Question About Engine Timing!!

[Sean_Cassidy]

Hello all, so I'm doing the head gasket and timing belt along with other maintenance and I'm buttoning everything up right now. I understand that I need to set both the camshaft and crankshaft to TDC by lining up the tick marks, but my question is this: I'm assuming the camshaft has more revolutions than the crank on a full engine revolution, (perhaps 2 turns of the cam for every 1 of the crank) so how am I sure that when they line up that they're at the right markings? If it's as easy as just lining up the marks and slapping it together, then surely they wouldn't make such a big deal on the DIY's to make sure everything is lined up when taking off the timing belt because one could just turn each with a wrench.. I'm stumped.

Thanks to anyone who may give input,

Sean

[nando]

it doesn't matter. TDC is TDC on the crank. IE, you can't be 180* off.

so yeah, line up the marks and put the belt on. push it on the tensioner last.

[TobyB]

Yep, there are 2 crank revs for every cam rotation.

However, since the valves and the pistons share space
(but not time) in the combustion chamber, you DON'T want
to turn the cam when the crank's at TDC. You'll bang valves
into the pistons.

So yes, align it all, then disassemble, clean, reassemble, but
if something wiggles a few degrees, just re- center it and be happy.

hth

t

[LJ851]

Hello all, so I'm doing the head gasket and timing belt along with other maintenance and I'm buttoning everything up right now. I understand that I need to set both the camshaft and crankshaft to TDC by lining up the tick marks, but my question is this: I'm assuming the camshaft has more revolutions than the crank on a full engine revolution, (perhaps 2 turns of the cam for every 1 of the crank) so how am I sure that when they line up that they're at the right markings? If it's as easy as just lining up the marks and slapping it together, then surely they wouldn't make such a big deal on the DIY's to make sure everything is lined up when taking off the timing belt because one could just turn each with a wrench.. I'm stumped.

Thanks to anyone who may give input,

Sean

Yes, it's that easy. Line up the marks.

[Sean_Cassidy]

Thanks to all of you guys. I really appreciate it!

[essi1553]

However, since the valves and the pistons share space (but not time) in the combustion chamber

I just had an "are we alone in the universe" moment after I finished "(but not time)". I don't know why, and I wanted to share.

Just to reiterate because I don't want to be a douche and just thread jack, even though Toby nailed it.

Set the timing before disassembly, remove the head, when reassembling set the timing on the head properly (the crank timing marks shouldn't have moved). After you have the waterpump and belt back on (meaning both the cam and crank will move in uni-son), rotate the crankshaft a full rotation (in turn rotating the camshaft twice automatically) and re-check the timing. I did the check twice, well worth the piece of mind in my opinion/experience.