ok: its a 1994 camaro z28 LT1 that I used as a learning tool to rebuild an engine (never did this before). Was very careful (took pics, labeled all parts, envelopes for all bolts, a checklist of everything done). took whole front suspension out from under front of car. had reputable machine shop bore/hone block; assembled everything in reverse order.

went to start it, it turns with basically no firing. fuel pump is presurizing; smell gas after cranking. in 5 or 6 cranking attempts of 5-8 seconds there was one pop like one cylinder tried to fire.

I checked #1 plug while cranking and there is spark there.

Even though I checked it 3 times--I am worried engine timing is off 180 degrees. The guide I used (GM manual) on assembly said that when valves on #1 stop moving and timing marks at 6 and 12 oclock match, that is TDC.

My question: how can I check whether I got it wrong (or right) with engine together using only #1 cylinder (the easiest to access).

I am depressed but hoping it might be something else.

also, if I was off 180--does that mean valves likely to be bent?
thanks for any advice.

To check for #1 TDC remove the #1 plug and put your thumb over the hole. Rotate the engine by hand (1/2" ratchet & 5/8" socket on balancer bolt) until you feel air blowing your thumb off the hole. Slowly rotate the engine until the air stops blowing, look at your timing tab/mark, should be at or very near 0 . Rotate it to 0 if it isn't on it alredy and you're done.

thanks morley-will try that tomorrow and let you all know.

ok; now still no start--I think maybe its electrical. when engine cranks and I watch on my obd scanner by "RPM"-- instead of zero or number of rpms there is a fixed value like 3395 that never changes. I am suspecting one of the wires from distributor to pcm but if anyone thinks something else, let me know.

just to refresh: engine just reinstalled in car after complete overhaul. there is cranking, fuel and spark (at least #1 cylinder), but no start.

here is more info on my no start situation. checked the ignition circuit wires and connectors. they seem ok. is there a way to prove the timing is off 180 degrees before tearing into timing cover to check dots on gears? I know I can turn crank to put #1 at top but how can I verify it is on compression stroke without removing timing cover? if I pull the valve cover would the valves both be up on #1?

180* off reffers to ignition time.

If your engine timing was off 180* you'd know.

just to close this out--ended up towing car to mechanic. problem was overtightened valves--manual says to make contact with pushrod then turn another 360 degrees. experienced mechanics said only 90 degrees necessary. started right up after adjustment. luckily no valve damage when they were too tight.

cool beans, thanks for the outcome :thumbsup: