to what BUZZEN said is to just mark your damper with a new mark at TDC and go on down the road...SCRAP

Assuming the 2 dots on the timing gears were aligned and the engine was not rotated before the timing cover and damper were installed; did you happen to notice if the TDC line on the damper was lined up with the 0 mark on the timing tab on the cover? This sounds very basic but is often overlooked.

With the engine now assembled I'd follow Hank's advice: "I would use a positive piston stop & make sure of your TDC on the damper."

I had to get the alternate part # for my 250 with the wider balancer for my pulley setup (still for a 250) but the timing mark was "X" distance from the left of the crank slot, and the original balancer, was the same distance from the right of the slot! Almost like it was installed backwards. I just set it by feel...

Thanks for all the help guys, I ended up finding true #1 TDC then re-marking the balancer at zero on the timing tab with a white paint pen. Timed out at 8 degs. BTDC like the book says. Lopes a little, but starts OK. Next project is to set the lifters HOT, the old fashion way. Engine running with modified open top valve cover. Back rocker nut off until it "clicks" tighten to zero lash then another 1/2 to 1/4 turn. Thanks Todd

What changes if I do the same with my 250 tapping the snout to accept a SBC balancer? Will timing be hard to find?

Fred,
Disconnect the battery.

Install the balancer then make or buy a piston stop that screws in place of #1 sparkplug. The piston stop must stop the piston from going all the way to TDC. Remove all the spark plugs so you can rotate the engine BY HAND.

GENTLY rotate the engine clockwise until the piston is stopped by the piston stop. Mark the balancer where the "O" is on the timing tab.

Rotate the engine counter-clockwise until the piston is again stopped by the piston stop. Mark the balancer at the "O" again.

Half way between the 2 marks on the balancer is true TDC. Either paint a TDC mark on the balancer or scribe a permanent mark there.

Now you have TDC.....accurately.

Ron