Timing after belt break
01-31-2014, 04:00 AM
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Timing after belt break
Hi guys. I recently bought a 93 V6 with a broken timing belt. I have it all taken apart and I've been reading through a few walkthroughs posted here. I wanted to confirm I just need to line up the top pulleys with the paint markers and the crank sprocket with the tick at 12:00 to get the timing right.
If I read things right, the #1 cylinder will be at TDC on the compression stroke as link as the paint mark is lined up. Is that right?
If I read things right, the #1 cylinder will be at TDC on the compression stroke as link as the paint mark is lined up. Is that right?
01-31-2014, 07:21 AM
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I might be wrong but is it not possible for the crank to be out 180 degrees when at the 12 o'clock position? Meaning that #1 might not be at TDC?
01-31-2014, 07:45 AM
#5
Most of the confusion comes from where the FSM tells you to "SET NO.1 CYLINDER TO TDC/COMPRESSION". Which is saying too much really. It should just tell you to set the No.1 cylinder to TDC. Since TDC can be compression or exhaust, stroke wise. What makes it compression or exhaust is the valve timing.
01-31-2014, 07:46 AM
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Being 180 degrees out of phase was my concern. Maybe i should have stated this better. The write ups I found were for a regular replacement, not for a break so I was hoping to get clarification.
By the way, I found a bunch of loose bearings (I think) between the bottom of the crankshaft timing pulley and the bottom lip of the engine cover. I think the rubbing is what caused the belt to break. The #1 idler pulley looks like it was recently replaced. Anyone ever see the bearings fall out when a idler goes out?
By the way, I found a bunch of loose bearings (I think) between the bottom of the crankshaft timing pulley and the bottom lip of the engine cover. I think the rubbing is what caused the belt to break. The #1 idler pulley looks like it was recently replaced. Anyone ever see the bearings fall out when a idler goes out?
01-31-2014, 07:47 AM
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No. TDC is TDC. That's what the marks indicate.
Most of the confusion comes from where the FSM tells you to "SET NO.1 CYLINDER TO TDC/COMPRESSION". Which is saying too much really. It should just tell you to set the No.1 cylinder to TDC. Since TDC can be compression or exhaust, stroke wise. What makes it compression or exhaust is the valve timing.
Most of the confusion comes from where the FSM tells you to "SET NO.1 CYLINDER TO TDC/COMPRESSION". Which is saying too much really. It should just tell you to set the No.1 cylinder to TDC. Since TDC can be compression or exhaust, stroke wise. What makes it compression or exhaust is the valve timing.
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01-31-2014, 07:56 AM
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01-31-2014, 12:47 PM
#9
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No. TDC is TDC. That's what the marks indicate.
Most of the confusion comes from where the FSM tells you to "SET NO.1 CYLINDER TO TDC/COMPRESSION". Which is saying too much really. It should just tell you to set the No.1 cylinder to TDC. Since TDC can be compression or exhaust, stroke wise. What makes it compression or exhaust is the valve timing.
Most of the confusion comes from where the FSM tells you to "SET NO.1 CYLINDER TO TDC/COMPRESSION". Which is saying too much really. It should just tell you to set the No.1 cylinder to TDC. Since TDC can be compression or exhaust, stroke wise. What makes it compression or exhaust is the valve timing.
01-31-2014, 02:30 PM
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Not if it was "properly" set up.
The crank turns twice for each turn of the cam. By definition, cylinder one is on the top of the compression stroke (both valves are closed) when the cam pointer points up. After one turn of the crank, the cam pointer is now pointing down (1/2 turn), and cylinder one is now at the top of the exhaust stroke.
The crank turns twice for each turn of the cam. By definition, cylinder one is on the top of the compression stroke (both valves are closed) when the cam pointer points up. After one turn of the crank, the cam pointer is now pointing down (1/2 turn), and cylinder one is now at the top of the exhaust stroke.
01-31-2014, 04:08 PM
#11
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Not if it was "properly" set up.
The crank turns twice for each turn of the cam. By definition, cylinder one is on the top of the compression stroke (both valves are closed) when the cam pointer points up. After one turn of the crank, the cam pointer is now pointing down (1/2 turn), and cylinder one is now at the top of the exhaust stroke.
The crank turns twice for each turn of the cam. By definition, cylinder one is on the top of the compression stroke (both valves are closed) when the cam pointer points up. After one turn of the crank, the cam pointer is now pointing down (1/2 turn), and cylinder one is now at the top of the exhaust stroke.
01-31-2014, 04:14 PM
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The crank turns twice (to get four strokes). So the mark on the harmonic balancer is lined up at the top of the compression stroke (what people most often mean when they say TDC), and again at the top of the exhaust stroke.
With your clarification, I'm pretty sure you've got it correctly.
With your clarification, I'm pretty sure you've got it correctly.
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