One More Time: Timing Gears Dot Alignment With #1 @ TDC
09-03-2015, 07:42 AM
#1
One More Time: Timing Gears Dot Alignment With #1 @ TDC I am sure I have read here that the LS engines are different from the SBC in that when #1 is at TDC, the cam gear dot should be at 12 o'clock and not dot-to-dot with the crank gear.
While reviewing the LS1 How-To on "F-Body Cam and Valvespring Swap", I came across this in the section on Changing The Valve Springs" and highlighted a contradiction. Which is correct or does it not matter?
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Option 2
Top dead center method
This method requires you to put the piston at the highest position in the bore, so that when you start to compress the spring, the valve can only drop until it hits the piston. When the piston is at top dead center, the valve can't move very far at all.
There are several ways to accomplish this:
A) You can place a small stick/rod/straw/something into the spark plug hole and have a buddy turn the crankshaft by putting the stock 24mm crank pulley bolt in and turning the bolt with a wrench. You should be able to feel when the piston comes up to the top.
B) This method is a bit more elegant. Rotate your motor over by hand until your cam gear and crank gear are dot to dot like you set them up as earlier. At this position, piston 1 and 6 should be at top dead center. You can change the 4 springs on these 2 cylinders now using the instructions below. After you change those 4, then, rotate the crankshaft a full 90 degrees, and the cam gear dot will turn 45 degrees, as if it is pointing to 7:30 if it were a clock. Now piston 8 and 5 are at the top and can be changed. Rotate another 90 degrees on the crank and your cam gear dot will now be at 9 o'clock. Piston 7 and 4 can now have their springs changed. And FINALLY, rotate the crank another 90 degrees and the cam gear dot will be at 10:30. You can now change your remaining four springs on piston 3 and 2.
--------------------------------
While reviewing the LS1 How-To on "F-Body Cam and Valvespring Swap", I came across this in the section on Changing The Valve Springs" and highlighted a contradiction. Which is correct or does it not matter?
----------------------------
Option 2
Top dead center method
This method requires you to put the piston at the highest position in the bore, so that when you start to compress the spring, the valve can only drop until it hits the piston. When the piston is at top dead center, the valve can't move very far at all.
There are several ways to accomplish this:
A) You can place a small stick/rod/straw/something into the spark plug hole and have a buddy turn the crankshaft by putting the stock 24mm crank pulley bolt in and turning the bolt with a wrench. You should be able to feel when the piston comes up to the top.
B) This method is a bit more elegant. Rotate your motor over by hand until your cam gear and crank gear are dot to dot like you set them up as earlier. At this position, piston 1 and 6 should be at top dead center. You can change the 4 springs on these 2 cylinders now using the instructions below. After you change those 4, then, rotate the crankshaft a full 90 degrees, and the cam gear dot will turn 45 degrees, as if it is pointing to 7:30 if it were a clock. Now piston 8 and 5 are at the top and can be changed. Rotate another 90 degrees on the crank and your cam gear dot will now be at 9 o'clock. Piston 7 and 4 can now have their springs changed. And FINALLY, rotate the crank another 90 degrees and the cam gear dot will be at 10:30. You can now change your remaining four springs on piston 3 and 2.
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09-03-2015, 08:02 AM
#2
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#1 and #6 are at too dead center at the same time. One will be on the exhaust stroke and the other on the compression stroke.
For the purpose of changing valve springs it doesn't matter since you are using the piston as a bump stop for the valve. You can do 1 and 6 without turning the engine. Then 8,5. Then 7,4. Then 2,3.
If you're lining up the timing set, I recommend dot to dot and not both at 12. It's much easier to be off by a tooth if you are eyeballing 12:00 than if you are making sure the dots are lined up right.
For the purpose of changing valve springs it doesn't matter since you are using the piston as a bump stop for the valve. You can do 1 and 6 without turning the engine. Then 8,5. Then 7,4. Then 2,3.
If you're lining up the timing set, I recommend dot to dot and not both at 12. It's much easier to be off by a tooth if you are eyeballing 12:00 than if you are making sure the dots are lined up right.
09-03-2015, 03:53 PM
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Also, rotate by hand 2 revolutions to make sure they line back up. Then you'll know for sure.
09-03-2015, 10:31 PM
#5
I always put the cam dot at 6 o clock and the crank gear at 12 o clock in order to put the bolts in. At this point the number six hole is ready to pop, however I eventually put both dots at 12 so that old school distributor thingy can be put in at number one cylinder.
Problem is most my customers put the engines in, screw the trans bolts in, and then the torque converter bolts while rotating the engine to get them all tight. Some will prime it, put the distributor in and call me pissed off when it keeps back firing out the carb and starting fires and ****......Ahhhh good times
Problem is most my customers put the engines in, screw the trans bolts in, and then the torque converter bolts while rotating the engine to get them all tight. Some will prime it, put the distributor in and call me pissed off when it keeps back firing out the carb and starting fires and ****......Ahhhh good times
09-04-2015, 01:09 AM
#6
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One More Time: Timing Gears Dot Alignment With #1 @ TDC Cam sprocket at 6 oclock or 12 oclock is the same thing... if crank turns 1 turn, cam turns 1/2 turn.
Last edited by joecar; 09-04-2015 at 01:27 AM.
09-04-2015, 08:32 AM
#7
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I always put the cam dot at 6 o clock and the crank gear at 12 o clock in order to put the bolts in. At this point the number six hole is ready to pop, however I eventually put both dots at 12 so that old school distributor thingy can be put in at number one cylinder.
Problem is most my customers put the engines in, screw the trans bolts in, and then the torque converter bolts while rotating the engine to get them all tight. Some will prime it, put the distributor in and call me pissed off when it keeps back firing out the carb and starting fires and ****......Ahhhh good times
Problem is most my customers put the engines in, screw the trans bolts in, and then the torque converter bolts while rotating the engine to get them all tight. Some will prime it, put the distributor in and call me pissed off when it keeps back firing out the carb and starting fires and ****......Ahhhh good times
