LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Need quick answer in regards to putting in timing chain correctly...

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Old Oct 2, 2004 | 06:43 PM
  #1  
texasTA's Avatar
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Need quick answer in regards to putting in timing chain correctly...

We are in the middle of installing a CC306 cam in my little brother's 95 Formula. We already have the new cam in the motor and all the valve train components swapped out. We are needing to install the cam sprocket and timing chain next. When we removed the cam sprocket and timing chain, the car was at #1 TDC (cam sprocket dot straight up and crank sprocket straight up and the cam dowel pin at 9:00 oclock).
In Shoebox's install guide it states to install the crank sprocket with the dot aiming at 12:00 oclock straight up and the cam sprocket with the dot facing straight down at 6:00 oclock to achieve #6 at TDC.

So, my question is, since we took the car apart at #1 TDC do we install the new timing chain/cam sprocket to what it came off like (#1 tdc) or do we go ahead and rotate the cam shaft over to 3:00 oclock and put the dots together to achieve #6 TDC????

Thanks
Old Oct 2, 2004 | 06:50 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

Install it the way shoebox's site says. The cam turns at half the speed of the crank that is why you can have the cam dot at 6 o clock and crank dot at 12 o clock. Then turn the crank one turn and the cam dot will be on top and the crank dot on top. So the reason people say align them with the cam on 6 and the crank on 12 o clock is its much harder to get the cam 1 tooth off that way.
Old Oct 2, 2004 | 06:57 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

So if the crank sprocket and crank are already at 12oclock, then just spin the cam to where the cam dowel pin is at 3 oclock and install the cam sprocket with the dot facing 6 oclock (which would put the cam and crank dots facing one another????)

Thanks and that would put us at #6 TDC. And we don't need to turn the crank at all right, since it is already at 12 oclock???????
Old Oct 2, 2004 | 07:19 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

turning the cam does not change which piston is at top dead center.
Old Oct 2, 2004 | 10:31 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

This is going to sound real stupid, but how do you spin the crank??? I would assume with the car being a 6 speed, you would put it in neutral and it should spin, correct?
I just want to make sure that we are doing this correctly.
Could you also take a look at my webshots Cam install album to see if the dots on the cam/crank sprockets look like they are lined up.
I really appreciate all the help.
Thanks

http://community.webshots.com/album/195009119yHLEre

Let me know if anything doesn't look good.
Old Oct 2, 2004 | 10:36 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

If #6 is at TDC, so is #1. One is starting the combustion stroke and the other is starting the intake stroke. You choose which by the orientation of the cam sprocket. Install it dot-to-dot since it's easier to verify correct alignment. When you correctly install the opti the PCM will fire the correct cylinder. In short, as long as #1 is at TDC, it doesn't matter whether you choose to orient the cam sprocket with the dot at 6 o'clock or 12 o'clock. It's just easier to see that it's correct choosing a 6 o'clock orientation.
Old Oct 2, 2004 | 10:36 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

When #1 is at TDC so is #6. Putting the cam at 3 o'clock or 9 o'clock will just determine which piston is going to be on the exhaust stroke or intake stroke which is why it doesnt matter which way you do it. Just easier is the cam is at 3 o'clock b/c the dots on teh cam and crank gear and right beside eachother where the cam at 9 o'clock you have to try to line up the dots with a 5" gap between them.
Old Oct 2, 2004 | 10:53 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

Originally Posted by texasTA
This is going to sound real stupid, but how do you spin the crank??? I would assume with the car being a 6 speed, you would put it in neutral and it should spin, correct?
I just want to make sure that we are doing this correctly.
Could you also take a look at my webshots Cam install album to see if the dots on the cam/crank sprockets look like they are lined up.
I really appreciate all the help.
Thanks

http://community.webshots.com/album/195009119yHLEre

Let me know if anything doesn't look good.
Ideally, those teeth should be directly in line with each other, but I bet if you nudged the crank just a little, they would be.
Old Oct 2, 2004 | 10:59 PM
  #9  
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Re: Need quick answer in regards to putting in timing chain correctly...

Thank you guys very much.
So am I correct in just putting the car in neutral to spin the crank?? Sorry for so many questions, this is the VERY first time we have ever done anything internally on any motor.
Old Oct 2, 2004 | 11:01 PM
  #10  
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Re: Need quick answer in regards to putting in timing chain correctly...

If the #1 piston is already at TDC then there is no need to turn the crank. Now if its not then yes by all means rotate it till it is. Put the crank gear on and rotate till the dot points straight up.
Old Oct 2, 2004 | 11:04 PM
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Re: Need quick answer in regards to putting in timing chain correctly...

why do you need to crank it over? just to make sure its lined up? if you need to move the crank a hair for that i would do it some other way. Like leave the car in gear and rock it you just need it to move a hair.
Old Oct 3, 2004 | 11:05 AM
  #12  
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Re: Need quick answer in regards to putting in timing chain correctly...

If #1 and #6 are at TDC together, what other cylinders are at TDC together?
Old Oct 3, 2004 | 03:58 PM
  #13  
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Re: Need quick answer in regards to putting in timing chain correctly...

Divide the firing order in half and put the numbers on top of each other like this:
1-8-4-3
6-5-7-2

The pistons in the cylinders in each column are at TDC at the same time.
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