find tdc on 12a? pulley was off....
 

So I goofed while disassembling my engine and rebuilding. I removed the pulley without thinking and lost the orientation.... So now I have 4 choices to orient it.

My thought Is to remove the leading plug out of housing one, feel the compression stroke and stop when it is done. I have a spark plug that I hollowed out and attached a tube with a bit of oil in it. Then I watch the oil move through the tube and when it reversed that should be "tdc" right? I know I'm a piston guy with wrong terms but hopefully you follow.

Would this work? It seems like it is lining up when I do that but still no pops when I try turning it over. I am getting a spark because timing light buy I know bunch of vasoline from the assembly is in the rotor housing. Might be limiting my success too.

I used the flat part of the flywheel. When that aligns with the inspection plate opening (meaing the machined flat part of the bell housing is parallel to the flat part of the flywheel). That's tdc.

Then take a punch and mark your crank bolt!

When I got my car, the timing was 180 off, dist. off 1 tooth, and pully off a 1/4.

F@ck the previous owner. That sH!t took a while to diagnose!

I know that on the FC the pulley can only be put ON one way..the correct way,as the bolts are not a True 4 bolt square pattern.One bolt hole is offset to prevent the pulley from being put on incorrectly and thus moving the timing mark.

NOW if the FB is set up that way then you should not have a problem in just putting the pulley back on and use the pulley timing marks and line it up with the front cover pin.

Yea they are definitely evenly spaced. Thanks for the flywheel trick! I'll go check that out. Seems easy enough.

sadly all the engines built before 1986 had a perfectly square bolt pattern so you could get any of 4 timing results, causing lots of lost time and grief.

never really made much sense to me, the early 70's motors had doweled pulleys that you have to physically remove the dowels to get the pulley off but they eliminated that on the later 12A engines.

Looking from the front of the eccentric shaft the key way should be at 9 o'clock position and the timing marks around the 12 o'clock position. This is true for all years but you have to take the front bolt off to see the key way and rotate the motor so that it is in the 9 o'clock position and I repeat the timing marks are at the 12 o'clock position. You will see the marks line up with the pointer on the front cover.

Another problem with swapped 12A pulleys is the marks can be off by as much as 7 degrees. Do you know whether your pulley has ever been swapped for another 12A pulley?

I got it started. The pulley i think is from a 84 and rotor set and shaft is from a 79.... Is there a way to be exact on getting 0*? I can compare the pullys and see if their marks are the same compared to the key

Seems to be running well at idle. Had to let it idle for 20 min at initial startup. I found that it idles best at about 5 degrees advanced from the second timing mark. Now I forget what those timing marks are.

It has been 2 years since I have timed the thing. I measures out marks every 5 degrees and have a locked distributor (Scca it7). I want to set it to 20* leading for reliability and races are 1.5 hours. I've looked and looked and find conflicting info.

Please forgive me. What are the two marks on the stock pulley? Is the one farthest to the right 0* leading? And left is -10*? Or is the right one 5* advanced?

the only way to get it exact is with a degree wheel, a matched set off another engine or an aftermarket pulley.

if it's off by a little bit on a non turbo engine then it won't be a big deal. if it is off by 10 degrees on a turbo engine it could cost you.

Na completely stock engine. Has to be to race in the spec class. Problem is that I want the engine to last. 25 advanced is great for the occasional street pull but hours of full throttle will kill an engine. I'd rather sacrifice 3hp and have another season out of the engine.

then it might be worth the few bucks to replace the pulley if they will allow you to.

setting the e-shaft keyway to 9 o'clock certainly gets you into the ballpark but its hardly accurate, you could very easily be off 5-10 degrees even trying to eyeball it perfectly. with the engine in the car, even less likely to be correct. a stamped timing pulley like RB i have tested with my own degree wheel to be accurately marked.

I've already done the timing marks on the pulley. This doesn't help varify if the timing marks are on 0.

What if I turn the engine over by hand with the ignition on and put a timing light on leading 1. Will it spark when it hits the trigger? I know old sbc will do that.... Then I could note where it sparks? This seems far fetched but hey I'd rather not buy a aftermarket pulley.....

won't work because the distributor can be installed in any of 360 different angles and is supposed to be timed off the pulley, not the other way around.

timing the engine based off the flywheel flat spot is actually about the most accurate method you can do aside from timing it with a known good pulley, that would probably put you within a few degrees of TDC.

this is the reason i verify the pulleys on the engines i send out, due to all the variations that are possible. i however don't have any 12A pulleys, but if worse comes to worse you could send it to me and i could stamp it to an accurate 0 degrees, but this requires removing the pulley and hub from the engine and that is a bitch.

Once all said and done purchasing an aftermarket pulley would be a much more cost effective solution. I might go back and measure the flywheel paralell and get it perfectly in line with the Bell housing and if something doesn't look right may just pull off the pulley and compare to the one that came off the eccentric shaft to begin with. (I know I have to keep the clutch pressured so doesn't damage my bearings.)

now the clutch method has even turned into a myth... wait til someone tries it on an FD and it pulls the e-shaft right back off the thrust bearings.

there is no safe method to pulling the hub, some just feel stabbing the clutch down is better. not touching the e-shaft while the hub is off is the simplest method.

Please delete.