Crank Position

[chilkoot]

So I broke three 1/2"-3/8" reducers trying to use my starter and a breaker bar to get the crank pulley bolt off. I realize now this was stupid, I won't try it again I promise. I set the engine to TDC and removed the timing belt first, so my cam pulleys are in the correct position, but now I don't know which rotation the crank is on, so just putting the mark to O could be off by a full 360 degrees, right?

I've ordered a CW-24 chain wrench ($50 shipped from shop.com) and will now be doing it the correct way, lesson learned.

Can I check for crank TDC through the #1 cylinder after I remove the spark plug? Is it easy to do? Thanks all.

[92Lex]

Did you align the mark on the crank before or after you removed the belt? It shouldn't matter anyways, unless you actually spun the crankshaft in circles, without the belt attached. The mark on the crankshaft probably only moved 1/4" either way. Just re-align it by spinning it a little to the left/right, when it's time to put everything back together.

[LS400_Fan]

Just take out the spark plug in #1 and rotate the crank until you hear the big WHOOOSH. that's the compression stroke.

[chilkoot]

I tried to remove the bolt after I removed the belt (LexLS tutorial says to remove crank pulley bolt after taking the timing belt off), so it's not still aligned with the cam pulleys, and after the socket broke it was spinning freely on starter power (maybe 1/2 sec though), so there's no telling how far it spun.

thanks LS400 fan, exactly what I was looking for. To clarify, when I hear the whoosh will the crank be at 0 and it's at TDC, or will the crank be at 0 and that's the beginning of the compression stroke and I need to do another full turn, or will I hear the whoosh somewhere in between 0's and I keep turning clockwise until the next time it's at 0? thanks mucho! i owe you guys.

on another note i replaced the (stock) spark plugs today with NGK iridiums, and while I'm impressed that they ran 130k miles I'm amazed I wasn't getting any misfires with the condition they were in. holy hell our ignition systems must be incredibly powerful to push electricity through those old factory plugs and wires. it idled a little low (500rpms) before I started, but idle was steady and it revved fine.

the people at Advance Auto are joking about starting to charge me rent, today was day 3 there and I have to wait another 3-4 for my chain wrench to get here. sigh.

[larryp]

Correct me if i'm wrong, but without a timing belt you will probably hear "whoosh's" on every stroke cause the valves won't be opening and closing. It would seem to me the crankshaft doesn't know the difference between a compression stroke and an exhaust stroke - it's job is just to move them pistons up and down. Therefore you should be able to just reposition the crank mark to 0 degrees and be good to go. Just my thoughts.

[chilkoot]

Correct me if i'm wrong, but without a timing belt you will probably hear "whoosh's" on every stroke cause the valves won't be opening and closing. It would seem to me the crankshaft doesn't know the difference between a compression stroke and an exhaust stroke - it's job is just to move them pistons up and down. Therefore you should be able to just reposition the crank mark to 0 degrees and be good to go. Just my thoughts.

this makes perfect sense, are the pistons always at exactly the same position when the crank is at 0, and it's only the cam pulleys that need two rotations to reset?

[larryp]

this makes perfect sense, are the pistons always at exactly the same position when the crank is at 0, and it's only the cam pulleys that need two rotations to reset?

Yep. 0 is TDC Cyl 1. It's the valves (camshaft) that determine whether it's TDC on the compression or the exhaust stroke. Anyway, that's my story and i'm sticking to it ;)