94badrag

iTrader: (1)

I have a LT1 but you wise LS1 guys should be able to help.

I'm doing a cam swap. I set the engine to TDC(I thought) by putting my finger over #1 spark plug hole, rotated the crank till the I felt the pressure coming out the hole and stopped when the crank hubs TDC indicater mark was at 12 o'clock.
When I took the timing cover off I thought I would find the dot on the crank sprocket at 12 o'clock (which it is) and the dot on the cam sprocket at 6 o'clock. BUT the cam sprocket dot is at 12 o'clock!
Is something wrong here???
Should I take everything off and put the new parts on in this way?
If I rotated the crank will the dots ever line up?

Thankz in advance for your wisdom! Brian

JoeyGC5

iTrader: (24)

Spin the crank one more time and the dots will line up.

94badrag

iTrader: (1)

So, one more time around will be actuall TDC? I guess the pressure I felt coming out the plug hole was just the beginning but not enough to get to TDC. Is that right?
THankz,Brian

JoeyGC5

iTrader: (24)

Man Sorry had a brain fart last night when I posted . The crankshaft will rotate two times per one revolution of the camshaft. So if the dots are at 12 o'clock and 12 o'clock, rotate the cam once more to get them to 6 and 12 o'clock

JoeyGC5

iTrader: (24)

It's still top dead center of the piston stroke, but think of it like being in the 3rd quater of a football game.

Shon Herron

iTrader: (25)

You could be at TDC of #1 or #6.
I would not rotate any part without the other parts turning. ie get the crank in the right position before pulling the timing set off.

94badrag

iTrader: (1)

Got it, so i'm at TDC now but I should rotate the crank 1 more turn till the dots line up. Doing this is just for ease of installing the new parts and doesn't matter if I rotate it past TDC. RIGHT?
thankz guys

FlamingChicken

iTrader: (2)

you will reach tdc twice on a four stroke engine. you are mostly likely at tdc exhaust instead of tdc compression. if you have a compression gauge stick it into the spark plug hole and when the needle rises you will know you are on the right stroke. both the crank and the cam are keyed so as long as you dont spin the crank with the chain off you cannot put it back together wrong.

94badrag

iTrader: (1)

I had my finger over the spark plug hole and felt the pressure come out so I have to be on the right stroke. My felling is that at TDC the dots on the crank sproket and cam gear are not lined up(12 & 12 o'clock). If this is true then rotating it so the dots line up(12 & 6 0'clock) is only so I can reinstall by matching the dots together. Am I on the right track?